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LIGHTHOUSES
AND
LIGHTSHIPS.
[Illustration: EDDYSTONE LIGHTHOUSE.]
[Illustration]
LIGHTHOUSES
AND
LIGHTSHIPS:
A DESCRIPTIVE AND HISTORICAL ACCOUNT OF THEIR MODE
OF CONSTRUCTION AND ORGANIZATION.
BY
W. H. DAVENPORT ADAMS,
AUTHOR OF “BURIED CITIES OF CAMPANIA,” “QUEEN OF THE
ADRIATIC,” “EARTH AND SEA,” ETC.
* * * * *
With Illustrations from Photographs and other sources.
* * * * *
NEW YORK:
CHARLES SCRIBNER AND CO.
1870.
Illustrated Library of Wonders.
PUBLISHED BY
Messrs. Charles Scribner & Co.,
654 BROADWAY, NEW YORK.
Each one volume 12mo. Price per volume, $1.50.
* * * * *
_Titles of Books._ _No. of Illustrations_
Thunder and Lightning, 39
Wonders of Optics, 70
Wonders of Heat, 90
Intelligence of Animals, 54
Great Hunts, 22
Egypt 3,300 Years Ago, 40
Wonders of Pompeii, 22
The Sun, by A. Guillemin, 58
Sublime in Nature, 50
Wonders of Glass-Making, 63
Wonders of Italian Art, 28
Wonders of the Human Body, 45
Wonders of Architecture, 58
Lighthouses and Lightships, 60
* Bottom of the Ocean, 68
* Wonders of Bodily Strength and Skill, 70
* Wonderful Balloon Ascents, 30
* Acoustics, 114
* Wonders of the Heavens, 48
* The Moon, by A. Guillemin, 60
* Wonders of Sculpture, 61
* Wonders of Engraving, 32
* Wonders of Vegetation, 45
* Wonders of the Invisible World, 97
* Celebrated Escapes, 26
* Water, 77
* Hydraulics, 40
* Electricity, 71
* Subterranean World, 27
* In Press for early Publication.
* * * * *
_The above works sent to any address, post paid, upon receipt of the
price by the publishers._
[Illustration]
Preface.
The importance of the Lighthouse system which protects our seamen
against the numerous dangers and difficulties of the British shores is
fully appreciated by every Englishman. But it may reasonably be doubted
whether the general public have any correct idea of its completeness,
of the administrative principles which regulate its management, or
of the steps by which it has attained its present development. They
know but little, moreover, of the engineering skill which has been so
successfully exercised in the construction of Lighthouses, or of the
scientific knowledge which has been brought to bear upon the perfection
of their illuminating apparatus. It may safely be said, that for a
large number of readers, the alpha of their information, on this
subject, is the Eddystone, and their omega the Bell Rock.
If such be the case, it may be presumed that the present volume will
be accepted as an honest attempt to supply an admitted deficiency. It
is based on the best authorities, and its pages have been revised by
competent critics. Its aim is to furnish in a popular and intelligible
form a description of the Lighthouse _as it is_ and _as it was_—of the
rude Roman pharos or old sea-tower, with its flickering fire of wood
or coal, and the modern pharos, shapely and yet substantial, with its
powerful illuminating apparatus of lamp and lenses, shining ten, or
twelve, or twenty miles across the waves. The gradual improvement of
this apparatus is concisely indicated. Sketches are furnished of the
most remarkable Lighthouses in Great Britain and France, and a detailed
account is given of the mode of life of their keepers, with full
particulars of the administrative systems adopted at home and abroad.
As auxiliaries in the noble work of guarding the seaman against the
perils of rock and shoal, the Lightship, the Buoy, and the Beacon, have
also found a place in our pages; and the volume closes with a list of
all the Lights existing on the coasts of England, Scotland, and Ireland
at the present time.
In my description of the _French_ Lighthouses I have been much indebted
to M. Renard’s book, “Les Phares.” The information given respecting
_British_ Lighthouses has been drawn from a variety of sources, the
more important of which are duly acknowledged. I have also derived many
particulars from personal examination; and some interesting data and
corrections have been supplied by Mr. Thomas Stevenson, the Engineer to
the Board of Northern Lights, and the worthy member of a family long
associated with lighthouse engineering.
The Illustrations are from photographs, unpublished sketches, and other
authentic originals. Those of the French Lighthouses are copied, by
permission, from M. Renard.
W. H. Davenport Adams.
_May 1870._
[Illustration]
Contents.
BOOK I.
ANCIENT HISTORY OF LIGHTHOUSES.
I. The Fire-towers of the Mediterranean, 9
II. The Pharos of Alexandria, 17
III. The “Tour d’Ordre” of Boulogne, 30
IV. The Tower at Dover, 38
V. The Colossus of Rhodes, 43
BOOK II.
THE SCIENCE OF LIGHTHOUSES.
I. How they are Administered, 49
II. Geographical Distribution of Lighthouses, 62
III. The Illuminating Apparatus of Lighthouses, 68
IV. The Interior of a Lighthouse, 95
BOOK III.
LIGHTHOUSES OF GREAT BRITAIN.
I. The Story of the Eddystone: A.D. 1696, 1706, 1759, 108
II. The Smalls Lighthouse, 133
III. The Bell Rock, A.D. 1807-1811, 139
IV. The Skerryvore Lighthouse, 171
V. North Unst, 1854.—Sunderland, 1841, 181
VI. Lighthouses on the English Coast, 180
BOOK IV.
LIGHTHOUSES IN FRANCE.
I. The Tour de Cordouan, 212
II. The Lighthouses of Cape La Hève, 224
III. The Lighthouse of the Héaux of Bréhat, 233
IV. The Grand Barge d’Olonne, A.D. 1861, 245
V. The Lighthouses of Walde, the Enfant Perdu,
and New Caledonia, A.D. 1859—1863—1865, 249
BOOK V.
THE AUXILIARIES OF LIGHTHOUSES.
I. Floating Lights: Lightships, 253
II. Landmarks, Beacons, and Buoys, 264
BOOK VI.
LIFE IN THE LIGHTHOUSE.
I. The Lighthouse-keepers, 276
APPENDIX.
I. A List of Lights on the British and Irish Coasts, 289
II. A Night in a Lightship, 312
Index, 315
[Illustration]
[Illustration]
LIGHTHOUSES
AND
LIGHTSHIPS.
BOOK I.
_ANCIENT HISTORY OF LIGHTHOUSES._
CHAPTER I.
THE FIRE-TOWERS OF THE MEDITERRANEAN.
We are apt to look upon the lighthouse as completely a modern
invention, but a little reflection would convince us that the early
navigators, in their arduous struggle against the ocean, could not
have failed to establish some sure indications by which to guide their
adventurous course. Undoubtedly, the first rude signal would be no
more than a huge fire blazing on the wave-washed promontory, or on the
summit of hoary hill or grassy mound nearest to the more dangerous
parts of the shore. But it can easily be conceived that the difficulty
of keeping these fires kindled on stormy nights would soon suggest to
man’s ingenuity the idea of erecting a suitable structure for their
shelter.
The value of this kind of coast defences was so apparent, that the
ancients felt unable to ascribe them to simple human invention. And
thus the Greeks attributed their origin to the demigod Hercules. But
there seems some reason to believe that, long before Greece became a
maritime nation, light-towers had been built by the Lybians and the
Cuthites along the coast-line of Lower Egypt. These towers, we are
told,[1] served as landmarks during the day, as beacons during the
night. Their purpose was a holy one, and accordingly they were also
used as temples, and each was dedicated to a divinity. The mariner, who
naturally held them in great veneration, enriched them with his votive
offerings. It has been conjectured by some authorities that their walls
at first were painted with charts of the Mediterranean coast and of the
navigation of the Nile; these charts being afterwards transferred to
papyrus. The priests of these singular but valuable institutions taught
the sciences of hydrography and pilotage, and the art of steering a
vessel’s course by the aid of the constellations. On the summit of
each tower a fire was continually burning; the fire being placed in a
machine of iron or bronze, composed of three or four branches, each
representing a dolphin or some other marine animal, and all bound
together by skilful decorative work. The machine was attached to the
extremity of a stout pole, and so placed that its radiance was directed
seaward.
[1] Renard, “Les Phares” (Paris, 1867).
According to the Baron de Zach, in his “Correspondance Astronomique,”
the Lybian appellation for these towers was _tar_, or _tor_.[2] As
_is_ signifies “fire,” we thus obtain the compound _Tor-is_, or
“fire-tower;” whence the Greeks derived their τύῤῥις, and the Latins
their _turris_. In like manner, the Latin _columna_ comes, it is said,
from _Col-On_, the “pillar of the sun.”
[2] _Tor_ is Celtic for a height, as in the _tors_, or granite hills,
of Dartmoor.
[Illustration: THE BEACON FIRE.]
Some authorities boldly carry this etymological diversion a little
further. When the fire-towers were situated upon eminences outside
the boundaries of cities, and constructed of a circular form, they
were called _Tith_. The mythological Tithonus, so celebrated for his
longevity, seems, they assert, to have been one of these edifices
dedicated to the sun; and Thetis, the ancient ocean-goddess, simply
a fire-tower near the sea, called _Thit-is_. Nor have ingenious
theorists been wanting to maintain that the massacre of the Cyclops,
who, according to the old legend, were stricken by Apollo’s arrows,
was nothing but a poetical version of the manner in which the fires of
the Cyclopean towers, planted on the eastern coasts of Sicily, were
extinguished by the rays of the rising sun.[3]
[3] As Mr. Stevenson says (in his “Treatise on Lighthouses”), a notion
so fanciful as this deserves little consideration.
The impression which the light-tower produced on the popular
imagination is, however, more beautifully, as well as more certainly,
described by Homer in a well-known passage of the “Iliad” (bk. xix.
375):—
“As to seamen o’er the wave is borne
The watch-fire’s light, which, high among the hills,
Some shepherd kindles in his lonely fold.”
In our English Bible the word _beacon_ occurs but once—namely in the
Prophecies of Isaiah (xxx. 17), who lived about two centuries later
than Homer; but in the Septuagint version, the same word is rendered as
a “flagstaff” or “perch,” and unquestionably refers to a _land_-signal
rather than to a maritime light.
* * * * *
The first pharos which performed its duties in a regular manner seems
to have been that which Lesches, the author of the “Little Iliad”
(who flourished about the 9th Olympiad), erected on the promontory of
Sigeum, at the entrance of the Hellespont. It is figured in the Iliac
Table.
Though the most ancient in our records, the honour was not reserved
to it of bequeathing its name to its successors, any more than to
Columbus the glory of leaving _his_ name to the New World. This honour
was gained by the mighty tower elevated on the island of Pharos, at
Alexandria, which served as a model for some of the most celebrated
lighthouses erected in later times. Such was the case with the pharos
built by the Emperor Claudian at Ostia, which appears to have been
the most remarkable of any on the Latin coast. It was situated upon a
breakwater, or artificial island, which occupied the mid space between
the two huge moles that formed the harbour;[4] and its ruins were
extant as late as the fifteenth century, when they were visited by Pope
Pius II. Not less stately was the pharos which guided the seamen into
the port of Puteoli, the emporium of the foreign trade of Imperial
Rome; nor that which Augustus erected at the entrance of his new
harbour of Ravenna, and which Pliny describes with so much enthusiasm;
nor that, again, which shed its warning light from the mole of Messina
over the whirlpool of Charybdis and the rock of Scylla; nor that which
blazed in the island of Capreæ, and was destroyed by an earthquake
shortly before the death of Tiberius.
[4] Suetonius, “Claudian,” 20.
* * * * *
Dionysius of Byzantium[5] describes a celebrated lighthouse planted
at the mouth of the river Chrysorrhoas, where the latter mingles its
waters with those of the Thracian Bosphorus (the modern channel of
Constantinople). “On the crest of the hill,” he says, “whose base
is washed by the Chrysorrhoas, may be seen the Timean tower, of an
extraordinary height; and from its summit the spectator beholds a vast
expanse of sea. It has been built for the safety of the navigator,
fires being kindled for their guidance; which was all the more
necessary because the shores of this sea are without ports, and no
anchor can reach its bottom. But the barbarians of the coast lighted
other fires on the loftiest points of the coast, to deceive the
mariner, and profit by his shipwreck. At present,” adds our author,
“the tower is partly ruined, and no lantern is lighted in it.”
[5] Author of an Αναπλους Βοσπόονρ, _circa_ A.D. 190.
Strabo refers in exaggerated terms to a superb pharos of stone at
Capio, or Apio, near the harbour of Menestheus—the modern Puerto de
Santa Maria. It stood on a rocky headland, nearly surrounded by the
sea, and served as a guide for vessels through the shallow channels at
the mouth of the Guadalquivir.[6]
[6] Strabo, Edit. Oxon., 1867, p. 184.
* * * * *
What was the form of the Roman light-towers? This is a question not
easily answered, when we remember that Herodian compares them to the
catafalques of the emperors. The catafalques were square; but it is
certain that quadrangular lighthouses were very seldom constructed.
Montfaucon reproduces a medallion, from the famous cabinet of the
Maréchal d’Estrées, which represents a Roman lighthouse as a circular
tower, built in four stories of decreasing diameter. Another medal,
discovered at Apameia, in Bithynia, and also figured by Montfaucon,
likewise depicts a circular building. This medal bore the following
inscription:—“Colonia Augusta Apameia, Colonia Julia Concordia decreto
decurionum.”
[Illustration: A ROMAN PHAROS (FROM A MEDAL IN THE D’ESTREES’
COLLECTION).]
Murleia, in Bithynia, was founded by a colony from Colophon, but having
been captured by Philip of Macedonia, he gave it to Prusias, King of
Bithynia, who called it after his wife Apameia. It was situated on
the south coast of the Gulf of Cius, and to the north-west of Prusa.
The Romans converted it into a _colonia_, apparently about the time
of Julius Cæsar; certainly not later than that of Augustus.[7] And we
shall hereafter see that the pharos at Dover, as at Boulogne, was also
of this form.
[7] See Dr. Smith’s “Dictionary of Greek and Roman Geography,” vol. i.,
_sub. nom._
[Illustration: ROMAN PHAROS (AFTER A MEDAL OF APAMEIA).]
[Illustration]
CHAPTER II.
THE PHAROS OF ALEXANDRIA.
One of the most famous lighthouses of antiquity, as I have already
pointed out, was the pharos of Alexandria, which ancient writers
included among the Seven Wonders of the World. It might naturally be
supposed that the founder of so remarkable a monument of architectural
skill would be well known; yet while Strabo and Pliny, Eusebius,
Suidas, and Lucian ascribe its erection to Ptolemæus Philadelphus, the
wisest and most benevolent of the Ptolemean kings of Egypt, by Tzetzes
and Ammianus Marcellinus the honour is given to Cleopatra; and other
authorities even attribute it to Alexander the Great.
All that can with certainty be affirmed is, that the architect was
named Sostrates. Montfaucon, in his great work, endeavours to explain
how it is that while we are thus informed as to the _architect_, we are
so doubtful as to the _founder_, whom, for his part, he believes to
have been Ptolemæus. Our ignorance, he says, is owing to the knavery
of Sostrates. He wished to immortalize his name; a blameless wish, if
at the same time he had not sought to suppress that of the founder,
whose glory it was to have suggested the erection. For this purpose
Sostrates devised a stratagem which proved successful; deep in the wall
of the tower he cut the following inscription: “Sostrates of Cnidos,
son of Dexiphanes, to the gods who Protect those who are upon the Sea.”
But, mistrustful that King Ptolemæus would scarcely be satisfied with
an inscription in which he was wholly ignored, he covered it with a
light coat of cement, which he knew would not long endure the action of
the atmosphere, and carved thereon the name of Ptolemæus. After a few
years the cement and the name of the king disappeared, and revealed the
inscription which gave all the glory to Sostrates.
Montfaucon, with genial credulity, adopts this anecdote as authentic,
and adds: Pliny pretends that Ptolemæus, out of the modesty and
greatness of his soul, desired the architect’s name to be engraved upon
the tower, and no reference to himself to be made. But this statement
is very dubious; it would have passed as incredible in those times, and
even to-day would be regarded as an ill-understood act of magnanimity.
We have never heard of any prince prohibiting the perpetuation of his
name upon magnificent works designed for the public utility, or being
content that the architect should usurp the entire honour.
To solve the difficulty, Champollion represents the pharos as
constructed by Ptolemæus Soter. But, as Edrisi solemnly remarks, “God
alone knows what is the truth.”
Much etymological erudition has been expended on the derivation of the
word _Pharos_. As far as the Alexandrian light-tower is concerned,
there can be no doubt that it was named from the islet on which it
stood; yet Isidore asserts that the word came from φὼς, “light,” and
ὁρἀν, “to see.” To quote again from Montfaucon: That numerous persons,
who have not read the Greek authors, should exercise their ingenuity to
no avail in the extraction of these etymologies, is far less surprising
than that so good a scholar as Isaac Vossius should seek the origin
of _Pharos_ in the Greek language. From ϕαἰνειν, “to shine,” he says,
comes ϕανερός, and from ϕανερός, ϕάρος.... But the island was called
_Pharos_ seven or eight hundred years before it possessed either tower
or beacon-light.
The most reasonable conjecture seems to be that the word is a Hellenic
form of _Phrah_, the Egyptian name of the sun, to whom the Alexandrian
lighthouse would naturally be compared by wondering spectators, or
dedicated by a devout prince.
At a later date we find the word applied to very different objects,
though always retaining the signification of _light_ or _brilliancy_.
A _pharos_ of fire—_i.e._, a ball or meteor—was seen, says Gregory
of Tours, to issue from the church of St. Hilaire, and descend
upon King Clovis. The same historian uses the word to describe a
conflagration:—“They (the barbarians) set fire to the church of St.
Hilaire, kindled a great pharos, and while the church was burning,
pillaged the monastery.” The old French historian frequently employs
the word in this sense, which leads us to suppose that in his time
an incendiary was probably designated “a maker of pharoses” (_un
faiseur de phares_). Still later, the term _pharos_ was applied to
certain machines in which a number of lamps or tapers were placed,
as in a candelabrum. A modern French writer quotes from Anastasius
the Librarian, that Pope Sylvester caused “a pharos of pure gold” to
be constructed; and that Pope Adrian I. made one, “in the form of a
cross,” capable of receiving one hundred and seventy candles or tapers.
And Leon of Ostia, in his “Chronicle of Monte Cassino,” says, that the
Abbot Didier had a pharos, or great silver crown, weighing one hundred
pounds, constructed, which was surmounted by twelve little turrets, and
from which were suspended six and thirty lamps.
We may add that the poets have employed the word “pharos” in a still
more metaphorical sense, to signify an object which instructs while it
illuminates, or those remarkable individuals whose genius becomes for
all time the light of the world, and a beacon to posterity. Says the
French poet Ronsard to Charles IX.:—
“Soyez mon phare, et gardez d’abymer,
Ma nef qui nage en si profonde mer.”
My guide, my pharos be, and save from wreck
My boat, which labours in so deep a sea.
But from this digression we return to the Alexandrian Wonder.
The long narrow island of Pharos lay in front of the city of
Alexandria, sheltering both its harbours—the Greater Harbour and the
Haven of Happy Return (Εὔνοστος)—from the fury of the north
wind and the occasional high tides of the Mediterranean.
It was a strip of white and dazzling calcareous rock, about a mile
from Alexandria, and 150 stadia from the Canobic mouth of the river
Nile. Its northern coast was fringed with small islets, which, in the
fourth and fifth centuries, became the resort of Christian anchorites.
A deep bay on the northern side was called the “Pirates’ Haven,”
because, in early times, it had been a place of refuge for the Carian
and Samian rovers. An artificial mound, or causeway, connected the
island with the mainland. From its extent (seven stadia, 4270 English
feet, or three-quarters of a mile), it was called the _Heptastadium_.
In its whole length two breaks occurred, to permit of the passage of
the water, and these breaks were crossed by drawbridges. At the insular
end stood a temple to Hephæstus, and at the other the great Gate of the
Moon. The famous lighthouse stood on a kind of peninsular rock at the
eastern end of the island; and as it was built of white stone, and rose
to a great height, it was scarcely a less conspicuous object from the
city than from the neighbouring waters.
Some remarkable discrepancies occur in the accounts of this noble
edifice, which have been handed down to us, but after all allowance
has been made for error and exaggeration, it remains obvious that
the wondering admiration bestowed upon it by the ancients was not
unjustified. The statements of the distance at which its light could be
seen are, however, most undeniably fictitious. That of Josephus, who
compares it to the second of Herod’s three towers at Jerusalem—called
Phasael, in honour of his brother—is the least incredible; yet even
he asserts that the fire which burned on its summit was visible
thirty-four English miles at sea! Such a range for a lighthouse on the
low shores of Egypt would require, says Mr. Alan Stevenson, a tower
about 550 feet in height.
Pliny affirms that its erection cost a sum of money equal, at the
present value, to about £390,000, and if this were true, we might not
dispute some of the assertions of ancient writers in reference to its
elevation and solidity. But the fact that it has entirely disappeared
seems to disprove the dimensions they have assigned to it. We are
wholly unable to decide whether the help it afforded to mariners was
from a common fire or from a more complete system of illumination. The
poet Lucan, in his “Pharsalia,” asserts that it indicated to Julius
Cæsar his approach to Egypt on the seventh night after he sailed from
Troy; and he makes use of the significant expression “lampada,” which
could hardly be applied, even poetically, to an _open_ fire. Pliny
expresses a fear lest its light, which, seen at a distance, had the
appearance of flames, should, from its steadiness, be mistaken for a
star (“periculum in continuatione ignium, ne sidus existimetur, quoniam
è longinquo similis flammarum aspectus est”[8]); but assuredly he would
not have spoken in such terms of the wavering, irregular, and fitful
light of an ordinary fire. We conclude, therefore, that its lighting
apparatus was more complete than has generally been supposed.
[8] Pliny, “Hist. Nat.,” xxxvi. 18.
When was this great monument destroyed?
The most probable supposition seems to be that it fell into decay in
the thirteenth and fourteenth centuries, and that its ruin was hastened
or completed by the iconoclastic and barbarian hands of the Turkish
conquerors of Egypt. That it existed in the twelfth century, we know
from the graphic description of Edrisi; a description which will enable
the reader to reproduce it before his “mind’s eye” in all its pristine
glory:—
“This pharos,” he says, “has not its like in the world for skill of
construction or for solidity; since, to say nothing of the fact
that it is built of excellent stone of the kind called _kedan_, the
layers of these stones are united by molten lead, and the joints are
so adherent that the whole is indissoluble, though the waves of the
sea from the north incessantly beat against it. From the ground to the
middle gallery or stage the measurement is exactly seventy fathoms, and
from this gallery to the summit, twenty-six.[9]
[Illustration: ANCIENT PHAROS OF ALEXANDRIA.]
“We ascend to the summit by a staircase constructed in the interior,
which is as broad as those ordinarily erected in towers. This staircase
terminates at about half-way, and thence the building becomes much
narrower. In the interior, and under the staircase, some chambers have
been built. Starting from the gallery, the pharos rises to its summit
with a continually increasing contraction, until at last it may be
folded round by a man’s arms. From this same gallery we recommence
our ascent by a flight of steps of much narrower dimensions than the
lower staircase: in every part it is pierced with windows to give light
to persons making use of it, and to assist them in gaining a proper
footing as they ascend.
“This edifice,” adds Edrisi, “is singularly remarkable, as much on
account of its height as of its massiveness; it is of exceeding
utility, because its fire burns night and day for the guidance of
navigators: they are well acquainted with the fire, and steer their
course in consequence, for it is visible at the distance of a day’s
sail (!). During the night it shines like a star; by day you may
distinguish its smoke.”
[9] These measurements amount to 576 feet; but we fear the Arabian
writer was incorrect in his calculations.
This latter passage shows that if any better mode of illumination
had once been in use, as we are inclined to believe, it had been
discontinued, or its secret forgotten, by the degenerate successors of
the Alexandrian Greeks.
Edrisi remarks, in language resembling Pliny’s, that from a distance
the light of the pharos was so like a star which had risen upon the
horizon, that the mariners, mistaking it, directed their prows towards
the other coast, and were often wrecked upon the sands of Marmorica.
Montfaucon also records this unfortunate peculiarity, which, however,
is not unknown in our own days. More than one of the lighthouses
intended to warn the seaman as he approaches a dangerous rock or
headland now carries a couple of lights: one at the summit, and one
below; that the upper may not be mistaken for a star.[10]
[10] Renard, “Les Phares,” p. 16.
* * * * *
In reference to the Alexandrian pharos, Montfaucon remarks that the
stories related by the Arabs and European travellers must be very
cautiously examined. For instance: we are told that Sostrates rested
its foundations on four huge crab-fish made of glass (_grands cancres
de verre_); a fable so gross, says one Benedictine, that it is not
worth the trouble of refuting it, though Isaac Vossius declares it to
be recorded in an ancient manuscript which he himself possessed.
[Illustration: MODERN LIGHTHOUSE OF ALEXANDRIA.]
Nor, continues Montfaucon, are we more disposed to credit the story
told by Martinus Crusius, in his _Turco-Græciæ_, book viii.—on the
authority of the Arabs—that Alexander the Great fixed on the summit of
the tower a mirror so skilfully made that it revealed the approach of
hostile fleets at a distance of one hundred leagues, and that after
the Macedonian hero’s death it was broken by a Greek, named Sodores,
while the guardians of the lighthouse slept. But, unfortunately for
this romantic fiction, the pharos was not built until after the time of
Alexander the Great.
[Illustration]
[Illustration]
CHAPTER III.
THE “TOUR D’ORDRE” OF BOULOGNE.
Boulogne is the ancient _Bononia_ or _Gesoriacum_, “a naval place,”
says Ptolemæus, “of the Morini,” and distant from the British coast,
according to Pliny, about fifty _millia passuum_. Pliny probably
measured from Boulogne to _Rutupiæ_ (or Richborough), where the Romans
had a fortified port, and which was their usual landing-place from
Gallia. His measurement, however, exaggerates the actual distance
between these places.
It was from Boulogne the Emperor Claudius embarked on his expedition
to Britain; and it was at Boulogne the Emperor Caligula bade his
soldiers collect the shells as spoils of ocean, and decreed himself a
triumph for victories he had only won in imagination. As a more durable
monument of his achievements, he erected, according to Suetonius, a
lofty tower; the extraordinary structure which, under the name of the
_Tour d’Ordre_, for centuries extorted the admiration of men.
Built as a memorial of imperial vain-gloriousness, when was it first
converted into a work of public utility? When did the triumphal tower
become a lighthouse? To these questions we can offer no authoritative
reply. But it seems probable that in A.D. 191 a light was blazing
from its summit; for a bronze medal of Commodus—on which he is
entitled Britannicus, in memory of his lieutenant’s victories over the
Britons—represents the pharos and its fire, and the departure of a
Roman fleet.
Planted at the usual point of embarkation for Britain, the tower of
Boulogne was carefully preserved so long as the Roman sway endured.
In 811 it was repaired, according to Eginhard, by the great Western
emperor, Charles, who was then preparing an expedition against the
Norman pirates. As late as the seventeenth century it seems to have
been employed as a lighthouse; and thence, according to a popular
but certainly erroneous etymology, its ancient name of _Turris
ardens_ became, by corruption, _Tour d’Ordre_. It also served as a
fortress, for which it was well adapted by its admirable position and
extraordinary massiveness.
In the sixteenth century, while Boulogne was occupied by an English
garrison—that is, from 1554 to 1559—the _Tour d’Ordre_ was enclosed
by two ramparts, one of brick, the other of earth, and both furnished
with artillery. This point was felicitously chosen for the attack or
defence of Boulogne, inasmuch as it dominated over the whole town, and
commanded both banks of the Liane. Yet the Tour d’Ordre suffered little
from the ravages of war, except that its lantern was several times
destroyed; and its ruin is wholly due to the neglect of successive
magistrates of Boulogne. Shaken at first by the waves, which in high
tides dashed furiously against the cliff—then by the subterranean
action of springs and watercourses—and, finally, by the imprudent
excavation of the adjoining quarries, both the fort and the tower
fell down—twice, according to some authorities—thrice, according to
others—between 1640 and 1645—along with the portion of the cliff on
which they were erected.
* * * * *
In the interval between these sad events, says Egger, nothing was
attempted in preservation of the remains of our precious monument,
which, however, in its ruined condition, still served as a night-beacon
for ships entering the port. When at length it perished utterly, the
municipality of Boulogne considered themselves released from the dues
which, for this portion of their territory, they had paid, in virtue of
an ancient right, to the Seigneur de Bainethun. As the soil no longer
existed, the tenants thought themselves freed from all obligations
towards its proprietor. The latter resorted to legal proceedings, and
judgment was given in his favour, July the 1st, 1656. Inasmuch as
the wise men of Boulogne had by their own negligence caused the loss
which they put forward as an excuse for denying their debt, they were
condemned to pay, as before, two thousand herrings, fresh and dry,
to be delivered at Arras, Amiens, and other towns, according to the
seigneur’s pleasure—or to restore the ground to its ancient condition,
and abandon to the Seigneur de Bainethun the toll which they levy from
all fishermen entering the harbour. And there is reason to believe that
this tribute of two thousand herrings was paid by the corporation of
Boulogne down to the epoch of the French Revolution.
[Illustration: BIRD’S EYE VIEW OF THE TOUR D’ORDRE OF BOULOGNE.
(_From an old drawing by Claude Châtillon._)]
There are little, if any, remains now extant of this ancient monument,
more glorious from the services which for generations it rendered to
humanity than from its origin, which only recalled the extravagance and
insane ostentation of Caligula; and M. Egger advises us to be cautious
how we place our confidence in the representations which have been
given of it. The most trustworthy seems to be the drawing executed by
Claude Châtillon, engineer to Henry IV., which we here reproduce.
The descriptions which are on record, says M. Renard, are equally
unsatisfactory. Still we can pick out of their rhodomontade some few
valuable and accurate particulars of its situation, dimensions, and
form, and of the materials employed in its construction. These were
simply gray and yellow stones, and red bricks, so arranged as to
compose an edifice of great solidity and yet of attractive appearance.
The tower was situated some two or three hundred yards from the
brink of the cliff; it was octagonal; 192 feet in circumference,
and about 64 feet in diameter: as with most of the Roman pharoses,
each of its twelve stories was a foot and a half narrower than the
story immediately below it, so that it assumed, on the whole, a
pyramidal shape. We are told that its height was about equal to its
circumference, or, in round numbers, 200 feet—which seems, as Egger
remarks, an extraordinary elevation for a lighthouse, already situated
on a cliff 100 feet above the sea-level. According to M. J. F. Henry,
its height was about 124 feet. However this may be, each story had on
the south side an opening like a gate. As late as the beginning of the
seventeenth century there might still be seen three vaulted chambers,
one above the other, connected by an inner flight of stairs, and
probably intended for the lodging of the keepers.
As for the place where the fire or light was kindled, we are entirely
left to conjecture; but from the fact that the chroniclers of the ninth
century assert that the summit was repaired with a view to prepare it
for the signal-fires, there seems reason to believe that before this
restoration they were kindled in a chamber on the uppermost story.
* * * * *
M. Egger puts forward the supposition that carefully directed
excavations might lead to the discovery of important remains. And
looking to the arguments by which he supports his hypothesis, we
are disposed to accept it as very plausible. It is to be regretted
that France possesses no archæological associations to undertake the
superintendence and prosecute the study of her memorials of antiquity.
With all her passion for national aggrandizement, she proves herself
strangely neglectful of her past, and the educated classes of France
exhibit little of that interest in archæological and antiquarian
pursuits which is shown by the scholars and gentry of England. Yet
on every ground it is desirable that a nation’s past should never be
divorced from its present; that the continuity of national life should,
as far as possible, be preserved unbroken; and much may be done for the
furtherance of so desirable an object by a due regard to the monuments
erected by our forefathers.
The _Commission des Phares_ has raised, however, in the place of the
Tour d’Ordre, a worthy substitute. In 1835 it established at Boulogne a
red light, fixed, and two other fixed lights, the first of which shed
its radiance for four, and the second and third for nine miles; ample
illumination this for a portion of the French coast which is already
lighted, at Cape Grisnez, by a powerful apparatus, whose lustre extends
as far as twenty-two miles, and at Pointe d’Alpreck, by a lighthouse
visible for twelve miles.
[Illustration]
[Illustration]
CHAPTER IV.
THE TOWER AT DOVER.
The summit of the lofty down at Dover, now crowned by the famous
castle, with its Norman keep and towers, was used as a military post
from a very remote antiquity. There can be little doubt that the
Britons here kept watch and ward: that it was the site of a Roman
stronghold, we know from indisputable evidence. A circular entrenchment
of Roman work is still extant, and so too are the remains of the Roman
lighthouse, whose steady blaze lighted the imperial galleys as they
hovered about the port, or guided the British oyster-boats returning
from their market at Boulogne.
With the history of the stronghold, however, we have nothing to do. It
is the pharos which attracts our steps, and induces us to ascend the
steep acclivity. A recent antiquary is of opinion that there were _two_
lights; one on the eastern, and the other on the western edge of the
hill. The ruins of the latter are so shapeless and indistinct that no
description of them could interest the reader, or enable him to picture
to his “mind’s eye” the form and structure of the ancient edifice. Of
the former enough remains to assist our imagination very materially.
[Illustration: THE TOWER AT DOVER.]
It is still, says Mr. Puckle,[11] a massive shell: the inner face
of its walls vertical and squared, the outside with a tendency to
a conical form, which was probably at one time much more distinct,
allowing for the quantities of external masonry and facing which by
degrees must have fallen or been hewn away. The basement only is of
Roman work; the octagon chamber above having been added in the reign
of Henry VIII. The dimensions are about fourteen feet square.
[11] Rev. J. Puckle, “Church and Fortress of Dover Castle” (ed. 1864).
The following description we borrow from Mr. Puckle’s learned monogram:—
Except fragments here and there, he says, such as might have been
picked up along the shore, the materials used in the pharos are few
and uniform throughout; each having its own peculiar character, quite
distinct from any supposed similar materials of subsequent date.
“1. _Tufa_: A substance freely used by the Romans wherever obtainable,
and always considered to mark their work as certainly as if dated and
recorded in some historical document. Quantities of it may still be dug
in parts of the valley of Dover, by the river. It was squared up, and
used in tolerably regular courses of blocks; those inside showing a
fair and even facing, hard, and little friable either by age or weather.
“2. _The concrete, or mortar_: This is of two kinds, found at two
levels of the lower mass of the tower. A small portion has been laid in
a pale, tawny-coloured mortar, mixed in the proportion of four parts of
sharp grit to one of lime. The greater part, however, has been carried
up with the pink or salmon-coloured mortar, peculiar to Roman work, and
mixed in the proportion of one part of lime to four of more or less
finely-pounded Roman brick. It is nothing like so hard as the concrete
found (for instance) lining the Roman baths discovered under the west
end of the nave of St. Mary’s parish-church; but it is too peculiar
a material not to be recognized wherever it appears, identifying its
Roman make.
“3. _The red tile-brick_: This, again, is always esteemed a very
distinctive element in materials of Roman building; but it requires
some attention to distinguish justly between the genuine Roman
production and subsequent imitations of the same thing. Without
digressing into the habits of a Roman brick-yard, it may suffice just
to refer to what is described in well-known ancient authorities, as
the careful process observed in the making of Roman tile-brick. A
very pure and smooth clay was selected, and so treated as to expel as
much as possible all gritty and non-homogeneous ingredients. Reduced
to something like the fineness and consistency of dough, it underwent
a treatment not very different from that of the dough itself; being
laboriously wrought and tempered by hand or otherwise, like bread
being kneaded in its trough; it was then shaped off in flat blocks of
the various sizes employed. The sizes vary considerably as found in
different places; but those commonly seen along the Kentish coast in
bonding-courses, or the construction of arches, are something over a
foot square, by about two inches in thickness. They are generally more
or less deeply scored on the under face, either in a rude pattern, or
simply with straight or wavy lines, making their hold on hard mortar
very tenacious; though these are not unfailing marks of Roman brick.”
Such are the materials of which the Roman pharos was constructed;
materials identical with those which compose the Tour d’Ordre at
Boulogne. When it was first disused as a lighthouse, it is impossible,
to say; but as its elevation must have constantly enveloped it in
mists, and rendered its fires useless, we should opine that it was
not employed after the Conquest. In course of time it was devoted
to military purposes, its lower chamber being converted into a
guard-room; and of late years it has been appropriated as a government
store-house. Lights are now established on the piers of Dover Harbour,
and with those of the South Foreland on the English coast, and of Cape
Grisnez and Boulogne on the French coast, amply suffice for the due
illumination of the Straits.
It is much to be desired that every care should be taken for the
preservation from further injury of so interesting a relic of Roman
times as the pharos at Dover.
[Illustration]
[Illustration]
CHAPTER V.
THE COLOSSUS OF RHODES.
“Men receive with indifference from one another, and without
examination, the traditions of past events, even of events connected
with the history of their own country. Thus, for the most part, in
their indolence to search out the truth, they accept at once all the
fables and exaggerations forced upon their notice.”
It is thus that Thucydides expresses himself; and though his
observation is two thousand years old, it has lost nothing of its point
or truth.
A striking example of its applicability is afforded by the striking
illustration now before us;—a representation of the Colossus of Rhodes,
according to the generally received idea that this celebrated statue of
Apollo was planted at the entrance to the harbour of Rhodes, where it
served as a pharos; and that it was of such surpassing magnitude that
ships under full sail could pass between its gigantic limbs.
But there is no evidence that the Colossus ever served as a pharos; at
least, no ancient author asserts that such was its employment. The
first writer who converted it into a beacon-light was Urbain Chevreau,
an industrious but not particularly able compiler of the seventeenth
century; but he neglects to say from what source he obtained his
information.
In the second place, the attitude traditionally ascribed to the
Rhodian Colossus—an attitude neither graceful nor dignified—is also
a pure conceit of comparatively modern times. It is, however, more
ancient than the former, since it dates from the sixteenth century,
when Blaise de Vigenère, the translator of Philostratus, transformed
the masterpiece of Chares, the pupil of Lysippus, into a fantastic
impossibility. Where he, too, obtained his information, no one can
ascertain; for on this important point he preserved the prudent silence
of Chevreau.
In an interesting paper, published by the French _Académie des
Inscriptions_, the Comte de Caylus proves—1st, That the Rhodian Apollo
was not constructed at the mouth of the harbour; and 2nd, That no ships
ever passed between its legs. He did not satisfy everybody, however,
and reference was made to the pages of the geographer Strabo. It was
found that he made no mention of the remarkable circumstance narrated
by Vigenère. He cites a fragment of an epigram in iambic metre, in
which the name of the sculptor, Chares of Lindos, is mentioned, and the
dimensions of his work—namely, seventy cubits—are given. Strabo adds
that the Colossus, in his time, lay prostrate on the ground—overthrown
by an earthquake, and with shattered knees; and that the Rhodians had
not restored it to its position because forbidden by an oracle.
[Illustration: IMAGINARY RESTORATION OF THE COLOSSUS OF RHODES.]
Turning to Pliny, we find that he confirms all the statements of
Strabo, and fixes the date of the fall of the statue at fifty-six years
after its erection. Though overthrown, he says, it is still a marvel.
Few men can embrace its thumb; its fingers are larger than those of
statues. Its disfigured limbs appear so many vast caverns; and in
the interior the enormous stones are seen with which they had been
weighted. It cost, says Pliny, 300 talents; being exactly the sum of
money which the Rhodians plundered from the war-ships abandoned before
their city by Demetrius, when he raised the siege, after protracting it
for many months.
Philo of Byzantium, a mechanician who lived about the end of the third
century B.C., and to whom is attributed a brief treatise on the “Seven
Wonders of the World,” describes at some length the Rhodian Colossus,
but makes no allusion to its supposed straddling attitude, or to its
employment as a pharos. The same silence is preserved by another
historian of the Seven Wonders, Lucius Ampellius. But as he possessed,
like Chevreau and Vigenère, an inventive faculty, this author says: “At
Rhodes is the colossal statue of the Sun, placed on a marble column,
with a chariot drawn by four horses.”
Putting aside the embellishments of tradition, let us inquire what this
monument really was:—
The brazen statue of Helios, popularly called the Colossus, was seventy
cubits in height; its gigantic size may be inferred from the fact that
few could compass one of its thumbs with their arms.[12] Fifty-six
years after its erection it was overthrown by an earthquake (_circa_
B.C. 224), and as already related, the Rhodians would not attempt
its restoration, though Ptolemæus offered them a contribution of 3000
talents, because prohibited by an oracle. And yet later authorities
describe it as standing erect; and the Emperor Commodus, among his
other extravagances, ordered his bust to be set upon its summit.
[12] Strabo, xiv., p. 364; Pliny, xxxiv. 18.
In 672 Rhodes was captured by the Saracens, and their leader, one of
the lieutenants of Othman, sold the brass of which the famous statue
was composed, to a Jewish merchant of Edessa, for a sum, it is said, of
£36,000. The bargain must have been very profitable, if it be true that
the materials thus acquired loaded a thousand camels.
* * * * *
A few words may be added in reference to the sculptor of the Colossus.
According to Pliny, he was a pupil of Lysippus, a native of Lindos, and
named Chares. Such, too, is the evidence of Strabo and the anonymous
author of the Greek epigram. But in the writings of the Pyrrhonist,
Sextus Empiricus, we find the honour of the achievement ascribed to one
Laches. According to Sextus, Chares, discovering that he was cheated
of half the sum of money promised for the completion of the statue,
killed himself in despair; and Laches, succeeding him, perfected the
glorious work. The authority of Pliny and Strabo, however, seems to
us preferable to that of Sextus: the Colossus was truly the work of
Chares, alone and unaided, and to him belongs the glory of having, as
Philo of Byzantium says, “Made a god like to a god, and endowed the
world with a second sun.”
[Illustration]
BOOK II.
_THE SCIENCE OF LIGHTHOUSES._
CHAPTER I.
HOW THEY ARE ADMINISTERED.
From antiquity we return to our own time, with the view of examining
the present condition of our coast-defences, so far as they include the
lighthouse, the lightship, the beacon, and the buoy.
To England belongs the praise, among modern nations, of having first
understood all the importance of lighthouses, and of having made their
erection, mode of illumination, and maintenance, a matter of national
concern.
The direction of the Imperial lighthouses is confided to three
Boards—one for each of the three kingdoms:—
1st, The _Corporation of the Trinity House of Deptford Strand_, who
possess the control of all the English lighthouses;—
2nd, The _Corporation of the Commissioners of Northern Lights_, to
whom is intrusted the management of the lighthouses of Scotland; and,—
3rd, The _Corporation for Preserving and Improving the Port of Dublin_,
who administer the coast-illumination of Ireland.
* * * * *
The history of the Trinity House is but imperfectly known, owing to
the destruction of a considerable portion of its archives by fire in
1714. It was founded by a charter of Henry VIII.—who may almost be
called the Father of English Navigation—on the 20th of March 1512,
and received the appellation of the “Brotherhood of the Trinity House
of Deptford of Strand and St. Clement,” This document opens with a
curious declaration:—“Out of the sincere and complete love and devotion
which we have for the very glorious and indivisible Trinity, and also
for Saint Clement the Confessor, His Majesty grants and gives license
for the establishment of a corporation, or perpetual brotherhood, to
certain of his subjects and their associates, men or women.”
At the outset, the duty of the members of the guild seems simply to
have been to pray for the souls of sailors drowned at sea, and for the
lives of those who were battling against the tempest. After a while
their functions increased in number, and, assuredly, in importance. The
charters which they received from Elizabeth, James I., Charles II., and
James II., placed in their hands the general control of the mercantile
marine, and even, under certain conditions, of the royal fleet. The
illumination of dangerous parts of the English coast necessarily became
a portion of their mission of patriotic beneficence. But the reader
must not suppose that no lighthouses burned along our shores until the
Trinity House was established. Rude signal-lights and beacon-fires
already blazed on rocky headlands, and at the mouths of the ports
most frequented by our shipping; but a greater number of lighthouses
became necessary, and on a more perfect system of organization, as
English commerce in the seventeenth century assumed its extraordinary
development.
But this was not all. The constructors of private lights and beacons
were not animated by a pure unadulterated zeal for the public welfare;
they levied excessive tolls on the vessels which profited by their
guiding rays. To erect and maintain a lighthouse constituted an
industry of so profitable a character that the privileges in virtue of
which they existed, and which were nearly all found in the hands of
the Trinity House, excited a very widespread feeling of jealousy and
discontent. The legislation which had taken place on this subject was
rigorously examined, and as a result these privileges disappeared. This
important discovery was made in the reign of James I. The king found
himself specially interested in making it; for, by its return to the
crown, the monopoly of licensing the erection of lighthouses would have
largely increased his private income.
* * * * *
The pretensions put forward by James I. greatly embarrassed the judges
charged with the examination of the rights of the Trinity House; and
the inquiry might have lasted for years had it not been abruptly
concluded, after our English fashion, by a compromise. It was decided
that the fraternity of the Trinity House should be authorized to erect
lighthouses, but that the crown should enjoy the same privilege in
virtue of the common law. From this decision it naturally came to pass
that, instead of remaining, as Elizabeth had designed, the exclusive
property of the Trinity House, the lease and monopoly of the fires
lighted on the coasts were granted or sold by the sovereign to certain
private individuals.
As a result of this decision, says M. Esquiros, in his lively manner,
there was not a bare and desolate angle of rock in the kingdom which
was not coveted by speculators as a site for a tower and a beacon-fire.
Lord Grenville, an able statesman and shrewd man of the world, wrote
in his diary in the form of a note or memorandum: “_Mem._ To watch the
moment when the King is in a good temper, to ask of him a lighthouse.”
It would be difficult to estimate the amount realized by those persons
whom the king favoured with such marks of his goodwill; but from the
luxurious state they maintained it is evident their profits must have
been immense.
* * * * *
We may readily conjecture the evil results of such a system. Many of
the lights were deficient in power; others were never kindled; yet in
every case heavy tolls were exacted from passing vessels. At length the
scandal grew intolerable, and in the reign of William IV. Parliament
interfered to establish a certain uniformity in the administration of
lighthouses, and to provide for a considerable reduction of the dues.
All the interests of the Crown were made over to the Trinity House,
which, moreover, was empowered to buy up the lighthouses belonging
to private individuals; and the Corporation having always acted
with singular zeal, efficiency, and public spirit, the system of
our coast-defences has gradually attained to a remarkable degree of
completeness.
* * * * *
A word or two may now be said on the interior organization of the
Trinity House. It includes two bodies of associates: the _Elder_, and
the _Younger Brothers_. At first no such distinction existed; but the
pretext put forward to justify the exclusion of the Younger Brethren
from sharing in the conduct of the Society was, that they showed too
much fervour at its meetings. The Younger Brethren, now-a-days, are
chosen by the Council on the motion of one of the Elder Brethren. Their
number was formerly unlimited. It cannot be too large, say the ancient
charters, because our seamen represent the strength of the nation. At
the present time there are 360.
The Elder Brethren, 31 in number, are chosen from the Younger. No one
can offer himself as a candidate if he has not first undergone an
examination, and served for at least four years as captain on board
a Queen’s ship or a merchant-vessel. On his election he pays £30 as
a contribution to the poor-box, and an equal sum for a complimentary
dinner.
The Elder Brethren, however, are divided into honorary and active
members. From a very early period, the Company recognized the advantage
of including in its ranks the most illustrious living Englishmen, even
though they should in no wise be concerned with navigation. In 1673,
the Bishop of Rochester, having preached before the Corporation on
Trinity Thursday, was admitted a member. For seventeen years William
Pitt occupied the honourable position of Master, which was afterwards
filled by William IV., when Duke of Clarence. Wellington, Prince
Albert, and Lord Palmerston, formerly belonged to the Corporation;
and, at present, the Prince of Wales, the Right Hon. W. E. Gladstone,
and Earl Russell, are among its members, while the Duke of Edinburgh
officiates as Master. These honorary members, limited to eleven, do not
engage in the administrative duties of the Trinity House; but they add
to its dignity, and serve to connect it with the highest classes of
English society. In fact, it would be difficult to name an association
which is more truly national in character.
The twenty active members, on whom the real burden of the work of
the Corporation rests, are experienced captains of men-of-war or
merchant-ships, who have retired from service. They are formed into six
committees, each of which has its separate functions; for, in addition
to its superintendence of the lighting of our coasts, the Trinity Board
examines our pilots, and delivers them their certificates; watches over
the ballasting of ships in the Thames; establishes and keeps in order
the various sea-marks; examines the scholars of Christ’s Hospital,
who are intended for a maritime career; collects the revenues; and
superintends the boarders in the houses of refuge which belong to
the Corporation. Its charters, moreover, confer upon it the right of
punishing seamen for mutiny, ill conduct, or desertion; but this power
is now-a-days never exercised.
* * * * *
The story of our two other Corporations may be briefly told. The
_Commission of Northern Lights_, incorporated in 1786, by an Act of
George III., is composed of two magistrates appointed by the Crown,
of the sheriffs of the sea-board counties, of the provosts of certain
royal burghs, and of the provost of Greenock.
* * * * *
The _Board of Ballast of Dublin_, which has under its charge the
lightage of the Irish coast, consists of merchants, bankers,
magistrates, railway directors; and the only seaman associated with
them is a coast-guard officer. It is subordinate to the Board of Trade.
* * * * *
The Trinity House, Northern Lights, and Ballast Board are under the
control of the Board of Trade. Before new lighthouses are erected by
the Trinity House, they must be sanctioned by the Board of Trade; and
before Scotch or Irish lighthouses are erected, the Trinity House are
consulted, and in the event of that Board differing with the Irish or
Scotch, the Board of Trade give their decision, which is final. It is
to be regretted that there should still exist a considerable number
of lighthouses which are under the control of about one hundred and
seventy local authorities;[13] and every person who appreciates the
importance of securing a vigorous and able administration will join
us in expressing a hope that before long the lightage of the United
Kingdom may form the subject of efficacious legislative action.
[13] See Report of the Royal Commissioners on Lights, Buoys, and
Beacons, 1861.—_Edinburgh Review_, Jan. 1862, p. 173.
* * * * *
The number and nature of the lights of the United Kingdom are as
follows:—
In England: lighthouses, lights on piers, harbour lights, &c.,
237. Add 49 lightships—total, 286.
In Scotland: lighthouses, lights on piers, harbour lights, &c.,
134. Add 1 lightship—total, 135.
In Ireland: lighthouses, lights on piers, harbour lights, &c.,
85. Add 8 lightships—total, 93.
The general result for the United Kingdom is, that we have 456
lighthouses, harbour lights, local lights, &c., and 58 lightships.
Total, 514.
* * * * *
We may compare these figures with those of the French lights.
Coast-line of England measures 2405 nautical miles.
Coast-line of Scotland " 4467 nautical miles.
Coast-line of Ireland " 2518 nautical miles.
Coast-line of France " 2763 nautical miles.
Now France has 224 lighthouses, but no floating lights. The proportion
of lights to the coast-line is,[14] therefore, as follows:—
In England 1 to every 8½ miles (nearly).
In Scotland 1 to every 33 miles.
In Ireland 1 to every 27 miles.
In France 1 to every 12.3 miles.
[14] This proportion will be slightly modified, but not materially, if
we deduct the harbour and pier lights from the English, Scotch, and
Irish totals.
We may here explain the French system of administration, which,
however, cannot be said to equal our own in efficiency or
comprehensiveness, nor to surpass it in economy. At all events, the
foregoing figures show that the English coast is far more numerously
lighted than the French.
The French system dates from the beginning of the present century, and
is administered by the Department of _Ponts et Chaussées_, composed
of naval officers, hydrographic engineers, members of the French
Institute, and other persons acquainted with the sciences which bear
upon navigation. The general direction of the service is committed to
the Inspector-General of Ponts et Chaussées, who has under his orders
a certain number of engineers, in each maritime district, charged with
the supervision, construction, and administration of lighthouses.
This board or directorate has its own manufactories in Paris, where
experiments are tried with lighting apparatus, and where the artisan
receives all the information necessary to guide him in the construction
of every part of the apparatus, such as the calculation of angles,
prisms, curves, lenses, and the like. One of the best results of this
centralization is the economy it insures; the entire cost of the French
service not exceeding £40,000 per annum. It may be added, that to
France, as to the United States, belongs the praise of having looked
upon the lightage of her coasts, not as a source of public or private
revenue, but as a work of humanity. We trust that England, before
any long period has elapsed, will abolish the tolls now levied upon
shipping for the maintenance of her lighthouses. We admit that they
have been considerably reduced; but they still remain a burden upon
commerce, and a burden which commerce ought not to bear.
[Illustration: TRINITY HOUSE.]
Let us now pay a visit to the _Trinity House_, in London, taking as our
guide the shrewd and lively author of “The English at Home.”
Opposite the Tower of London, he says, or, more strictly speaking,
opposite the ancient fosses of that fortress, now converted into an
agreeable promenade, extends a fine open area of green turf, edged
round with shrubs; and, in the rear of this square, rises an edifice
which seems purposedly to isolate itself from the noise of the
multitude—it is the Trinity House.
The abode of this important maritime Society was formerly situated in
Water Lane, whence it was driven out by two successive conflagrations;
otherwise, could any better choice be made than the immediate
neighbourhood of the Thames, of the great docks, and of the forest of
masts which crowds it for many miles, like the parks or plantations of
great trees which surround at a distance the manorial mansions of the
English aristocracy?
The principal features of the edifice, erected in 1793 by James Wyatt,
are, a massive basement, surmounted by a single story enriched with
Doric columns and pilasters, the whole built of Portland stone. On
the façade, numerous genii, which, with round faces and puffed-out
cheeks, might be taken for so many cupids, hold in their hands anchors,
compasses, and marine charts. These emblems, however, sufficiently
indicate the character of the institution.
The ground-floor in the interior is occupied by offices; the upper
contains some noble apartments, to which admission can only be procured
by special favour. A noble vestibule leads to a double staircase of
stone, whose two branches, after ascending in different directions,
unite in a central landing-place, enriched with ornaments and
sculptures. On the right, in a semicircle described by the wall, is
framed a large oil painting, by Gainsborough’s nephew, representing
a body of _past_ “Elder Brethren,” grouped together, and in uniform.
On the left, in panels of glass, are inscribed the names of various
benefactors of the establishment, and the amount of their bequests.
Massive doors of mahogany introduce the visitor into the Board Room,
whose ceiling, painted in 1796, by a French artist named Rigaud, and
loaded with sprawling allegories, exhibits the Prosperity of England as
springing from Navigation and Commerce. The British Neptune advances
in triumph, surrounded by sea-horses, and attended by Tritons. In one
hand he carries a trident, in the other the shield of the United
Kingdom. His march is protected by cannons and other instruments of
war, while genii hovering round him wave the standard of Great Britain.
The standard may pass muster; but cannons! Is not this an abuse of
anachronism even for a picture? On the other side, Britannia, seated
on a rock, receives in her bosom the products of different countries.
Sea nymphs, bending under their weight of riches, hasten from every
quarter, and seamen spread upon the shores of England the fruits
of an extended commerce. Children wave to and fro their torches in
representation of the lights which encircle the coasts of the British
Isles, and during the darkness of night direct the movements of her
ships.
The walls of this saloon are decorated with portraits of George IV.,
William IV., and their queens, for royalty itself is no stranger to the
annals of the Trinity House, and monarchs honour themselves by figuring
among the insignia of the fraternity of which they have been the
members and the patrons. The Duke of Wellington’s portrait, by Lucas,
is considered the best in existence of the Conqueror of Waterloo. The
busts of the Queen and the late Prince Consort, in white marble, by
Noble—one of the few living sculptors who have attained to celebrity
in England—rest solemnly at the two corners of the mantelpiece.
Twenty arm-chairs ranged round a large table shaped like a crescent,
and covered with a green cloth, mark the places of the members of
the Council at their various meetings. The associates of the Trinity
House think, with Ben Jonson, that good repasts encourage brotherly
feeling. The dining-room, lighted by a kind of circular lantern which
surmounts the ceiling, displays what may very justly be called a quiet
and substantial luxury. Here we may remark the bust of William Pitt, by
Chantrey; portraits of the Earl of Sandwich, the Duke of Bedford, Sir
Francis Drake, and, especially, that of Sir Kenelm Digby, by Vandyke.
At regular intervals, some excellent models of lighthouses in relief,
preserved under glass, remind the visitor of the all-important object
of this ancient Corporation.
* * * * *
The French Lighthouses Commission is not so splendidly lodged as the
Trinity Board, nor is its Museum equal to the one at Edinburgh.[15]
But, side by side with models of modern lighthouses, are models of the
most ancient, from the ungainly tower whose summit was lit up with a
rude fire of sea-coal, to the elegant edifice of the Héaux de Bréhat.
It also contains numerous examples of all the catoptric or dioptric
apparatus which are, or have been, in use, as well as specimens of
clocks, buoys, and beacons. The Lighthouse Museum is, finally, the
central depôt where experiments are conducted in reference to all the
elements of maritime lightage, under the supreme direction of M. Emile
Allard, the engineer-in-chief.
[15] We refer to the Exhibition of Lighthouse Models in the Industrial
Museum.
[Illustration]
[Illustration]
CHAPTER II.
GEOGRAPHICAL DISTRIBUTION OF LIGHTHOUSES.
In reference to the military protection of our coasts, the civilian is
frequently warned of the necessity of maintaining more than one “line
of defence;” a similar necessity exists as regards their complete and
satisfactory lightage. We know, too, that at one point a battery is
erected; at another, a simple earthwork is pronounced sufficient; at a
third, the eye ranges over an intricate combination of forts. The same
variety exists in the disposition of those coast-defences which are
designed in the interests of secure and peaceful navigation. Follow,
with the mind’s eye, the long coast-line of our country, and how many
differences we shall note in the situation of its lighthouses, in their
mode of construction, their elevation, their system of illumination.
Each pharos has, as it were, a speech of its own; each addresses, in
significant language, the seaman who turns to it for advice or warning.
This points out the entrance to a commodious haven, where, after being
much tossed by unquiet waves, the weary mariner may repose in safety;
that indicates the site of a perilous rock or sand-bank, on which a
storm-driven vessel must assuredly perish. Here we see a noble tower,
whose genial rays are visible at a distance of twenty-seven nautical
miles; there burns a steady light, whose extent of illumination is
restricted to five miles. One is a fixed light, glowing constantly like
a brilliant star; another, more mysterious, suddenly flashes forth from
the deep darkness, flings over the sea its arrow of flame, and then
is again extinguished, to reappear, a few moments later, in the same
strange and impressive manner. Nor are all lights of an uniform colour.
Some are red, with an intense ruby-like splendour; others white;
others, again, are blue or green. This variety in the range and aspect
of the “beacon-fires” has, like the variety in the size and position of
our forts and batteries, a special object.
The system of lightage generally adopted, says M. Renard, consists in
surrounding the coast with _three_ lines of defence; the outmost being
composed of lighthouses with a very extensive range. It has justly
been deemed of the highest importance to signal to the mariner the
proximity of the land, since it is in the waters near the coast that
navigation is exposed to the greatest dangers. The littoral presents a
number of capes, promontories, and headlands, more or less projecting
beyond the general level, as well as islets, and reefs, and shallows,
which require to be carefully avoided. Now, lighthouses of the first
class, as we may call them, or “sea-lights,” are usually planted on
these promontories or rocks; and along the British shore they are so
arranged that it is impossible, except in a dense fog, to arrive in its
neighbourhood without catching sight of one or more of them.
[Illustration: THE LIGHTHOUSE ON THE ROCKY HEADLAND.]
When he has overpassed the first line of defence, the navigator
encounters a second circle—“secondary-lights”—composed of lighthouses
of the second and third orders, indicating secondary capes, reefs, and
sand-banks, to which it is prudent to give a good offing. When the
mouth of a river or the entrance of a port is only accessible by narrow
channels, whose direction an experienced and veteran pilot can hardly
determine by night, other lights of the same class are placed in the
line of the channel, and point out the exact course which should be
taken.
Finally, when the ship has arrived near the port which is the goal of
her voyage, she perceives lights—“harbour-lights”—upon its piers or
breakwaters, which guide her to her much-wished-for berth.
* * * * *
When the best positions for illumination have been selected, the
most difficult task is, or rather was, to provide for their easy
distinction, so that the sailor may not be misled by too close a
resemblance of one to another. Suitable variations and modifications
have been, fortunately, supplied by the valuable labours of Fresnel,
and of the engineers who have followed in his track.
At first, however, the embarrassment was considerable. Thus, the code
laid down by the celebrated French Commission in 1825, admitted of only
three characters for lighthouses of the first order: the “fixed light,”
the “revolving minute light,” and the “revolving half-minute light.”
But it was soon discovered that merchant seamen did not sufficiently
heed the differences observed between the intervals of the appearance
and disappearance of the latter lights; and the number of lighthouses,
moreover, having multiplied beyond all prevision, it became absolutely
indispensable to allow of a greater number of distinctive characters.
Now-a-days we recognize five: the “fixed light,” the “flashing light,”
the “revolving,” the “intermittent,” and the “double lights in one
tower.”
The “flashing light” is that which shows alternately two flashes and
two eclipses, or more, in the interval of a minute.
The “flashing light,” the “intermittent,” and the “double lights in one
tower” were all first proposed and introduced into Scotland by the late
Mr. R. Stevenson.
The lustre of the “revolving light” gradually increases to a maximum,
and diminishes to a minimum, until wholly eclipsed, at equal intervals
of half a minute, one, two, or three minutes, and sometimes thrice in a
minute.
We designate it an “intermittent light” when the ray suddenly appears,
remains visible for a moment, and afterwards is again suddenly eclipsed
for a brief interval.
* * * * *
With this scientific arrangement before us, it seems strange to
recollect that even so lately as the year 1816, the Isle of May light,
in the Firth of Forth, consisted of nothing better than a coal-fire.
Nor had England made any greater progress in the art of illumination,
for the magnificent tower of the Eddystone, says Mr. Stevenson, about
fifty years after it came from the hands of Smeaton, could boast of no
better light than that derived from a few miserable tallow candles.
Nay, so lately as the year 1801, the light at Harwich, in addition to
the coal-fires, had a _flat plate_ of rough brass on the landward side,
to serve as a reflector! Such methods, continues Mr. Stevenson, were
most imperfect, not only in point of efficiency and power, but also as
respects the distinction of one light from another; an object which,
on a difficult and rugged coast, may be considered as of almost equal
importance with the distance at which the lights can be seen.[16]
[16] Stevenson, “On Lighthouses,” pp. 60, 61.
It must also be remembered that too great a multiplicity of lights
would not be less dangerous than a deficiency in number. Were the
littoral too abundantly illuminated, the effect produced on the
navigator would be that of a continuous and confused line of fire. He
would be dazzled by the blaze, and unable to determine the particular
point to which he should steer his vessel. Before the Royal Commission
of 1861, one witness actually gave it as his opinion that there
were too many lights on the English coast, and that the consequence
was an increase of collisions, a neglect of the lead, and continual
shipwrecks. He added, however, that without the increase of light,
steamers could not run in and out of ports at night. The extent of
illumination being necessary, the only method of reducing the danger
of confusion to a minimum is that adopted by our engineers—a clear and
distinct variety of lights.
[Illustration]
[Illustration]
CHAPTER III.
THE ILLUMINATING APPARATUS OF LIGHTHOUSES.
It has very justly been said that the object of placing in a lighthouse
an illuminating apparatus is, that, whether it be constructed of
glass or of metal, it may _bend the rays_ (which would otherwise and
naturally proceed in straight lines), and illuminate a hollow sphere,
so that those rays which would otherwise be thrown upon the sky, and
thereby wasted, may be made to fall on points at sea, where they will
be clearly visible. If the light is to be a fixed one, intended to be
seen all round, and from the horizon to the base of the light-tower,
the upper rays issuing from an illuminating apparatus must be
directed downwards, and the lower rays upwards, so as to increase the
illumination. If it is desired to light up a narrow belt of the sea,
extending from the horizon to the base of the lighthouse, all the rays
must be bent laterally; or they may all be concentrated and thrown upon
one or more spots of larger or smaller size, according as the light may
be needed—as in the case of fixed lights placed at the end of narrow
channels, and of revolving lights which are made visible all round
by causing the lenses and reflectors to revolve about the source of
light, or with that source about a centre.[17]
[17] _Edinburgh Review_, Jan. 1862, pp. 178, 179.
Two methods have been employed for the purpose of throwing light in
the desired direction: first, by silvered parabolic reflectors, which
is called the _Catoptric System_; second, by the employment of lenses
of a peculiar construction, which is known as the _Dioptric_ (or
_Refracting_) _System_.
Occasionally these two systems are combined, as in the ordinary
_Catadioptric_, and in Mr. Stevenson’s admirable _Holophotal_
arrangement, whether Catoptric or Dioptric.
Before describing them, however, it will be desirable to offer a brief
history of lighthouse illumination.
It was at a comparatively recent epoch that wood and coal fires were
for the first time replaced by candles, and the open summit of the
tower covered in with glass. About the end of the eighteenth century,
for these insufficient producers of light, lamps were substituted,
whose lustre was directed to a distance by reflectors of polished
metal. Many of the lighthouses of this epoch were provided with the
species of apparatus here described; among others, those of Capes
de l’Ailly and de la Hève, the isles Rhé and Oléron. In 1782, an
identical mode of lightage was established at Cordouan; but though this
lighthouse did not include less than twenty-four lamps, accompanied
each by a reflector, it diffused so feeble a light, that the seamen
immediately insisted on a return to the barbarous system of the Middle
Ages.
The apparatus of which they complained was, in truth, exceedingly
defective; its lamps, differing but little from those which the
seven foolish virgins suffered to die out, had broad wicks, and if
they produced but little light, by way of compensation they emitted
an enormous amount of smoke. It was natural, therefore, that men
of science should, with a view to improvement, first direct their
attention to the _lamp_. The pioneer in this course of inquiry was
Argand, who, about 1748, contrived to secure “a double current of air;”
which consists, as any one may see in the first lamp he meets with, of
a wick, shaped like a hollow cylinder, enclosed in a glass tube. The
heat caused by the combustion of the oil produces a vigorous draught,
which leads to an abundant circulation of air both internally and
externally; and air is for the lamp, as for man, the plant, and the
animal—life!
Various modifications and improvements of Argand’s system have been
successively introduced. The glass tube, for instance, by one inventor,
was contracted at a short distance above the burner, so as to project
more immediately the current of air upon the flame, and stimulate
combustion. In his turn, Carcel bethought himself of supplying the wick
with a superabundant quantity of oil, so as to avoid the heating of
the burner, and to render the flame more regular; he thus succeeded in
keeping the lamps burning for a longer period without a replenishment
of the wick.
There then remained the _reflectors_. Curved in the form of a
spherical segment, these received but a small portion of the luminous
rays, and rarely returned them in the proper direction. Teulère, the
engineer-in-chief of the province of Bordeaux, who was to distinguish
himself at a later period by the erection of the Cordouan Tower, was
ordered to make an examination of both the lamps and the reflectors,
and to study the best means of remedying the evils complained of. His
studies resulted in a paper of great interest, published in 1783. To
concentrate in a single direction a large portion of the rays which
were lost on all sides, he proposed the use of mirrors of perfect
polish and a better form. By causing these mirrors to revolve around
a lamp—that is, by projecting successively towards every point of the
horizon the lustre formed by a large portion of the rays thus collected
into a single sheaf—he invented at the same time the eclipse.
It was not at Cordouan, nevertheless, that the system was first
applied, but at Dieppe, where the celebrated Borda, having studied
Teulère’s paper, had a small revolving apparatus of five parabolic
reflectors made[18] in 1784. The apparatus of Cordouan, likewise
established by Borda, was not placed in the lighthouse tower until
after its restoration by Teulère—that is, in 1790.
[18] To be more exact than have been the majority of authors who have
written on lighthouses, we must add that a small revolving apparatus,
with three reverberators (probably with spherical shells), had been
planted at the mouth of the port of Marstrand, in Sweden, prior to
1783. The French engineer, however, had thought out the invention for
himself, in ignorance that it had been elsewhere realized, and his
was the merit of imagining a system so complete and so rational in
all its parts, that nothing has since been added to or taken from his
conception.
M. Leonel Reynard informs us that we are likewise wrong in attributing
to Argand the idea of a lamp with a double current of air. It is to
Teulère that it should, in the main, be attributed. However, this
engineer, who has asserted the priority of his claim to the invention
of the reflectors, and the system of eclipses, has not insisted upon
that of the lamp. He limits himself to saying that Argand entertained
the same idea as himself, and derived great profit from it.
* * * * *
This method of lightage was obviously a great improvement, and all
the maritime powers hastened to adopt it. As the _Catoptric System_,
it was, until within the last few years, exclusively employed on the
coast of England. Though less esteemed in France, its use has not been
entirely abandoned; and the French still employ catoptric apparatus
for “the illumination of narrow channels, or for harbour-lights; to
strengthen in a given direction a light whose range is sufficient for
the maritime horizon generally; to illuminate lightships; and for
service as provisional appliances.”
[Illustration: CATOTROPIC APPARATUS.]
In the accompanying design we represent a plan and elevation of a
catoptric apparatus, which is composed, as will be seen, of nine
reflectors arranged in groups of threes. A small rotatory machine sets
the system in motion, and eclipses at greater or shorter intervals are
obtained by the varying speed with which it is worked. The range of the
apparatus depends partly on its power, and partly on its position.
The reflectors, as used in the best lighthouses, are made, says Mr.
Stevenson,[19] of sheet copper, plated in the proportion of six
ounces of silver to sixteen ounces of copper. They are moulded to a
paraboloidal form by a delicate and laborious process of beating with
mallets and hammers of various forms and materials, and are frequently
tested during the operation by the application of a mould carefully
formed. After being brought to the curve, they are stiffened round
the edge by means of a strong bizzle, and a strap of brass which is
attached to it for the purpose of preventing any accidental alteration
of the figure of the reflector. Polishing powders are then applied, and
the instrument receives its latest finish.
[19] Stevenson, “On Lighthouses,” pp. 92, 93.
To prove the form of the reflector, two gauges of brass are employed.
One is for the back, and used by the workmen during the process of
hammering; the other—while the mirror undergoes its final touches—is
applied to the concave face. The mirror is then tested by trying a
burner in the focus, and measuring the intensity of the light at
various points of the reflected conical beam.
The flame generally used in reflectors is derived from an Argand lamp,
with wicks an inch in diameter. The burners are sometimes tipped with
silver to prevent the wick from being wasted by the great heat which
is evolved. They are also fitted, in many of the Scottish lighthouses,
with a sliding apparatus of accurate shape, by which they can be
removed from the interior of the mirror at cleaning time, returned
exactly to the same place, and locked by means of a key.
* * * * *
Catoptric lights, we may add, are divided into _nine_ separate
classes, differing in some respect from those recognized by the French
authorities. The nine classes are called _fixed_, _revolving white_,
_revolving red and white_, _revolving red with two whites_, _revolving
white with two reds_, _flashing_, _intermittent_, _double fixed
lights_, and _double revolving white lights_.
[Illustration: AN ARGAND FOUNTAIN LAMP.]
The following account of the distinctive character of each class of
light is condensed from a valuable treatise by Mr. Alan Stevenson:—
The _fixed_ exhibits a regular and steady appearance, and is not
subject to any change; and the reflectors employed are smaller than
those required for revolving lights. This is necessary, in order
that they may be ranged round the circular frame, with their axes so
inclined as to admit of their illuminating every point of the horizon.
The _revolving light_ is produced by the revolution of a three or four
sided frame, having large reflectors grouped on each side, with their
axes parallel; and as the revolution exhibits once a minute, or once in
two minutes, a light gradually increasing to the maximum, and then just
as gradually decreasing to total darkness, its effect is remarkably
impressive.
The _revolving red and white_ is obtained by the revolution of a frame
whose different sides present red and white lights, and exhibit the
following succession:—two white lights after one red, or two red
lights after one white.
The _flashing light_ is effected in the same manner as the revolving;
but, owing to a different construction of the frame, the reflectors
on each of the eight sides are arranged with their rims or faces
in one vertical plane, and their axes in a line inclined to the
perpendicular—a disposition of the mirrors which, together with the
greater quickness of the revolution, showing a flash once in five
seconds of time, produces an impressive effect, wholly different
from that of a revolving light, and presenting the appearance of an
alternating rising and sinking illumination. The brightest and darkest
periods being but momentary, this light is also characterized by a
rapid succession of bright flashes; whence its name.
[Illustration: REVOLVING APPARATUS ON THE CATOPTRIC PRINCIPLE.]
The _intermittent light_ is distinguished by bursting suddenly into
view and continuing steady for a short time, after which it is suddenly
eclipsed for half a minute. This is due to the perpendicular motion
of circular shades in front of the reflectors, by which the light is
alternately revealed and hidden.
The _double lights_ (“which are seldom used except where exists a
necessity for a _leading_ line, as a guide for taking some channel
or avoiding some danger”) are generally exhibited from two towers,
one of which is higher than the other. At the Calf of Man, says
Mr. Stevenson,[20] a striking variety has been introduced into the
character of leading lights, by substituting for two _fixed_ lights,
two lights which revolve in the same periods, and exhibit their flashes
at the same instant; and these lights are, of course, susceptible of
the other variety enumerated above, that of the revolving red and white
lights, or flashing lights, coming into view at equal intervals of
time. The utility of all these distinctions is to be estimated with
reference to their property of at once striking the eye of an observer,
and being instantaneously obvious to strangers.
[20] Stevenson, “On Lighthouses,” pp. 105-107.
The introduction of _colour_ as a source of distinction, is the only
means of obtaining a sufficient number of varieties. Yet, in itself,
it is an evil of no small magnitude. The effect being produced by
interposing coloured media between the burner and the eye of the
observer, much light is lost by the absorption of those rays which are
retained in order to produce the desired appearance. Experiments have
been made with almost every colour; but only red, blue, and green have
proved useful, and the two latter merely at such short distances as
to unfit them for “sea-lights.” Owing to the depth of tint required to
produce a marked effect, the red shades generally absorb about from
six-sevenths to five-sevenths of the whole light; a loss so immense
as certainly to discourage their adoption whenever it can possibly be
avoided. The red glass used in France absorbs only four-sevenths of
the light; but then, as might be expected, its colour produces a much
less signal distinction to the seaman’s eye. In some of the British
lighthouses, the lights are very simply and conveniently coloured, by
the use of chimneys of red glass, instead of placing large discs in
front of the reflectors.
We come now to the _Dioptric_[21] _System of Lights_.
The application of lenses to lighthouses seems to have been proposed
in England, and essayed at the South Foreland, as far back as 1752;
but owing to mechanical imperfection, they were found to give a light
inferior to that of the paraboloidal reflectors, and consequently were
abandoned. Buffon, the great naturalist, suggested that a lens might
be constructed in concentric zones out of a solid piece of glass; but
the difficulties of the process have proved too great to be overcome.
In, or about 1773, Condorcet proposed that burning lenses should be
built up in separate pieces; and a similar method was described by Sir
David Brewster in 1811. The same construction was quite independently
discovered by the ingenious Fresnel in 1819; and soon afterwards
he constructed a lens, placed a powerful lamp in its focus, and
rendered it available for the practical purposes of a lighthouse. He
is therefore the author, if not the inventor, of the highly successful
system of illumination which bears his name.
[21] From the Greek δίοπτρον, an optical instrument with tube for
looking through. Δίοπτρον is from διἁ, through; and ὅπτομαι, I see.
But before entering into a minuter description of the work, let us
learn a few particulars of the man.
[Illustration: ANNULAR BUILT LENS.]
Jean Augustin Fresnel was born at Broglie, near Bernay, in the French
department of the Eure, on the 10th of May 1788. When eight years old
the future savant was still ignorant of his letters; a fact, says
one of his biographers, to be attributed not so much to his delicate
constitution as to a deep-rooted dislike for the study of languages,
and, in general, for all exercises dependent upon the memory. But, on
the other hand, at nine years of age, he was already distinguished by
the experimental researches he had made in the domain of physics; which
induced his parents to send him to the Polytechnic School. Here, rising
step by step with remarkable rapidity, he eventually became Engineer of
Ports et Chaussèes.
In 1819 he carried off the prize proposed by the Academy of Sciences on
the difficult question of the diffraction of light. His investigations
had long been directed to optical subjects, and hence, when the French
Government established the Lighthouse Commission, Arago, who was
nominated president, immediately appointed Fresnel to the important
post of secretary.
Fresnel recognized the peculiar advantages of a plano-convex lens to
refract in lines nearly parallel to their axis all the rays emanating
from their foci. Like Condorcet and Brewster, who, as we have seen, had
also turned their attention to the problem, though only for so far as
concerned burning instruments, he asked himself whether, by arranging
the lenses in stages, it was not possible to correct their spherical
aberration—a defect which becomes all the more signal as the size of
the lenses is enlarged—and, consequently, to obtain full command over
the rays of a lamp.
* * * * *
Let us now transport ourselves to the upper story of a lighthouse,
and putting aside the motive mechanism of the apparatus, let us
penetrate into the lantern. Cast your glance upon the interior of
that immense diamond which we call a _dioptric apparatus_. The first
object which strikes our attention is the lamp. As the fire which
shone on the summit of the edifice was the soul of the pharos, so the
lamp is the soul of the modern lighthouse. It was to this lamp Teulère
first directed his attention, when he brought the catoptric system to
perfection; and it was to this lamp that Arago and Fresnel addressed
themselves when engaged, in their time, in improving the work of
Teulère, Argand, and Borda. Only, every lighthouse does not employ
the same kind of lamp. In one, we meet with the Carcel lamp, where the
oil is elevated to the wick by a clock-work mechanism. In another, it
is the Moderator, in which the same function is discharged by a heavy
weight surrounding a roller. In others, whose range is limited, it
is the Permanent-level lamp, where the reservoir of oil is placed by
the side and on the level of the burner, which possesses the power of
regulating the supply.
Let us draw near, however, and carefully examine the lamp now before
us, because in several details it differs from those we have described.
It will specially interest us as an English invention.
At the epoch when Teulère and Argand had made the progress already
specified in the construction of a suitable lamp, Rumford, desirous
of effecting a still greater improvement, asked himself whether, by
adapting it to burners with several concentric wicks, it would not be
possible to increase its power of illumination. The attempt was made,
but did not prove successful; he experienced considerable difficulty in
regulating the flame of these multiple wicks, and in preventing their
carbonization under the action of the intense heat developed by their
combination. It was the study of this question which led Fresnel and
Arago to their beautiful experiments on the illumination of lighthouses.
After repeated essays, these two men of science decided on the type
of the lamp which we are now contemplating; an instrument remarkable
not only for the whiteness and intensity of its light, but also for
what I may call its power of endurance; it will burn for upwards of
twelve hours without requiring to be touched. And that this advantage
is most important the reader will apprehend, when he remembers that the
lighthouse-flame must be kept kindled throughout the longest nights of
winter.
* * * * *
At the present day, lighthouses of the third class are illuminated by
lamps with two concentric wicks; which, in a certain sense, means two
lamps in one. In lighthouses of the second class, each lamp has three;
and in those of the first class, each has four wicks. In the latter
we obtain, with a single illuminating apparatus, the full power of
twenty-three Carcel lamps. The luminous focus, though gifted with so
much potency, presents, nevertheless, but a flame of moderate breadth,
and its light is as white as it is brilliant.
The oil employed in the lighthouses of Great Britain, Ireland, and
France is the colza, which has of late years entirely superseded
spermaceti oil, as producing an equal quantity of light at little more
than half the expense. The electric light has, however, been proposed
as a more powerful method of illumination. One system, in which the
light is produced between carbon points by the revolution of magnets
fixed on wheels, worked by a steam-engine, was tried with much success
by Professor Holmes at the South Foreland; and is still, we believe,
in use at Dungeness, as it is, in France, at the two lighthouses of
La Hève. In the latter case, the mechanism producing the currents
is composed of two steam-engines, each with a five-horse power, and
of four electro-magnetic machines of six discs, composed each of
sixteen bobbins. It is placed in a boat, adapted for the purpose, at
an equal distance from the two towers. Under ordinary atmospheric
conditions, a single steam-engine is kept in motion, communicating with
a magneto-electric machine for each lighthouse. During fogs and mists,
both engines are in activity, and each lighthouse receives the currents
of two magneto-electric batteries, which are then associated.
[Illustration: ELECTRIC APPARATUS FOR A FIXED LIGHT.]
Both lighthouses are supplied with two lenticular apparatus, placed
one above another in the same lantern. The regulators of the progress
of the carbons were invented by M. Serrin, whose object has been to
augment their sensibility, and, consequently, the regularity of the
light; in which respect, now-a-days, little is left to be desired.
The mean intensity of the light produced by a machine of six discs is
computed as equal to 200 Carcel burners. The intensity of the cone of
light emanating from the lenticular apparatus, when illuminated in this
manner, rises to 5000 burners.
The electric light, as yet, is applied only to lighthouses with fixed
lights, for a special arrangement would be necessary in the lenticular
apparatus before it could be employed with the same advantage in the
production of intermittent lights (_feux à éclipses_). Experiments,
however, have been made in this direction, which promise good results.
Yet, in the present state of its mechanical conditions, the system
of electric illumination does not seem susceptible of any very great
development upon our shores. It cannot be applied economically to
lights which require no very great intensity,—and these lights are the
most numerous; and, on the other hand, the intricate constructions
which it necessitates, the chances of accident which it presents, and
the quantity of coal which it consumes, are obstacles to its employment
in lighthouses isolated at sea, whose communications with the mainland
are liable to interruption, and where it is of importance to reduce as
much as possible the dimensions of the edifice as well as the amount of
transport. However this may be, the electric light would seem destined
to render valuable services to navigation at every point where it
can be employed, and like the two great inventions which the history
of marine lightage signalizes—that of paraboloidal reflectors, and
next, that of the lenticular apparatus—it constitutes a special and
noteworthy progress, under the threefold aspect of intensity of light,
diversity of character, and the value of luminous unity.
We may add that Mr. Wilde, of Manchester, has invented a powerful
electro-magnetic apparatus for lighthouse illumination, which may
probably prove valuable. Modifications of the lime light, resulting
from the action of an oxy-hydrogen flame upon a surface of prepared
lime, have also been suggested; and the least powerful of these
surpasses in brilliancy the best oil-lamp, as that surpasses the open
coal-fire. We may, therefore, expect that as the latter barbarous mode
of illumination gave way to the catoptric, or _reflecting_ system,
so will the dioptric, before many years have passed, succumb to some
ingenious apparatus capable of utilizing either the lime or the
electric light.
* * * * *
We now return to Fresnel’s system, the _dioptric_, which is pretty
generally adopted in the British lighthouses.
We must here premise that the system is based upon the laws of the
refraction of light.
But, says the non-scientific reader, what do you mean by the
_refraction_ of light? I know very well what reflection is; I am not so
clear as to refraction.
A ray of light, when transmitted _obliquely_ from one transparent
body to another of different density, undergoes, at the point where
it strikes the common surface of the two planes, a sudden change
of direction. This change of direction is called _refraction_. For
instance, plunge one half of a straight ruler into a basin of water.
The ruler no longer appears straight, but _bent back_ or _broken_
(_re_, and _fractum_) at the point where it enters the water.
We have already stated that the great object to be gained in lighthouse
illumination is this very _refraction_; that is, the rays of the lamp
must be refracted, or bent back, so as to strike and illuminate the
sea.
Fresnel saw that this object might be secured by the employment of
lenses to intercept, as it were, and refract the rays proceeding from
the lamp. What kind of lens possessed the greatest power of refraction?
He preferred the plano-convex lenses, which, instead of having two
curve surfaces, have one surface a curve, and the other a plane. And
the lens thus adopted he built up in separate pieces, for the still
greater economization and intensity of light; and, says Mr. Stevenson,
he has subdivided with so much judgment the whole surface of the lens
into a centre lens and concentric annular bands, and has so carefully
determined the elements of curvature for each, that it seems unlikely
any improvement will soon be effected in their construction.
[Illustration: ANNULAR LENS OF FIRST ORDER.]
The central disc of the lens, marked B in the accompanying diagram—as
employed in lights of the first order—is about 11 inches in diameter,
and the focus distance equals 920 millimètres, or 36.22 inches. The
annular rings surrounding it gradually decrease in breadth as they
recede from the centre, from 2¾ to 1¼ inches. The lens, we should add,
is made of crown glass.
A lens of this magnitude costs about £60. Its weight is about 109
lbs., and its surface consists of about 1300 square inches; but though
composed of so many parts, it is held together simply by two narrow
strips of polished glass, united by a thin film of cement.
* * * * *
The following illustration, representing a segment of the profile
of a dioptric apparatus, will give the reader a sufficient idea of
the manner in which the rays proceeding from the focus of a lamp are
refracted on issuing from the lens; it also shows the central disc, and
the rings placed above and below it.
When the drum is circular instead of being polygonal, the lenses
are cylindrical and not annular; the luminous rays are uniformly
distributed in the horizontal plane, and act—in a meridian section—in
the same manner as those of the annular lenses.
Yet there is something more than lenses in a dioptric apparatus, for
this reason, that the lamp does something more than illuminate the
frame. The rays streaming below it vainly poured their light at the
foot of the tower, and those which rose above it were diffused in the
upper region of the atmosphere, and consequently, for all purposes of
marine illumination, would have been useless, had not Fresnel conceived
the idea of collecting, concentrating, and despatching them in the same
direction as the lenses threw the others. This he effected by means of
the cylindrical rings of glass which, above and beneath the lenses,
cover over the framework, as it were, or make use of it as a base, in
expanding themselves as they approach the centre of the apparatus.
[Illustration: DIAGRAM, ILLUSTRATING THE PROGRESS OF A LUMINOUS RAY IN
A CATADIOPTRIC RING.]
The subjoined illustration represents the progress of a luminous ray
in one of the rings of glass, technically termed _catadioptric rings_.
Issuing from the focus F at the summit of the angle formed by the
lines G and I, it is refracted at A in the direction A B, undergoes a
complete reflection on the surface M N, takes the direction B C, and
finally emerges from the ring in the horizontal line C H.
At this solution of the difficulty Fresnel did not arrive all at once,
owing to the absolute want of workmen suitable for carrying out the
novel industry which his genius had created. But by degrees these
were trained and perfected; and the inventor had, moreover, the good
fortune of discovering in an able and ingenious optician, M. Soleil, an
efficient assistant in the construction on a large scale of the novel
instrument he required. Afterwards the erection of lighthouses becoming
an important branch of industry, he completed several edifices, which
prospered all the more that strangers immediately gave up any attempt
at rivalry, and left to him the work of supplying every maritime nation
with lenticular apparatus.
* * * * *
Having said thus much of the central lens and its concentric rings of
glass, a few words become necessary in reference to the lamp which
feeds them, as it were, with light. Fresnel’s lamp may be shortly
described as containing four concentric burners, which are defended
from the excessive heat produced by their own combined flames by a
superabundant supply of oil. This oil is pumped up from a cistern below
by means of a clockwork movement, and overflows the wicks incessantly.
To supply fresh currents of air to each wick with a rapidity sufficient
to support the combustion, a very tall chimney-tube is found requisite.
And yet the wicks do not carbonize with the extreme speed that might be
supposed. It is even found, we are told, that after they have suffered
a good deal, the flame does not perceptibly decrease, because the
intense heat evolved from its mass encourages the rising of the oil in
the cotton. Mr. Stevenson informs us that he has seen the large lamp
in the Tour de Corduan burn for seven hours, and yet the wicks were
neither snuffed nor raised. In the Scotch lighthouses a full flame is
often maintained, with Colza oil, for no less a period than seventeen
hours, and yet the lamp is untouched.
* * * * *
The only risk in using the Fresnel lamp, says Mr. Stevenson, arises
from the liability to occasional derangement of the leathern valves
that force up the oil by means of clockwork. Several lights on the
French coast, and, more especially, the Tour de Corduan, have been
extinguished by the failure of the lamp for a few minutes; an accident
which has never happened, and scarcely _can_ happen, with the fountain
lamps of the Catoptric system. To prevent such dangerous mishaps,
which, under some circumstances, might entail the loss of a “tall
ship,” various precautions have been adopted. The most efficacious
seems to be this: an alarum is attached to the lamp, consisting of a
small cup pierced in the bottom, which receives a portion of the oil
overflowing from the wicks, and is capable, when full, of balancing a
weight placed at the opposite end of a lever. The moment the machinery
stops, the cup ceases to receive the supply of oil, and the remainder
escaping at the bottom, the equilibrium of the lever is destroyed; it
falls, and disengages a spring, which rings a bell with sufficient
force to arouse a sleeping keeper. But, says Mr. Stevenson, shrewdly,
it may justly be doubted whether such an arrangement might not actually
tempt a keeper to relax in his vigilance, and rely on the alarum to
waken him in case of need. In all the dioptric lamps on the British
coast, therefore, the converse method is adopted of causing the bell to
cease when the clockwork stops.
Another and more important precaution consists in keeping always at
hand, in the light-room, a _spare lamp_, trimmed, and adjusted to the
proper height for the focus, and in every respect ready to act as a
substitute for the other if any accident occurs.
But while I am tracing these words, I read that experiments have been
successfully made with _gas_ for the illumination of the lenticular
apparatus, and that, if it will afford a steadier and fuller light, at
less expense, and with no risk of accident, it will probably be adopted.
* * * * *
To continue:—
Once having acquired a full command of all the rays amplified from
the lamp, the next desideratum was to diversify the appearance of
the light which they constituted; for, as I have already said, it is
not enough to stretch a belt of warning fires around the coast,—we
must take care that each shall in some wise be distinguished from the
other, so as to afford the navigator a clue to its particular locality.
Hence arose the division into fixed, revolving, intermittent lights,
and so on, which I have already described, and which is secured in the
following manner:—
[Illustration: FRESNEL’S REVOLVING LIGHT.]
If a _fixed light_ be required, the apparatus as invented by Fresnel
takes the form of an annular glass frame produced by the revolution
of the section passing through the centre of a circular lens, and
reflecting prisms around a vertical elevated on the principal axis of
this section, as shown in the diagram.
For _revolving apparatus_, Fresnel’s apparatus, as employed in all
lighthouses prior to the introduction of the holophotal arrangement,
consisted, as may be seen in the diagram, of annular lenses, _L_, for
acting on the central part of the light, while the upper rays were
refracted by inclined hanging lenses, _a_, and ultimately reflected
into the proper direction by silvered mirrors marked _b_, placed above.
The lower rays were intercepted by fixed light prisms, _p p_ (_which
did not revolve_), and which, showing a fixed light all round, were,
of course, of very inferior power to the solid beams proceeding from
the large lenses =L=, and the smaller lenses and mirrors placed above.
Strictly speaking, Fresnel’s revolving light consisted of a _revolving_
and a weak _fixed_ light. As the frame revolved round the central
lamp, the mariner saw the luminous beam when the lenses were turned
towards him, and the number of flashes depended on the quickness of the
rotation.
[Illustration: STEVENSON’S HOLOPHOTAL REVOLVING LIGHT.]
The apparatus adopted by Fresnel for the _fixed_ light may be regarded
as perfect; but his _revolving_ light has been now superseded by the
holophotal apparatus of Mr. Thomas Stevenson. The inclined mirrors
and lenses employed in Fresnel’s apparatus are done away with in Mr.
Stevenson’s, shown in the diagram, in which, by the single agency of
lenses, _L_, and totally reflecting prisms, _p_, all the rays are
rendered parallel. In this form the _whole_ glass frame, consisting
of lenses and reflecting prisms, revolves round the central lamp. As
Fresnel’s lighthouse prisms only gathered the light vertically, they
could not produce the sheaf of rays required for the revolving light
unless when combined with others which gathered the rays horizontally.
The first lighthouse in which single prisms were made to revolve
was the Horsburgh light, near Singapore, the apparatus of which was
designed by Mr. Stevenson in 1850. In this form of revolving light
apparatus the prisms are generated about a horizontal instead of a
vertical axis, as in fixed light. The forms of the beams of light
issuing forth from Fresnel and Stevenson’s apparatus are shown opposite
to the diagram of each, and marked _x, y_.
[Illustration: STEVENSON’S FIXED LIGHT VARIED BY FLASHES.]
In France there is frequently employed what Fresnel called a “_fixed
light varied by flashes_.” This effect is produced, as already
explained, by causing panels of glass, curved horizontally but not
vertically, to revolve outside of Fresnel’s fixed apparatus, as shown
in the diagram. The ordinary fixed apparatus only acts in the vertical
plane, while the straight panels only act in the horizontal plane.
So that when the fixed apparatus is alone visible the rays are only
gathered from the vertical plane, and the light is comparatively weak;
but when the panels come opposite the eye, the rays are gathered from
both planes into one powerful beam, as in a revolving light. Here,
as in the former case, two agents are employed, causing great loss
of light and great unnecessary expense, where one, if of the proper
form, is sufficient. Mr. Stevenson’s modification of the holophotal
arrangement for this purpose is shown in the diagram. It consists of
alternate panels of the fixed light and holophotal apparatus; and thus,
by single agency, a weak fixed light and a stronger revolving light are
shown time-about to the mariner, which is the required characteristic.
[Illustration: FRESNEL’S FIXED LIGHT APPARATUS.]
[Illustration: FRENCH FORM OF APPARATUS FOR A FIXED LIGHT VARIED BY
FLASHES.]
If, for the sake of further diversity, the lights are to be coloured,
we content ourselves in the case of a fixed light, as already stated,
with enclosing the flame in a green or red tube. In the French
eclipsing apparatus, polished sheets of coloured glass are placed, on
one side or the other, against the lenses intended to emit the flashes
of colour.
While doing all honour to Fresnel and his great invention, we must not
forget that its present comparative perfection is due to Mr. Thomas
Stevenson, whose improvements, in truth, have eventuated in almost a
new system, now known as the _Holophotal_,[22] and already partially
described. By a peculiar combination of dioptric spherical mirrors and
other apparatus, it also succeeds in economizing and condensing into
one beam the whole of the rays thrown off from the burners; but I fear
that any explanation of it which could here be attempted would, from
its necessary introduction of technical language, prove unintelligible
to the non-scientific reader.
[22] From ὅλος, entire; and φὼς light.
[Illustration]
[Illustration]
CHAPTER IV.
THE INTERIOR OF A LIGHTHOUSE.
After having devoted so many pages to what we have called—perhaps
somewhat fancifully—the _soul_ of the lighthouse, it becomes necessary
to say a few words in reference to the _body_ which encases it.
In building up this body, no less ingenuity and science have been
displayed than in perfecting and expanding the light which gives it
life and value. Whether the lighthouse-tower is situated on some
wave-washed rock surrounded by a hungry sea, or on the summit of
a conspicuous headland, the highest skill is exercised upon its
construction, and it becomes, in many instances, a monument of the
most brilliant architectural genius. Not, indeed, that it exhibits
those beautiful features of clustered columns and lofty arches, or that
elaboration of picturesque ornament, which delight us in the lordly
mansion and the ancient cathedral; but that an equal perfection of
art is revealed in its massive simplicity and impregnable solidity,
and in its admirable adaptation to the grand purposes for which it is
intended.
Two primary conditions, it is obvious, must always govern the
construction of a lighthouse: it must be raised to an elevation
suitable for the full display of its warning radiance, and it must be
built with a strength and solidity which will defy the assault of wind
or wave.
So far as the first condition is concerned, the proper height of a
lighthouse-tower is easily ascertained, when the distance is determined
at which its rays should be visible. This distance will necessarily
depend on the character of the neighbouring seas, and the nature of
the reef, rock, or shallow from which the lighthouse is to warn the
navigator; but, once determined, the elevation of the tower will easily
be calculated by means of the known relations existing between the form
of the earth, the effects of atmospheric refraction, and the proper
height of an object which is to be seen from a given distance. The
state of the atmosphere at any particular point is also an important
point of consideration. It is quite possible that the lighthouse, when
erected at what seems a suitable elevation, may be rendered useless by
a prevalence at that elevation of dense mists and heavy fogs. In 1785,
the Trinity Board commenced the erection of a lighthouse on the summit
of St. Catherine’s Down, in the Isle of Wight, and from so lofty an
altitude it might well be supposed that its radiance would illuminate
the Channel for leagues around. But, unfortunately, the crest of St.
Catherine’s is, for the greater part of the year, enveloped in cloud
and mist, which effectually prevents the escape of a single ray of
light; and, consequently, the Trinity Board were compelled to abandon
their design. The shell of the building still crowns the bleak summit
of the down, as a warning to future lighthouse-builders.
Still more recently, the lighthouse on the Needles Down (also in the
Isle of Wight), which for years had pointed out the dangerous character
of the western entrance to the Solent, has been abandoned on account
of the mists so frequently obscuring its lustre; and a new lighthouse
has been erected on the outermost of the celebrated Needle Rocks, in a
position of far greater utility.
The question regarding the _interior_ accommodation of the tower
must, in like manner, be answered by the nature of the locality where
it is erected. Where it is easily accessible, and its stores can be
replenished with ease at very short intervals, obviously the interior
accommodation may be reduced within very narrow limits. But in exposed
situations, as, for instance, on an isolated rock, whose communication
with the mainland may be cut off for weeks at a time, room must be
provided for ample supplies, and conveniences for the keepers must be
arranged on a liberal scale. In the long and dreary nights of winter,
where, in the northern parts of Great Britain, it is necessary to keep
the light burning for about seventeen hours, not even for a moment is
it left without the watchful care of at least one keeper; and thus, as
he will require an interval of repose, its superintendence will occupy
_two_ persons; but in open, exposed places like the Eddystone, the Bell
Rock, the Wolf, and the Skerryvore, where it is frequently impossible
to communicate with the mainland for three, four, and even six weeks,
circumstances have rendered it desirable that there should not be
fewer than _three_ men on duty. Hence, sleeping apartments have to be
provided, as well as receptacles for sufficient supplies of water,
food, fuel, and other matters.
* * * * *
The second condition to which we have adverted is, that the building
shall be capable of resisting the force of the wind and waves. The wind
is baffled with comparative ease, but the sea is a far more formidable,
and, moreover, is an ever-present foe. Even in the summer months the
pressure of the waves is very considerable, averaging, perhaps, about
611 lbs. per square foot of surface exposed to it. In the winter,
however, the average rises to 2086 lbs. per square foot; while, during
stormy weather, the force has amounted to no less than 4335 lbs.[23]
To oppose this immense pressure, not only must the masonry be of the
solidest description, but such a form must be given to the building as
will expose that masonry to the least possible stress. From various
experiments it has been found that the most effective form is that
of the cylinder; and with certain modifications, the cylindrical
is now almost universally adopted in the erection of lighthouses.
Scientifically speaking, however, it is not so much a cylinder as
the union of frustra of different cones, with a curve osculating the
outline of the successive frustra. To the youthful reader this may not
be very intelligible, and we will, therefore, refer him to the form
of the Eddystone as an illustration of what we mean. Smeaton himself
relates that it was suggested to him by the trunk of an oak, but there
seems reason to believe that this was an after-thought, intended
for the benefit of the large class of minds which cannot appreciate
scientific reasonings.
[23] These figures are the results of experiments made with an
instrument invented by Mr. Thomas Stevenson, and called the Marine
Dynamometer.
* * * * *
Let us now pass into the interior of a lighthouse, and take notice of
its general arrangements.
And, first, observe the massive door of bronze which opens to admit
us into the lowermost story. Here are collected the stores of wood,
cordage, oil, and water; and here too is placed the carpenter’s shop.
On the next story we find the kitchen and the dining-room. Then we
ascend to the sleeping-rooms of the three keepers; they are exquisitely
neat and clean, but in other respects do not call for notice. On the
highest story we enter that portion of the structure more particularly
destined for the special service of the tower. It contains numerous
vessels of oil, lenses, lamps, a thermometer, a barometer, and a
chronometer. The spiral staircase by which we have hitherto ascended
terminates at this point, and to reach the lantern we must climb a
ladder before us. Entering the cupola, which enshrines the magic
light, we are surprised by its exquisite propriety of arrangement. The
form of the lantern is light and graceful; and to avoid the necessity
of painting it, the framework is made of gun metal, and the dome of
copper. A lantern for a light of the first order is twelve feet in
diameter, and its glass frames are two feet high. The glazing is thick,
and great care is exercised in fixing it that the plates may not be
broken during high winds. Panes glazed in frames padded with cushions,
and capable of being temporarily fixed in a few minutes, are always
kept ready for use in Scotland. These are called _storm-panes_. The
total cost of a lantern such as we have been describing is about £1260.
[Illustration: CUPOLA OF A LIGHTHOUSE OF THE FIRST CLASS.]
To secure a good and efficient light it is necessary that the lantern
should be well ventilated. Otherwise its sides will be continually
covered by the water of condensation produced by the contact of the
ascending current of heated air, and the glass, thus obscured, impedes
the passage of the rays and diminishes their power. To prevent such an
evil an excellent system of mechanical ventilation was devised by the
late Professor Faraday.
The ventilating pipe or chimney is a copper tube four inches in
diameter, divided into three or four lengths; the lower end of each for
about an inch and a half being opened out into a conical form, about
five inches and a half in diameter at the lowest part. When the chimney
is put together, the upper end of the bottom piece is inserted about
half an inch into the cone of the next piece above, and fixed there by
three ties or pins, so that the two pieces are firmly held together;
but there is still plenty of airway or entrance into the chimney
between them. The same arrangement holds good with each succeeding
piece. When the ventilating chimney is fixed in its place, it is so
adjusted that the lamp chimney enters about half an inch into the lower
cone, and the top of the ventilating chimney into the cowl or head of
the lantern.
With this arrangement (I use the Professor’s own words) it is found
that the action of the ventilating flue is to carry up every portion
of the products of combustion into the cowl; none passes by the cone
apertures out of the flue into the air by the lantern, but a portion of
the air passes from the lantern by these apertures into the flue, and
so the lantern itself is in some degree ventilated.
The important use of these cone apertures is, that when a sudden gust
or eddy of wind strikes into the cowl of the lantern, it should not
have any effect in disturbing or altering the flame. It is found that
the wind may blow suddenly in at the cowl, and the effect never reaches
the lamp. The upper, or the second, or the third, or even the fourth
portion of the ventilating flue might be entirely closed, yet without
influencing the flame. The cone junctions in no way interfere with the
tube in carrying up all the products of combustion; but if any downward
current occurs, they dispose of the whole of it into the room without
ever affecting the lamp. The ventilating flue is, in fact, a tube
which, as regards the lamp, can carry everything up but conveys nothing
_down_.
* * * * *
The British lighthouses, as I have stated, are under the charge
of either two or three keepers, whose duties are to cleanse and
prepare the apparatus for nocturnal illumination, and to mount guard
alternately after the light is exhibited. The rule is, that under
no circumstance shall the keeper on duty leave the light-room until
relieved by his comrade; and that no pretence may exist for disobeying
this all-important regulation, the dwelling-houses are invariably built
in immediate proximity to the light-tower, and means are provided for
signaling directly from the light-room to the sleeping apartments below.
For greater security in all such exposed situations as the Eddystone or
the Bell Rock, _four_ keepers are provided for one light-room. One of
these is always ashore, on leave, with his family, and the other three
are on guard in the lighthouse, so that, in the case of the illness
of one light-keeper, an efficient establishment of two keepers for
watching the light may remain.
The following interesting details we borrow verbatim from Mr. Alan
Stevenson:[24]—
[24] Alan Stevenson, “On Lighthouses,” Weale’s Series, pp. 169, 170.
Each of the two (or three) light-keepers has a house for himself and
family, both being under a common roof, but entering by separate doors.
The principal keeper’s house consists of six rooms, two of which are
at the disposal of the visiting officers of the Board, whose duty in
inspecting the lighthouse or superintending repairs may call them to
the station; and the assistant has four rooms, one of which is used as
a barrack-room for the workmen who, under the direction of the foreman
of the light-room works, execute the annual repairs of the apparatus.
The greatest care must be bestowed on securing the utmost cleanliness
in every detail connected with a lighthouse, whose optical apparatus is
peculiarly sensitive to the effect of dust. For this purpose covered
ash-pits are provided at all the dwelling-houses, in order that the
refuse of the fireplaces may not be carried on “the wings of the wind”
to the light-room; and, for similar reasons, iron floors are used in
the light-rooms instead of stone, which is often liable to abrasion,
and all the stonework near the lantern is regularly painted in oil.
If, in all that belongs to a lighthouse, the greatest cleanliness is
desirable, it is in a still higher degree necessary in every part of
the light-room apparatus, without which the optical instruments and
the machinery will neither last long nor work well. Every part of the
apparatus, whether lenses or reflectors, should be carefully freed
from dust before being either washed or burnished; and without such a
precaution the cleansing process would only serve to scratch them.
For burnishing the reflectors, prepared _rouge_ (tritoxide of iron)
of the finest description, which should be prepared in the state of
an impalpable powder of a deep orange-red colour, is applied by means
of soft chamois skins, as occasion may require; but the great art of
keeping reflectors clean consists in the daily patient and skilful
application of manual labour in rubbing the surface of the instrument
with a perfectly dry, soft, and clean skin, without rouge. The form
of the hollow paraboloid is such that some practice is necessary in
order to acquire a free movement of the hand in rubbing reflectors;
and its attainment forms one of the principal lessons in the course
of the preliminary instruction to which candidates for the situation
of a lighthouse-keeper are subjected. For cleansing the lenses and
glass-mirrors spirit of wine is used. Having washed the surface of
the instrument with a linen cloth steeped in spirit of wine, it is
carefully dried with a soft and dry linen rubber, and finally rubbed
with a fine chamois skin free from any dust, which would injure the
polish of the glass, as well as from grease. It is sometimes necessary
to use a little fine rouge with a chamois skin for restoring any
deficiency of polish which may occur from time to time; but in a
well-managed lighthouse this application will seldom, if ever, be
required.
* * * * *
Before we quit this subject, it may interest the reader to be informed
that the glass of the lantern is frequently broken, not by wind and
wave, but by the sea-birds which dash violently against it. In a single
night at Cape de Bréhat nine panes were shattered from this cause.
At the lighthouse of Bréhat a wild duck forced its way through two rows
of mirrors and fell upon the lamp. A thousand of these birds were on
one occasion caught by the crew of a British lightship, who made them
into a gigantic pie. It is necessary to defend with trellis-work the
lights most exposed to visits of this kind.
[Illustration: SEA-BIRDS ATTRACTED BY THE RAYS OF A LIGHTHOUSE.]
Fortunately, all sea-birds are not so dangerous. Some of them even
render to the navigator a service like that which the goose of the
capitol, according to Livy, once rendered to the Romans. At the South
Stock lighthouse, near Holyhead, which is situated in the middle of an
islet, tamed sea-birds are made use of as signals. The gulls perch on
the lighthouse walls and utter loud cries, which wave off approaching
seamen. This lighthouse possesses a bell and a cannon, but the natural
signal has been esteemed so superior that the cannon has been removed
to a distance from the rock, lest its discharge should alarm the birds.
The young gulls roam about the island among the white rabbits, living
in perfect harmony with them, and providing the keepers with society;
a pleasanter society than that of the wind and waves which incessantly
vent their fury on the solitary pharos.
[Illustration]
[Illustration]
BOOK III.
_LIGHTHOUSES OF GREAT BRITAIN._
CHAPTER I.
THE STORY OF THE EDDYSTONE: A.D. 1696, 1706, 1759.
The first lighthouse of a regular character erected on the shores
of England seems to have been that of Lowestoft, in 1609. Among its
successors we may refer to those of Hunstanton Point, 1665, and of
the Scilly Islands, 1680. To the same epoch belong the lighthouses of
Dungeness, Orfordness, and the Eddystone; the latter being the most
important, the most remarkable, and the most interesting, as, I think,
the following brief narrative will not fail to show.
* * * * *
The _Eddystone_ is the name of the highest summit of a reef of rocks
which lie in deep water about fourteen miles to the south-west of
Plymouth harbour. As they are in a line with Lizard Head, in Cornwall,
and Start Point, in Devonshire, they are not only in the track of
vessels bound for the great Devonian seaport, but of vessels coasting
up and down the English Channel. At high water they are barely visible,
and their position could only be told by the waves which _eddy_ and
seethe above them; at low water several low, broken, and dismal-looking
ridges of gneiss become conspicuous. When the wind blows from the
south-west, they are the centre of “a hell of waters,” and no ship
involved in the vortex could hope to escape destruction.
It may readily be conceived that so perilous a reef, when unprotected
by any beacon, was a source of deep alarm to the mariner, who, to give
it the widest possible berth, was accustomed to enter the Channel in a
much more southerly latitude than is now done. But in avoiding Scylla
he often fell into Charybdis, and hence the numerous wrecks which
occurred on the French coast, and more particularly upon the dangerous
rocks surrounding the islands of Jersey, Guernsey, and Alderney.
The erection of a lighthouse upon the Eddystone was, therefore, a
matter of national concern; yet no one could be found to undertake a
task whose accomplishment nature seemed to have rendered impossible,
until Henry Winstanley, a country gentleman of Littleberry, in Essex,
chivalrously came forward in the year 1696, and having obtained the
necessary legal powers, proceeded to carry his design into execution.
This same Winstanley was one of those eccentric geniuses who find a
pleasure in mystifying their friends, and in investing their daily life
with an air of legerdemain. He adapted science to practical jokes with
an ingenuity which, we think, has never been surpassed. If a guest in
his bedroom kicked an old slipper out of his way, immediately a ghost
started from the floor. If, in another, he threw himself into a chair,
it suddenly flung out its two arms, and held him fast as a prisoner. Or
if in the garden he retired into an arbour, and rested on a particular
seat, he was straightway set afloat in the middle of the adjoining
canal.
To the native eccentricity of the man, it has been justly remarked,
may be ascribed the fantastical character of the first Eddystone
Lighthouse. Its erection was begun in 1696. The first summer—and it
was only in summer the work could be carried on—was occupied in making
twelve holes in the rock, and fastening as many irons in them, to serve
as the superstructure.[25] The task progressed but slowly, for, as
Winstanley himself relates, though it was summer, the weather would at
times prove of such terrible violence, that for ten or fourteen days
together the sea would so rage about the rocks—agitated by out-winds
and the inrush of the ground-swell from the main ocean—as to mount and
leap upwards some two hundred feet, completely burying the works, and
preventing all approach to them.
[25] “Smeaton and Lighthouses” (ed. 1844), pp. 24, 25; Smiles, “Lives
of the Engineers,” ii. 17.
* * * * *
The second summer was spent in constructing a solid round pillar twelve
feet high and fourteen feet in diameter. In the third year the pillar
was enlarged two feet at the base, and the edifice carried up to a
height of sixty feet. “Being all finished,” says the engineer, “with
the lantern, and all the rooms that were in it, we ventured to lodge
there soon after midsummer, for the greater dispatch of the work. But
the first night the weather came bad, and so continued, that it was
eleven days before any boats could come near us again; and not being
acquainted with the height of the sea’s rising, we were almost drowned
with wet, and our provisions in as bad a condition, though we worked
night and day as much as possible to make shelter for ourselves. In
this storm we lost some of our materials, although we did what we could
to save them; but the boat then returning, we all left the house to be
refreshed on shore: and as soon as the weather did permit we returned
and finished all, and put up the light on the 14th November 1698; which
being so late in the year, it was three days before Christmas before we
had relief to go on shore again, and were almost at the last extremity
for want of provisions; but, by good Providence, then two boats came
with provisions and the family that was to take care of the light; and
so ended this year’s work.”
[Illustration: WINSTANLEY’S LIGHTHOUSE AT THE EDDYSTONE.]
The fourth year was devoted to strengthening the foundations and
enlarging the structure, which, when completed, resembled nothing
so much as “a Chinese pagoda, with open galleries and fantastic
projections.” The gallery around the lantern was so wide and open, that
it was possible, when the sea ran high, for a six-oared boat to be
lifted by the waves and driven through it. Such an edifice could not
long resist the fury of the waters or the violence of the gale; but,
at least, it served to prove that a lighthouse _could_ be erected on
the rock, and its achievement was one of the most laudable enterprises
which any heroic mind could undertake, for it filled the breast of the
mariner with new hope.
Winstanley was proud of his work, and so convinced, it is said, of its
entire solidity, that he expressed a wish to be beneath its roof in
the greatest storm that ever blew under the face of heaven, convinced
that it could not shake one joist or beam. He had his presumptuous
wish fulfilled. With his workmen and keepers he had taken up his abode
in the lighthouse, when a terrible gale blew up, and on the 26th of
November attained to an unparalleled excess of fury. In truth, it was
of so frightful a character that contemporary annals vividly record its
destructive effects, and the alarm it produced.
All through that memorable night the tempest raged. As soon as morning
came the people of Plymouth hastened to the beach, and turned their
gaze instinctively towards the Eddystone. But no structure crowned the
rock, over which the waves were tossing and swirling all unchecked. The
lighthouse was swept away, and no vestiges remained of its adventurous
occupants.
* * * * *
The question now arose, Who was to rebuild the lighthouse? Three years
passed before it was answered; and then the task was taken up by one
Captain Lovet, who obtained a ninety-nine year‘ lease from the Trinity
Corporation, and immediately engaged as his architect a _silk-mercer_
on Ludgate Hill, named John Rudyerd. What reasons guided Lovet in his
curious choice we cannot ascertain; probably Rudyerd had given some
signal proofs of mechanical ingenuity; but, at all events, the choice
proved a felicitous one. Rudyerd submitted for the new building an
elegant and admirable design; instead of a polygon, he chose a circle
for the outline, and instead of the projections and ornaments with
which Winstanley had arrested every breeze that blew, he studied the
utmost simplicity, so as to offer wind or wave the slightest possible
resistance.
He secured the foundation with the utmost care. He divided the
irregular surface of the rock into seven rather unequal stages, and
cut thirty-six holes in these, to the depth of from twenty to thirty
inches. These holes were six inches square at the top, gradually
narrowing to five inches, and then again expanding and flattening to
nine inches by three at the bottom. Into these dove-tailed holes strong
iron bolts or branches were keyed; each bolt being fitted exactly in
size to the hole it was intended to fill, and weighing from two to five
hundredweight, according to its length and structure.
The bolts made fast, Rudyerd proceeded to fix a course of squared oak
timbers lengthwise upon the lowest step, so as to reach the level of
the step above. Another set of timbers were then laid crosswise, so
as to cover those already laid, and to raise the level surface to
the height of the third stage. The third structure was again laid
lengthwise, the fourth crosswise, and so on, alternately, until a
basement of solid wood was secured, two courses higher than the highest
point of the rock; all being fitted together and to the rock, by means
of the bolts, as firmly as possible, and all, in their intersections
with one another, being closely trenailed.
The bolts originally let into the solid rock were perforated in their
upper parts—some with three, and some with four holes; so that in every
pair, collectively called a _branch_, there would be about seven holes.
As the branches numbered thirty-six, there would be 252 holes, each
about seven-eighths of an inch in diameter, and consequently as many
large “bearded spikes” or “jag-bolts,” which, being driven through the
branches into the solid timber, held the mass firmly down.
* * * * *
Rudyerd’s lighthouse is generally described as a timber edifice. This
is not correct. Knowing that weight is best resisted and counteracted
by weight, and to insure a sufficient amount of resistance, he combined
with his courses of timber solid courses of Cornish granite, in this
manner: the foundation was of oak for two courses; then came five
courses of stone, each a foot in thickness, kept together by iron
cramps; and then two courses more of timber. Thus was completed the
basement.
The remainder of the edifice, which rose to an elevation of 69 feet, on
a base of 23 feet, was built of timber. The interior consisted of four
rooms, one above the other; and above the topmost was the lantern—an
octagon of 10 feet 6 inches in diameter, crowned by a ball of 2 feet 3
inches in diameter. The whole height of the lighthouse, from the lowest
side of the rock to the top of the ball, was 92 feet. It was completely
finished in 1709.
In connection with this ingenious structure an anecdote is always
related, illustrative of the kindly feeling which Louis XIV.
occasionally exhibited. There was war at the time between England and
France, and a French privateer seized the opportunity of carrying off
the workmen employed in building the lighthouse as prisoners. As soon
as their capture was made known to the king, he ordered their immediate
release, and that they should be sent back to their work, with some
presents to compensate for their detention. “Though at war with
England,” said the king, “I am not at war with mankind.” The Eddystone
lighthouse is so situated as to be of equal service to all nations
having occasion to navigate the Channel that separates France from
England.
* * * * *
Yet another anecdote: Some visitors to the lighthouse, after inspecting
its internal arrangements, observed to one of the keepers that he
thought it quite possible to live very comfortably in its quiet
seclusion. “That might be,” said the man, “if we had but the use of our
tongues; but it is now fully a month since my partner and I have spoken
to each other.”
* * * * *
Rudyerd’s lighthouse continued to brave “the elemental fury,” and warn
the seamen from the fatal rocks, until the 2nd of December 1755, when
it fell before a most unexpected enemy. Through some unknown cause
the building caught fire. Three keepers at the time were within the
lighthouse; and when one of them, whose turn it was to watch, entered
the lantern, at about two o’clock in the morning, to snuff the candles,
he discovered it to be filled with smoke,[26] and on his opening the
door which led to the balcony, a flame instantly burst from the inside
of the cupola. He hastened to alarm his companions, and they used
every exertion to extinguish the fire; but, owing to the difficulty
of raising a sufficient supply of water to the top of the building,
and the dryness of the internal timber, they soon found their efforts
vain, and as the fire increased in force, were compelled to retreat
downwards from stage to stage.
[26] It is obvious that this could never have happened had the modern
regulation been in force which forbids the lantern, after the light is
once exhibited, being left without the presence of a keeper.
Early in the morning the fire was descried by some fishermen, who
carried the news ashore, and a well-manned boat was immediately
dispatched to the relief of the poor keepers.
It reached the Eddystone at ten o’clock, when the fire had been burning
eight hours. The light-keepers had been driven from the building to
avoid the falling beams, and molten lead and red-hot iron; and were
found, stupefied with terror, in a cave on the east side of the rock.
With difficulty they were removed into the boat, and carried ashore. No
sooner were they landed than one of them, strange to say, immediately
made off, and was never afterwards heard of. So singular a circumstance
naturally engendered a suspicion that he had originated the fire; but
when we remember that a lighthouse affords no means of retreat for its
inmates, and that the probability is they will perish with it, we can
barely believe it to be the place which an incendiary would choose
for his nefarious design. As Smeaton says, we would rather impute the
man’s sudden flight to that kind of panic which sometimes, on important
occasions, overpowers a weak mind; making it act without reason,
and influencing it to commit unwittingly the most preposterous and
injurious mistakes.
Of the other two light-keepers, one, named Henry Hall, met his death
in an extraordinary manner. While engaged in throwing some buckets of
water on the flaming roof of the cupola, he happened to look upwards,
and a quantity of lead, melted by the heat, descended suddenly from
the roof, and fell on his head, face, and shoulders, burning him
severely. His mouth was open at the time, and he persisted in declaring
that a portion of the lead had gone down his throat. The medical
practitioner who attended him after his removal ashore not unnaturally
regarded the story as incredible; but the man continued to grow worse,
and on the twelfth day of his illness, after some violent spasms,
expired. A post-mortem examination of his body was then made, and the
poor man’s assertion found to be literally true, for in the stomach lay
a flat oval piece of lead seven ounces and five drachms in weight.
* * * * *
Before we quit the subject of Rudyerd’s Lighthouse, we must refer to
another romantic narrative of which it was the scene.
For some years after its establishment it was attended by two
custodians only, whose duty it was to keep the windows of the lantern
clean, and who were on guard for four hours alternately. Each at
the conclusion of his watch was bound to call the other, and before
he retired, to see that his successor took up his proper post. It
happened, however, that, on one occasion, when the keeper on duty went
to call his colleague, he found him—dead. Immediately he hoisted his
flag on the balcony, from whence it was visible at the Rame Head, near
Plymouth, and waited eagerly for the assistance this signal usually
brought. Unhappily, the weather became so boisterous that no boat
could put out from the shore, and the lonely keeper was reduced to the
miserable companionship of a dead body. It is difficult to conceive of
any situation more wretched or alarming; he dared not dispose of the
corpse; for if he flung it into the waves—his only means of getting
rid of it—he justly feared that he might be charged with the murder of
his companion; and yet, each day that it remained, his own life was
endangered by its extremely offensive condition. For nearly a month
this long agony lasted. When, at last, a boat succeeded in reaching the
rock, the building was found to be filled with an intolerable odour,
and the corpse in such a condition that it was impossible to remove it
to Plymouth for interment; it was therefore consigned to the deep.
This incident led to the employment thenceforward of three keepers, so
that in case one of them died, or was sick, there might always be two
on duty.
* * * * *
The value of a lighthouse on the Eddystone had been so abundantly
proved, and, owing to the rapidly increasing commerce of the kingdom,
its necessity was now so absolute, that the authorities resolved
to lose no time in erecting a new one in the place of Rudyerd’s
unfortunate structure.
As on the two previous occasions, says Mr. Smiles, when, first,
a country gentleman, and, next, a London mercer, had been called
upon to undertake this difficult work, the person now appointed was
neither a builder, an architect, nor an engineer, but a mathematical
instrument maker. John Smeaton, however—to whom the difficult task was
entrusted—had already given proof of a signal capacity for mechanics,
and in the general estimation of scientific men no better or more
fortunate selection could possibly have been made.
At this time Smeaton was only thirty-two years of age, having been
born at Ansthorpe Lodge, near Leeds, on the 8th of June 1724. His
father was a respectable attorney, but, from his earliest youth, John
Smeaton had exhibited a natural predisposition for the engineer’s
business. In truth, he was a mechanic born; in his childhood his
playthings were mechanical tools; and before his sixth year he had
designed a windmill and the model of a pump. He was sent to school at
Leeds, but seems to have made no progress in any other branches than
geometry and arithmetic. He occupied his holidays with mechanical
pursuits, and on one occasion constructed a forcing-pump, which
exhausted all the water in his father’s fish-pond. At the age of
fourteen he was an adept at smithery and turnery. He forged his iron
and steel, and melted his metal. Tools had he in abundance, and of
every kind, for working in metals, wood, or ivory. What was to be done
with such a lad? His father wished him to be a “gentleman,” and follow
his own profession; Smeaton was content to become an “operative,”
and apprenticed himself to a mathematical instrument maker. He soon
attained to such proficiency, that, in 1750, he commenced business on
his own account. In 1751 he invented a machine to measure a ship’s
way at sea, as also a compass of peculiar construction. Enlarging the
range of his studies, he submitted to the Royal Society, in 1752, some
improvements which he had contrived in the air-pump, and experiments on
the natural power of water and wind to turn mills and other machines
dependent on circular motion.
Such was the man—ingenious, able, earnest, patient, and persevering—to
whom was entrusted the erection of the _third_ lighthouse upon the
Eddystone rock.
On examining into the nature of the work he was required to undertake,
his first conclusion was, that both Winstanley’s and Rudyerd’s
lighthouses had been deficient in want of _weight_, and he announced
it as his intention to build a structure of such solidity that the sea
should give way to the lighthouse, and not the lighthouse to the sea.
He therefore resolved to build it of stone.
His predecessors had lost much valuable time from the difficulty
of landing on the rock, and of working on it continuously for any
considerable period. To obviate this, Smeaton decided on mooring a
vessel within a quarter of a mile of it, which should accommodate the
workmen and their tools, and enable them to seize every favourable
opportunity of putting out their boat and carrying their materials to
the Eddystone, instead of making a long voyage from Plymouth on each
occasion.
With respect to the _form_ of his intended erection, he resolved
to adopt Rudyerd’s idea of a cone, but to enlarge the diameter
considerably, and, on the whole, to keep before him as a model the
trunk of a stately oak tree.[27]
[27] This is Smeaton’s own statement, but the reader is referred, for
Mr. Alan Stevenson’s view of it, to p. 98.
* * * * *
The first actual work done on the rock was in August 1756, but the
autumn was mainly occupied in the transportation and preparation of the
granite and other materials, and in excavating the steps or stages for
the reception of the foundation.
Early in June 1757 Smeaton resumed his task with great energy and
decision. On the 12th, the first stone was laid, weighing two tons and
a quarter. On the next day the first course was finished, consisting
of four stones. These were ingeniously dove-tailed together, and into
the rock, so as to form a compact mass, from which it was impossible to
separate any particular stone. The sloping form of the rock, remarks
Mr. Smiles,[28] to which the foundation of the building was adapted,
required but this small number of stones for the first course; the
diameter of the building increasing until it reached the level of the
rock. Then the second course, completed on the 30th of June, consisted
of thirteen stones; the third, completed on the 11th of July, of
twenty-five pieces; the fourth, on the 31st, of thirty-three. The
sixth course was finished on the 11th of August, and rose above the
general wash of the tide, so that Smeaton might fairly consider he had
surmounted the greatest difficulties of his task.
[28] Smiles, “Lives of the Engineers,” ii. 38.
Up to this level, the highest point of the rock, all the courses had
been begun by the stones that were securely dove-tailed into the rock,
and also made fast by oak wedges and cement. To receive these wedges, a
couple of grooves were cut in the waist of each stone, from the top to
the bottom of the course, an inch deep and three inches wide. We borrow
from Smeaton’s own narrative his description of the manner in which
each stone was laid:—
“The stone to be set being hung in the tackle, and its bed of mortar
spread, was then lowered into its place, and beaten with a heavy wooden
mall, and levelled with a spirit-level; and the stone being accurately
brought to its marks, it was then considered as set in its place. The
business now was to retain it exactly in that position, notwithstanding
the utmost violence of the sea might come upon it before the mortar
was hard enough to resist it. The carpenter now dropped into each
groove two of the oaken wedges, one upon its head, the other with its
point downwards, so that the two wedges in each groove would lie heads
and points. With a bar of iron about two inches and a half broad, a
quarter of an inch thick, and two feet and a half long, the ends being
square, he could easily (as with a rammer) drive down one wedge upon
the other; very gently at first, so that the opposite pairs of wedges,
being equally tightened, they would equally resist each other, and the
stone would therefore keep place. A couple of wedges were also, in like
manner, pitched at the top of each groove; the dormant wedge, or that
with the point upward, being held in the hand, while the drift-wedge,
or that with its point downward, was driven with a hammer. The whole
of what remained above the upper surface of the stone was then cut off
with a saw or chisel; and, generally, a couple of thin wedges were
driven very moderately at the butt-end of the stone; whose tendency
being to force it out of its dove-tail, they would, by moderate
driving, only tend to preserve the whole mass steady together, in
opposition to the violent agitation that might arise from the sea.”
When the stone was firmly secured, the next step was to liquefy a
certain portion of mortar; and the joints having been carefully
pointed, up to the upper surface, this mortar or cement was poured in
with iron ladles so as to occupy every empty space. The more consistent
parts of the cement naturally fell to the bottom, and the watery were
absorbed by the stone; the vacancy thus left at the top was repeatedly
refilled, until all remained solid; then the top was pointed, and,
where necessary, defended by a layer of plaster.
The whole of the foundation having thus been elevated to a proper
level, some other means was required to obtain a similar amount of
security for the substructure.
A hole of one foot square was accordingly cut right through the middle
of the central stone in the sixth course; and at equal distances in
the circumference were sunk eight other depressions of one foot square
and six inches deep. A strong plug of hard marble, from the rocks near
Plymouth, one foot square, and _twenty-two inches_ long, was set with
mortar in the central cavity, and driven firmly into it with wedges. As
this course was _thirteen inches high_, it is evident that the marble
plug which reached through it rose _nine inches_ above the surface.
Upon this was fixed the central stone of the next course, having a
similar bore in its middle, bedded with mortar, and wedged as before.
By this means, no force of the sea acting horizontally upon the central
stone, unless it was able to cut in two the marble plug, could move
it from its position; and the more effectually to prevent the stone
from being lifted, in case its bed of mortar should chance to be
destroyed, it was fixed down by four trenails. The stones surrounding
the central were dove-tailed to it in the same manner as before, and
thus one course rose above another, with no other interruption than the
occasional violence of the waves or inclemency of the weather.
In every stage of the laborious and difficult work Smeaton himself was
foremost. When it had proceeded so far as to present the appearance
of a level platform, he could not deny himself the gratification of
enjoying the limited promenade which it afforded; but making a false
step, and being unable to recover himself, he fell over the brink
of the work, and among the rocks on the west side. The tide having
retired, he sustained no very serious injury; but he dislocated his
thumb, and as no medical assistance could be procured, set it himself,
and returned to his work. The incident is characteristic of the courage
and tenacity of the man.
* * * * *
The ninth course was laid on the 30th of September, and the weather
becoming boisterous, further operations were suspended for that year.
The following winter was very tempestuous, and it was the 12th of
May before Smeaton and his workmen again saw the Eddystone. To their
delight and surprise they found the entire work in the same condition
as when they left it. The cement appeared to have become as hard as the
stone itself, the whole being concreted into one solid mass.
Thenceforward the work made vigorous and successful progress, and,
by September, the twenty-fourth course was reached and laid. This
completed what is called “the Solid” part of the building, and formed
the floor of the store-room; so that Smeaton had no reason to be
dissatisfied with the operations of the season. But as he had long been
meditating on the advantage to the public which would accrue if a light
could be exhibited that very winter, he resolved on a vigorous effort
to complete the store-room and erect a light above it.
The building, says an accurate authority,[29] had hitherto been carried
up solid as high as there was any reason to imagine it would be
subjected to the heavy rush of the sea; that is, to 35 feet 4 inches
above its base, and 27 feet above the top of the rock, on the common
spring-tide high-water mark. At this elevation it was reduced to 16
feet 8 inches diameter; and it was needful to make the best use of this
space, and economize it to the utmost advantage consistent with the one
primary and indispensable condition of _strength_. The rooms were built
with a diameter of 12 feet 4 inches, having for the walls a thickness
of 2 feet 2 inches. These walls were made of single blocks, and so
shaped that a complete circle was formed by sixteen pieces, which were
cramped together with iron, and also secured to the lower courses by
marble plugs as before. To prevent any humidity penetrating through
the vertical joints, flat stones were introduced into each, in such
a manner as to be lodged partly in one stone and partly in another.
With all these ingenious precautions, the twenty-eighth course was
completely set on the 30th of September.
[29] “Smeaton and Lighthouses” (edit. 1844), pp. 57, 58.
This, and the next course, received the vaulted floor, which formed
at once the _ceiling_ of the store-room, and the _floor_ of the upper
store-room. For additional security, therefore, a groove was cut round
the upper surface of the course, in which was lodged a massive chain
of iron. Upon this chain, in the groove, melted lead was poured, until
the cavity was filled up. The next course was laid and completed in a
similar manner; and by the 10th of October Smeaton had nearly perfected
his arrangements for establishing a light and light-keepers at the
Eddystone, when his hopes were suddenly stricken by a prohibition from
the Trinity House, based upon legal difficulties. But this being at
last removed, the work was recommenced for the next and last season on
the 5th of July. On the 21st, the second floor was finished; on the
29th, the fortieth course was laid, and the third floor finished.
[Illustration: SMEATON’S LIGHTHOUSE AT THE EDDYSTONE.]
On the 17th of August 1759, the main column of the lighthouse was
completed. Forty-six courses of masonry had been laid, and the graceful
structure raised to its specified height of seventy feet. The last
work done, very appropriately, was the engraving of the words “Laus
Deo” (Praise be to God!) on the last stone set over the lantern. At
an earlier date, Smeaton, with devout humility, had inscribed on the
course beneath the ceiling of the upper store-room, “Except the Lord
build the house, they labour in vain that build it.” The iron-work
of the balcony and the lantern were next erected, and the whole was
surmounted by a gilt ball.
The internal arrangements of the lighthouse were as follow:—
First, the store-room, with a doorway, but no windows.
Second, the upper store-room.
Third, the kitchen, with a fireplace and sink, two settles with
lockers, a dresser with drawers, two cupboards, and a rack for dishes.
Fourth, the bedroom, with three cabin-beds, to hold one man in each,
with three drawers and two lockers in each to receive his separate
property.
Fifth, the lantern, in which a seat was placed all round, except at the
doorway.
* * * * *
Besides the windows of the lantern, ten other windows were constructed
for the edifice—namely, for the store-room two, and for each of the
upper rooms four. In fixing their bars, an accident happened to
Smeaton, which was nearly attended with fatal results.
“After the boat was gone,” he says, “and it became so dark that
we could not see any longer to pursue our occupations, I ordered
a charcoal-fire to be made in the upper store-room, in one of the
iron pots we used for melting lead, for the purpose of annealing the
blank ends of the bars; and they were made red-hot altogether in the
charcoal. Most of the workmen were set round the fire, and by way of
making ourselves comfortable, by screening ourselves and the fire
from the wind, the windows were shut; and, as well as I remember,
the copper cover or hatch put over the man-hole of the floor of the
room where the fire was—the hatch above being left open for the heated
vapour to ascend. I remember to have looked into the fire attentively
to see that the iron was made hot enough, but not overheated: I also
remember I felt my head a very little giddy; but the next thing of
which I had any sensation or idea was finding myself upon the floor of
the room below, half drowned with water. It seems that, without being
further sensible of anything to give me warning, the effluvia of the
charcoal so suddenly overcame all sensation, that I dropped down upon
the floor; and had not the people hauled me down to the room below,
where they did not spare for cold water to throw in my face and upon
me, I certainly should have expired upon the spot.”
Escaping this and other perils, Smeaton saw his beautiful edifice
finally brought to completion; and on the 16th of October a light was
once more shown from the Eddystone rock.
The lighthouse has now, as Mr. Smiles remarks, withstood the storms of
upwards of a century—a solid monument to the genius of its architect
and builder. Sometimes, he says,[30] when the sea rolls in with more
than ordinary fury from the Atlantic, and the billows are driven up the
Channel by the force of a south-west wind, the lighthouse is enveloped
in spray, and its light momentarily obscured. But the shadow passes,
and once more it beams across the waters like a star, a signal and
a warning to the homeward bound. Occasionally, when a strong wave
strikes it, the central portion of the wave shoots up the perpendicular
shaft and leaps quite over the lantern. At other times, a colossal
billow hurls itself upon the lighthouse, as if to shake it from its
foundation; and to its inmates the shock is like that of a cannon;
the windows rattle, the doors jar, and the building trembles to its
very base. But the vibration felt throughout the lighthouse on such an
occasion, instead of being a sign of weakness, is the best evidence
that can be desired of the unity of the fabric and the cohesion of all
its parts.
[30] Smiles, “Lives of the Engineers,” ii. 45.
* * * * *
When the Eddystone was built, scarcely any other light guided the
mariner in his intricate navigation of the Channel; but now it is
abundantly illuminated along its whole extent, and its course is
almost as easily tracked as that of a main thoroughfare in London.
First comes the St. Agnes Light, on one of the Scilly Isles, revolving
every minute, at an elevation of 138 feet above high water. Next are
made the two Lizard Lights, which crown the rugged cliffs at the
southernmost point of the English coast. In the deep curve between this
bold headland and the craggy promontories of Bolt Head and Start Point,
lie the revolving light on St Anthony’s Point, and the two lights on
Plymouth Breakwater; while out at sea, almost in front of Plymouth
Sound, and midway between the Lizard and the Start, the waves beat and
swirl around the Eddystone. On Start Point there are two lights: one
revolving, for the Channel; and another fixed, to guide ships inshore
clear of the Skerries.
[Illustration: THE LIGHTSHIP AT THE NORE.]
Continuing our voyage up Channel, we see on the south, off the coast
of Jersey, the three Casquet Lights, and on the north the two fixed
lights of Portland Hill. If we make for Portsmouth, we are guided by
the light on the outermost Needle Rock and the harbour signals; but
keeping out at sea, we pass St. Catherine’s, on the extreme southerly
headland of the Isle of Wight, and next, the lights displayed at
different heights on the Nab, and the single fixed light on the Owers
vessel.
At Beachy Head the light, which revolves in two minutes, is 285 feet
above high water. At Dungeness, the light, a red one of great power,
is situated on the low projection of Dungeness beach. Next are sighted
the harbour lights of Folkestone and Dover; whilst on the French coast
beams the flashing light of the Varne Bank, and the splendid revolving
light of Cape Grisnez.
We quit the Channel with the South Foreland Lights, one above the
other, on our left, and enter the historic waters of the Downs—so
often traversed by the keels of our victorious fleets—with the South
Sandhead floating light on the right. Then, on the one hand, our course
is guided by the floating lights of the Gull and the North Sandhead—on
the other by the friendly ray of the North Foreland lighthouse—until we
reach the broad estuary of the Thames, where the lightship of the Nore
marks the entrance of the greatest marine highway in the world.
[Illustration]
[Illustration]