No stir in the air, no stir in the sea,
The Ship was still as she could be;
Her sails from heaven received no motion,
Her keel was steady in the ocean.
Without either sign or sound of their shock,
The waves flow’d over the Inchcape Rock;
So little they rose, so little they fell,
They did not move the Inchcape Bell.
The Abbot of Aberbrothok
Had placed that bell on the Inchcape Rock;
On a buoy in the storm it floated and swung,
And over the waves its warning rung.
When the Rock was hid by the surge’s swell,
The Mariners heard the warning Bell;
And then they knew the perilous Rock,
And blest the Abbot of Aberbrothok.
The Sun in heaven was shining gay,
All things were joyful on that day;
The sea-birds scream’d as they wheel’d round,
And there was joyaunce in their sound.
The buoy of the Inchcape Bell was seen
A darker speck on the ocean green;
Sir Ralph the Rover walk’d his deck,
And he fix’d his eye on the darker speck.
He felt the cheering power of spring,
It made him whistle, it made him sing;
His heart was mirthful to excess,
But the Rover’s mirth was wickedness.
His eye was on the Inchcape Float;
Quoth he, “My men, put out the boat,
And row me to the Inchcape Rock,
And I’ll plague the Abbot of Aberbrothok.”
The boat is lower’d, the boatmen row,
And to the Inchcape Rock they go;
Sir Ralph bent over from the boat,
And he cut the Bell from the Inchcape Float.
Down sunk the Bell with a gurgling sound.
The bubbles rose and burst around;
Quoth Sir Ralph, “The next who comes to the Rock
Won’t bless the Abbot of Aberbrothok.”
Sir Ralph the Rover sail’d away,
He scour’d the seas for many a day;
And now grown rich with plunder’d store,
He steers his course for Scotland’s shore.
So thick a haze o’erspreads the sky
They cannot see the sun on high;
The wind hath blown a gale all day,
At evening it hath died away.
On the deck the Rover takes his stand,
So dark it is they see no land.
Quoth Sir Ralph, “It will be lighter soon,
For there is the dawn of the rising Moon.”
“Canst hear,” said one, “the breakers roar?
For methinks we should be near the shore.”
“Now, where we are I cannot tell,
But I wish we could hear the Inchcape Bell.”
They hear no sound, the swell is strong;
Though the wind hath fallen they drift along,
Till the vessel strikes with a shivering shock,
“Oh Christ! it is the Inchcape Rock!”
Sir Ralph the Rover tore his hair;
He curst himself in his despair;
The waves rush in on every side,
The ship is sinking beneath the tide.
But even in his dying fear
One dreadful sound could the Rover hear,
A sound as if with the Inchcape Bell,
The Devil below was ringing his knell.
1820.
No. III.
[Sidenote: Light-house Duties.]
ABSTRACT ACCOUNT of LIGHT-HOUSE DUTIES, furnished to the COMMITTEE of
the HOUSE of COMMONS, in reference to the Bell Rock Act.
“ABSTRACT STATE of ADDITIONAL DUTIES that will arise from the District
to be included in the Collection by the Erection of a Light-House on
the Cape or Bell Rock; calculated from the Custom-House Returns, 13th
May 1806, at the rate of 1½d. _per_ ton, whether Outwards or Inwards.
‘ 1804.{ Foreign, { Inwards, 93,782
{ { Outwards, 67,633
{ Coastways, { Inwards, 239,037
{ { Outwards, 170,174 Tons.
------- 570,626 L. 3566 8 3
‘ 1805.{ Foreign, { Inwards, 81,123
{ { Outwards, 73,289
{ Coastways, { Inwards, 259,997
{ { Outwards, 203,564
------- 617,973 3862 6 7½
‘ 1806.{ Foreign, { Inwards, 97,205
{ { Outwards, 86,739
{ Coastways, { Inwards, 270,737
{ { Outwards, 215,637
------- 670,318 4,189 9 9
--------- -----------------
Total of three years, 1,858,917 L. 11,618 4 7½
“The tonnage of the ports of the Firth
of Forth, already pay ½d. _per_ ton
for Inchkeith light, so that the
additional duty payable by them, will
be only one penny _per_ ton, the total
tonnage thus paying ½d. is, for the
whole three years, 971,482.
Deduct, therefore, ½d. _per_ ton for
this amount, L. 2023 18 5
Deduct also expences of collection,
and the charges of management, say
15 _per cent._ 1742 14 9
--------- 3766 13 2
-------------
“Nett total for three years, L. 7851 11 5½
-------------
“Nett yearly total L. 2617 3 9½
(Signed) “C. CUNINGHAM,
Secretary to the Commissioners of the Northern
Light-houses.”
_Note._--The District of coast referred to in the above Abstract,
lies between Peterhead, in Aberdeenshire, towards the north, and
Berwick-upon-Tweed, to the south, both inclusive.
No. IV.
[Sidenote: Relative Reports.]
Containing REPORTS relative to the BELL ROCK LIGHT-HOUSE, addressed
to the COMMISSIONERS of the Northern Light-houses, by JOHN RENNIE and
ROBERT STEVENSON, Civil Engineers.
REPORT by Mr Stevenson.
_Edinburgh, 23d December 1800._
During the reign of his present Majesty (George III.), a spirit for
discovery and improvement, in maritime affairs, has been pursued
with the greatest energy, and crowned with a success, which can only
be equalled by the happy effects that have followed to commerce. In
proportion, therefore, as the pursuits of the navigator are considered
essential to the wealth of the community, every effort to Assist
him, in his course through the pathless ocean, must be regarded both
as the call of interest and humanity. The most prominent causes of
the perfection to which coasting-navigation has been brought, may be
ascribed to the accuracy of our charts, and an increase of land-marks,
by which the mariner, after braving the dangers of the seas, is enabled
to guide his ship with safety into her intended port. It is well
known, that before the Maritime Survey of the Orkneys and Hebrides,
by Mackenzie; and until an act of Parliament was passed, appointing
Commissioners for erecting Light-houses upon the coast of Scotland,
mariners were left to grope their way from the Firth of Forth to the
Firth of Clyde, without the assistance either of proper charts or
land-marks. Under these circumstances, they passed the Pentland Firth ,
and generally held a course to the northward of the Orkney islands;
then steering westward, they sailed on the outward side of the Lewis
Isles into the Atlantic Ocean, exposed to many dangers, and unable
to avail themselves of the advantages of the sheltered sounds and
harbours of the Friths of Lewis and Uist. Hence the difficulty of
navigating this district, was long a great bar to the improvement of
the Highlands, and to the extension of the British fisheries. It was,
likewise, a material drawback to the present flourishing trade, carried
on through these sounds to the Baltic and other parts of the northern
Continent of Europe.
From the earliest accounts which tradition gives of the navigation of
the Firth of Forth, a Light-house upon the Bell Rock appears to have
been looked forward to as an essential pre-requisite to the advancement
of its commerce: And in proportion to the extent of the one, the call
for the other has become more and more urgent, and is now regarded as a
matter of the greatest importance.
Since the publication of Adair’s Charts, there has been no want of a
survey of the Firth of Forth; but this important estuary still remains
extremely deficient with regard to land-marks, and the reporter will
venture to say, that there is not any where a more dangerous reef in
the kingdom, or one that calls more loudly for something to be done,
than the Cape or Bell Rock. When, therefore, the extensive benefits
derived from those powers, which have enabled the Commissioners of
the Northern Light-houses to erect and maintain six Light-houses upon
the coast, are considered, it is much to be wished that some measure
were adopted for enabling that Board to add to the number of these
land-marks, by the erection of one upon this most destructive rock.
From the numerous losses by shipwreck, which have happened upon the
Bell Rock, it is presumed, that some account of its position and
extent, from actual survey,--a few remarks upon the description of
building best suited to the situation of the rock,--together with an
attempt to point out the extensive use of such a light,--and the ports
which appear to be within the limits of any duty to be levied for its
support, will not be deemed unnecessary at a time when the public look
forward, with anxious expectation, to this Board, in a matter of so
much importance, not only to the navigation of the Firth of Forth, but
in general, to the eastern coast of Great Britain.
Having finished a design and model of a pillar-formed light-house for
the Bell Rock, immediately after the very fatal storm which occurred
in the month of December 1799, the next object of the Reporter, was to
survey the rock itself, that he might judge more fully of its fitness
for the situation. Accordingly, in the month of April following, he
set off for the rock, and had reached Fifeness, when, from the state
of the weather, he was obliged to return, after an absence of ten
days, without accomplishing his purpose. Soon after his return from
his annual voyage to the Northern Light-houses, Mr Gray, secretary for
the Commissioners, requested of the Board of Customs to grant the use
of one of its yachts, to make another attempt. An order having been
accordingly obtained for the Osnaburgh cutter, Captain Campbell, then
lying at the Elie, the reporter, accompanied by his friend Mr James
Haldane, architect, set off for that place. But the Osnaburgh being
then under repair, and the period of spring-tides being at hand, it
was found advisable to proceed along the coast to West-haven, on the
northern side of the Firth of Tay; and upon Sunday the 5th of October
1800, a landing was effected upon the Rock, and an ample opportunity
afforded of gaining all necessary information.
The Bell Rock, as appears by the best charts of the coast, is situated
at the mouth of the Firth of Forth, in west longitude 2° 22´, and north
latitude 56° 29´. It lies nearly fifteen miles from the Island of May,
in a north-eastern direction _per_ compass, and twelve miles south-west
from the Red-head in Angusshire, which it resembles, being a free-stone
of a reddish colour, though of a much harder body, and closer grit.
Besides its natural asperities, the surface in general is thickly
coated with sea-weed, and, on the higher parts, the barnacle, white
buckie or whelk, and limpets, abound, and altogether it presents a very
rugged appearance, owing to the sloping of the strata from south,
where highest, to north, at an angle of about 30 degrees. The material
part of the rock, which lies north-east and south-west, measures, on
an average, about 300 feet in length, and 240 feet in breadth. The
highest part above the surface of the sea, does not exceed seven feet
at low-water of spring-tides; which part, at high-water of same tides,
is from nine to ten feet under water. The reporter also found, that the
medium height of the foundation of any building erected upon it, will
not exceed two or three feet above the surface of the sea at low-water
of spring-tides. The above dimensions may be termed the material part
of the rock; but, south-west of this, there runs a reef or shoal, of
considerable extent, which is only visible in very low tides.
The short time which the Bell Rock is seen above water, and the
irregularity of the soundings in its vicinity, are the cause of many
wrecks upon it. Indeed, after the water has flowed, in ordinary tides,
but a very short time, the most skilful mariner cannot point out its
place, without its proper meaths or land-marks in sight, which lie
from twelve to twenty miles distant. Under these circumstances, the
Bell Rock will be found more dangerous to vessels coming near it, than
perhaps any of those reefs upon which Light-houses have as yet been
erected.
The Edystone Rock, for example, is about eleven miles from land,
situate at the entrance of Plymouth Sound. Before the rock was reduced
for the foundation of the Light-house, it was about three feet above
high-water of spring-tides. The Longships Rock, situate three miles
off the Lands-End, is about forty feet above high-water mark, though
barely large enough for the foundation of the Light-house. The
Smalls lie fourteen miles off St David’s Head; and the rock on which
the light-house is built, is about five feet above high-water of
spring-tides. The South Rock, lying three miles off the land, between
Loch Strangford and Donaghadee, is about four feet under the surface
at high-water of spring-tides. The Tour de Corduan, upon the coast of
France, is built upon a sunken rock at the entrance of the Garonne,
and is said to be about eight feet under the surface of the sea at
high-water of spring-tides. And, lastly, the Bell Rock, the subject of
this report, lying upwards of eleven miles from land, is from nine to
ten feet under water, as before stated.
Ever since the reporter had an opportunity to know the danger and
inconvenience that must attend the navigation of the Firth of Forth,
while the Bell Rock remains without some signal upon it, to forewarn
seamen, he has been much employed in considering what kind of building
would be most applicable to its situation; and he has, therefore,
endeavoured to obtain as much information as possible about works of
this kind. The first light-house erected upon an insulated rock on
the coast of Great Britain or Ireland, appears to have been that of
the Edystone, which was begun in 1696, and was scarcely finished,
when a dreadful storm carried it completely away. This erection
was constructed of timber, and was designed and executed by Mr
William Winstanly, who, with his artificers and the light-keepers,
unfortunately perished in its ruins. The next light-house that was
built upon the Edystone Rocks, consisting partly of stone and partly
of wood, it was finished in 1709, and was the work of Mr John Rudyard,
who, carefully avoiding the errors of his predecessor, lopped off all
superfluous ornaments, and produced a plain building; which, after
withstanding the fury of the waves for forty-nine years, had the
misfortune to be destroyed by fire. The present Edystone Light-house
was begun in 1756, and finished in 1759. It has now stood forty-four
years, a memorial of the ingenuity and indefatigable labours of Mr John
Smeaton, who, guarding against the defects of the two former buildings,
constructed the whole of stone; the blocks of the solid part are
curiously dove-tailed into each other; and every thing unnecessarily
tending to give resistance to the water is carefully avoided, while
the whole is completely fire-proof. The next light-house erected upon
a situation of this kind, was the Smalls, which is placed upon eight
beams of oak, arranged round a centre one. The latest light-house
built on an insulated situation, is that upon the South Rock on the
coast of Ireland. The reporter made three successive journeys to this
light-house, during its progress: First in 1796, when it was only 12
feet in height; again in 1797, when it was nearly finished; and a
third time in the month of August 1800. This light-house is built of
granite, quarried in the mountains of Morne. The method of dove-tailing
or joggling the stones, and attaching the courses to each other, is
different from that of the Edystone; throughout the solid part of the
masonry, and eighteen inches within the circumference of the building,
six great bars of malleable iron are carried up, each four inches
square; and upon the top of every alternate course, a circular plate
of iron is let into the stone, and fixed by spear-bolts to the upright
bars. The building is of a conical figure, and was built in the course
of three years from a design by Mr John Rodgers of Dublin.
Before being properly certified as to the possibility of getting a
foundation for a building of any kind upon the Bell Rock, the reporter
thought of a Floating-light, like those moored off the Dudgeon-shoal,
and other sand-banks on the coast of England. But the foulness of the
ground about the Bell Rock, the great depth of water near it, together
with the unsteadiness of a light of this description,--and above all,
the perplexing uncertainty which must ever attend such a light in
a storm, cannot fail to unhinge the confidence of the mariner, and
thereby prevent him from making free with his course; and when, from
an error in it, or in the distance run, he is disappointed in seeing
the light, wrong conclusions are apt to be formed: he supposes that the
Floating-light has drifted, and by changing his course, perhaps turns
upon the very point of danger. These were considerations from which
much relief was felt, upon learning that the rock was large enough to
form the foundation of a permanent building; but, till the moment he
landed upon it, he was uncertain if a building of stone was applicable;
and foreseeing the difficulties which would be avoided, if, instead of
carrying up the lower part solid, it could be formed of pillars, after
the manner of the Smalls Light-house; reflecting also upon that elegant
and useful application lately made of cast-iron, in the construction of
bridges, choice was made of this metal, in his first model for the Bell
Rock, as being more substantial than timber, and also less liable to
corrosion from the action of the atmosphere than malleable-iron. This
light-house (see Plate VII.), was to consist of six hollow tubes or
pillars, built each to the height of ninety feet, measuring two feet in
diameter at the base, and diminishing to six inches at the top, ranged
round a common centre so as to form a diameter of thirty-five feet at
the base, and eight feet at the top, immediately under the light-room.
The pillars were to be cast in lengths or pieces of ten feet each; and
at every joint horizontal bars were made to grasp the pillars, and the
whole was also connected diagonally with various cross braces. Under
the light-room, the building was to be laid out into four heights of
apartments for the light-keepers and stores, formed within the range of
the pillars, which occupying 45 feet of their height, the part below
being of similar height, was left free for the passage of the sea, thus
presenting the least possible resistance to the waves. These apartments
were to be formed and covered in with strong copper, which, to prevent
its acting upon the iron, was to be coated with tin. The lower part,
or floor nearest to the sea, was to form an inverted cone, presenting
a surface calculated to disperse the seas which might strike against
it. In order still more to increase the common base, and strengthen
this fabric, Professor Robison advised that a diagonal bar should be
attached to the exterior side of each of the pillars.
In this first design, provision was made chiefly against the impulse
of the sea, without taking into account the possibility of a vessel
or wreck getting near it; but he found, after landing upon the rock,
that it was possible for a vessel at high-water to come, without
interruption, against the pillars. To guard against misfortune from
this quarter, the reporter first thought of defending the pillars in
various ways, particularly by throwing a kind of _Chevaux de Frise_
round them, with beams of oak. He, however, found it difficult to
suppose any set of pillars of adequate strength to resist the force
of a loaded vessel, violently agitated in a winter storm, which must
render the pillar-formed construction very uncertain, even after
every precaution should be taken to guard against such accidents. Nor
ought the danger to which such a mass of metal, constantly exposed to
the effects of the marine-acid, to be wholly overlooked, in giving
a preference to a circular building of stone, which being a compact
figure of solid matter, would resist any force that might be brought
against it. The reporter has estimated the Pillar-formed Light-house
at L. 15,000; and, although that for the Tower of masonry amounts to
L. 42,636, 8s., yet, as it is treading a beaten path, which leads to
certainty, it is surely to be preferred in a work of this kind: the
foundation-course of stone must be more tedious than that of so many
pillars, yet, in this there is nothing impracticable; and when the
difficulties of the first courses are surmounted, the superiority of a
fabric of stone over one of iron will readily be admitted.
In the model for a building of stone, made since the reporter first
landed upon the Bell Rock, he has retained nearly the same elevation
as that of the Edystone Light-house, which presents less resistance,
and preserves a greater base than perhaps any other figure that could
have been thought of. In this design he has also followed Mr Smeaton in
the use of oak-trenails to keep the stones in their places, while the
work is in progress; but has differed in the mode of diminishing the
interior-walls, as the building rises in height. Instead, also, of Mr
Smeaton’s plan of dove-tailing the stones, and connecting the floors,
various other modes are resorted to, for effecting this perpendicularly
as well as laterally, with the view of introducing larger materials,
and keeping the stones in a more entire state. One of these is by an
iron-bat, which is inserted into the joints of the lower courses, while
the void or upper courses are to be indented, or let perpendicularly
into one another. Upon inspection of the models and drawings of this
design, it will perhaps be found to render the construction more
simple, to divide the strength of the walls more equally, and, upon
the whole, to give that stability which the situation of the Bell Rock
seems so peculiarly to require. (See Plate VII.)
Upon comparing the pillar-formed Light-house, with the circular tower
of masonry, it is matter of surprise that ever the Smalls Light-house
should have been erected upon that plan, unless it were to avoid
the additional expence of a stone building. There is, however, one
circumstance which materially favours the pillar-formed construction
at the Smalls, the want of which becomes a principal objection to its
application at the Bell Rock; namely, that the Smalls Rock being five
feet above high-water of spring-tides, the pillars are more obviously
defended from injury in the event of a vessel or wreck coming against
them, and also from the violence of the sea, whereas the Bell Rock, at
certain periods of the tide, is from nine to ten feet under water.
When Mr John Rennie, civil engineer, obligingly favoured the reporter
by examining his models, he gave a decided preference to the structure
of stone, as did Professors Robison and Playfair. And Captain Huddart
also, upon seeing the pillar-formed model, mentioned that the
Trinity-House did not approve of iron pillars which, in the instance
of the Smalls, were considered not so proper as beams of oak. The
chief motives which induced the reporter to model a light-house upon
the plan of the Smalls, were the uncertainty of procuring a foundation
for a stone building; the small resistance which the pillars present
to the force of the waves, and the first cost being very considerably
less. But although this is true, with regard to the resistance, it must
also be remembered, that the pillars come prodigiously short of the
weight of a tower of masonry, of the dimensions of the one modelled,
containing upwards of 2000 tons; whereas the iron pillars, even in
their most improved state, do not exceed 200 tons. When, therefore,
the stone light-house is compared with the iron one, all idea of the
greater resistance of the former is lost in its solid contents, and in
the uniformity of its figure.
In alluding to the great utility of an erection on the Bell Rock, it
may, in general, be observed, that it is in the same degree of latitude
with the Town of Holstebro in Denmark, and that the Naze of Norway, or
entrance to the Baltic, lies north of Holstebro 1° 30´. It therefore
follows, that all vessels bound to the Baltic, from, any port south
of the River Tweed, must cross the latitude of the Bell Rock, while
the degree of east or west longitude, in which such vessels pass,
must depend upon the direction of the winds and other circumstances.
In order to avoid the enemy in the time of war, it is common for
shipping in this track, first to make the land about Buchanness in
Aberdeenshire, and from thence take their departure either over seas,
or along shore to their respective ports. With regard to ships bound
for Archangel and Greenland, they, at all times, make the Islands of
Shetland, and from thence take their departure. If, therefore, lines be
drawn from Buchanness and Girdleness in Aberdeenshire, to Flamborough
Head in Yorkshire, and the mouth of the Tyne in Northumberland, the
Bell Rock will only be found to lie from six to ten leagues distant
from these courses or lines. So that vessels crossing the mouth of the
Firth of Forth, from Buchanness to the Humber and Thames, &c., may
not only come in sight of a light upon this rock, but be materially
benefited by it, according to the state of the weather, while those
upon the course of the nearest line bound for Newcastle and Sunderland,
&c. must, in every voyage which carries them north of the Tweed, be
essentially served by a light upon the Bell Rock.
It further deserves notice in this place, that the principal estuaries
on the eastern coast of Great Britain, are those of the Friths of Moray
and Forth, and the Rivers Humber, and Thames. The most material general
purpose which would be answered by a Light upon the Bell Rock, is the
opening of the Firth of Forth as a place of safety, in storms from
south-east, east, and north-east. When mariners at sea are overtaken
with a gale under such circumstances, they make for the most contiguous
of these four inlets; but are often known to avoid the Forth, on
account of this Rock, which, like another Cerberus, guards its
entrance. Of this, a melancholy example occurred (which will long be
remembered with that regret which never fails to accompany the forlorn
case of the widow and fatherless), in that heavy gale at south-east,
which happened in the winter of 1799, and drove many vessels from their
moorings in Yarmouth Roads, put them past the Humber, and the crews
being afraid to make free with the Firth of Forth, even though the
wind was fair, were, with others, driven ashore between the Redhead
in Forfarshire, and Kinnaird Head in Aberdeenshire, to the number of
about thirty sail. Nor were they all saved that weathered Kinnaird
Head; several were wrecked in Orkney and Shetland; and the whole loss
occasioned by this gale has been stated as high as seventy sail, with
many of their crews! amongst which are reckoned two that were known to
have been lost upon the Bell Rock. This fatal catastrophe, of which the
history of our coast affords few examples, is the more to be lamented,
when it is considered that a light upon the Bell Rock, by opening the
way to a place of safety, would infallibly have been the means of
preventing much calamity, to those who sought safety, with various
fortune, in more northern latitudes. In conclusion, it may be observed,
that until this improvement of the coast comes from the Commissioners
of the Northern Light-houses, it is much to be feared that the cause
continuing, the sad effects will not cease.
(Signed) ROBERT STEVENSON.
To the Honourable the COMMISSIONERS }
of the Northern Light-houses. }
REPORT by Mr RENNIE.
_London, 30th December 1805._
GENTLEMEN,
In consequence of your directions, I set out in a vessel called the
Pharos, from Leith, on the 15th of August last, early in the morning,
in company with ROBERT HAMILTON, Esq. one of your Commissioners, and
Mr STEVENSON, your Engineer, to view the Bell or Cape Rock, for the
purpose of considering the practicability of building a Light-house
thereon. But, owing to the want of wind, we did not get near the Rock
till dusk, _i. e._ about half-past seven, which was near half ebb;
but although we were not above a mile distant, we could discover but
little of the rock itself. Its situation, however, was sufficiently
apparent, by the breakers upon it, which, although the sea was very
little agitated where we were, yet the waves were very high on the Rock
itself, breaking over it with considerable violence. We approached
within less than half a mile of it, and took soundings; but it becoming
dark, we judged it advisable to sail further off, and anchored about
a mile from the Rock all the night, in expectation we should be able
to land on it next morning, which, from the serene appearance of the
sky, we doubted not we should be able to effect. We had not dropped the
anchor long, when the little wind there was during the day ceased, and
it became a dead calm, but, notwithstanding this, there was a heavy
swell, and the vessel rolled much. Frequently, during the night, I
viewed the place where the Rock lies, and saw the heavy breakers which
played about it, till near three quarters flood, when they nearly
ceased, and no appearance of such a place was to be observed. They
commenced again about quarter ebb, and continued increasing for some
time; but, by nine in the morning, the sea became more smooth, and
about half-past nine, the rock appearing several feet above water, we
left the Pharos in a small boat, and had the satisfaction of landing on
it about half-past ten, a little before low water. The spring-tides,
however, were rather past their height, being five days after the full
moon. We landed on the north-east side of the Rock, in a little bay or
inlet, through some breakers, but these were just on the verge of the
Rock, for when we got in, the water was quite smooth.
The Rock lies in a direction nearly south-west and north-east, magnetic
bearing. That part which was dry, saving some small inlets, I found
to be about 280 feet long, and 220 feet wide. Its general surface was
about 4 feet above the level of low water, though some places were
about 6 feet high. The Rock, however, extends for some distance all
round that part which was dry, and dips downward. It extends under
the surface for about 400 feet on the south-west side, about 100 feet
on the north-east side, and about 50 on the south-east and north-west
sides; and on those parts the water is shallow. At about 300 feet
south-west, I found about 13 feet water, but, on account of the
breakers, could not sound on the low parts of the Rock, or either of
the other sides. At the extremities of the main Rock above mentioned,
the dip is sudden; the bottom, however, is rocky for a considerable
extent round its bed, but the water is deep.
The Rock itself is a hard red freestone, in beds dipping to the
south-east, about one in five; these beds are various in their
thickness, some being much greater than others; but, generally, well
connected together. Such parts as are not immediately exposed to the
violent wash of the waves, are coated with a hard crust, and covered
with limpets; and, indeed, when it is exposed to the full fury of
the sea, there seems to be little appearance of decay, so that I
have no doubt, were a Light-house constructed here, no fears need be
entertained for the durability of the Rock, as it seems to me well
calculated to resist the effects of the waves.
We remained on the Rock for about an hour and a half, when the tide
began to flow rather quickly, and having got all the necessary
measurements as to height and size, we left it, and returned to our
vessel, having been much gratified with the ample view we had of it,
and soon after our getting on board the vessel, we weighed anchor at
one, and the wind suiting, we arrived at Arbroath about four o’clock.
The Inch Cape, or Bell Rock, lies in West longitude 2° 22´; North
latitude 56° 29´, as stated by Mr STEVENSON. It is about eleven miles
distant from the harbour of Arbroath, about ten miles from the Bluff
Point of the Sands of Barry, at the northern side of the entrance to
the River Tay, and about eleven miles from the Red Head, which lies
between Arbroath and Montrose; so that in fact it is about the same
distance from the shore as the Edystone Rock, on which Mr SMEATON
completed a stone light-house in the year 1759. The soundings on the
south-west side, and near to this Rock, as taken at low water, were
about 7 fathoms, within half a mile of it; and, in the same direction,
about 15 fathoms, bottom rock. About three-fourths of a mile, 19 to 20
fathoms, bottom gravel. At the north-east side, and near to the Rock,
the soundings were 6 fathoms. About three-fourths of a mile north-west
of the Rock 15 fathoms, and about a mile and a quarter in the same
direction 18 fathoms. We did not take the soundings on any other side
of the Rock, or at a greater distance; but I was informed they were
full as much as those we had taken.
Such being the situation of the Cape or Bell Rock, lying nearly in
the direction which vessels generally take in sailing into the Firth
of Forth, from northerly directions, or out of it, in sailing to
the north or east, it is no wonder that many accidents should arise
in hazy weather or dark nights, there being no means of discovering
its situation correctly, unless when the land-marks are to be seen,
for the deep water lying so close all round the Rock, nothing can be
ascertained from soundings, until too near to enable vessels to get out
of the way. Breakers, no doubt, frequently point out its situation,
but these, in dark nights, and hazy weather, often are not sufficient,
and at high-water, even in good nights, are not always discernible;
for want of other means, many vessels have been wrecked thereon, and
numberless valuable lives and much property lost.
Vessels trading from the Humber, and northwards to the Baltic, to
Norway, Greenland, &c. are often, by stress of weather, driven towards
the coast, and even those from more southerly ports often share the
unfortunate fate of coasting vessels. It is therefore of the utmost
importance that something should be done to mark out the situation of
this dangerous and frightful Rock.
A Beacon has been proposed, but this would but ill answer the purpose.
Nothing, in my opinion, would do it effectually, except a Light-house;
and the question is, whether a Light-house could be built on this Rock,
and, if so, of what materials it should be composed, and which, in
point of strength and durability, are most likely to become a lasting
work, without which the mariner can never make free with his course.
Of all the works which could be erected here, perhaps a wooden
Light-house would be the cheapest. But were a wooden Light-house
to be constructed, I apprehend a solid base of stone must first be
constructed, similar to that built on the Edystone by Mr RUDYARD;
but wood is liable to decay; it would require constant repairs, and
would also be liable to be destroyed by fire, as that of Mr RUDYARD’S
was. A Light-house of cast-iron might also be constructed here, and
I will allow that it might have a coating of lead, or other metallic
substance, so as for a long time at least to resist the effects of
the marine acid. But to make a Light-house that would last of such
materials, would be nearly, if not wholly, as expensive as one of
stone, which I believe, I need scarcely say, no human ingenuity could
render as durable; and as the durability of such a work as this is of
the utmost consequence, I apprehend a moderate sum of extra expence
ought not to be looked on as an object of material consideration, when
put in competition with the advantages of durability. But, besides
these objections to a work constructed of wood or iron, vessels being
apt to be driven against it at high-water, there being at spring-tides
from nine to ten feet deep on the top of the Rock, and should the
vessel be a large one, and acted on by a heavy sea, it would not be
difficult to foretell the consequences.
The durability and efficacy of a stone Light-house has been proved in
the most satisfactory manner at the Tour de Corduan, near the mouth of
the River Garonne, on the coast of France; at the Edystone, off the
mouth of Plymouth Harbour, and in other situations. Why, therefore,
with such incontestible proofs before our eyes, should recourse be had
to a material new in itself for such purposes, and untried? a material
which, if fitted and joined together as it ought to be, would consume
nearly as much time in getting the lower part laid, as the laying of
three or four courses at the bottom of a stone Light-house, and when
the stone-work is got to the height of five or six feet above the
Rock, the greatest part of the difficulty may be said to be over; and
besides, such a solid mass of materials would resist any violent shock
of a vessel which might be brought against it by the sea. I have,
therefore, no hesitation in giving a decided opinion in favour of a
stone Light-house.
As to the practicability of erecting such a work on the Bell Rock, I
think no doubt can be entertained, with such examples before us as the
Tour de Corduan and Edystone before mentioned.--In the 4th volume of
the _Architecture Hydraulique_ of BELIDER, an account is given of the
Tour de Corduan. It is built on a low rocky island, dry at low water,
and whose surface is nearly level; it is covered at high-water, as near
as I can ascertain from his draughts and description, about 8 or 9
feet. It is exposed to a very heavy swell of the sea, lying quite open
to the Bay of Biscay, from whence it is well known very heavy swells
come, and beat against it with great fury; yet this Light-house has
resisted the fury of the waves for above 250 years.
The Edystone Light-house is built even in a more exposed situation than
that of the Tour de Corduan, and upon a rock whose surface is little
larger than the base of the Light-house itself. The top of this rock
is shelving, and was seldom covered by ordinary spring-tides before
Mr SMEATON began his foundation; the lower part, however, was always
covered over at the top of neap-tides. At the lowest place, when he
began his work, the rock was dry about six hours each tide, although
there the Edystone Rock is less in size than the Cape Rock, yet the
advantage of being so long dry, is greatly in favour of building a
Light-house; the most difficult and tedious part of the work being the
establishment of the four or five lower courses of the foundation.
The higher parts of the Cape Rock, as I have before stated, are little
more than six feet above the low water of an ordinary spring-tide.
But I apprehend, when a place sufficiently large for the foundation
is levelled, its surface will be little more than three and a half
feet above the low water of an ordinary spring-tide. I do not think
that above three hours’ time for work can be expected, which is about
half of what was got at the Edystone. The depth of the water all round
it, and its exposure to the German Ocean, renders it as difficult a
situation to construct a durable work upon as that of the Edystone, if
not more so. I doubt, therefore, more time will be required for the
work; but this depends so much on the state of the weather, that no
certain calculation can be made. It is better, therefore, to reckon on
a sufficient time, and this I would beg leave to state at four years;
and if it can be done in less time so much the better. The Rock upon
which the Edystone Light-house stands is certainly harder than the Cape
Rock, and of course required more time to work; but, on the other hand,
the Cape Rock lying in a more northerly latitude, and where the weather
is more variable, it is likely that greater interruption will be given
to the proceedings than in the other; so that, all circumstances
considered, the time I have mentioned, I doubt, will be little enough.
Mr STEVENSON, to whose merit I am happy to bear ample testimony, has
been indefatigable in obtaining information respecting this Rock, and
he has made a model of a stone Light-house, nearly resembling that
of the Edystone, in which he has proposed various ingenious methods
of constructing the work, by way of facilitating the operations. I
own, however, after considering these in the fullest manner I have
been able, and comparing them with the construction of Mr SMEATON’S, I
mean in the building, and also that there is undoubted proofs of the
stability of the Edystone, I am inclined to give it the preference.
No doubt some methods different from the Edystone will require to be
put in practice for the foundation; but its general construction, in
my opinion, renders it as strong as can well be conceived,--in fact,
it may be looked upon as a solid mass of rock. Viewing the matter,
therefore, in this light, it will be unnecessary for me to accompany
this Report with the design of a Light-house. It will be time enough
to make such a design, when the Commissioners shall be in a situation
to give orders for the erection, and then I have no doubt Mr STEVENSON
will furnish much valuable matter towards the perfecting of it.
The total height of the Edystone Light-house, from the lower course
of stones on the rock to the top of the platform or balcony-floor,
is about 70 feet; from thence to the bottom of the iron-frame of the
lantern about 6 feet 9 inches; and the lantern itself is about 8 feet
3 inches; so that the total height to the eve of the cupola is about
84 feet 6 inches. Now, as the Bell Rock lies so much lower than that
of the Edystone, I think the height of the shaft or tower of the
Light-house should not be less than 80 feet, or, perhaps, a little
more, say 85 feet; so that the cupola will, in this case, be about 100
feet above the surface of the rock. With such a height of Light-house
as is here proposed, I would advise that the diameter of the base
should be greater, and as it is less surrounded by such an extent of
rock, it will give facility to the gradual diminution of the effects of
the waves breaking upon it; will render the fabric more steady, and, as
it will diminish quickly, no great additional surface will be presented
to the sea.
The floor of the lower room, _i. e._ the height of the solid part
of the Light-house, I would propose to be about 50 feet, and from
thence to the top of the platform 35 feet, making a total height, from
the rock to the platform or gallery, of 85 feet. As to the lantern
itself, I need say little on that head, as lanterns for light-houses
have, of late years, been greatly improved, as well as the lights.
The substitution of lamps with reflectors, in place of coal or candle
lights, has been found of the greatest advantage to the mariner; and
it is not unlikely, from what I have been lately made acquainted with,
that the substitution of the hydrogen gas in place of lamps, will not
only prove a much cheaper, but a better light than even lamps. I am
told that it will not cost above one-eighth of the price of oil. The
kind of light to be used is also a matter of consideration, for unless
lights are so constructed as to enable the mariner to distinguish
between one and another, he may be apt to mistake his situation; but
that also can be easily arranged, when this part of the subject comes
to require consideration. The new light on the Skerries in Orkney is
a revolving one; perhaps a similar one may also be judged advisable
here, as, if the Light-house on the Island of May was to be fitted up
with reflectors in the usual manner, it would not always be easy to
distinguish this from the Cape Rock, unless one of them was to be made
a revolving, or the lights to be placed in different situations of the
house.
A Light-house has, of late years, been built on the South Rock, near
the mouth of Loch Strangford, on the coast of Ireland. This Light-house
was begun on the 11th of June 1795, and completed the 25th March 1797.
It is 30 feet diameter at the base, and about 15½ feet just below
the balcony floor. It is 56 feet high from the rock to the platform or
balcony floor, and its shape is the frustum of a cone. It is built of
granite from the Mountains of Morne; and the lantern, from the platform
to the cupola, is about 12 feet high, and 10 feet wide. The light is
a revolving one, and lighted by 10 lamps with reflectors, 3 in the
upper course, 3 in the lower course, and 4 in the middle, and makes
a revolution in five minutes. This distinguishes it from the Copland
lights.
The rock on which this Light-house stands is about 400 yards long, and
about 100 wide, and is covered about 18 inches deep at high-water,
ordinary spring-tides. The rock is composed of beds of schistus,
intermixed with beds of a kind of indurated clay, which are wearing
fast away by the washing of the sea; and, unless some speedy and
effectual means are taken to secure it, this Light-house will not be of
long duration. It has cost about L. 22,000, and it is said that L. 7000
more will be required to secure the rock from washing away. I will not
take upon me to say that this sum will be sufficient for the purpose;
but it seems to me that it will not be a very difficult matter to
secure the rock, if proper means are taken. The channel is here narrow,
and the seas cannot be very heavy; indeed MACCULLOCH the Light-house
keeper informed me, that they seldom rise above the first landing,
which is only about 27 feet from the top of the rock.
In the construction of a Light-house at the Cape Rock, great care
will be necessary in choosing stone of the most durable quality, fit
to resist the effects of the waves. For this purpose, I examined the
rocks lying along the shore nearest adjoining the Inch Cape Rock, but
found none of a very durable quality; most of it is a red freestone,
softer than the rock itself, which has been much worn away by the
wash of the sea, and therefore by no means fit for the exterior work
of such a building; and there does not appear to be any fit for that
purpose nearer than Kingoodie, about three or four miles from Dundee.
This stone is a hard millstone-grit, of an excellent quality; very
hard to work, but can be raised in blocks of any size and thickness
required. It therefore appears to me to be most fit for the exterior
work of a Light-house to be built on the Cape Rock; but as the price
the proprietor asks for it is very high, it becomes a question whether
the solid part of the building may not be done with the stone from
near Arbroath, which, although not fit for exterior work, is yet of
a pretty strong quality, and might be used in the solid part of the
building, not exposed to the weather or wash of the sea: Or, it may be
a question, whether the saving that would arise from using the stone
near Arbroath, is a consideration, when put in competition with the
superior strength and specific gravity of the Kingoodie stone.
Granite is also a stone that will resist the waves without wearing, and
it is therefore a matter of consideration, whether granite stone might
not be had from Peterhead or Aberdeen for this purpose. Granite, it is
true, cannot conveniently be had in such large blocks as the Kingoodie
stone, but it may be had in blocks sufficiently large to answer the
purpose, and, if well dove-tailed, and properly cemented together, the
whole may be made to act as one solid body of rock.
As to the expence of a Light-house in such a situation, it is not
a very easy matter to form any thing like a correct calculation.
So much depends on weather, on the untoward circumstances that may
probably happen while the work is in hand, that they baffle even the
most experienced artist to make the proper allowances. The price and
quantity of materials is by no means difficult to ascertain; but the
expence of putting them together must be more a matter of guess than
of correct and well founded calculation. I have, however, computed the
expence that such a work ought to cost, and have made every allowance
for contingencies, from my own experience of works in the sea, and from
what I have been able to collect from the experience of others, in
which, I think, I have made a very full allowance for contingencies,
and the cost amounts, by my estimate, to L. 41,844, but I will say
L. 42,000, and, I trust, if ever the work is executed, and done with
judgment, it will not exceed that sum.
I have gone on the supposition, that the outside is to be made of
Kingoodie stone, and the hearting of stone from near Arbroath. I am,
Gentlemen, your most humble servant,
(Signed) JOHN RENNIE.
To the Honourable the COMMISSIONERS}
of the Northern Light-houses. }
REPORT by Mr STEVENSON.
_Edinburgh, 15th November 1806._
In the year 1800, when the Reporter laid before the Commissioners
various models of a Light-house for the Bell Rock, the prospect of
the undertaking was so distant, that it then appeared unnecessary
to trouble the Board with any scheme for carrying the work into
execution; but since the passing of the act of Parliament for this
purpose, the case is materially altered. In preparing any method for
carrying on a work, the most difficult in its nature, and one to which
the common tests of experience can hardly be applied, he is aware,
that it is impossible, by any previous arrangement, to determine what
will answer in all respects. In so far as the operations on shore are
considered, the ordinary rules of practice apply, but, in forming plans
for the Rock itself, matters must be adjusted to the situation and
circumstances of the case.
Certain measures, of a preliminary nature, are, however, indispensably
necessary, while others may be of doubtful application; among the
former, it appears to be essentially necessary to provide a vessel to
be moored at the distance of from three quarters to one mile north-west
of the Rock. She must, of course, be fitted up as a store-ship, with
accommodation for the artificers, and ground-tackle for riding in from
17 to 20 fathoms water, on rather a hard bottom. This vessel, besides
answering as a store-ship for water and provisions, may occasionally
take on board lime, cement, and other materials from the small craft
at the Rock, when lying at anchor with them on board may be found
inconvenient. There is also another and most important service, which
this vessel will fall to perform in terms of the act of Parliament,
which is the carrying of a Light upon her mast, for the benefit of
shipping, and to enable a duty to be collected, even before the
commencement of the work, agreeably to the suggestion of Mr CUNINGHAM.
The Reporter, in order to inform himself more fully regarding the
construction of such a vessel, while attending the progress of the
Bill in London, visited the Floating-light ship at the Nore, under the
command of Mr BENNET, who very politely described every particular
connected with the business. He had also frequent communications with
Captain HUDDART of the Trinity House, who takes a particular charge of
the Floating-lights under the management of that Board, since which he
has also corresponded with him upon the subject, who has obligingly
stated his ideas relative to a vessel and moorings fitted for the
Bell Rock. Upon the whole, the Reporter is of opinion, that a dogger,
or Dutch-built vessel, is best calculated for this service. Such a
vessel would require to be from 80 to 100 tons burden, moored with a
mushroom-anchor, weighty iron mooring-irons, having likewise on board a
hempen cable of 16 inches in circumference. The mushroom-anchor, which
is but a late invention, is now in use at all the Floating-lights on
the coast, and even in some of his Majesty’s store-ships. Its great
property consists in its being hardly possible for a vessel to _foul
her anchor_ with it; and the construction is such, that it may be
made in part, or wholly, of cast-iron, agreeably to the accompanying
model, from which an idea may more easily be formed of its application.
(See Plate X.). This vessel must be furnished with such a light as
to be readily distinguishable from the Coal-light on the Island of
May; and although the Dudgeon Floating-light, off the Norfolk coast,
which carries two lanterns, is at a great distance, yet, as it is
the nearest Floating-light to the Bell Rock, it may be advisable to
distinguish it from that also. As a vessel cannot be dispensed with for
the accommodation of the artificers, it will be found to be a great
saving to employ her as a store-ship. As this vessel is only meant to
answer a temporary purpose, by purchasing one of the Dutch or Prussian
prize-ships, now for sale in Leith, she might perhaps be fitted up for
about L. 2000.
Although it would be perfectly impossible to do any thing with much
effect at the Bell Rock, without a vessel stationed in the offing; yet
as she must necessarily be moored at the distance of about a mile from
it, to give a sufficient birth for swinging, according to the wind, and
also to give sea-room to clear the Rock, in the event of her breaking
adrift, the inconveniency and difficulty of the frequent passage
between the Floating-light and the Rock must be very considerable. It
therefore occurs to the Reporter, that the greatest advantages would
arise from the erection of a temporary residence for the artificers
upon the Rock during the working-months of summer, and also to answer
as a store for some of the materials. The greatest difficulties
which Mr SMEATON had to struggle with at the Edystone, arose from the
smallness of the rock, which at once precluded any attempt of this kind
from being undertaken, and subjected the work to all the disadvantages
and trouble so particularly described as experienced in communicating
on all occasions with the store-ship. But, from the extent of the Bell
Rock, an opportunity may be had for erecting a temporary residence,
for facilitating the work. It was under the conviction that such an
accommodation might be constructed, that the clause was introduced into
the act for allowing the collection of half-duties upon the erection
of a Beacon. But, independently of these advantages, the Reporter
conceives some erection of this kind necessary, to give confidence
to the artificers, in the event of accident to the boats, of which
they might lay hold, until assistance could be procured from the
store-vessel. This temporary residence is provided for in his estimate
for the Light-house, and having modelled it, he proposes that it should
consist of beams of timber, not less than 50 feet in length, and of
proportional strength; the beams are coupled together at the top, where
they form a cabin for the workmen, and, at the same time, answer all
the purposes of a Beacon.
The next material object to be considered, is a method which may
prolong or extend the working hours at the Rock, especially in the
first instance, to low water of neap, as well as spring tides. In
this respect we also find, that Mr SMEATON had no alternative, having
had barely extent for the foundation of the Light-house; but, in this
respect, he had less occasion for such an apparatus, as the top of the
Edystone Rock was rather above high-water, although, from its shelving
form, the level of the ground-course was not more than nine feet above
low water of spring-tides. The ground-course of the Bell Rock, however,
will not be more than about two feet above low-water of such tides.
It therefore becomes an object of great importance, to construct a
water-tight fence round the site of the building, which might be the
means of saving a whole season with the work, and securing the proper
execution of the lower courses, by enabling the workmen to go on in
a more deliberate manner with their operations. The Reporter has had
several methods in view for raising a coffer-dam for this purpose to
the height of about six feet or thereby, which would allow the work
to proceed regularly in moderate weather at low water of neap as well
as spring-tides. He has, accordingly, modelled a coffer-dam with this
view, which he proposes to be three feet more in diameter than the
base of the building, and, from its exposed situation, the greatest
attention must be paid to the strength and fitness of the materials.
At first he intended this to be of timber, but at length fixed upon
cast-iron, strongly connected with iron-bolts, passing through flanges
raised upon the joints, which are to be provided with a groove, for
the conveniency of tightening them. The whole of this apparatus is
estimated to weigh about 40 tons, and is so constructed, that when
all the pieces are landed on the rock, and laid in their places, the
foundation for them being prepared, they may be set up, and temporarily
fixed, in the course of a good spring-tide.
There is no part of this critical work which will be attended with
so much difficulty as the landing of heavy materials, nor is there
any part of the business that has occupied so much of the Reporter’s
attention. Mr SMEATON appears to have had a great deal of trouble upon
this head; and in conversing with one of those having charge at the
South Rock Light-house, on the coast of Downshire in Ireland, while
it was building, it was stated, that there was more time lost in
getting a regular supply of materials, and more vexation attending this
department, than any other part of the operations, although this rock
is exposed and dry at every tide, and only 3 miles from the shore, with
a beach where vessels were laid to discharge their cargoes; whereas the
Bell Rock is about 11 miles from land, forming neither a steep-face,
like that of the Edystone, nor a sloping beach, like that of the South
Rock, while it is so low in the water, that it can afford little or no
shelter to vessels, if brought alongside of it. Under all these adverse
circumstances, the landing of the materials becomes a consideration of
the most perplexing nature. He has sometimes thought that the depth
of water upon the rock might be turned to advantage in landing the
stones at high-water; yet this mode has its disadvantages, and could
not always be depended upon; others must, therefore, be resorted to,
more certain in their application. Vessels of an easy draught of water,
and not exceeding 20 tons burden, might in very moderate weather be
brought close into some of the small creeks of the rock. Some of these
will admit of improvement, where cranes might be fixed for unloading
them. This may, perhaps, turn out to be the surest mode upon trial;
but it may also be necessary to resort to others, such as having buoys
moored in different directions, at a convenient distance from the
rock; by making fast a hawser to the buoy best suited to the direction
of the wind; the hawser may be veered out till the vessel with the
materials gets so close to the Rock as to discharge. Some have even
supposed, that the materials may be transported to the Rock under these
circumstances by a float of cork or timber, and when the vessel is thus
cleared of her cargo, she may be hauled off again, and so make sail.
The stones, when landed, if not immediately built, may be stowed into
the cast-iron coffer-dam, which, for this purpose, will be found of the
greatest use, while the lower courses of the building are in progress;
and as the work advances, other plans will present themselves.
* * * * *
In the Report dated 23d December 1800, on the subject of the Bell
Rock, the Reporter explained his reasons for laying aside the plan
of a cast-iron Light-house, and, after what has since been stated in
Mr RENNIE’s report 30th December 1805, it is unnecessary for him to
enter again upon that subject, especially as it has been fixed that
the building is to be of stone. The matter which he, therefore, now
submits to the consideration of the Board, is, the quarry or quarries
from which these materials should be taken. It is to be regretted,
that the extensive quarries in the neighbourhood of Arbroath are not
of so durable a nature as to render them fit for outside work. On his
way from Fraserburgh lately, he passed through Aberdeen, Arbroath, and
Dundee, and, in addition to former inquiries, brought with him a note
of prices, and specimens of the stone of the quarries of these places.
Upon the whole, there seems to be objection to the use of best Arbroath
or Red Head stone, for the hearting or inside-work, which may be had
for 9s. 4d. per ton. The Mylnefield or Dundee stone at 25s., but for
the granite, of the sizes wanted, no price could be quoted. Stone is
the principal material that requires consideration. As for lime, we
have an extensive choice in this country, and nothing can perhaps
answer the purpose better for securing the outside joints than Parker’s
cement. The Reporter has a specimen of Aberthaw lime, which Mr SMEATON
used with so much advantage; it would be no difficult matter to get a
cargo of it, which would be sufficient for the whole building.
* * * * *
With regard to the Lantern, and other parts of the building which
require to be of metal, without entering into particulars, they
will no doubt fall to be made of copper, at least such parts as are
more particularly exposed to the action of the air or water. As to
the nature of the Light itself, there may be some improvements and
alterations upon the present system, before the building is completed;
but, after erecting such a fabric as will be necessary at the Bell
Rock, no pains will of course be spared upon so essential a part as the
quality or description of Light to be exhibited.
* * * * *
Supposing the work to commence in the Spring of the year 1807, it
is already time that the store-vessel were in preparation, and the
necessary arrangements made for fitting her up as a Floating-light,
that the collection of the duties may commence; and, when got to her
moorings, the workmen may begin to the temporary residence or beacon,
and prepare the rock for the building, which would form the primary
operations, and occupy the first Summer. If the beams are found to
withstand the storms of winter, the upper part can then be covered
in as a residence for the artificers in 1808; and, at all events, be
habitable for the Summer of 1809. While these measures are carrying
forward, and the site of the building is in progress, the lower course
of stones will be in preparation on shore. The place which the Reporter
would propose for carrying on these works is Arbroath, as the port most
contiguous to the Rock, being situate at the northern side of that
range of coast which forms St Andrew’s Bay, in which the Bell Rock
holds a centrical situation. A passage may be made from Arbroath to the
Rock with much more regularity than from the Tay. On the southern side
of this great Bay, there is no convenient harbour between the Tay and
Fifeness. The stones, being transported from Mylnefield and Aberdeen,
would be hewn at Arbroath, and after being laid and marked upon a
platform, course by course, would then be shipped for the Rock.
* * * * *
It is unnecessary at this time to enter further into particulars. When
the dimensions of the building are finally arranged, it will then be
proper to enter into contracts for the materials, and shipping for
conveying them, and to provide implements and artificers for the work.
(Signed) ROBERT STEVENSON.
To the Honourable the COMMISSIONERS}
of the Northern Light-houses. }
JOINT REPORT by JOHN RENNIE and ROBERT STEVENSON.
_Edinburgh, 26th December 1806._
GENTLEMEN,
You having at your meeting on the 10th instant resolved that the
Light-house to be erected on the Bell Rock shall be of stone, we,
according to your request, went to Aberdeen and Mylnefield, for the
purpose of examining into the quality and price at which stone for the
erection of the Light-house could be delivered at Arbroath, the place
where it is proposed the materials shall be prepared for the work.
At Aberdeen, we found that many additional quarries had lately been
opened, some of them of an excellent quality, and capable of producing
larger blocks of stone than granite quarries usually do; but still
it is doubtful, as has been formerly mentioned, whether any one
quarry will be found to produce a sufficiency of large blocks in any
reasonable time; but by purchasing from different quarries, a regular
supply may be procured for all the purposes wanted, in case you
shall determine upon using the granite in preference to stones from
Kingoodie. The Aberdeen granite is of so very strong and durable a
nature, and has been used in works where the sea has acted upon it for
time immemorial, that no doubt can possibly be entertained respecting
its adaptation to a work of this kind. There is also every reason to
believe, that the Kingoodie stone resists the sea and weather equally
well, but we have not been able to collect such positive proofs of this
as of the other; for, although a good deal of that stone has been used
in the piers of the harbour of Dundee, yet, as this has been mixed with
other sorts of the same appearance, and nearly of the same composition
of those of Kingoodie, it prevents the possibility of our saying
whether some of the stones that have wasted may not be Kingoodie,
although we have great reason to believe that they are not. However,
where facts cannot be positively ascertained, doubts exist; and we
think, that a Light-house upon the Bell Rock is too important a work
to suffer even a doubt to exist; and we have no hesitation, therefore,
in recommending, that the under part of the building, at least as high
as the first apartment, should be of Aberdeen granite; and as this is
the great bulk of the work, it may be as well, perhaps, to complete the
outer course of granite to the top.
As to the extra price this will incur, we cannot at present correctly
say. We have had two offers for granite from the Rubislaw and
Dancing-Cairn Quarries. The former by Robert Spalding, is at 10d. per
cubic foot, delivered on the quay at Aberdeen, but, as the expence
of shipping and shore-dues are not included, this may be fairly
reckoned at 2d. per cubic foot more. The other is from Snell, Ranie
and Thom, at 1s. 4d. per cubic foot, delivered free on board a vessel
at the quay. Now, as the freight from Aberdeen to Arbroath will be
about 7d. per cubic foot, and as an agent must be employed to examine
and see the stone delivered by the different quarry-men, we suppose
that 1d. per foot may be added for commission; so that, exclusive of
Government duties, the offer for Aberdeen stones will stand nearly as
follows: Spalding’s offer, with charges, will amount to 1s. 8d. per
cubic foot, and Snell and Company’s at 2s. The expence of working the
Aberdeen stone will come high, we doubt, for such a work as this. Where
dove-tails, and other devices for the security of the building will be
necessary, it cannot cost less than 2s. 6d. per cubic foot. Now, taking
the price of stone at the average of the above offers, it will amount,
with workmanship and freights, to 4s. 4d. per cubic foot, so that the
casing or outside course of granite will amount to about L. 7266.
Mr Mylne offers to supply blocks of Dundee or Kingoodie stone, put
free on ship-board, at 1s. per cubic foot; the freight from thence to
Arbroath will be about 4d. per cubic foot, so that the stone will cost
at Arbroath 1s. 4d. The working of this stone will cost about 1s. 6d.
per foot, making the cost of the Kingoodie stone 2s. 10d.; therefore a
casing of Dundee stone would amount to L. 4760, making a difference in
favour of Kingoodie stone of L. 2506.
The next question that arises here is, what kind of stone should be
used for the hearting of the building, where nothing can affect the
stone, of whatever quality it may be; and here the Arbroath or Redhead
quarries may come into competition. There are arguments in favour of
both; the Kingoodie will be more expensive, but its specific gravity is
greater, and it is of a much stronger nature than the Arbroath stone.
If Kingoodie stone is used for the hearting, the cost of the stone,
with freight and cutting, will be about L. 2124. The Arbroath stone
will cost, delivered at the work, about 9s. per ton of 16 cubic feet,
and cutting about 1s. per cubic foot, so that the total cost will be
about L. 1172, a difference in favour of the Arbroath stone, besides
duty, of about L. 952. Now, whether you may agree to pay this extra
price we will not venture to anticipate, but we have no hesitation in
saying that the Kingoodie stone is the best.
Another object which occupied our attention, was the procuring of
a piece of ground at Arbroath, with proper sheds and warehouses,
near the harbour, for the purpose of dressing the stones, laying the
courses as they are to be in the Light-house, keeping stores, &c.
&c. For this purpose we applied to Messrs Duncan and Cargill, who
have a ship-builder’s yard adjoining the harbour, and who some time
since intimated their intention of disposing of it; but we found that
the place was not of the dimensions necessary for the work, that the
warehouses on the ground did not belong to the ship-yard, and that the
people had not finally determined upon disposing of this place. We
therefore inquired further, and found a piece of ground much larger
than the carpenter’s yard, and nearly as well situated, but there
are no buildings upon it; and indeed, there is no other spot at all
convenient, or near the harbour, that can be had. We therefore saw the
proprietor John Taylor, and he has offered to let the whole for seven
years, at the rent of Twenty Guineas per annum. The rent is high, but
the situation is such as to render it more suitable than any other, and
therefore we advise Mr Taylor’s proposal to be accepted.
Having now stated the result of the several objects for which our
journey northward was undertaken, it may be proper to mention
what occurs to us as the best mode of proceeding respecting the
measures to be taken for the erection of the Light-house, with the
construction that appears best suited to the stability of the work.
The first object that naturally presents itself is the establishment
of the Floating-Light, now in preparation, respecting which some
correspondence has taken place between Mr Stevenson and Captain
Huddert of the Trinity Board of London, which is now before you. Their
information is very satisfactory, and from the measures taken in
advising with the Trinity-House of Leith, it is hoped that every thing
relative to the fitting out of the Prussian-dogger, purchased for this
service, will be the most complete of the kind, and the sooner she can
be got to her moorings the better, that the operations at the Rock
may be commenced, and that the duties may be collected for paying the
Treasury loan, and otherwise adding to the general fund.
The second object that comes under consideration is the inclosing the
piece of ground at Arbroath for a work-yard. This may either be done by
a ruble wall or a wooden fence, but the former is preferable, because
several buildings must be made for stores, and for floors, to mark out
the different courses with the dove-tails as they form the building, so
that the ruble wall may form part of these buildings. Sheds must also
be erected for the masons to work in.
Thirdly, Two vessels, of about 30 tons each, for conveying stones from
Arbroath to the Rock, should, without delay, be contracted for. These
vessels must be built strong, and of good materials, and calculated to
work well at sea, that no opportunity of going to the Rock may be lost.
Fourthly, A crane for unloading the vessels should be established at
Arbroath, and another at the Rock, for landing the materials, as also
the necessary tools and triangles, with tackle for setting the stones
in the work-yard, and at the Rock likewise, stone-carriages, jacks, &c.
Fifthly, Mooring-chains, anchors, buoys, with ropes, &c., to assist in
landing the materials, and for enabling the men to leave the Rock when
the tide prevents them from working.
Sixthly, A coffer-dam will be wanted, to the height of 4 or 5 feet, so
as to enable the workmen to continue so much longer on the Rock than
they could do, were the tide allowed to flow over the foundation when
it rises above the level of the Rock.
Seventhly, Although we do not pretend to say that a stage, for the
accommodation of the workmen, can with certainty be constructed on the
Rock, yet it might be worth while to attempt the establishment of such
a work, as, if it did answer, great facility in carrying forward the
work would be obtained; and, should the project fail, the timber and
iron can be applied to other uses, and the expence of the experiment
cannot be great.
Eighthly, A variety of small tools, for cutting the foundation of the
Rock, for dove-tailing the stones, and sundry other uses too tedious to
mention, will also be wanted.
Ninthly, A quantity of Aberthaw lime should be procured, as well as
other lime of the best quality which the country affords, and a small
lime-kiln for burning it erected, and no more burned at once than
can be used in a short time, that it may be always had as fresh as
possible, as the less it is exposed to the air after being burned
the better will it cement. Pozzolano or tarras should be got, if
possible, to mix with the lime, these making the best cement that has
yet been discovered; but, if it cannot be had, manganese, or even
burnt ironstone, will form a good substitute. A quantity of Parker and
Company’s Roman cement will be wanted, to keep the sea from washing out
the other cement before it has time to harden in the joints.
Tenthly, Oak trenails will be required for fixing down the stones,
while the building is in operation, and the several courses liable to
be washed by the waves. Lead for running bolts into the Rock, &c. will
also be necessary.
As to the construction of the Light-house itself, we are of opinion,
that it is much better to follow what has been found to answer at the
Edystone, a situation nearly similar to the present, than, in a work so
important, to look for other methods that have not stood the test of
trial. It must, however, be observed, that some alteration, suited to
the difference of local circumstances, ought to be adopted. The Rock at
the Edystone differs both in form and quality from the Bell Rock; it
lies in a slanting direction, and the higher part was never covered by
the tide. It is of a harder quality, and but small in size; nothing,
therefore, was to be found in this case in regard to the wearing or
wasting of the Rock; and from its limited size, there was no more space
than what merely enabled the engineer to make the erection upon it.
The case at the Bell Rock is very different, the Rock being, on an
average, not more than four feet higher than low-water of spring-tides.
It is of a softer quality, but the dimensions are large. It therefore
becomes necessary that the base should be more extended and flat
where it is connected with the Rock, so that when the waves break
upon it, they may spend their fury on the base of the Light-house,
instead of the Rock itself, and thereby prevent it from wearing away.
The tower should also be higher, as the tide rises more upon it than
on the Edystone. These, and a few other alterations, will adapt the
Edystone plan to the Bell Rock, unless in so far as the light itself is
connected; but this need not now be a subject of inquiry. A Plan of the
Light-house, nearly similar to what is proposed, is handed herewith,
but no plan of the dove-tailing has been made, nor can it well be done
at present, as the dove-tails must be suited to the different courses
of stone as they come from the quarry; but, as the principle is similar
to that of the Edystone, the design may be easily judged of.
It is of much importance, that, in so hazardous a work as the present,
recourse should speedily be had to advice when occasion requires;
and, as a Quorum at all times cannot be got, it might be advisable to
appoint a Sub-Committee of your number, to be called together when
necessity may require.
(Signed) JOHN RENNIE.
ROBERT STEVENSON.
To the Honourable the COMMISSIONERS }
of the Northern Light-houses. }
REPORT by Mr RENNIE.
_Edinburgh, October 29. 1807._
GENTLEMEN,
I went to the Bell Rock on the 5th instant, when I found Mr Stevenson
with his workmen engaged in preparing the Rock to receive the
foundation of the Light-house; also in erecting a Beacon on it, for the
double purpose of pointing out to mariners the situation of the Rock
more correctly than can be done by the Floating-Light, and as an asylum
to the men employed on the Rock, in case they should be overtaken by
the tide before the boats had time to take them to the vessel. Mr
Stevenson had been constantly engaged in the different operations for
about two months, during which time he had never been ashore; and it
was fortunate he had taken the resolution of remaining constantly on
board, for, without this, there is every reason to believe that the
workmen could not have been prevailed on to continue at the work, they
having previously shewn a disposition to leave it; but by perseverance,
and by allowing them their provisions while on board the vessel and
working at the Rock, they have not only been prevailed on to remain at
the work, but they now seem to be better satisfied when at the Rock
than on shore; and as no accident has happened, although the weather
has several times been very stormy, there is great reason to believe
that the workmen, being now accustomed to the work, and having gained
entire confidence by the success of the past year, will return with
redoubled vigour next season, and that the work will proceed with much
spirit and regularity.
The work performed in the course of the present season, consists
first of preparing the Rock for the foundation of the Light-house
to a certain extent; but owing to that part of the Rock where the
Light-house is to stand being very uneven in the surface, and some
of it within 2½ feet of the level of the sea at low-water of
spring-tides, the time at which the men can work is of course very
limited; and as there would be great danger of shivering the Rock, if
blasting or any other violent measure were resorted to for expediting
the work, it has been thought better to proceed in the more secure
mode of cutting the stone by picks and chisels, which, as the Rock is
hard, and so consumes much time, considerable progress has been made
towards this; and I hope, by the end of next June, the whole of the
Rock will be completely ready to receive the foundation-course of the
Light-house: perhaps it may even be ready sooner; but so much depends
on weather, I do not venture to state particularly the time when this
most essential object will be completed; but I have great confidence in
the zeal Mr Stevenson has shewn in the past season, to prognosticate
that he will do all that can be done in the next to expedite the work.
A large beacon, consisting of six main beams of timber, about 13 inches
square, and 44 feet long, has been erected on the Rock; it forms a
pyramid of about 42 feet high, and a base of the same extent. This
is well secured to the Rock with dove-tail cramps, and with chains
and braces. Near the top are cross-bars to stiffen the upper part
of it, which have been found of great use, as the smith’s forge for
sharping tools was erected there, and for the last fortnight the tools
were sharped, and various other works done, which tended greatly to
facilitate the operations at the Rock. The workmen continued there
during the time the Rock was covered with the tide, which enabled
them to begin working the moment the part was uncovered where they
were employed, and it likewise enabled them to work till the last
moment, when the tide began to cover the work. Had no such asylum been
provided, the workmen would not only have lost much time in getting
from the vessel to the Rock, but also in getting from it. This beacon
is not yet entirely finished: a few good tides would enable the workmen
to complete it, and when done, I have great hopes it will be found
to resist the storms; indeed it has resisted several even in the
unfinished state it is, and therefore is a favourable prognostication
that it would be stable when completed.
There is, besides, a provision-chest intended to be placed on its top,
and above this a ball and flag-staff, so that I hope it will be a very
useful additional mark for mariners to avoid this dangerous Rock, and
should be advertised as well as the Floating-Light.
The advanced state of the year renders it necessary that the operations
at the Rock should stand until the spring of the year. This is proposed
to be done whenever the beacon is completed; but during the winter
every requisite measure should be taken to proceed with the work for
the Rock as expeditiously as possible. For this purpose I must beg
leave to recommend to the Commissioners that the remainder of the
articles mentioned in our Report of the 26th December last, should be
provided with as little delay as possible.
The ground taken on lease from John Taylor, at Arbroath, for a
wood-yard, has been covered in part with the necessary buildings and
workshops, but sheds for the masons to work in during the winter season
are not yet done. These may be got of the most temporary kind; if they
just keep off the rain it will be enough, and no delay should take
place in procuring them.
Several cargoes of Aberdeen and Dundee stones have been laid down
and landed at the yard, part of which are worked, and the masons are
engaged in working the remainder. I am sorry, however, to say, that
neither the supply from Aberdeen nor Kingoodie has been so abundant
as could be wished. Unless exertions far greater than has hitherto
appeared be made, it will be impossible to proceed with the building
on the Rock next season. I accompanied Mr Stevenson both to Aberdeen
and Kingoodie. In viewing the former, it appears, that unless stones
are purchased from such quarries near Aberdeen, as may turn them out,
it is scarcely probable a sufficient quantity of large stones for
the lower courses of the Light-House can be had in due time from the
Rubieslaw quarries alone. It therefore will be advisable, that Mr Skene
empower his agent to purchase from the other quarries whenever blocks
of the requisite size can be found. As to the Kingoodie quarry, it only
wants a little exertion on the part of Colonel Mylne’s agents, as the
quantity wanted would be easily got in a few weeks, if exertion such as
has been promised be made.
The Floating-Light was completed and moored within the distance of
one mile from the Rock on the 9th July, and for some time the people
employed at the Rock lodged in her; but the situation in which she
was moored has been found not to answer, as, after the gale of the
6th September last, which she rode out with perfect safety, it was
found that her cable had been cut by a piece of rock or wreck. She
went adrift next day, luckily without receiving any injury, but it has
been found that there is no clear ground, (at least that has yet been
discovered), less than the distance of about two miles and a half from
the Rock, which will render her of no use as a place to accommodate the
workmen; another vessel of some sort must therefore be provided. The
Yacht has been used since the Float was removed to such a distance,
but as neither the manner she was rigged, nor her accommodation, is
suitable, nor indeed can she well be spared from attending the other
light-houses, she cannot be counted upon in future. In my opinion a
proper vessel should be purchased, and fitted up for this purpose, and
she will sell at little discount after the work is completed.
One vessel of the description mentioned in the second article of the
Report of 26th December 1806, has been built and fitted out. She has
been engaged in carrying materials to the Rock; in carrying stones
to the yard; and sundry other matters. A second vessel of the like
description should be got ready against the spring, to carry the
stones and materials to the Rock, &c. Two cranes have been purchased
for loading and unloading stones; one has been erected at Aberdeen,
and the other at Arbroath; and they both answer the purpose very
well. Triangles, and other necessary apparatus are preparing for the
work on the Rock, and will be ready against the time they are wanted.
Mooring-chains and buoys for the vessels employed about the Rock have
also been prepared and laid down.
It was proposed, in the Report of December last, to have a coffer-dam
on the Rock, for keeping out the water during a part of the time the
tide is flowing; but it rises so quickly here, after having turned,
that I do not think a coffer-dam will produce advantages adequate
to the expence. It is therefore proposed to do the work without any
coffer-dam at all: there has been sufficient trial already made,
to satisfy us respecting its practicability without a coffer-dam.
The beacon already erected, and which there is reason to believe
will stand, renders a stage of the description formerly mentioned
unnecessary. It is intended, should this beacon stand over the winter,
to erect places for the accommodation of the workmen employed at the
Rock on its top. This will greatly facilitate the operations, as before
stated.
Most of the small tools mentioned in article 9th of Report of December
last, have been procured. Some are still wanting; but these are few.
No Aberthaw lime has been procured, nor any pozzolano. Mr Stevenson
intends to send the Yacht for a cargo of Aberthaw limestone, as soon
as she can be spared from the service of the Light-houses; and, if a
vessel is purchased for the accommodation of the workmen at the Rock,
she may also be sent for a cargo of Aberthaw lime. I have not been able
to procure any pozzolano, although many trials have been made. I have
some hopes that a small quantity may still be procured; but I cannot
speak with certainty: if not, tarras, or burnt ironstone, must be
used. No oak trenails for the stones have yet been got. Mr Stevenson,
however, is about to order some from Southampton; and I hope they will
be in time for the work. Lead is, at this time, very cheap. I submit it
to the wisdom of the Commissioners, whether it might not be advisable
to purchase now what may be wanted for the work.
As to the construction of the Light-house, I submitted a plan to your
consideration in the month of February last, (see Plate VII.) According
to this plan, the works are proceeding; plans of each course of stone
have been made; the whole is dove-tailed, but somewhat different from
the mode pursued at the Edystone; they are less in length on the
outside, but deeper in the direction of the radius of the Light-house,
which will render the structure, on the whole, stronger than the
Edystone plan. The extension of the base of the building is also much
greater; and the base is considerably different. By this means, not
only the impulse of the waves on the building will be less, but their
action on the part of the rock adjoining the foundation will be much
easier. The Rock is softer than that on which the Edystone is built,
but it is harder than I imagined when last here. On the whole, I feel
confident, that this work will be brought to a successful termination,
within a reasonable period. The knowledge which has been acquired
by the operations of the last season, impresses me with additional
confidence in the practicability of the work, although confident, from
the commencement, that, with proper care and attention, such a work
might, with certainty, be completed.
The necessity of Mr Stevenson’s remaining much at the Rock while the
operations are going forward, render it necessary that some person,
by way of agent, should be appointed to pay money at Arbroath, and to
credit and settle accounts. As to this the Commissioners will order
as they think right. I am, honourable gentlemen, your most obedient
servant,
(Signed) JOHN RENNIE.
To the Honourable the Commissioners }
of the Northern Light-houses. }
REPORT by Mr RENNIE.
_Edinburgh, 12th December 1808._
GENTLEMEN,
I visited the Bell Rock on the 25th _ult._ The weather was favourable,
but the tide did not ebb so low as to allow me to examine the
foundation of the masonry so completely as I could have wished; but
as there was little swell, I was enabled to form a tolerable judgment
concerning the perfection with which it is executed, and this, I have
the pleasure to say, is very favourable.
The Rock was nearly all cut last season, but several parts in the
interior was hollow, and others appearing unsound, they could not be
cut out without a serious expence in money, as well as a great loss
of time. It was therefore judged preferable to make up these places
with stone, and, accordingly, 17 stones have been let into different
parts of the foundation, which brought the whole on which the Tower
stands to a level; on which level, the first course of 12 inches was
laid in August, and the outer-edge margin of this course, was nicely
fitted all round to the rock, which, in every place except one, as I
have been told by Mr Stevenson, projects higher than the upper part of
it, by which, the base may be said to be completely indented into the
Rock. Above this 12 inch course, two others, of 18 inches, have been
laid, and it gives me great satisfaction to inform you, that they are
done in a very complete manner, and the mortar, in all the outside
joints, has not been at all affected by the sea beating upon it. A very
small quantity was out of some of the inside joints, which, I am told,
had arisen from the sea catching it (the weather being unfavourable)
while the course was laying; this has been directed to be made up, and
covered with Roman cement, which will render it as perfect as if no
such thing had happened.
It is here proper to remark, that although the pozzolano mortar
forms the best of all cements I have seen, yet it does not acquire a
sufficient degree of induration to resist the effect of heavy waves for
several weeks after it is used. The Roman, or Parker’s cement, acquires
almost an immediate induration, capable of resisting the heavy waves;
but it never acquires so great a degree of induration, nor does it bind
the stones so well together as the pozzolano mortar ultimately does.
Its use, therefore, is to guard or preserve the pozzolano mortar until
it has time to harden, which it does most effectually, and therefore
every joint should be plastered over with this cement as soon as laid.
The place where the lower or 12 inch course is above the Rock, should
be made up with stone of the same quality as the Rock itself. These
stones should be dove-tailed into the rock, and laid with pozzolano
mortar, secured by the Roman cement, the same as the other; for if
done with harder stone (should the rock waste at all) it would resist
the waves better than the soft, and occasion a more speedy waste of
the other parts of the Rock than the Tower. All the protuberances of
the Rock round the base of the Tower, should likewise be cut off, and
smoothed, so as to form a regular curve at the base of the Tower, by
this means there will be no place for the waves to catch, and their
action will be regular on the whole, and I have no doubt, when so done,
there will be little or no wasting in the rock itself.
The operations in the work-yard seem to be proceeding with much
regularity, and there is a good stock of materials now there. Two
courses are nearly completed on the platform, and as the diameter
of the Tower diminishes fast, I have little doubt that there will
be several other courses ready by the season that the work can with
safety be resumed on the Rock; so that if the next season is at all
favourable, I would fain hope the whole solid part of the Tower may
be completed; every course of stone will raise it so much above the
rock, and, of course, prolong the time of working a tide, until it is
above the top of the springs, and then, if materials can be landed at
the rock in sufficient quantity, the laying of them on the Tower will
proceed with little or no interruption.
To secure a regular supply, another Praam or Stone-lighter should be
got ready by the end of April next. Mr Stevenson has already received
proposals for the building of one, and the sooner it is set about the
better. It will also be necessary to build or hire another vessel, to
assist the Smeaton in carrying out the stones from the work-yard; I
apprehend it will be best to hire a vessel for that purpose, as the
services required of her will be of short duration. About 10 tons more
of pozzolano will probably be wanted, and this I have been able to
procure through the friendship of the Hull Dock Company; it is already
ground, and now lying there to be shipped. A small additional quantity
of Aberthaw limestone is likewise to be procured, by the kelp-vessels
that trade to Bristol, as a return freight.
It happens, rather unfortunately, that some of the granite quarries
about Aberdeen have veins of a soft sort, which I have reason to
believe decomposes with the sea and weather. Some of these stones have,
unluckily, been sent to the work-yard. My decided opinion is, that all
of this kind should be laid aside for the out-side work, and others of
a good quality procured in their place. They can be substituted for the
Dundee stone, and, therefore, although some loss will by this means be
sustained, it will, on the whole, be trivial. I am, Gentlemen, your
most humble servant,
(Signed) JOHN RENNIE.
To the Honourable the Commissioners}
of the Northern Light-houses. }
No. V.
REMARKS relative to the Ground-swells of the Sea.
[Sidenote: Wasting Effects of the Ocean.]
In the Memoirs of the Wernerian Natural History Society, Vol. III. p.
814., and in the Edinburgh Philosophical Journal, Vol. III. p. 42.,
the subject of the Wasting Effects of the Sea upon the firm ground, is
variously treated by the writer; and is here alluded to, in reference
to the production of the appearance termed a Ground-swell, so often
observed on our shores. In these papers it has been assumed, that the
German Ocean, or North Sea, bounded partly by the coasts of Great
Britain, Norway, Denmark, Germany, Holland, and France, as will be
seen from Plate III., is almost every where wasting and extending its
margin, upon the principle of its forming the great receptacle for all
the debris of the surrounding countries above mentioned, which have a
direct tendency to lessen its capacity for containing the waters which
flow into it from the Atlantic, by the apertures between the shores of
Scotland and Norway, towards the north, and between Dover and Calais,
to the south. These passages may respectively be conceived as admitting
a constant quantity, while this great basin is continually receiving
the debris of the extensive tracts of country which surround it,
through the medium of the innumerable rivers and streams that fall into
it.
[Sidenote: Wasting Effects of the Ocean.]
Upon similar principles, the extensive lakes of interior countries
become so many receptacles for the debris of their respective
districts; and must in the lapse of time, contain less water, in
proportion to the cubical contents of solid matters carried into them.
So it is upon the great scale with the basin of the North Sea, from
the extensive banks deposited therein, which lessen its capacity, and
thereby give a tendency to the water which flows into it to overflow
and waste its margin, producing, under various modifications, those
heavy swells in the Sea to which we now allude. With this state of
things in view, we may now inquire into the effects of the storms which
agitate the waters of the Atlantic, and reach our shores only in the
form of what has been significantly termed a Ground-swell; which may
partly be illustrated from the storm described in page 312. of this
work. We accordingly find the waters of the North Sea often in an
agitated state, without any apparent cause, though no doubt proceeding
from distant storms at sea. Hence, a continued gale from the westward,
passing along the Atlantic Ocean, overcharges all the seas and inlets
communicating immediately with it. Under these circumstances, although
the surface of the North Sea be comparatively smooth, yet having
acquired motion to a considerable depth from the distant storm, it
continues to produce the effect of a Ground-swell for a considerable
period. A swell of this description is almost constantly observable in
the Bay of Biscay, owing to its exposure to the Atlantic, and from the
configuration of the bounding land between Cape Finesterre in Spain,
Ushant in France, and the relative position of the British Isles. Here
the Ground-swells, proceeding from the same cause as those of the North
Sea, are either the precursors of a gale of wind, or the effects of one
which does not reach us.
Similar, though less evident effects, are produced by gales of wind
which may be conceived to be confined to the boundary of the North
Sea itself. Hence the heavy waves which often break upon the eastern
shores of Great Britain, without any apparent cause at the time,
are afterwards found to arise from storms at sea. But the heaviest
Ground-swells of the North Sea are produced by gales from the
north-east, which proceed in a progressive manner along the inclined
plane of its bed, until the waves, by impinging upon the bottom and
sides of the firm ground, are so disturbed that they ultimately cease,
after wasting the whole extent of the shores, and sometimes causing
the most destructive effects upon the coast of Holland, forming the
southern extremity of this great basin.
No. VI.
[Sidenote: Materials.]
SCHEDULE, containing an Enumeration of the MATERIALS used in the
Erection of the Bell Rock Light-House.
Key:
A Total 90
+--+---+----+----+-----+--------+---+----+----+-----+-----+--------+
|Course.
| |Granite |
| |in Pieces. |
| | |Sandstone |
| | |in Pieces. |
| | | |Granite in |
| | | |cubic feet. |
| | | | |Sandstone in |
| | | | |cubic feet. |
| | | | | |Tons of Sandstone |
| | | | | |and Granite. |
| | | | | | |Sandstone |
| | | | | | |Joggles. |
| | | | | | | |Oak |
| | | | | | | |Trenails. |
| | | | | | | | |Oak Wedges |
| | | | | | | | |in pairs. |
| | | | | | | | | |Pozzolano |
| | | | | | | | | |in Barrels. |
| | | | | | | | | | |Lime in |
| | | | | | | | | | |Barrels. |
| | | | | | | | | | | |Sand in |
| | | | | | | | | | | |Barrels.|
---+---+----+----+-----+--------+---+----+----+-----+-----+--------+
| 1| 4| 14| 6| 146| 10.891| | | | 1.5| 2.2| 1.1|
| 2| 52| 71| 508| 876| 101.648| 13| 246| 378| 13.6| 19.9| 10.7|
| 3| 52| 84| 808| 1269| 152.797| 13| 246| 437| 16.9| 24.8| 13.3|
| 4| 52| 71| 696| 1009| 125.609| 13| 246| 400| 14.5| 21.2| 11.4|
| 5| 53| 54| 593| 849| 106.258| 13| 212| 336| 12.5| 18.3| 9.8|
| 6| 26| 71| 492| 790| 94.275| 13| 194| 270| 11.8| 17.2| 9.2|
| 7| 26| 58| 238| 767| 73.094| 13| 168| 242| 8.3| 12.3| 6.6|
| 8| 26| 45| 196| 547| 54.148| 13| 142| 268| 7.4| 11.0| 5.8|
| 9| 26| 45| 264| 426| 50.737| 13| 142| 229| 6.3| 9.3| 5.0|
|10| 26| 45| 292| 606| 65.748| 13| 142| 229| 7.6| 11.0| 5.9|
|11| 26| 45| 339| 363| 52.006| 13| 142| 229| 6.3| 9.3| 5.0|
|12| 16| 37| 160| 462| 45.308| 8| 108| 184| 5.7| 8.4| 4.5|
|13| 16| 37| 194| 347| 39.709| 8| 108| 184| 5.0| 7.4| 3.9|
|14| 16| 37| 168| 329| 36.423| 8| 108| 184| 4.8| 7.0| 3.7|
|15| 16| 37| 188| 301| 35.962| 8| 108| 184| 4.6| 6.8| 3.6|
|16| 16| 37| 153| 321| 34.698| 8| 108| 184| 4.7| 6.9| 3.7|
|17| 16| 37| 182| 308| 36.000| 8| 103| 184| 4.7| 6.9| 3.7|
|18| 16| 37| 153| 297| 32.983| 8| 108| 184| 4.4| 6.4| 3.4|
|19| 16| 37| 180| 304| 35.560| 8| 108| 184| 4.5| 6.6| 3.5|
|20| 16| 29| 196| 308| 37.077| 8| 108| 152| 4.3| 6.3| 3.4|
|21| 16| 29| 211| 264| 35.088| 8| 92| 152| 4.2| 6.1| 3.2|
|22| 16| 29| 100| 311| 29.906| 8| 92| 152| 3.9| 5.7| 3.0|
|23| 16| 29| 177| 238| 30.615| 8| 92| 152| 3.9| 5.7| 3.0|
|24| 16| 29| 147| 303| 32.951| 8| 92| 152| 3.9| 5.6| 3.0|
|25| 16| 29| 149| 235| 28.248| 8| 92| 152| 3.5| 5.2| 2.8|
|26| 6| 39| 142| 250| 28.780| 8| 92| 152| 3.5| 5.2| 2.8|
|27| | 38| | 315| 22.500| 8| 79| 67| 3.0| 4.4| 2.4|
|28| | 33| | 259| 18.500| 8| 66| 58| 2.8| 4.1| 2.2|
|29| | 26| | 236| 16.857| 8| 54| 61| 2.9| 4.2| 2.2|
|30| | 26| | 249| 17.786| 8| 52| 54| 2.4| 3.4| 1.8|
|31| | 25| | 238| 17.000| 8| 50| 68| 2.2| 3.3| 1.8|
|32| | 26| | 274| 19.571| 8| 52| 69| 2.3| 3.3| 1.8|
|33| | 28| | 302| 21.571| 8| 56| 78| 2.6| 3.8| 2.0|
|34| | 30| | 296| 21.143| 8| 60| 80| 2.7| 4.0| 2.1|
|35| | 32| | 271| 19.357| 8| 64| 80| 3.0| 4.5| 2.4|
|36| | 32| | 266| 19.000| 8| 64| 80| 2.5| 3.7| 2.0|
|37| | 32| | 279| 19.929| 8| 64| 80| 2.3| 3.5| 1.8|
|38| | 24| | 275| 19.643| | | | 1.5| 2.2| 2.0|
|39| | 16| | 138| 9.857| | | | 1.2| 1.8| 1.6|
|40| | 16| | 136| 9.714| | | | 1.2| 1.7| 1.5|
|41| | 14| | 133| 9.500| | | | 1.1| 1.6| 1.4|
|42| | 14| | 142| 10.143| | | | 1.1| 1.6| 1.4|
|43| | 16| | 140| 10.000| | | | 1.1| 1.6| 1.4|
|44| | 16| | 139| 9.929| | | | 1.2| 1.8| 1.6|
|45| | 16| | 135| 9.643| | | | 1.1| 1.7| 1.4|
|46| | 16| | 132| 9.429| | | | 1.1| 1.6| 1.4|
|47| | 18| | 261| 18.643| 16| | 64| 2.0| 3.0| 1.5|
|48| | 16| | 118| 8.429| | | | 1.0| 1.5| 0.8|
|49| | 16| | 115| 8.214| | | | 1.0| 1.5| 0.8|
|50| | 14| | 114| 8.143| | | | 1.0| 1.5| 0.8|
|51| | 14| | 123| 8.786| | | | 0.9| 1.4| 0.7|
|52| | 16| | 122| 8.714| | | | 0.9| 1.4| 0.7|
|53| | 16| | 115| 8.214| | | | 1.0| 1.5| 0.8|
|54| | 16| | 113| 8.072| | | | 1.0| 1.5| 0.8|
|55| | 16| | 102| 7.286| | | | 0.9| 1.4| 0.7|
|56| | 18| | 258| 18.428| 16| | 64| 2.0| 3.1| 1.5|
|57| | 16| | 97| 6.929| | | | 0.9| 1.4| 0.7|
|58| | 16| | 104| 7.429| | | | 0.9| 1.4| 0.7|
|59| | 14| | 96| 6.857| | | | 0.9| 1.4| 0.7|
|60| | 14| | 102| 7.286| | | | 0.7| 1.1| 0.5|
|61| | 16| | 100| 7.143| | | | 0.8| 1.2| 0.6|
|62| | 16| | 97| 6.929| | | | 0.8| 1.3| 0.6|
|63| | 16| | 90| 6.429| | | | 0.7| 1.1| 0.5|
|64| | 16| | 86| 6.143| | | | 2.0| 3.1| 1.5|
|65| | 18| | 228| 16.288| 16| | 64| 0.6| 0.9| 0.4|
|66| | 16| | 83| 5.929| | | | 0.7| 1.0| 0.5|
|67| | 16| | 82| 5.859| | | | 0.6| 0.9| 0.4|
|68| | 16| | 88| 6.286| | | | 0.4| 0.7| 0.3|
|69| | 12| | 76| 5.429| | | | 0.6| 0.9| 0.4|
|70| | 16| | 74| 5.286| | | | 0.6| 0.9| 0.4|
|71| | 16| | 95| 6.786| | | | 1.0| 1.5| 0.8|
|72| | 16| | 77| 5.500| | | | 2.0| 3.1| 1.5|
|73| | 16| | 75| 5.357| | | | 2.5| 3.7| 2.0|
|74| | 18| | 225| 16.071| 16| | 64| 2.0| 3.1| 1.5|
|75| | 16| | 73| 5.216| | | | 0.6| 0.8| 0.4|
|76| | 16| | 73| 5.216| | | | 0.7| 1.1| 0.5|
|77| | 16| | 82| 5.859| | | | 0.6| 0.7| 0.4|
|78| | 12| | 62| 4.429| | | | 0.5| 0.7| 0.4|
|79| | 12| | 62| 4.429| | | | 0.6| 0.9| 0.4|
|80| | 12| | 75| 5.357| | | | 0.6| 0.9| 0.4|
|81| | 16| | 70| 5.000| | | | 1.0| 1.5| 0.8|
|82| | 16| | 181| 12.929| | | | 1.0| 1.5| 0.8|
|83| | 16| | 190| 13.571| 16| | | 2.0| 3.1| 1.5|
|84| | 16| | 257| 18.357| 16| | | 2.0| 3.1| 1.5|
|85| | 16| | 298| 21.286| 16| | | 2.5| 3.7| 2.0|
|86| | 8| | 62| 4.429| | | | 0.4| 0.7| 0.3|
|87| | 8| | 60| 4.286| | | | 0.4| 0.6| 0.3|
|88| | 8| | 56| 4.000| | | | 0.3| 0.6| 0.2|
|89| | 8| | 52| 3.716| | | | 0.3| 0.5| 0.2|
|90| | 8| | 48| 3.429| | | | 0.2| 0.5| 0.1|
+--+---+----+----+-----+--------+---+----+----+-----+-----+--------+
|A |599|2236|6932|21598|2075.945|450|4065|6585|255.0|377.9| 204.5|
+--+---+----+----+-----+--------+---+----+----+-----+-----+--------+
Masonry, 2075.945
Lantern, and its Apparatus, 7.500
--------
Total in Tons, 2083.445
In this Table, 13 cubic feet are allowed to a ton of Granite, and 14
cubic feet to a ton of Sandstone.
[Sidenote: Workmanship.]
SCHEDULE, shewing the Extent and Description of WORK executed on
the Sandstone and Granite employed in the Erection of the Bell Rock
Light-house.
Key:
A Total 90