FAMOUS ECLIPSES OF THE SUN
What is thought to be the earliest reference to an eclipse comes down to
us from the ancient Chinese records, and is over four thousand years
old. The eclipse in question was a solar one, and occurred, so far as
can be ascertained, during the twenty-second century B.C. The story runs
that the two state astronomers, Ho and Hi by name, being exceedingly
intoxicated, were unable to perform their required duties, which
consisted in superintending the customary rites of beating drums,
shooting arrows, and the like, in order to frighten away the mighty
dragon which it was believed was about to swallow up the Lord of Day.
This eclipse seems to have been only partial; nevertheless a great
turmoil ensued, and the two astronomers were put to death, no doubt with
the usual _celestial_ cruelty.
The next eclipse mentioned in the Chinese annals is also a solar
eclipse, and appears to have taken place more than a thousand years
later, namely in 776 B.C. Records of similar eclipses follow from the
same source; but as they are mere notes of the events, and do not enter
into any detail, they are of little interest. Curiously enough the
Chinese have taken practically no notice of eclipses of the moon, but
have left us a comparatively careful record of comets, which has been
of value to modern astronomy.
The earliest mention of a _total_ eclipse of the sun (for it should be
noted that the ancient Chinese eclipse above-mentioned was merely
partial) was deciphered in 1905, on a very ancient Babylonian tablet, by
Mr. L.W. King of the British Museum. This eclipse took place in the year
1063 B.C.
Assyrian tablets record three solar eclipses which occurred between
three and four hundred years later than this. The first of these was in
763 B.C.; the total phase being visible near Nineveh.
The next record of an eclipse of the sun comes to us from a Grecian
source. This eclipse took place in 585 B.C., and has been the subject of
much investigation. Herodotus, to whom we are indebted for the account,
tells us that it occurred during a battle in a war which had been waging
for some years between the Lydians and Medes. The sudden coming on of
darkness led to a termination of the contest, and peace was afterwards
made between the combatants. The historian goes on to state that the
eclipse had been foretold by Thales, who is looked upon as the Founder
of Grecian astronomy. This eclipse is in consequence known as the
"Eclipse of Thales." It would seem as if that philosopher were
acquainted with the Chaldean saros.
The next solar eclipse worthy of note was an annular one, and occurred
in 431 B.C., the first year of the Peloponnesian War. Plutarch relates
that the pilot of the ship, which was about to convey Pericles to the
Peloponnesus, was very much frightened by it; but Pericles calmed him by
holding up a cloak before his eyes, and saying that the only difference
between this and the eclipse was that something larger than the cloak
prevented his seeing the sun for the time being.
An eclipse of great historical interest is that known as the "Eclipse of
Agathocles," which occurred on the morning of the 15th of August, 310
B.C. Agathocles, Tyrant of Syracuse, had been blockaded in the harbour
of that town by the Carthaginian fleet, but effected the escape of his
squadron under cover of night, and sailed for Africa in order to invade
the enemy's territory. During the following day he and his vessels
experienced a total eclipse, in which "day wholly put on the appearance
of night, and the stars were seen in all parts of the sky."
A few solar eclipses are supposed to be referred to in early Roman
history, but their identity is very doubtful in comparison with those
which the Greeks have recorded. Additional doubt is cast upon them by
the fact that they are usually associated with famous events. The birth
and death of Romulus, and the Passage of the Rubicon by Julius Cæsar,
are stated indeed to have been accompanied by these marks of the
approval or disapproval of the gods!
Reference to our subject in the Bible is scanty. Amos viii. 9 is thought
to refer to the Nineveh eclipse of 763 B.C., to which allusion has
already been made; while the famous episode of Hezekiah and the shadow
on the dial of Ahaz has been connected with an eclipse which was partial
at Jerusalem in 689 B.C.
The first solar eclipse, recorded during the Christian Era, is known as
the "Eclipse of Phlegon," from the fact that we are indebted for the
account to a pagan writer of that name. This eclipse took place in A.D.
29, and the total phase was visible a little to the north of Palestine.
It has sometimes been confounded with the "darkness of the Crucifixion,"
which event took place near the date in question; but it is sufficient
here to say that the Crucifixion is well known to have occurred during
the Passover of the Jews, which is always celebrated at the _full_ moon,
whereas an eclipse of the sun can only take place at _new_ moon.
Dion Cassius, commenting on the Emperor Claudius about the year A.D. 45,
writes as follows:--
"As there was going to be an eclipse on his birthday, through fear of a
disturbance, as there had been other prodigies, he put forth a public
notice, not only that the obscuration would take place, and about the
time and magnitude of it, but also about the causes that produce such an
event."
This is a remarkable piece of information; for the Romans, an
essentially military nation, appear hitherto to have troubled themselves
very little about astronomical matters, and were content, as we have
seen, to look upon phenomena, like eclipses, as mere celestial
prodigies.
What is thought to be the first definite mention of the solar corona
occurs in a passage of Plutarch. The eclipse to which he refers is
probably one which took place in A.D. 71. He says that the obscuration
caused by the moon "has no time to last and no extensiveness, but some
light shows itself round the sun's circumference, which does not allow
the darkness to become deep and complete." No further reference to this
phenomenon occurs until near the end of the sixteenth century. It
should, however, be here mentioned that Mr. E.W. Maunder has pointed
out the probability[6] that we have a very ancient symbolic
representation of the corona in the "winged circle," "winged disc," or
"ring with wings," as it is variously called, which appears so often
upon Assyrian and Egyptian monuments, as the symbol of the Deity (Fig.
7).
[Illustration: FIG. 7.--The "Ring with Wings." The upper is the Assyrian
form of the symbol, the lower the Egyptian. (From _Knowledge_.) Compare
the form of the corona on Plate VII. (B), p. 142.]
The first solar eclipse recorded to have been seen in England is that of
A.D. 538, mention of which is found in the _Anglo-Saxon Chronicle_. The
track of totality did not, however, come near our islands, for only
two-thirds of the sun's disc were eclipsed at London.
In 840 a great eclipse took place in Europe, which was total for more
than five minutes across what is now Bavaria. Terror at this eclipse is
said to have hastened the death of Louis le Debonnaire, Emperor of the
West, who lay ill at Worms.
In 878--_temp._ King Alfred--an eclipse of the sun took place which was
total at London. From this until 1715 no other eclipse was total at
London itself; though this does not apply to other portions of England.
An eclipse, generally known as the "Eclipse of Stiklastad," is said to
have taken place in 1030, during the sea-fight in which Olaf of Norway
is supposed to have been slain. Longfellow, in his _Saga of King Olaf_,
has it that
"The Sun hung red
As a drop of blood,"
but, as in the case of most poets, the dramatic value of an eclipse
seems to have escaped his notice.
In the year 1140 there occurred a total eclipse of the sun, the last to
be visible in England for more than five centuries. Indeed there have
been only two such since--namely, those of 1715 and 1724, to which we
shall allude in due course. The eclipse of 1140 took place on the 20th
March, and is thus referred to in the _Anglo-Saxon Chronicle_:--
"In the Lent, the sun and the day darkened, about the noon-tide of the
day, when men were eating, and they lighted candles to eat by. That was
the 13th day before the calends of April. Men were very much struck with
wonder."
Several of the older historians speak of a "fearful eclipse" as having
taken place on the morning of the Battle of Crecy, 1346. Lingard, for
instance, in his _History of England_, has as follows:--
"Never, perhaps, were preparations for battle made under circumstances
so truly awful. On that very day the sun suffered a partial eclipse:
birds, in clouds, the precursors of a storm, flew screaming over the two
armies, and the rain fell in torrents, accompanied by incessant thunder
and lightning. About five in the afternoon the weather cleared up; the
sun in full splendour darted his rays in the eyes of the enemy."
Calculations, however, show that no eclipse of the sun took place in
Europe during that year. This error is found to have arisen from the
mistranslation of an obsolete French word _esclistre_ (lightning), which
is employed by Froissart in his description of the battle.
In 1598 an eclipse was total over Scotland and part of North Germany. It
was observed at Torgau by Jessenius, an Hungarian physician, who noticed
a bright light around the moon during the time of totality. This is said
to be the first reference to the corona since that of Plutarch, to which
we have already drawn attention.
Mention of Scotland recalls the fact that an unusual number of eclipses
happen to have been visible in that country, and the occult bent natural
to the Scottish character has traditionalised a few of them in such
terms as the "Black Hour" (an eclipse of 1433), "Black Saturday" (the
eclipse of 1598 which has been alluded to above), and "Mirk Monday"
(1652). The track of the last-named also passed over Carrickfergus in
Ireland, where it was observed by a certain Dr. Wybord, in whose account
the term "corona" is first employed. This eclipse is the last which has
been total in Scotland, and it is calculated that there will not be
another eclipse seen as total there until the twenty-second century.
An eclipse of the sun which took place on May 30, 1612, is recorded as
having been seen "through a tube." This probably refers to the then
recent invention--the telescope.
The eclipses which we have been describing are chiefly interesting from
an historical point of view. The old mystery and confusion to the
beholders seem to have lingered even into comparatively enlightened
times, for we see how late it is before the corona attracts definite
attention for the sake of itself alone.
It is not a far cry from notice of the corona to that of other
accompaniments of a solar eclipse. Thus the eclipse of 1706, the total
phase of which was visible in Switzerland, is of great interest; for it
was on this occasion that the famous red prominences seem first to have
been noted. A certain Captain Stannyan observed this eclipse from Berne
in Switzerland, and described it in a letter to Flamsteed, the then
Astronomer Royal. He says the sun's "getting out of his eclipse was
preceded by a blood-red streak of light from its left limb, which
continued not longer than six or seven seconds of time; then part of the
Sun's disc appeared all of a sudden, as bright as Venus was ever seen in
the night, nay brighter; and in that very instant gave a Light and
Shadow to things as strong as Moonlight uses to do." How little was then
expected of the sun is, however, shown by Flamsteed's words, when
communicating this information to the Royal Society:--
"The Captain is the first man I ever heard of that took notice of a Red
Streak of Light preceding the Emersion of the Sun's body from a total
Eclipse. And I take notice of it to you because it infers that _the Moon
has an atmosphere_; and its short continuance of only six or seven
seconds of time, tells us that _its height is not more than the five or
six hundredth part of her diameter_."
What a change has since come over the ideas of men! The sun has proved a
veritable mine of discovery, while the moon has yielded up nothing new.
The eclipse of 1715, the first total at London since that of 878, was
observed by the famous astronomer, Edmund Halley, from the rooms of the
Royal Society, then in Crane Court, Fleet Street. On this occasion both
the corona and a red projection were noted. Halley further makes
allusion to that curious phenomenon, which later on became celebrated
under the name of "Baily's beads." It was also on the occasion of this
eclipse that the _earliest recorded drawings of the corona_ were made.
Cambridge happened to be within the track of totality; and a certain
Professor Cotes of that University, who is responsible for one of the
drawings in question, forwarded them to Sir Isaac Newton together with a
letter describing his observations.
In 1724 there occurred an eclipse, the total phase of which was visible
from the south-west of England, but not from London. The weather was
unfavourable, and the eclipse consequently appears to have been seen by
only one person, a certain Dr. Stukeley, who observed it from Haraden
Hill near Salisbury Plain. This is the last eclipse of which the total
phase was seen in any part of England. The next will not be until June
29, 1927, and will be visible along a line across North Wales and
Lancashire. The discs of the sun and moon will just then be almost of
the same apparent size, and so totality will be of extremely short
duration; in fact only a few seconds. London itself will not see a
totality until the year 2151--a circumstance which need hardly distress
any of us personally!
It is only from the early part of the nineteenth century that serious
scientific attention to eclipses of the sun can be dated. An _annular_
eclipse, visible in 1836 in the south of Scotland, drew the careful
notice of Francis Baily of Jedburgh in Roxburghshire to that curious
phenomenon which we have already described, and which has ever since
been known by the name of "Baily's beads." Spurred by his observation,
the leading astronomers of the day determined to pay particular
attention to a total eclipse, which in the year 1842 was to be visible
in the south of France and the north of Italy. The public interest
aroused on this occasion was also very great, for the region across
which the track of totality was to pass was very populous, and inhabited
by races of a high degree of culture.
This eclipse occurred on the morning of the 8th July, and from it may be
dated that great enthusiasm with which total eclipses of the sun have
ever since been received. Airy, our then Astronomer Royal, observed it
from Turin; Arago, the celebrated director of the Paris Observatory,
from Perpignan in the south of France; Francis Baily from Pavia; and Sir
John Herschel from Milan. The corona and three large red prominences
were not only well observed by the astronomers, but drew tremendous
applause from the watching multitudes.
The success of the observations made during this eclipse prompted
astronomers to pay similar attention to that of July 28, 1851, the total
phase of which was to be visible in the south of Norway and Sweden, and
across the east of Prussia. This eclipse was also a success, and it was
now ascertained that the red prominences belonged to the sun and not to
the moon; for the lunar disc, as it moved onward, was seen to cover and
to uncover them in turn. It was also noted that these prominences were
merely uprushes from a layer of glowing gaseous matter, which was seen
closely to envelop the sun.
The total eclipse of July 18, 1860, was observed in Spain, and
photography was for the first time _systematically_ employed in its
observation.[7] In the photographs taken the stationary appearance of
both the corona and prominences with respect to the moving moon,
definitely confirmed the view already put forward that they were actual
appendages of the sun.
The eclipse of August 18, 1868, the total phase of which lasted nearly
six minutes, was visible in India, and drew thither a large concourse of
astronomers. In this eclipse the spectroscope came to the front, and
showed that both the prominences, and the chromospheric layer from which
they rise, are composed of glowing vapours--chief among which is the
vapour of hydrogen. The direct result of the observations made on this
occasion was the spectroscopic method of examining prominences at any
time in full daylight, and without a total eclipse. This method, which
has given such an immense impetus to the study of the sun, was the
outcome of independent and simultaneous investigation on the part of the
French astronomer, the late M. Janssen, and the English astronomer,
Professor (now Sir Norman) Lockyer, a circumstance strangely reminiscent
of the discovery of Neptune. The principles on which the method was
founded seem, however, to have occurred to Dr. (now Sir William) Huggins
some time previously.
The eclipse of December 22, 1870, was total for a little more than two
minutes, and its track passed across the Mediterranean. M. Janssen, of
whom mention has just been made, escaped in a balloon from then besieged
Paris, taking his instruments with him, and made his way to Oran, in
Algeria, in order to observe it; but his expectations were disappointed
by cloudy weather. The expedition sent out from England had the
misfortune to be shipwrecked off the coast of Sicily. But the occasion
was redeemed by a memorable observation made by the American astronomer,
the late Professor Young, which revealed the existence of what is now
known as the "Reversing Layer." This is a shallow layer of gases which
lies immediately beneath the chromosphere. An illustration of the
corona, as it was seen during the above eclipse, will be found on Plate
VII. (A), p. 142.
In the eclipse of December 12, 1871, total across Southern India, the
photographs of the corona obtained by Mr. Davis, assistant to Lord
Lindsay (now the Earl of Crawford), displayed a wealth of detail
hitherto unapproached.
The eclipse of July 29, 1878, total across the western states of North
America, was a remarkable success, and a magnificent view of the corona
was obtained by the well-known American astronomer and physicist, the
late Professor Langley, from the summit of Pike's Peak, Colorado, over
14,000 feet above the level of the sea. The coronal streamers were seen
to extend to a much greater distance at this altitude than at points
less elevated, and the corona itself remained visible during more than
four minutes after the end of totality. It was, however, not entirely a
question of altitude; the coronal streamers were actually very much
longer on this occasion than in most of the eclipses which had
previously been observed.
The eclipse of May 17, 1882, observed in Upper Egypt, is notable from
the fact that, in one of the photographs taken by Dr. Schuster at Sohag,
a bright comet appeared near the outer limit of the corona (see Plate
I., p. 96). The comet in question had not been seen before the eclipse,
and was never seen afterwards. This is the third occasion on which
attention has been drawn to a comet _merely_ by a total eclipse. The
first is mentioned by Seneca; and the second by Philostorgius, in an
account of an eclipse observed at Constantinople in A.D. 418. A fourth
case of the kind occurred in 1893, when faint evidences of one of these
filmy objects were found on photographs of the corona taken by the
American astronomer, Professor Schaeberle, during the total eclipse of
April 16 of that year.
The eclipse of May 6, 1883, had a totality of over five minutes, but
the central track unfortunately passed across the Pacific Ocean, and the
sole point of land available for observing it from was one of the
Marquesas Group, Caroline Island, a coral atoll seven and a half miles
long by one and a half broad. Nevertheless astronomers did not hesitate
to take up their posts upon that little spot, and were rewarded with
good weather.
The next eclipse of importance was that of April 16, 1893. It stretched
from Chili across South America and the Atlantic Ocean to the West Coast
of Africa, and, as the weather was fine, many good results were
obtained. Photographs were taken at both ends of the track, and these
showed that the appearance of the corona remained unchanged during the
interval of time occupied by the passage of the shadow across the earth.
It was on the occasion of this eclipse that Professor Schaeberle found
upon his photographs those traces of the presence of a comet, to which
allusion has already been made.
Extensive preparations were made to observe the eclipse of August 9,
1896. Totality lasted from two to three minutes, and the track stretched
from Norway to Japan. Bad weather disappointed the observers, with the
exception of those taken to Nova Zembla by Sir George Baden Powell in
his yacht _Otaria_.
The eclipse of January 22, 1898, across India _viâ_ Bombay and Benares,
was favoured with good weather, and is notable for a photograph obtained
by Mrs. E.W. Maunder, which showed a ray of the corona extending to a
most unusual distance.
[Illustration: PLATE I. THE TOTAL ECLIPSE OF THE SUN OF MAY 17TH, 1882
A comet is here shown in the immediate neighbourhood of the corona.
Drawn by Mr. W.H. Wesley from the photographs.
(Page 95)]
Of very great influence in the growth of our knowledge with regard to
the sun, is the remarkable piece of good fortune by which the countries
around the Mediterranean, so easy of access, have been favoured with a
comparatively large number of total eclipses during the past sixty
years. Tracks of totality have, for instance, traversed the Spanish
peninsula on no less than five occasions during that period. Two of
these are among the most notable eclipses of recent years, namely, those
of May 28, 1900, and of August 30, 1905. In the former the track of
totality stretched from the western seaboard of Mexico, through the
Southern States of America, and across the Atlantic Ocean, after which
it passed over Portugal and Spain into North Africa. The total phase
lasted for about a minute and a half, and the eclipse was well observed
from a great many points along the line. A representation of the corona,
as it appeared on this occasion, will be found on Plate VII. (B), p.
142.
The track of the other eclipse to which we have alluded, _i.e._ that of
August 30, 1905, crossed Spain about 200 miles to the northward of that
of 1900. It stretched from Winnipeg in Canada, through Labrador, and
over the Atlantic; then traversing Spain, it passed across the Balearic
Islands, North Africa, and Egypt, and ended in Arabia (see Fig. 6, p.
81). Much was to be expected from a comparison between the photographs
taken in Labrador and Egypt on the question as to whether the corona
would show any alteration in shape during the time that the shadow was
traversing the intervening space--some 6000 miles. The duration of the
total phase in this eclipse was nearly four minutes. Bad weather,
however, interfered a good deal with the observations. It was not
possible, for instance, to do anything at all in Labrador. In Spain the
weather conditions were by no means favourable; though at Burgos, where
an immense number of people had assembled, the total phase was,
fortunately, well seen. On the whole, the best results were obtained at
Guelma in Algeria. The corona on the occasion of this eclipse was a very
fine one, and some magnificent groups of prominences were plainly
visible to the naked eye (see the Frontispiece).
The next total eclipse after that of 1905 was one which occurred on
January 14, 1907. It passed across Central Asia and Siberia, and had a
totality lasting two and a half minutes at most; but it was not observed
as the weather was extremely bad, a circumstance not surprising with
regard to those regions at that time of year.
The eclipse of January 3, 1908, passed across the Pacific Ocean. Only
two small coral islands--Hull Island in the Phoenix Group, and Flint
Island about 400 miles north of Tahiti--lay in the track. Two
expeditions set out to observe it, _i.e._ a combined American party from
the Lick Observatory and the Smithsonian Institution of Washington, and
a private one from England under Mr. F.K. McClean. As Hull Island
afforded few facilities, both parties installed their instruments on
Flint Island, although it was very little better. The duration of the
total phase was fairly long--about four minutes, and the sun very
favourably placed, being nearly overhead. Heavy rain and clouds,
however, marred observation during the first minute of totality, but the
remaining three minutes were successfully utilised, good photographs of
the corona being obtained.
The next few years to come are unfortunately by no means favourable
from the point of view of the eclipse observer. An eclipse will take
place on June 17, 1909, the track stretching from Greenland across the
North Polar regions into Siberia. The geographical situation is,
however, a very awkward one, and totality will be extremely short--only
six seconds in Greenland and twenty-three seconds in Siberia.
The eclipse of May 9, 1910, will be visible in Tasmania. Totality will
last so long as four minutes, but the sun will be at the time much too
low in the sky for good observation.
The eclipse of the following year, April 28, 1911, will also be
confined, roughly speaking, to the same quarter of the earth, the track
passing across the old convict settlement of Norfolk Island, and then
out into the Pacific.
The eclipse of April 17, 1912, will stretch from Portugal, through
France and Belgium into North Germany. It will, however, be of
practically no service to astronomy. Totality, for instance, will last
for only three seconds in Portugal; and, though Paris lies in the
central track, the eclipse, which begins as barely total, will have
changed into an _annular_ one by the time it passes over that city.
The first really favourable eclipse in the near future will be that of
August 21, 1914. Its track will stretch from Greenland across Norway,
Sweden, and Russia. This eclipse is a return, after one saros, of the
eclipse of August 9, 1896.
The last solar eclipse which we will touch upon is that predicted for
June 29, 1927. It has been already alluded to as the first of those in
the future to be _total_ in England. The central line will stretch from
Wales in a north-easterly direction. Stonyhurst Observatory, in
Lancashire, will lie in the track; but totality there will be very
short, only about twenty seconds in duration.
[6] _Knowledge_, vol. xx. p. 9, January 1897.
[7] The _first photographic representation of the corona_ had, however,
been made during the eclipse of 1851. This was a daguerreotype taken by
Dr. Busch at Königsberg in Prussia.