THE ECLIPSES
Among all the celestial phenomena at which it may be our lot to assist
during our contemplation of the universe, one of the most magnificent
and imposing is undoubtedly that which we are now going to consider.
The hirsute comets, and shooting stars with their graceful flight,
captivate us with a mysterious and sometimes fantastic attraction. We
gladly allow our thoughts, mute questioners of the mysteries of the
firmament, to rest upon the brilliant, golden trail they leave behind
them. These unknown travelers bring a message from eternity; they tell
us the tale of their distant journeys. Children of space, their ethereal
beauty speaks of the immensity of the universe.
The eclipses, on the other hand, are phenomena that touch us more
nearly, and take place in our vicinity.
In treating of them, we remain between the Earth and the Moon, in our
little province, and witness the picturesque effects of the combined
movements of our satellite around us.
Have you ever seen a total eclipse of the Sun?
The sky is absolutely clear: no fraction of cloud shadows the solar
rays. The azure vault of the firmament crowns the Earth with a dome of
dazzling light. The fires of the orb of day shed their beneficent
influence generally upon the world.
Yet, see! The radiance diminishes. The luminous disk of the Sun is
gradually corroded. Another disk, as black as ink, creeps in front of
it, and little by little invades it entirely. The atmosphere takes on a
wan, sepulchral hue; astonished nature is hushed in profound silence; an
immense veil of sadness spreads over the world. Night comes on suddenly,
and the stars shine out in the Heavens. It seems as though by some
mysterious cataclysm the Sun had disappeared forever. But this
tribulation is soon over. The divine orb is not extinct. A flaming jet
emerges from the shadow, announcing his return, and when he reappears we
see that he has lost nothing in splendor or beauty. He is still the
radiant Apollo, King of Day, watching over the life of the planetary
worlds.
This sudden night, darkening the Heavens in the midst of a fine day, can
not fail to produce a vivid impression upon the spectators of the superb
phenomenon.
The eclipse lasts only for a few moments, but long enough to make a deep
impression upon our minds, and indeed to inspire anxious spirits with
terror and agitation--even at this epoch, when we know that there is
nothing supernatural or formidable about it.
In former days, Humanity would have trembled, in uneasy consternation.
Was it a judgment from Heaven? Must it not be the work of some invisible
hand throwing the somber veil of night over the celestial torch?
Had not the Earth strayed off her appointed path, and were we not all to
be deprived eternally of the light of our good Sun? Was some monstrous
dragon perhaps preparing to devour the orb of day?
The fable of the dragon devouring the Sun or Moon during the eclipses is
universal in Asia as in Africa, and still finds acceptance under more
than one latitude. But our readers already know that we may identify the
terrible celestial dragon with our gentle friend the Moon, who would not
be greatly flattered by the comparison.
We saw in the preceding lesson that the Moon revolves round us,
describing an almost circular orbit that she travels over in about a
month. In consequence of this motion, the nocturnal orb is sometimes
between the Sun and the Earth, sometimes behind us, sometimes at a right
angle in relation to the Sun and the Earth. Now, the eclipses of the Sun
occur invariably at the time of New Moon, when our satellite passes
between the Sun and ourselves, and the eclipses of the Moon, at the
moment of Full Moon, when the latter is opposite to the Sun, and behind
us.
This fact soon enabled the astronomers of antiquity to discover the
causes to which eclipses are due.
The Moon, passing at the beginning of its revolution between the Sun and
the Earth, may conceal a greater or lesser portion of the orb of day. In
this case there is an eclipse of the Sun. On the other hand, when it is
on the other side of the Earth in relation to the Sun, at the moment of
Full Moon, our planet may intercept the solar rays, and prevent them
from reaching our satellite. The Moon is plunged into _the shadow of the
Earth_, and is then eclipsed. Such is the very simple explanation of the
phenomenon. But why is there not an eclipse of the Sun at each New Moon,
and an eclipse of the Moon at each Full Moon?
If the Moon revolved round us in the same plane as the Earth round the
Sun, it would eclipse the Sun at each New Moon, and would be itself
eclipsed in our shadow at each Full Moon. But the plane of the lunar
orbit dips a little upon the plane of the terrestrial orbit, and the
eclipses can only be produced when the New Moon or the Full Moon occur
at the line of intersection of these two planes, _i.e._, when the Sun,
the Moon, and the Earth are upon the same straight line. In the majority
of cases, instead of interposing itself directly in front of the
sovereign of our system, our satellite passes a little above or a little
below him, just as its passage behind us is nearly always effected a
little above or below the cone of shadow that accompanies our planet,
opposite the Sun.
When the Moon intervenes directly in front of the Sun, she arrests the
light of the radiant orb, and conceals a greater or less portion of the
solar disk. The eclipse is partial if the Moon covers only a portion of
the Sun; total if she covers it entirely; annular, if the solar disk is
visible all round the lunar disk, as appears when the Moon, in her
elliptical orbit, is beyond medium distance, toward the apogee.
On the other hand, when the Moon arrives immediately within the cone of
shadow that the Earth projects behind it, it is her turn to be eclipsed.
She no longer receives the rays of the Sun, and this deprivation is the
more marked in that she owes all her brilliancy to the light of the orb
of day. The Moon's obscurity is complete if she is entirely plunged into
the cone of shadow. In this case, the eclipse is total. But if a portion
of her disk emerges from the cone, that part remains illuminated while
the light of the other dies out. In that case there is a partial
eclipse, and the rounded form of the Earth's shadow can be seen
projected upon our satellite, a celestial witness to the spherical
nature of our globe.
Under certain conditions, then, the Moon can deprive us of the luminous
rays of the Sun, by concealing the orb of day, and in other cases is
herself effaced in crossing our shadow. Despite the fables, fears, and
anxieties it has engendered, this phenomenon is perfectly natural: the
Moon is only playing hide-and-seek with us--a very harmless amusement,
as regards the safety of our planet.
But as we said just now, these phenomena formerly had the power of
terrifying ignorant mortals, either when the orb of light and life
seemed on the verge of extinction, or when the beautiful Phoebus was
covered with a veil of crape and woe, or took on a deep coppery hue.
It would take a volume to describe all the notable events which have
been influenced by eclipses, sometimes for good, more often with
disastrous consequences. The recital of these tragic stories would not
be devoid of interest; it would illustrate the possibilities of
ignorance and superstition, and the power man gains from intellectual
culture and scientific study.
Herodotus records that the Scythians, having some grievance against
Cyaxarus, King of the Medes, revenged themselves by serving up the limbs
of one of his children, whom they had murdered, at a banquet as rare
game. The scoundrels who committed this atrocious crime took refuge at
the Court of the King of Lydia, who was ill judged enough to protect
them. War was accordingly declared between the Medes and Lydians, but a
total eclipse of the Sun occurring just when the battle was imminent,
had the happy effect of disarming the combatants, who prudently retired
each to their own country. This eclipse, which seems to have occurred on
May 28, 584 B.C., had been predicted by Thales. The French painter
Rochegrosse has painted a striking picture of the scene (Fig. 75).
In the year 413 B.C. the Athenian General Nicias prepared to return to
Greece after an expedition to Sicily. But, terrified by an eclipse of
the Moon, and fearing the malign influence of the phenomenon, he put off
his departure, and lost the chance of retreat. This superstition cost
him his life. The Greek army was destroyed, and this event marks the
commencement of the decadence of Athens.
In 331 B.C. an eclipse of the Moon disorganized the troops of Alexander,
near Arbela, and the great Macedonian Captain had need of all his
address to reassure his panic-stricken soldiers.
Agathocles, King of Syracuse, blocked by the Carthaginians in the port
of this city, had the good fortune to escape, but was disturbed on the
second day of his flight by the arrival of a total eclipse of the Sun
which alarmed his companions. "What are you afraid of?" said he,
spreading his cloak in front of the Sun. "Are you alarmed at a shadow?"
(This eclipse seems to be that of August 15, 309, rather than that of
March 2, 310.)
[Illustration: FIG. 75.--Battle between the Medes and Lydians arrested
by an Eclipse of the Sun.]
On June 29, 1033, an epoch at which the approaching end of the world
struck terror into all hearts, an annular eclipse of the Sun occurring
about midday frustrated the designs of a band of conspirators who
intended to strangle the Pope at the altar. This Pope was Benedict IX, a
youth of less than twenty, whose conduct is said to have been anything
but exemplary. The assassins, terrified at the darkening of the Sun,
dared not touch the Pontiff, and he reigned till 1044.[15]
On March 1, 1504, a lunar eclipse saved the life of Christopher
Columbus. He was threatened with death by starvation in Jamaica, where
the contumacious savages refused to give him provisions. Forewarned of
the arrival of this eclipse by the astronomical almanacs, he threatened
to deprive the Caribs of the light of the Moon--and kept his word. The
eclipse had hardly begun when the terrified Indians flung themselves at
his feet, and brought him all that he required.
In all times and among all people we find traces of popular
superstitions connected with eclipses. Here, the abnormal absence of the
Moon's light is regarded as a sign of divine anger: the humble penitents
betake themselves to prayer to ward off the divine anger. There, the
cruelty of the dread dragon is to be averted: he must be chased away by
cries and threats, and the sky is bombarded with shots to deliver the
victim from his monstrous oppressor.
In France the announcement of a solar eclipse for August 21, 1560, so
greatly disturbed our ancestors' peace of mind as to make them idiotic.
Preparations were made for assisting at an alarming phenomenon that
threatened Humanity with deadly consequences! The unhappy eclipse had
been preceded by a multitude of ill omens! Some expected a great
revolution in the provinces and in Rome, others predicted a new
universal deluge, or, on the other hand, the conflagration of the world;
the most optimistic thought the air would be contaminated. To preserve
themselves from so many dangers, and in accordance with the physicians'
orders, numbers of frightened people shut themselves up in tightly
closed and perfumed cellars, where they awaited the decrees of Fate. The
approach of the phenomenon increased the panic, and it is said that one
village _cure_, being unable to hear the confessions of all his flock,
who wanted to discharge their souls of sin before taking flight for a
better world, was fain to tell them "there was no hurry, because the
eclipse had been put off a fortnight on account of the number of
penitents"!
[Illustration: FIG. 76.--Eclipse of the Moon at Laos (February 27,
1877).]
These fears and terrors are still extant among ignorant peoples. In the
night of February 27, 1877, an eclipse of the Moon produced an
indescribable panic among the inhabitants of Laos (Indo-China). In order
to frighten off the Black Dragon, the natives fired shots at the
half-devoured orb, accompanying their volley with the most appalling
yells. Dr. Harmand has memorialized the scene in the lively sketch given
on p. 269.
During the solar eclipse of March 15, 1877, an analogous scene occurred
among the Turks, who for the moment forgot their preparations for war
with Russia, in order to shoot at the Sun, and deliver him from the
toils of the Dragon.
The lunar eclipse of December 16, 1880, was not unnoticed at Tackhent
(Russian Turkestan), where it was received with a terrific din of
saucepans, samovars and various implements struck together again and
again by willing hands that sought to deliver the Moon from the demon
Tchaitan who was devouring her.
In China, eclipses are the object of imposing ceremonies, whose object
is to reestablish the regularity of the celestial motions. Since the
Emperor is regarded as the Son of Heaven, his government must in some
sort be a reflection of the immutable order of the sidereal harmonies.
As eclipses were regarded by astrologers as disturbances of the divine
order, their appearance indicates some irregularity in the government of
the Celestial Empire. Accordingly, they are received with all kinds of
expiatory ceremonies prescribed thousands of years ago, and still in
force to-day.
In the twentieth century, as in the nineteenth, the eighteenth, or in
ancient epochs, the same awe and terror operates upon the ignorant
populations who abound upon the surface of our planet.
To return to astronomical realities.
We said above that these phenomena were produced when the Full Moon and
the New Moon reached the line of intersection, known as the line of
nodes, when the plane of the lunar orbit cuts the plane of the ecliptic.
As this line turns and comes back in the same direction relatively to
the Sun at the end of eighteen years, eleven days, we have only to
register the eclipses observed during this period in order to know all
that will occur in the future, and to find such as happened in the past.
This period was known to the Greeks under the name of the Metonic Cycle,
and the Chaldeans employed it three thousand years ago under the name of
Saros.
On examining this cycle, composed of 223 lunations, we see that there
can not be more than seven eclipses in one year, nor less than two. When
there are only two, they are eclipses of the Sun.
The totality of a solar eclipse can not last more than seven minutes,
fifty-eight seconds at the equator, and six minutes, ten seconds in the
latitude of Paris. The Moon, on the contrary, may be entirely eclipsed
for nearly two hours.
Eclipses of the Sun are very rare for a definite spot. Thus not one
occurred for Paris during the whole of the nineteenth century, the last
which happened exactly above the capital of France having been on May
22, 1724. I have calculated all those for the twentieth century, and
find that two will take place close to Paris, on April 17, 1912, at
eighteen minutes past noon (total for Choisy-le-Roi, Longjumeau, and
Dourdan, but very brief: seven seconds), and August 11, 1999, at 10.28
A.M. (total for Beauvais, Compiegne, Amiens, St. Quentin, fairly long:
two minutes, seventeen seconds). Paris itself will not be favored before
August 12, 2026. In order to witness the phenomenon, one must go and
look for it. This the author did on May 28, 1900, in Spain.
The progress of the lunar shadow upon the surface of the Earth is traced
beforehand on maps that serve to show the favored countries for which
our satellite will dispense her ephemeral night. The above figure shows
the trajectory of the total phase of the 1900 eclipse in Portugal,
Spain, Algeria, and Tunis.
[Illustration: FIG. 77.--The path of the Eclipse of May 28, 1900.]
The immutable splendor of the celestial motions had never struck the
author so impressively as during the observation of this grandiose
phenomenon. With the absolute precision of astronomical calculations,
our satellite, gravitating round the Earth, arrived upon the theoretical
line drawn from the orb of day to our planet, and interposed itself
gradually, slowly, and exactly, in front of it. The eclipse was total,
and occurred at the moment predicted by calculation. Then the obscure
globe of the Moon pursued its regular course, discovered the radiant orb
behind, and gradually and slowly completed its transit in front of him.
Here, to all observers, was a double philosophical lesson, a twofold
impression: that of the greatness, the omnipotence of the inexorable
forces that govern the universe, and that of the inexorable valor of
man, of this thinking atom straying upon another atom, who by the
travail of his feeble intelligence has arrived at the knowledge of the
laws by which he, like the rest of the world, is borne away through
space, through time, and through eternity.
The line of centrality passed through Elche, a picturesque city of
30,000 inhabitants, not far from Alicante, and we had chosen this for
our station on account of the probability of fine weather.
From the terrace of the country house of the hospitable Mayor, a farm
transformed into an observatory by our learned friend, Count de la Baume
Pluvinel, there were no obstacles between ourselves and any part of the
sky or landscape. The whole horizon lay before us. In front was a town
of Arab aspect framed in a lovely oasis of palm-trees; a little farther
off, the blue sea beyond the shores of Alicante and Murcia: on the
other side a belt of low mountains, and near us fields and gardens. A
Company of the Civic Guard kept order, and prevented the entrance of too
many curious visitors, of whom over ten thousand had arrived.
At the moment when the first contact of the lunar disk with the solar
disk was observed in the telescope, we fired a gun, in order to announce
the precise commencement of the occultation to the 40,000 persons who
were awaiting the phenomenon, and to discover what difference would
exist between this telescopic observation and those made with the
unaided eyes (protected simply by a bit of smoked glass) of so many
improvised spectators. This had already been done by Arago at Perpignan
in 1842. The verification was almost immediate for the majority of eyes,
and may be estimated at eight or ten seconds. So that the commencement
of the eclipse was confirmed almost as promptly for the eye as with the
astronomical instruments.
The sky was splendidly clear; no cloud, no mist, deep blue; blazing Sun.
The first period of the eclipse showed nothing particular. It is only
from the moment when more than half the solar disk is covered by the
lunar disk that the phenomenon is imposing in its grandeur. At this
phase, I called the attention of the people standing in the court to the
visibility of the stars, and indicating the place of Venus in the sky
asked if any with long sight could perceive her. Eight at once
responded in the affirmative. It should be said that the planet was at
that time at its period of maximum brilliancy, when for observers
blessed with good sight, it is always visible to the unaided eye.
When some three-quarters of the Sun were eclipsed, the pigeons which had
flown back to the farm huddled into a corner, and made no further
movement. They told me that evening that the fowls had done the same a
little later, returning to the hen-house as though it had been night,
and that the small children (who were very numerous at Elche, where the
population is certainly not diminishing) left off their games, and came
back to their mothers' skirts. The birds flew anxiously to their nests.
The ants in one garden were excessively agitated, no doubt disconcerted
in their strategics. The bats came out.
A few days before the eclipse I had prepared the inhabitants of this
part of Spain for the observation of the phenomenon by the following
description, which sums up the previous accounts of the astronomers:
"The spectacle of a total eclipse of the Sun is one of the most
magnificent and imposing that it is possible to see in nature. At the
exact moment indicated by calculation, the Moon arrives in front of the
Sun, eats into it gradually, and at last entirely covers it. The light
of the day lessens and is transformed. A sense of oppression is felt by
all nature, the birds are hushed, the dog takes refuge with his master,
the chickens hide beneath their mother's wing, the wind drops, the
temperature falls, an appalling stillness is everywhere perceptible, as
though the universe were on the verge of some imminent catastrophe.
Men's faces assume a cadaverous hue similar to that given at night by
the flame of spirits of wine and salt, a livid funereal light, the
sinister illumination of the world's last hour.
"At the moment when the last line of the solar crescent disappears, we
see, instead of the Sun, a black disk surrounded with a splendid
luminous aureole shooting immense jets into space, with roseate flames
burning at the base.
"A sudden night has fallen on us, a weird, wan night in which the
brightest of the stars are visible in the Heavens. The spectacle is
splendid, grandiose, solemn, and sublime."
This impression was actually felt by us all, as may be seen from the
following notes, written in my schedule of observation during the event,
or immediately after:
"3.50 P.M. Light very weak, sky leaden gray, mountains standing out with
remarkable clearness from the horizon, and seeming to approach us.
"3.55 P.M. Fall of temperature very apparent. Cold wind blowing through
the atmosphere.
"3.56 P.M. Profound silence through nature, which seems to participate
in the celestial phenomenon. Silence in all the groups.
"3.57 P.M. Light considerably diminished, becoming wan, strange, and
sinister. Landscape leaden gray, sea looks black. This diminution of
light is not that of every day after the sunset. There is, as it were, a
tint of sadness spread over the whole of nature. One becomes accustomed
to it, and yet while we know that the occultation of the Sun by the Moon
is a natural phenomenon, we can not escape a certain sense of
uneasiness. The approach of some extraordinary spectacle is imminent."
At this point we examined the effects of the solar light upon the seven
colors of the spectrum. In order to determine as accurately as possible
the tonality of the light of the eclipse, I had prepared seven great
sheets, each painted boldly in the colors of the spectrum, violet,
indigo, blue, green, yellow, orange, red; and a similar series in pieces
of silk. These colors were laid at our feet upon the terrace where my
wife, as well as Countess de la Baume, were watching with me. We then
saw the first four disappear successively and entirely and turn black in
a few seconds, in the following order: violet, indigo, blue, green. The
three other colors were considerably attenuated by the darkness, but
remained visible.
It should be noted that in the normal order of things--that is, every
evening--the contrary appears; violet remains visible after the red.
This experiment shows that the last light emitted by the eclipsed Sun
belongs to the least refrangible rays, to the greatest wave-lengths, to
the slowest vibrations, to the yellow and red rays. Such therefore is
the predominating color of the solar atmosphere.
This experiment completed, we turn back to the Sun. Magical and splendid
spectacle! Totality has commenced, the Sun has disappeared, the black
disk of the Moon covers it entirely, leaving all round it a magnificent
corona of dazzling light. One would suppose it to be an annular eclipse,
with the difference that this can be observed with the naked eye,
without fatigue to the retina, and drawn quietly.
This luminous coronal atmosphere entirely surrounds the solar disk, at a
pretty equal depth, equivalent to about the third of half the solar
diameter. It may be regarded as the Sun's atmosphere.
Beyond this corona is an aureole, of vaster glory but less luminous,
which sends out long plumes, principally in the direction of the
equatorial zone of the Sun, and of the belt of activity of the spots and
prominences.
At the summit of the disk it is conical in shape. Below it is double,
and its right-hand portion ends in a point, not far from Mercury, which
shines like a dazzling star of first magnitude, and seems placed there
expressly to give us the extent and direction of the solar aureole.
I draw these various aspects (which, moreover, change with the movement
of the Moon), and what strikes me most is the distinction in light
between this aureole and the coronal atmosphere; the latter appears to
be a brilliant silvery white, the former is grayer and certainly less
dense.
My impression is that there are _two solar envelopes of entirely
different nature_, the corona belonging to the globe of the Sun, and
forming its atmosphere properly so-called, very luminous; the aureole
formed of particles that circulate independently round it, probably
arising from eruptions, their form as a whole being possibly due to
electric or magnetic forces, counterbalanced by resistances of various
natures. In our own atmosphere the volcanic eruptions are distinct from
the aerial envelope.
The general configuration of this external halo, spreading more
particularly in the equatorial zone, is sufficiently like that of the
eclipse of 1889, published in my _Popular Astronomy_, which also
corresponded with a minimum of solar energy. The year 1900 is in fact
close upon the minimum of the eleven-year period. This equatorial form
is, moreover, what all the astronomers were expecting.
[Illustration: FIG. 78.--Total eclipse of the Sun, May 28, 1900, as
observed from Elche (Spain).]
There can no longer be the slightest doubt that the solar envelope
varies with the activity of the Sun....
"But the total eclipse lasted a much shorter time than I have taken to
write these lines. The seventy-nine seconds of totality are over. A
dazzling light bursts from the Sun, and tells that the Moon pursuing its
orbit has left it. The splendid sight is over. It has gone like a
shadow.
"Already over! It is almost a disillusion. Nothing beautiful lasts in
this world. Too sad! If only the celestial spectacle could have lasted
two, three, or four minutes! It was too short....
"Alas! we are forced to take things as they are.
"The surprise, the oppression, the terror of some, the universal silence
are over. The Sun reappears in his splendor, and the life of nature
resumes its momentarily suspended course.
"While I was making my drawing, M. l'Abbe Moreux, my colleague from the
Astronomical Society of France, who accompanied me to Spain for this
observation, was taking one of his own, without any reciprocal
communication. These two sketches are alike, and confirmatory.
"The differential thermometers that I exposed to the Sun, hanging
freely, and protected from reflection from the ground, were read every
five minutes. The black thermometer went down from 33.1 deg. to 20.7
deg., that is 12.4 deg.; the white from 29 deg. to 20.2 deg.--that is,
8.8 deg. The temperature in the shade only varied three degrees.
"The light received during totality was due: first, to the luminous
envelope of the Sun; second, to that of the terrestrial atmosphere,
illuminated at forty kilometers (twenty-five miles) on the one side and
the other of the line of centrality. It appeared to be inferior to that
of the Full Moon, on account of the almost sudden transition. But, in
reality, it was more intense, for only first-magnitude stars were
visible in the sky, whereas on a night of full moon, stars of second,
and even of third magnitude are visible. We recognized, among others,
Venus, Mercury, Sirius, Procyon, Capella, Rigel, Betelgeuse."
* * * * *
From these notes, taken on the spot, it is evident that the
contemplation of a total eclipse of the Sun is one of the most marvelous
spectacles that can be admired upon our planet.
Some persons assured me that they saw the shadow of the Moon flying
rapidly over the landscape. My attention was otherwise occupied, and I
was unable to verify this interesting observation. The shadow of the
Moon in effect took only eleven minutes (3.47 P.M. to 3.58 P.M.) to
traverse the Iberian Peninsula from Porto to Alicante, _i.e._, a
distance of 766 kilometers (475 miles). It must therefore have passed
over the ground at a velocity of sixty-nine kilometers per minute, or
1,150 meters per second, a speed higher than that of a bullet. It can
easily be watched from afar, on the mountains.
Some weeks previous to this fine eclipse, when I informed the Spaniards
of the belt along which it could be observed, I had invited them to note
all the interesting phenomena they might witness, including the effects
produced by the eclipse upon animals. Birds returned hurriedly to their
nests, swallows lost themselves, sheep huddled into compact packs,
partridges were hypnotized, frogs croaked as if it were night, fowls
took refuge in the hen-house, and cocks crowed, bats came out, and were
surprised by the sun, chicks gathered under their mothers' wing,
cage-birds ceased their songs, some dogs howled, others crept shivering
to their masters' feet, ants returned to the antheap, grasshoppers
chirped as at sunset, pigeons sank to the ground, a swarm of bees went
silently back to their hive, and so on.
These creatures behaved as though the night had come, but there were
also signs of fear, surprise, even of terror, differing only "in degree"
from those manifested during the grandiose phenomenon of a total
eclipse by human beings unenlightened by a scientific education.
At Madrid the eclipse was only partial. The young King of Spain, Alfonso
XIII, took care to photograph it, and I offer the photograph to my
readers (Fig. 79), as this amiable sovereign did me the honor to give it
me a few days after the eclipse.
[Illustration: FIG. 79.--The Eclipse of May 28, 1900, as photographed by
King Alfonso XIII, at Madrid.]
The technical results of these observations of solar eclipses relate
more especially to the elucidation of the grand problem of the physical
constitution of the Sun. We alluded to them in the chapter devoted to
this orb. The last great total eclipses have been of immense value to
science.
The eclipses of the Moon are less important, less interesting, than the
eclipses of the Sun. Yet their aspect must not be neglected on this
account, and it may be said to vary for each eclipse.
Generally speaking, our satellite does not disappear entirely in the
Earth's cone of shadow; the solar rays are refracted round our globe by
our atmosphere, and curving inward, illumine the lunar globe with a rosy
tint that reminds one of the sunset. Sometimes, indeed, this refraction
does not occur, owing doubtless to lack of transparency in the
atmosphere, and the Moon becomes invisible. This happened recently, on
April 11, 1903.
For any spot, eclipses of the Moon are incomparably more frequent than
eclipses of the Sun, because the cone of lunar shadow that produces the
solar eclipses is not very broad at its contact with the surface of the
globe (10, 20, 30, 50, 100 kilometers, according to the distance of the
Moon), whereas all the countries of the Earth for which the Moon is
above the horizon at the hour of the lunar eclipse are able to see it.
It is at all times a remarkable spectacle that uplifts our thoughts to
the Heavens, and I strongly advise my readers on no account to forego
it.