But the moon is
not always at her zenith when she reaches her perigee, which is once a
month. She is only under the two conditions simultaneously at long
intervals of time. This coincidence of perigee and zenith must be waited
for. It happens fortunately that on December 4th of next year the moon
will offer these two conditions; at midnight she will be at her perigee
and her zenith—that is to say, at her shortest distance from the earth
and at her zenith at the same time.
"Regarding question No. 5, 'At what point in the heavens ought the
cannon destined to hurl the projectile be aimed?'
"The preceding observations being admitted, the cannon ought to be aimed
at the zenith of the place (the zenith is the spot situated vertically
above the head of a spectator), so that its range will be perpendicular
to the plane of the horizon, and the projectile will pass the soonest
beyond the range of terrestrial gravitation. But for the moon to reach
the zenith of a place that place must not exceed in latitude the
declination of the luminary—in other words, it must be comprised
between 0° and 28° of north or south latitude. In any other place the
range must necessarily be oblique, which would seriously affect the
success of the experiment.
"Regarding question No. 6, 'What place will the moon occupy In the
heavens at the moment of the projectile's departure?'
"At the moment when the projectile is hurled into space, the moon, which
travels forward 13° 10' 35" each day, will be four times as distant from
her zenith point—i.e., by 52° 42' 20", a space which corresponds to the
distance she will travel during the transit of the projectile. But as
the deviation which the rotatory movement of the earth will impart to
the shock must also be taken into account, and as the projectile cannot
reach the moon until after a deviation equal to sixteen radii of the
earth, which, calculated upon the moon's orbit, is equal to about 11°,
it is necessary to add these 11° to those caused by the
already-mentioned delay of the moon, or, in round numbers, 64°. Thus, at
the moment of firing, the visual radius applied to the moon will
describe with the vertical line of the place an angle of 64°.
"Such are the answers to the questions proposed to the Observatory of
Cambridge by the members of the Gun Club.
"To sum up—
"1st. The cannon must be placed in a country situated between 0° and 28°
of north or south latitude.
"2nd. It must be aimed at the zenith of the place.
"3rd. The projectile must have an initial speed of 12,000 yards a
second.
"4th. It must be hurled on December 1st of next year, at 10hrs. 46mins.
40secs. p.m.
"5th. It will meet the moon four days after its departure on December
4th, at midnight precisely, at the moment she arrives at her zenith.
"The members of the Gun Club ought, therefore, at once to commence the
labour necessitated by such an enterprise, and be ready to put them into
execution at the moment fixed upon, for they will not find the moon in
the same conditions of perigee and zenith till eighteen years and eleven
days later.
"The staff of the Observatory of Cambridge puts itself entirely at their
disposition for questions of theoretic astronomy, and begs to join its
congratulations to those of the whole of America.
"On behalf of the staff,
"J.M. BELFAST,
"Director of the Observatory of Cambridge."
*
A spectator endowed with infinite power of sight, and placed at the
unknown centre round which gravitates the universe, would have seen
myriads of atoms filling all space during the chaotic epoch of creation.
But by degrees, as centuries went on, a change took place; a law of
gravitation manifested itself which the wandering atoms obeyed; these
atoms, combined chemically according to their affinities, formed
themselves into molecules, and made those nebulous masses with which the
depths of the heavens are strewed.
These masses were immediately animated by a movement of rotation round
their central point. This centre, made of vague molecules, began to turn
on itself whilst progressively condensing; then, following the immutable
laws of mechanics, in proportion as its volume became diminished by
condensation its movement of rotation was accelerated, and these two
effects persisting, there resulted a principal planet, the centre of the
nebulous mass.
By watching attentively the spectator would then have seen other
molecules in the mass behave like the central planet, and condense in
the same manner by a movement of progressively-accelerated rotation, and
gravitate round it under the form of innumerable stars. The nebulae, of
which astronomers count nearly 5,000 at present, were formed.
Amongst these 5,000 nebulae there is one that men have called the Milky
Way, and which contains eighteen millions of stars, each of which has
become the centre of a solar world.
If the spectator had then specially examined amongst these eighteen
millions of stars one of the most modest and least brilliant, a star of
the fourth order, the one that proudly named itself the sun, all the
phenomena to which the formation of the universe is due would have
successively taken place under his eyes.
In fact, he would have perceived this sun still in its gaseous state,
and composed of mobile molecules; he would have perceived it turning on
its own axis to finish its work of concentration. This movement,
faithful to the laws of mechanics, would have been accelerated by the
diminution of volume, and a time would have come when the centrifugal
force would have overpowered the centripetal, which causes the molecules
all to tend towards the centre.
Then another phenomenon would have passed before the eyes of the
spectator, and the molecules situated in the plane of the equator would
have formed several concentric rings like that of Saturn round the sun.
In their turn these rings of cosmic matter, seized with a movement of
rotation round the central mass, would have been broken up into
secondary nebulae—that is to say, into planets.
If the spectator had then concentrated all his attention on these
planets he would have seen them behave exactly like the sun and give
birth to one or more cosmic rings, origin of those secondary bodies
which we call satellites.
Thus in going up from the atom to the molecule, from the molecule to the
nebulae, and from the nebulae to the principal star, from the principal
star to the sun, from the sun to the planet, and from the planet to the
satellite, we have the whole series of transformations undergone by the
celestial powers from the first days of the universe.
The sun seems lost amidst the immensities of the stellar universe, and
yet it is related, by actual theories of science, to the nebula of the
Milky Way. Centre of a world, and small as it appears amidst the
ethereal regions, it is still enormous, for its size is 1,400,000 times
that of the earth. Around it gravitate eight planets, struck off from
its own mass in the first days of creation. These are, in proceeding
from the nearest to the most distant, Mercury, Venus, the Earth, Mars,
Jupiter, Saturn, Uranus, and Neptune. Between Mars and Jupiter circulate
regularly other smaller bodies, the wandering débris, perhaps, of a
star broken up into thousands of pieces, of which the telescope has
discovered eighty-two at present. Some of these asteroids are so small
that they could be walked round in a single day by going at a gymnastic
pace.
Of these attendant bodies which the sun maintains in their elliptical
orbit by the great law of gravitation, some possess satellites of their
own. Uranus has eight, Saturn eight, Jupiter four, Neptune three
perhaps, and the Earth one; this latter, one of the least important of
the solar world, is called the Moon, and it is that one that the
enterprising genius of the Americans means to conquer.
The Queen of Night, from her relative proximity and the spectacle
rapidly renewed of her different phases, at first divided the attention
of the inhabitants of the earth with the sun; but the sun tires the
eyesight, and the splendour of its light forces its admirers to lower
their eyes.
The blonde Phoebe, more humane, graciously allows herself to be seen in
her modest grace; she is gentle to the eye, not ambitious, and yet she
sometimes eclipses her brother the radiant Apollo, without ever being
eclipsed by him. The Mahommedans understood what gratitude they owed to
this faithful friend of the earth, and they ruled their months at 29-1/2
days on her revolution.
The first people of the world dedicated particular worship to this
chaste goddess. The Egyptians called her Isis, the Phoenicians Astarte,
the Greeks Phoebe, daughter of Jupiter and Latona, and they explained
her eclipses by the mysterious visits of Diana and the handsome
Endymion. The mythological legend relates that the Nemean lion traversed
the country of the moon before its apparition upon earth, and the poet
Agesianax, quoted by Plutarch, celebrated in his sweet lines its soft
eyes, charming nose, and admirable mouth, formed by the luminous parts
of the adorable Selene.
But though the ancients understood the character, temperament, and, in a
word, moral qualities of the moon from a mythological point of view, the
most learned amongst them remained very ignorant of selenography.
Several astronomers, however, of ancient times discovered certain
particulars now confirmed by science.
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