the heavens at the moment of the projectile’s departure?”
_Answer._– At the moment when the projectile shall be discharged
into space, the moon, which travels daily forward 13@ 10′ 35”,
will be distant from the zenith point by four times that quantity,
_i. e._ by 52@ 41′ 20”, a space which corresponds to the path
which she will describe during the entire journey of the projectile.
But, inasmuch as it is equally necessary to take into account the
deviation which the rotary motion of the earth will impart to the
shot, and as the shot cannot reach the moon until after a deviation
equal to 16 radii of the earth, which, calculated upon the moon’s
orbit, are equal to about eleven degrees, it becomes necessary to
add these eleven degrees to those which express the retardation of
the moon just mentioned: that is to say, in round numbers, about
sixty-four degrees. Consequently, at the moment of firing the
visual radius applied to the moon will describe, with the vertical
line of the place, an angle of sixty-four degrees.
These are our answers to the questions proposed to the
Observatory of Cambridge by the members of the Gun Club:
To sum up–
1st. The cannon ought to be planted in a country situated
between 0@ and 28@ of N. or S. lat.
2nd. It ought to be pointed directly toward the zenith of the place.
3rd. The projectile ought to be propelled with an initial
velocity of 12,000 yards per second.
4th. It ought to be discharged at 10hrs. 46m. 40sec. of the 1st
of December of the ensuing year.
5th. It will meet the moon four days after its discharge,
precisely at midnight on the 4th of December, at the moment of
its transit across the zenith.
The members of the Gun Club ought, therefore, without delay, to
commence the works necessary for such an experiment, and to be
prepared to set to work at the moment determined upon; for, if
they should suffer this 4th of December to go by, they will not
find the moon again under the same conditions of perigee and of
zenith until eighteen years and eleven days afterward.
The staff of the Cambridge Observatory place themselves entirely
at their disposal in respect of all questions of theoretical
astronomy; and herewith add their congratulations to those of
all the rest of America.
For the Astronomical Staff,
J. M. BELFAST,
_Director of the Observatory of Cambridge._
CHAPTER V
THE ROMANCE OF THE MOON
An observer endued with an infinite range of vision, and placed
in that unknown center around which the entire world revolves,
might have beheld myriads of atoms filling all space during the
chaotic epoch of the universe. Little by little, as ages went
on, a change took place; a general law of attraction manifested
itself, to which the hitherto errant atoms became obedient:
these atoms combined together chemically according to their
affinities, formed themselves into molecules, and composed those
nebulous masses with which the depths of the heavens are strewed.
These masses became immediately endued with a rotary motion
around their own central point. This center, formed of
indefinite molecules, began to revolve around its own axis
during its gradual condensation; then, following the immutable
laws of mechanics, in proportion as its bulk diminished by
condensation, its rotary motion became accelerated, and these
two effects continuing, the result was the formation of one
principal star, the center of the nebulous mass.
By attentively watching, the observer would then have perceived
the other molecules of the mass, following the example of this
central star, become likewise condensed by gradually accelerated
rotation, and gravitating round it in the shape of innumerable stars.
Thus was formed the _Nebulae_, of which astronomers have reckoned
up nearly 5,000.
Among these 5,000 nebulae there is one which has received the
name of the Milky Way, and which contains eighteen millions of
stars, each of which has become the center of a solar world.
If the observer had then specially directed his attention to one
of the more humble and less brilliant of these stellar bodies,
a star of the fourth class, that which is arrogantly called the
Sun, all the phenomena to which the formation of the Universe is to