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Chapter 6



The immediate result of Barbicane's proposition was to place upon
the orders of the day all the astronomical facts relative to the
Queen of the Night. Everybody set to work to study assiduously.
One would have thought that the moon had just appeared for the
first time, and that no one had ever before caught a glimpse of
her in the heavens. The papers revived all the old anecdotes in
which the "sun of the wolves" played a part; they recalled the
influences which the ignorance of past ages ascribed to her; in
short, all America was seized with selenomania, or had become moon-mad.

The scientific journals, for their part, dealt more especially with
the questions which touched upon the enterprise of the Gun Club.
The letter of the Observatory of Cambridge was published by them,
and commented upon with unreserved approval.

Until that time most people had been ignorant of the mode in which
the distance which separates the moon from the earth is calculated.
They took advantage of this fact to explain to them that this
distance was obtained by measuring the parallax of the moon.
The term parallax proving "caviare to the general," they further
explained that it meant the angle formed by the inclination of two
straight lines drawn from either extremity of the earth's radius
to the moon. On doubts being expressed as to the correctness of
this method, they immediately proved that not only was the mean
distance 234,347 miles, but that astronomers could not possibly
be in error in their estimate by more than seventy miles either way.

To those who were not familiar with the motions of the moon,
they demonstrated that she possesses two distinct motions, the
first being that of rotation upon her axis, the second being
that of revolution round the earth, accomplishing both together
in an equal period of time, that is to say, in twenty-seven and
one-third days.

The motion of rotation is that which produces day and night on
the surface of the moon; save that there is only one day and one
night in the lunar month, each lasting three hundred and
fifty-four and one-third hours. But, happily for her, the face
turned toward the terrestrial globe is illuminated by it with an
intensity equal to that of fourteen moons. As to the other
face, always invisible to us, it has of necessity three hundred
and fifty-four hours of absolute night, tempered only by that
"pale glimmer which falls upon it from the stars."

Some well-intentioned, but rather obstinate persons, could not
at first comprehend how, if the moon displays invariably the
same face to the earth during her revolution, she can describe
one turn round herself. To such they answered, "Go into your
dining-room, and walk round the table in such a way as to always
keep your face turned toward the center; by the time you will
have achieved one complete round you will have completed one
turn around yourself, since your eye will have traversed
successively every point of the room. Well, then, the room is
the heavens, the table is the earth, and the moon is yourself."
And they would go away delighted.

So, then the moon displays invariably the same face to the
earth; nevertheless, to be quite exact, it is necessary to add
that, in consequence of certain fluctuations of north and south,
and of west and east, termed her libration, she permits rather
more than half, that is to say, five-sevenths, to be seen.

As soon as the ignoramuses came to understand as much as the
director of the observatory himself knew, they began to worry
themselves regarding her revolution round the earth, whereupon
twenty scientific reviews immediately came to the rescue.
They pointed out to them that the firmament, with its infinitude
of stars, may be considered as one vast dial-plate, upon which the
moon travels, indicating the true time to all the inhabitants of
the earth; that it is during this movement that the Queen of
Night exhibits her different phases; that the moon is _full_
when she is in _opposition_ with the sun, that is when the three
bodies are on the same straight line, the earth occupying the
center; that she is _new_ when she is in _conjunction_ with the
sun, that is, when she is between it and the earth; and, lastly
that she is in her _first_ or _last_ quarter, when she makes
with the sun and the earth an angle of which she herself occupies
the apex.

Regarding the altitude which the moon attains above the horizon,
the letter of the Cambridge Observatory had said all that was to
be said in this respect. Every one knew that this altitude
varies according to the latitude of the observer. But the only
zones of the globe in which the moon passes the zenith, that is,
the point directly over the head of the spectator, are of
necessity comprised between the twenty-eighth parallels and
the equator. Hence the importance of the advice to try the
experiment upon some point of that part of the globe, in order
that the projectile might be discharged perpendicularly, and so
the soonest escape the action of gravitation. This was an
essential condition to the success of the enterprise, and
continued actively to engage the public attention.

Regarding the path described by the moon in her revolution round
the earth, the Cambridge Observatory had demonstrated that this
path is a re-entering curve, not a perfect circle, but an
ellipse, of which the earth occupies one of the _foci_. It was
also well understood that it is farthest removed from the earth
during its _apogee_, and approaches most nearly to it at its _perigee_.

Such was then the extent of knowledge possessed by every
American on the subject, and of which no one could decently
profess ignorance. Still, while these principles were being
rapidly disseminated many errors and illusory fears proved less
easy to eradicate.

For instance, some worthy persons maintained that the moon was
an ancient comet which, in describing its elongated orbit round
the sun, happened to pass near the earth, and became confined
within her circle of attraction. These drawing-room astronomers
professed to explain the charred aspect of the moon-- a disaster
which they attributed to the intensity of the solar heat; only,
on being reminded that comets have an atmosphere, and that the
moon has little or none, they were fairly at a loss for a reply.

Others again, belonging to the doubting class, expressed certain
fears as to the position of the moon. They had heard it said
that, according to observations made in the time of the Caliphs,
her revolution had become accelerated in a certain degree.
Hence they concluded, logically enough, that an acceleration of
motion ought to be accompanied by a corresponding diminution in
the distance separating the two bodies; and that, supposing the
double effect to be continued to infinity, the moon would end by
one day falling into the earth. However, they became reassured
as to the fate of future generations on being apprised that,
according to the calculations of Laplace, this acceleration of
motion is confined within very restricted limits, and that a
proportional diminution of speed will be certain to succeed it.
So, then, the stability of the solar system would not be deranged
in ages to come.

There remains but the third class, the superstitious.
These worthies were not content merely to rest in ignorance;
they must know all about things which had no existence whatever,
and as to the moon, they had long known all about her. One set
regarded her disc as a polished mirror, by means of which people
could see each other from different points of the earth and
interchange their thoughts. Another set pretended that out of
one thousand new moons that had been observed, nine hundred and
fifty had been attended with remarkable disturbances, such as
cataclysms, revolutions, earthquakes, the deluge, etc. Then they
believed in some mysterious influence exercised by her over human
destinies-- that every Selenite was attached to some inhabitant
of the earth by a tie of sympathy; they maintained that the
entire vital system is subject to her control, etc. But in time
the majority renounced these vulgar errors, and espoused the true
side of the question. As for the Yankees, they had no other
ambition than to take possession of this new continent of the sky,
and to plant upon the summit of its highest elevation the star-
spangled banner of the United States of America.

Jules Verne

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