THE PERMISSIVE LIMITS OF IGNORANCE AND BELIEF IN THE
UNITED STATES.
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
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 seleno-mania, 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 70 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 that of revolution round the
earth, accomplishing both together in an equal period of time, that is
to say, in 27⅓ 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 354⅓ hours. But, happily for her, the
face turned towards the terrestrial globe is illuminated by it with an
intensity equal to the light of fourteen moons. As to the other face,
always invisible to us, it has of necessity 354 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 always to keep your face turned towards the centre; by the
time you will have achieved one complete round you will have completed
one turn round 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 the 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 then 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 centre; 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 that 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 then was the extent of knowledge possessed by every American on the
subject, and of which no one could decently profess ignorance. Still,
while these true 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 so 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, &c. 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, &c.,
&c. 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.
Illustration: BARBICANE HOLDS FORTH.