<h2 id="sigil_toc_id_13">CHAPTER VI.</h2>
<h3 id="sigil_toc_id_14">THE PERMISSIVE LIMITS OF IGNORANCE AND BELIEF IN THE UNITED STATES.</h3>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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."</p>
<p>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.</p>
<p>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.</p>
<p>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 <i>full</i> when she is in
<i>opposition</i> with the sun, that is when the three bodies are on
the same straight line, the earth occupying the centre; that she is
<i>new</i> when she is in <i>conjunction</i> with the sun, that is,
when she is between it and the earth; and lastly, that she is in her
<i>first</i> or <i>last</i> quarter, when she makes with the sun and
the earth an angle of which she herself occupies the apex.</p>
<p>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.</p>
<p>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 <i>foci</i>. It was also well
understood that it is farthest removed from the earth during its
<i>apogee,</i> and approaches most nearly to it at its
<i>perigee.</i></p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<p>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.</p>
<div class="illus"><ANTIMG alt="Illustration: BARBICANE HOLDS FORTH." id="forth" src="images/forth.jpg" /></div>
<div class="caption">BARBICANE HOLDS FORTH.</div>
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