CHAPTER VI.
THE PERMISSIVE LIMITS OF IGNORANCE AND BELIEF IN THE UNITED STATES.
The immediate result of Barbicane's proposition was to place upon theorders of the day all the astronomical facts relative to the Queen ofNight. Everybody set to work to study assiduously. One would have thoughtthat the moon had just appeared for the first time, and that no one hadever before caught a glimpse of her in the heavens. The papers revivedall the old anecdotes in which the "sun of the wolves" played a part;they recalled the influences which the ignorance of past ages ascribedto her; in short, all America was seized with seleno-mania, or had becomemoon-mad.
The scientific journals, for their part, dealt more especially with thequestions which touched upon the enterprise of the Gun Club. The letterof the Observatory of Cambridge was published by them, and commented uponwith unreserved approval.
Until that time most people had been ignorant of the mode in which thedistance which separates the moon from the earth is calculated. They tookadvantage of this fact to explain to them that this distance was obtainedby measuring the parallax of the moon. The term parallax proving "caviareto the general," they further explained that it meant the angle formedby the inclination of two straight lines drawn from either extremityof the earth's radius to the moon. On doubts being expressed as to thecorrectness of this method, they immediately proved that not only wasthe mean distance 234,347 miles, but that astronomers could not possiblybe in error in their estimate by more than 70 miles either way.
To those who were not familiar with the motions of the moon, theydemonstrated that she possesses two distinct motions, the first beingthat of rotation upon her axis, the second that of revolution round theearth, accomplishing both together in an equal period of time, that isto say, in 27-1/3 days.
The motion of rotation is that which produces day and night on thesurface of the moon; save that there is only one day and one night inthe lunar month, each lasting 354-1/3 hours. But, happily for her, theface turned towards the terrestrial globe is illuminated by it with anintensity 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 firstcomprehend how, if the moon displays invariably the same face to the earthduring her revolution, she can describe one turn round herself. To suchthey answered, "Go into your dining-room, and walk round the table insuch a way as always to keep your face turned towards the centre; by thetime you will have achieved one complete round you will have completedone turn round yourself, since your eye will have traversed successivelyevery point of the room. Well, then, the room is the heavens, the tableis 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, inconsequence of certain fluctuations of north and south, and of west andeast, termed her libration, she permits rather more than the half, thatis to say, five-sevenths, to be seen.
As soon as the ignoramuses came to understand as much as the Director ofthe Observatory himself knew, they began to worry themselves regardingher revolution round the earth, whereupon twenty scientific reviewsimmediately came to the rescue. They pointed out to them then that thefirmament, with its infinitude of stars, may be considered as one vastdial-plate, upon which the moon travels, indicating the true time to allthe inhabitants of the earth; that it is during this movement that theQueen of Night exhibits her different phases; that the moon is _full_when she is in _opposition_ with the sun, that is when the three bodiesare on the same straight line, the earth occupying the centre; that sheis _new_ when she is in _conjunction_ with the sun, that is, when sheis 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 ofwhich she herself occupies the apex.
Regarding the altitude which the moon attains above the horizon, theletter of the Cambridge Observatory had said all that was to be saidin that respect. Every one knew that this altitude varies according tothe latitude of the observer. But the only zones of the globe in whichthe moon passes the zenith, that is, the point directly over the headof the spectator, are of necessity comprised between the twenty-eighthparallels and the equator. Hence the importance of the advice to trythe experiment upon some point of that part of the globe, in order thatthe projectile might be discharged perpendicularly, and so the soonestescape the action of gravitation. This was an essential condition to thesuccess of the enterprise, and continued actively to engage the publicattention.
Regarding the path described by the moon in her revolution round theearth, the Cambridge Observatory had demonstrated that this path is are-entering curve, not a perfect circle, but an ellipse, of which theearth occupies one of the _foci_. It was also well understood that it isfarthest removed from the earth during its _apogee,_ and approaches mostnearly to it at its _perigee._
Such then was the extent of knowledge possessed by every American on thesubject, and of which no one could decently profess ignorance. Still,while these true principles were being rapidly disseminated many errorsand illusory fears proved less easy to eradicate.
For instance, some worthy persons maintained that the moon was an ancientcomet which, in describing its elongated orbit round the sun, happened topass near the earth, and became confined within her circle of attraction.These drawing-room astronomers professed so to explain the charred aspectof the moon--a disaster which they attributed to the intensity of thesolar heat; only, on being reminded that comets have an atmosphere, andthat 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 asto the position of the moon. They had heard it said that, according toobservations made in the time of the Caliphs, her revolution had becomeaccelerated in a certain degree. Hence they concluded, logically enough,that an acceleration of motion ought to be accompanied by a correspondingdiminution in the distance separating the two bodies; and that, supposingthe double effect to be continued to infinity, the moon would end byone day falling into the earth. However, they became reassured as tothe fate of future generations on being apprised that, according to thecalculations of Laplace, this acceleration of motion is confined withinvery restricted limits, and that a proportional diminution of speed willbe certain to succeed it. So, then, the stability of the solar systemwould not be deranged in ages to come.
There remains but the third class, the superstitious. These worthies werenot content merely to rest in ignorance; they must know all about thingswhich had no existence whatever, and as to the moon, they had long knownall about her. One set regarded her disc as a polished mirror, by meansof which people could see each other from different points of the earthand interchange their thoughts. Another set pretended that out of onethousand new moons that had been observed, nine hundred and fifty had beenattended with remarkable disturbances, such as cataclysms, revolutions,earthquakes, the deluge, &c. Then they believed in some mysteriousinfluence exercised by her over human destinies--that every Selenitewas attached to some inhabitant of the earth by a tie of sympathy; theymaintained that the entire vital system is subject to her control, &c.,&c. But in time the majority renounced these vulgar errors, and espousedthe true side of the question. As for the Yankees, they had no otherambition than to take possession of this new continent of the sky, and toplant upon the summit of its highest elevation the star-spangled bannerof the United States of America.
Illustration: BARBICANE HOLDS FORTH.