Barbicane, however, lost not one moment amid all the enthusiasm of which he had become the object. His first care was to reassemble his colleagues in the board-room of the Gun Club.
There, after some discussion, it was agreed to consult the astronomers regarding the astronomical part of the enterprise.
Their reply once ascertained, they could then discuss the mechanical means, and nothing should be wanting to ensure the success of this great experiment.
A note couched in precise terms, containing special interrogatories, was then drawn up and addressed to the Observatory of Cambridge in Massachusetts. This city, where the first university of the United States was founded, is justly celebrated for its astronomical staff. There are to be found assembled all the most eminent men of science. Here is to be seen at work that powerful telescope which enabled Bond to resolve the nebula of Andromeda, and Clarke to discover the satellite of Sirius. This celebrated institution fully justified on all points the confidence reposed in it by the Gun Club.
So, after two days, the reply so impatiently awaited was placed in the hands of President Barbicane.
It was couched in the following terms:
_The Director of the Cambridge Observatory to the President of the Gun Club at Baltimore._CAMBRIDGE, October 7.
On the receipt of your favor of the 6th instant, addressed to the Observatory of Cambridge in the name of the members of the Baltimore Gun Club, our staff was immediately called together, and it was judged expedient to reply as follows:
The questions which have been proposed to it are these--"1. Is it possible to transmit a projectile up to the moon?
"2. What is the exact distance which separates the earth from its satellite?
"3. What will be the period of transit of the projectile when endowed with sufficient initial velocity? and, consequently, at what moment ought it to be discharged in order that it may touch the moon at a particular point?
"4. At what precise moment will the moon present herself in the most favorable position to be reached by the projectile?
"5. What point in the heavens ought the cannon to be aimed at which is intended to discharge the projectile?
"6. What place will the moon occupy in the heavens at the moment of the projectile's departure?"Regarding the _first_ question, "Is it possible to transmit a projectile up to the moon?"_Answer._-- Yes; provided it possess an initial velocity of 1,200 yards per second; calculations prove that to be sufficient.
In proportion as we recede from the earth the action of gravitation diminishes in the inverse ratio of the square of the distance;that is to say, _at three times a given distance the action is nine times less._ Consequently, the weight of a shot will decrease, and will become reduced to _zero_ at the instant that the attraction of the moon exactly counterpoises that of the earth; that is to say at 47/52 of its passage. At that instant the projectile will have no weight whatever; and, if it passes that point, it will fall into the moon by the sole effect of the lunar attraction.
The _theoretical possibility_ of the experiment is therefore absolutely demonstrated; its _success_ must depend upon the power of the engine employed.
As to the _second_ question, "What is the exact distance which separates the earth from its satellite?"_Answer._-- The moon does not describe a _circle_ round the earth, but rather an _ellipse_, of which our earth occupies one of the _foci_; the consequence, therefore, is, that at certain times it approaches nearer to, and at others it recedes farther from, the earth; in astronomical language, it is at one time in _apogee_, at another in _perigee_. Now the difference between its greatest and its least distance is too considerable to be left out of consideration. In point of fact, in its apogee the moon is 247,552 miles, and in its perigee, 218,657 miles only distant; a fact which makes a difference of 28,895 miles, or more than one-ninth of the entire distance. The perigee distance, therefore, is that which ought to serve as the basis of all calculations.
To the _third_ question.
