But although the moon passes her perigee every month, she does not reach the zenith always at exactly the same moment .
But, in order that the moon should reach the zenith of a given place, it is necessary that the place should not exceed in latitude the declination of the luminary; in other words, it must be comprised within the degrees 0@ and 28@ of lat.
-- At the moment when the projectile shall be discharged into space, the moon, which travels daily forward 13@ 10' 35'', will be distant from the zenith point by four times that quantity,
But, inasmuch as it is equally necessary to take into account the deviation which the rotary motion of the earth will impart to the shot, and as the shot cannot reach the moon until after a deviation equal to 16 radii of the earth, which, calculated upon the moon's orbit, are equal to about eleven degrees, it becomes necessary to add these eleven degrees to those which express the retardation of the moon just mentioned: that is to say, in round numbers, about sixty-four degrees.
It will meet the moon four days after its discharge, precisely at midnight on the 4th of December, at the moment of its transit across the zenith.
As to the sixth question, "What place will the moon occupy in the heavens at the moment of the projectile's departure?"
The members of the Gun Club ought, therefore, without delay, to commence the works necessary for such an experiment, and to be prepared to set to work at the moment determined upon; for, if they should suffer this 4th of December to go by, they will not find the moon again under the same conditions of perigee and of zenith until eighteen years and eleven days afterward.
Recognising the force of the argument, and having cast one more despairing look at the bright face of the moon, for never did the most ardent astronomer with a theory to prove await a celestial event with such anxiety, I stepped with all the dignity that I could command between the prostrate girl and the advancing spear of Scragga.
Come but one pace nearer, and we will put out the moon like a wind-blown lamp, as we who dwell in her House can do, and plunge the land in darkness.
hear him!" piped Gagool; "hear the liar who says that he will put out the moon like a lamp.
I glanced up at the moon despairingly, and now to my intense joy and relief saw that we--or rather the almanack--had made no mistake.
"The moon grows black before your eyes; soon there will be darkness-- ay, darkness in the hour of the full moon.
"It will pass," she cried; "I have often seen the like before; no man can put out the moon; lose not heart; sit still--the shadow will pass."
Slowly and in the midst of this most solemn silence the minutes sped away, and while they sped the full moon passed deeper and deeper into the shadow of the earth, as the inky segment of its circle slid in awful majesty across the lunar craters.
"The moon is dying--the white wizards have killed the moon," yelled the prince Scragga at last.