Caustic potash has a great affinity for carbonic acid; and it is sufficient to shake it in order for it to seize upon the acid and form bicarbonate of potassium. By these two means they would be enabled to restore to the vitiated air its life- supporting properties.
It is necessary, however, to add that the experiments had hitherto been made in anima vili. Whatever its scientific accuracy was, they were at present ignorant how it would answer with human beings. The honor of putting it to the proof was energetically claimed by J. T. Maston.
“Since I am not to go,” said the brave artillerist, “I may at least live for a week in the projectile.”
It would have been hard to refuse him; so they consented to his wish. A sufficient quantity of chlorate of potassium and of caustic potash was placed at his disposal, together with provisions for eight days. And having shaken hands with his friends, on the 12th of November, at six o’clock A.M., after strictly informing them not to open his prison before the 20th, at six o’clock P.M., he slid down the projectile, the plate of which was at once hermetically sealed. What did he do with himself during that week? They could get no information. The thickness of the walls of the projectile prevented any sound reaching from the inside to the outside. On the 20th of November, at six P.M. exactly, the plate was opened. The friends of J. T. Maston had been all along in a state of much anxiety; but they were promptly reassured on hearing a jolly voice shouting a boisterous hurrah.
Presently afterward the secretary of the Gun Club appeared at the top of the cone in a triumphant attitude. He had grown fat!
CHAPTER XXIV.
THE TELESCOPE OF THE ROCKY MOUNTAINS
On the 20th of October in the preceding year, after the close of the subscription, the president of the Gun Club had credited the Observatory of Cambridge with the necessary sums for the construction of a gigantic optical instrument. This instrument was designed for the purpose of rendering visible on the surface of the moon any object exceeding nine feet in diameter.
At the period when the Gun Club essayed their great experiment, such instruments had reached a high degree of perfection, and produced some magnificent results. Two telescopes in particular, at this time, were possessed of remarkable power and of gigantic dimensions. The first, constructed by Herschel, was thirty-six feet in length, and had an object-glass of four feet six inches; it possessed a magnifying power of 6,000. The second was raised in Ireland, in Parsonstown Park, and belongs to Lord Rosse. The length of this tube is forty-eight feet, and the diameter of its object-glass six feet; it magnifies 6,400 times, and required an immense erection of brick work and masonry for the purpose of working it, its weight being twelve and a half tons.
Still, despite these colossal dimensions, the actual enlargements scarcely exceeded 6,000 times in round numbers; consequently, the moon was brought within no nearer an apparent distance than thirty-nine miles; and objects of less than sixty feet in diameter, unless they were of very considerable length, were still imperceptible.
In the present case, dealing with a projectile nine feet in diameter and fifteen feet long, it became necessary to bring the moon within an apparent distance of five miles at most; and for that purpose to establish a magnifying power of 48,000 times.