Page:Works of Jules Verne - Parke - Vol 1.djvu/254



" have been made frequently, gentlemen, to ascend and descend at will, without losing the gas in a balloon. A French aëronaut, M. Meumier, attempted to do this by compressing the air. A Belgian, Dr. Van Hecke, by means of wings and paddles, gained a vertical force, which has proved ineffective in the majority of instances. The practical results obtained by the above means are insignificant.

"I then resolved to go into the question boldly, and at once put the ballast on one side, if it were not a case of absolute necessity as to the breaking of my apparatus, or in case of being obliged to rise suddenly to avoid any obstacle.

"My means of ascent and descent consist equally in the dilation or contraction by varying temperatures of the gas confined in the balloon. And this is how I manage it.

"You have already seen put on board certain chests with the car, of which you did not understand the utility. These chests are five in number.

"The first contains about twenty-five gallons of water, to which I add sulphuric acid to increase its conductibility, and I resolve it into its component parts by means of a strong Bautzen galvanic battery. Water, as you are aware, is composed of two volumes hydrogen gas to one of oxygen.

"The oxygen under the battery action goes off by the positive pole into a second chest. A third chest, placed on the top of it, and of about twice the size, receives the hydrogen which enters it by the negative pole.

"Two taps, one of which has an opening double that of the other, keep up a communication between these two cases and a fourth, which is known as the mixing chest. Here in fact the gases arising from the decomposition of the water mingle together. The capacity of this chest is about forty-one cubic feet. In the upper part of it is a platinum tube with a stop-cock.

"You will already have perceived, gentlemen, that the apparatus I have described is nothing more than an oxyhydrogen blow-pipe, the heat evolved by which by which surpasses that of a forge fire.

"That matter settled, I pass on to the second part of the apparatus.