Jules Verne: Five Weeks in a Balloon

10. CHAPTER TENTH. (continued)

"On the upper part of this tank is a platinum tube provided with a stopcock.

"You will now readily understand, gentlemen, the apparatus that I have described to you is really a gas cylinder and blow-pipe for oxygen and hydrogen, the heat of which exceeds that of a forge fire.

"This much established, I proceed to the second part of my apparatus. From the lowest part of my balloon, which is hermetically closed, issue two tubes a little distance apart. The one starts among the upper layers of the hydrogen gas, the other amid the lower layers.

"These two pipes are provided at intervals with strong jointings of india-rubber, which enable them to move in harmony with the oscillations of the balloon.

"Both of them run down as far as the car, and lose themselves in an iron receptacle of cylindrical form, which is called the heat-tank. The latter is closed at its two ends by two strong plates of the same metal.

"The pipe running from the lower part of the balloon runs into this cylindrical receptacle through the lower plate; it penetrates the latter and then takes the form of a helicoidal or screw-shaped spiral, the rings of which, rising one over the other, occupy nearly the whole of the height of the tank. Before again issuing from it, this spiral runs into a small cone with a concave base, that is turned downward in the shape of a spherical cap.

"It is from the top of this cone that the second pipe issues, and it runs, as I have said, into the upper beds of the balloon.

"The spherical cap of the small cone is of platinum, so as not to melt by the action of the cylinder and blow-pipe, for the latter are placed upon the bottom of the iron tank in the midst of the helicoidal spiral, and the extremity of their flame will slightly touch the cap in question.