Five Weeks in a Balloon, Jules Verne [top reads txt] 📗

“Ay! ay! that’s all right! But can a man get a drop of the real stuff there?” said a sailor who liked his toddy.

“Not a drop!” was Joe’s answer. “No! old fellow, not in the moon. But we’re going to skip round among those little twinklers up there—the stars—and the splendid planets that my old man so often talks about. For instance, we’ll commence with Saturn—”

“That one with the ring?” asked the boatswain.

“Yes! the wedding-ring—only no one knows what’s become of his wife!”

“What? will you go so high up as that?” said one of the ship-boys, gaping with wonder. “Why, your master must be Old Nick himself.”

“Oh! no, he’s too good for that.”

“But, after Saturn—what then?” was the next inquiry of his impatient audience.

“After Saturn? Well, we’ll visit Jupiter. A funny place that is, too, where the days are only nine hours and a half long—a good thing for the lazy fellows—and the years, would you believe it—last twelve of ours, which is fine for folks who have only six months to live. They get off a little longer by that.”

“Twelve years!” ejaculated the boy.

“Yes, my youngster; so that in that country you’d be toddling after your mammy yet, and that old chap yonder, who looks about fifty, would only be a little shaver of four and a half.”

“Blazes! that’s a good ‘un!” shouted the whole forecastle together.

“Solemn truth!” said Joe, stoutly.

“But what can you expect? When people will stay in this world, they learn nothing and keep as ignorant as bears. But just come along to Jupiter and you’ll see. But they have to look out up there, for he’s got satellites that are not just the easiest things to pass.”

All the men laughed, but they more than half believed him. Then he went on to talk about Neptune, where seafaring men get a jovial reception, and Mars, where the military get the best of the sidewalk to such an extent that folks can hardly stand it. Finally, he drew them a heavenly picture of the delights of Venus.

“And when we get back from that expedition,” said the indefatigable narrator, “they’ll decorate us with the Southern Cross that shines up there in the Creator’s button-hole.”

“Ay, and you’d have well earned it!” said the sailors.

Thus passed the long evenings on the forecastle in merry chat, and during the same time the doctor went on with his instructive discourses.

One day the conversation turned upon the means of directing balloons, and the doctor was asked his opinion about it.

“I don’t think,” said he, “that we shall succeed in finding out a system of directing them. I am familiar with all the plans attempted and proposed, and not one has succeeded, not one is practicable. You may readily understand that I have occupied my mind with this subject, which was, necessarily, so interesting to me, but I have not been able to solve the problem with the appliances now known to mechanical science. We would have to discover a motive power of extraordinary force, and almost impossible lightness of machinery. And, even then, we could not resist atmospheric currents of any considerable strength. Until now, the effort has been rather to direct the car than the balloon, and that has been one great error.”

“Still there are many points of resemblance between a balloon and a ship which is directed at will.”

“Not at all,” retorted the doctor, “there is little or no similarity between the two cases. Air is infinitely less dense than water, in which the ship is only half submerged, while the whole bulk of a balloon is plunged in the atmosphere, and remains motionless with reference to the element that surrounds it.”

“You think, then, that aerostatic science has said its last word?”

“Not at all! not at all! But we must look for another point in the case, and if we cannot manage to guide our balloon, we must, at least, try to keep it in favorable aerial currents. In proportion as we ascend, the latter become much more uniform and flow more constantly in one direction. They are no longer disturbed by the mountains and valleys that traverse the surface of the globe, and these, you know, are the chief cause of the variations of the wind and the inequality of their force. Therefore, these zones having been once determined, the balloon will merely have to be placed in the currents best adapted to its destination.”

“But then,” continued Captain Bennet, “in order to reach them, you must keep constantly ascending or descending. That is the real difficulty, doctor.”

“And why, my dear captain?”

“Let us understand one another. It would be a difficulty and an obstacle only for long journeys, and not for short aerial excursions.”

“And why so, if you please?”

“Because you can ascend only by throwing out ballast; you can descend only after letting off gas, and by these processes your ballast and your gas are soon exhausted.”

“My dear sir, that’s the whole question. There is the only difficulty that science need now seek to overcome. The problem is not how to guide the balloon, but how to take it up and down without expending the gas which is its strength, its life-blood, its soul, if I may use the expression.”

“You are right, my dear doctor; but this problem is not yet solved; this means has not yet been discovered.”

“I beg your pardon, it HAS been discovered.”

“By whom?”

“By me!”

“By you?”

“You may readily believe that otherwise I should not have risked this expedition across Africa in a balloon. In twenty-four hours I should have been without gas!”

“But you said nothing about that in England?”

“No! I did not want to have myself overhauled in public. I saw no use in that. I made my preparatory experiments in secret and was satisfied. I have no occasion, then, to learn any thing more from them.”

“Well! doctor, would it be proper to ask what is your secret?”

“Here it is, gentlemen—the simplest thing in the world!”

The attention of his auditory was now directed to the doctor in the utmost degree as he quietly proceeded with his explanation.

CHAPTER TENTH.

Former Experiments.—The Doctor’s Five Receptacles.—The Gas Cylinder.— The Calorifere.—The System of Manoeuvring.—Success certain.

“The attempt has often been made, gentlemen,” said the doctor, “to rise and descend at will, without losing ballast or gas from the balloon. A French aeronaut, M. Meunier, tried to accomplish this by compressing air in an inner receptacle. A Belgian, Dr. Van Hecke, by means of wings and paddles, obtained a vertical power that would have sufficed in most cases, but the practical results secured from these experiments have been insignificant.

“I therefore resolved to go about the thing more directly; so, at the start, I dispensed with ballast altogether, excepting as a provision for cases of special emergency, such as the breakage of my apparatus, or the necessity of ascending very suddenly, so as to avoid unforeseen obstacles.

“My means of ascent and descent consist simply in dilating or contracting the gas that is in the balloon by the application of different temperatures, and here is the method of obtaining that result.

“You saw me bring on board with the car several cases or receptacles, the use of which you may not have understood. They are five in number.

“The first contains about twenty-five gallons of water, to which I add a few drops of sulphuric acid, so as to augment its capacity as a conductor of electricity, and then I decompose it by means of a powerful Buntzen battery. Water, as you know, consists of two parts of hydrogen to one of oxygen gas.

“The latter, through the action of the battery, passes at its positive pole into the second receptacle. A third receptacle, placed above the second one, and of double its capacity, receives the hydrogen passing into it by the negative pole.

“Stopcocks, of which one has an orifice twice the size of the other, communicate between these receptacles and a fourth one, which is called the mixture reservoir, since in it the two gases obtained by the decomposition of the water do really commingle. The capacity of this fourth tank is about forty-one cubic feet.

“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.

“You all know, gentlemen, what a calorifere, to heat apartments, is. You know how it acts. The air of the apartments is forced to pass through its pipes, and is then released with a heightened temperature. Well, what I have just described to you is nothing more nor less than a calorifere.

“In fact, what is it that takes place? The cylinder once lighted, the hydrogen in the spiral and in the concave cone becomes heated, and rapidly ascends through the pipe that leads to the upper part of the balloon. A vacuum is created below, and it attracts the gas in the lower parts; this becomes heated in its turn, and is continually replaced; thus, an extremely rapid current of gas is established in the pipes and in the spiral, which issues from the balloon and then returns to it, and is heated over again, incessantly.

“Now, the cases increase 1/480 of their volume for each degree of heat applied. If, then, I force the temperature 18 degrees, the hydrogen of the balloon will dilate 18/480 or 1614 cubic feet, and will, therefore, displace 1614 more cubic feet of air, which will increase its ascensional power by 160 pounds. This is equivalent to throwing out that weight of ballast. If I augment the temperature by 180 degrees, the gas will dilate 180/480 and will displace 16,740 cubic feet more, and its ascensional force will be augmented by 1,600 pounds.

“Thus, you see, gentlemen, that I can easily effect very considerable changes of equilibrium. The volume of the balloon has been calculated in such manner