It is scarce possible to talk of a paper kite, without thinking of that other and greater aerostatic contrivance—a balloon.

Karl had thought of it, long before this time; and so had Caspar, just as long: for the kite had suggested it simultaneously to the minds of both.

It may be asked why they had not entertained the thought, and endeavoured to carry it into practical effect: since a balloon would have been far more likely to have delivered them out of their “mountain prison” than a paper kite?

But they had entertained the thought—at least, Karl had done so—and examined it in all its bearings. Caspar had permitted it to pass out of his mind, under the impression that they could not make a balloon; and Karl had arrived at the same conclusion; but only from a belief that they had not the materials with which to make one. Given the materials, Karl felt quite equal to the construction of a balloon—a rude one, it is true; but one which might have served the purpose for which they required it.

During the days when they had been occupied in making the paper-bird, he had given his thoughts a good deal to this subject; for, to say the truth, he had never been very sanguine about the success of the kite experiment. He had pondered long and patiently on the subject of balloons—endeavouring to recall to mind what little he had studied of aerostatics—and had mentally examined all the material objects within reach, in the hope of discovering some substance out of which one might be constructed.

Unfortunately, he had not been able to think of anything that appeared to be suitable. The daphne paper—even had it been in abundance—would not do: for paper of itself, however close in texture, is not strong enough to withstand the pressure of the outside air—that is, in a balloon of sufficient size to carry any considerable weight. But it was of no use to talk of paper: since there was not enough; and Karl had given over thinking of a balloon: because there was nothing within reach likely to serve for its construction.

He knew that that great sphere would require to be air-proof. He had thought of the skins of animals; but such of these as might have been obtained in sufficient quantity, were entirely too thick and heavy to make the covering of a balloon. The hemp, of which there was an abundance, might be woven into a cloth, and then coated over by gum obtained from some tree; for in the valley were several species of gum-exuding trees. But the question was, could they manufacture a cloth out of hemp that would be light enough when thus coated over? It was very doubtful whether they could—at all events they would have to practise the weaving trade for a long time, before they should arrive at a sufficient expertness to accomplish such a feat. The plan was too unpromising to be seriously entertained; and Karl had dismissed it, along with the whole subject of the balloon.

That had been previous to the experiment of the kite, and its unfortunate ending. But now that all hope from this quarter had been brought to an end, the balloon once more began to shape itself in his mind, as well as in that of Caspar; and for the first time they proceeded to talk over the subject together.

“Cords we could have in plenty,” remarked Caspar, “but they’d be of no use, without the stuff to cover the great globe. They make it of silk, don’t they?”

“Yes,” replied Karl, “silk is the best material for the purpose.”

“And why?” inquired Caspar.

“Because it combines the three properties of lightness, strength, and closeness of texture, in a greater degree than any other known substance.”

“Would nothing else do?”

“Oh, yes; many things would answer to make a balloon, that might carry up a certain amount of weight. Even a paper balloon can be constructed to take up a few pounds—a cat, or a small dog; and people in many countries have been cruel enough to dispatch such creatures into the air, not caring what became of them.”

“Very cruel indeed!” assented Caspar, who, although a hunter, was far from having an unfeeling heart. “Such people should be sent up themselves in paper balloons.”

“Yes, if paper balloons would carry them; which, unfortunately for us, they wouldn’t. Even if we had an unlimited supply of paper, it would be of no use to us. We require something stronger, and more tenacious.”

“Can we not think of something? Let us try, Karl!”

“Ah! dear brother, I have been trying for days, and in vain. There is nothing within this valley at all suitable for the purpose.”

“Would canvas do? Have you thought of that?”

“I have. It would be too coarse and heavy.”

“But, with great pains, could we not make it light enough? We might choose the finer fibres of the hemp; and spin and weave it with scrupulous care. Ossaroo here is a perfect Omphale in his way. I’ll warrant he could beat Hercules with the distaff.”

“Ho! brother!” exclaimed Karl, a little astonished. “You are quite classical in your speech this morning. Where learnt you the history of Hercules—you who have never seen the inside of ............