The Cliff Climbers

Chapter Forty Eight.

No more paper-trees!

There was nothing mysterious in the disappearance of the cord. The kite was no longer visible on the summit of the cliff. The wind had carried it away; and, of course, its rope along with it.

When the first moment of surprise had passed, our adventurers turned towards each other with glances that spoke something more than disappointment. Notwithstanding the number of times that the kite had failed to fix itself, still it had once taken a fast hold, and it was but reasonable to suppose it would have done so again. Besides, there were other places where the precipice was as low, and even lower, than where they had made the trials; and at some of these they might have been more successful. Indeed, there was every probability that, had they not lost that kite, they would have been able in due time to have climbed out of their rock-bound prison by a ladder of rope; but now all chance of doing so was gone for ever – swept off by a single puff of wind.

You may be fancying, that the misfortune was not irremediable. Another kite, you will be saying, might be constructed out of similar materials as those used in making the one carried away. But to say this, would be to speak without a full knowledge of the circumstances.

The same thought had already passed through the minds of our adventurers, when they perceived that the kite they were flying was getting torn and otherwise damaged.

“We can easily make another,” suggested Caspar at that crisis.

“No, brother,” was the answer of Karl; “never another, I fear. We have paper enough left to patch this one; but not enough to make another.”

“But we can make more paper, can we not?” urged Caspar, interrogatively.

“Ah!” again replied Karl, with a negative shake of the head, “no more – not another sheet!”

“But why? Do you think there are no more daphne trees?”

“I think there are not. You remember we stripped all there were in the thicket; and since then, thinking we might need more bark, I have gone all through the valley, and explored it in every direction, without meeting with a single shrub of the daphne. I am almost certain there are none.”

This conversation between the brothers had occurred, long before the losing of the kite. When that event came to pass, it was not necessary for them to repeat it; and, both being thus acquainted with the fact that it was impossible for them to construct another, they felt that they had sustained an irreparable loss.

In what direction had the kite been carried off? Might it not be blown along the line of cliffs, and tossed back again into the valley?

As there appeared some probability that such a chance might arise, all three ran outward from the rocks – in order to command a better view of the precipice, on each side.

For a long time they stood watching – in hopes that they might see the great paper-bird returning to the scene of its nativity. But it never came back; and they became at length convinced, that it never would. Indeed, the direction of the wind – when they paused to consider it – rendered the thing not only improbable, but impossible. It was blowing from the cliffs, and towards the snowy ridge. No doubt the kite had been carried up the sloping acclivity; and had either passed clear over the mountains, or become lodged in some deep defile, where the wind could no longer reach it. At all events, it was certain, that both kite and cord were lost to them for ever.

“Ach! how very unfortunate!” exclaimed Caspar, in a vexed tone, when they had finally arrived at this conviction. “What ill-starred luck we have, to be sure!”

“Nay! brother,” remarked Karl, in a tone of reproval; “do not chide Fortune for what has happened just now. I acknowledge it is a great misfortune; but it is one for which we may justly blame ourselves, and only ourselves. By sheer negligence we have lost the kite, and along with it, perhaps, the last chance of regaining our liberty.”

“Yes, you speak truly,” rejoined Caspar, in a tone of mingled regret and resignation. “It was our fault, and we must suffer for it.”

“But are you quite sure, brother Karl,” resumed he, after a pause, and referring to the conversation that had already passed between them – “are you quite sure there are no more of these paper-bearing trees?”

“Of course,” replied the plant-hunter, “I am not positive – though I fear it is as I have said – that there are no more. It will be easy for us to determine the point, by making a complete exploration of the valley. It may be that something else might turn up which would answer the purpose equally as well. There is a birch-tree indigenous to the Himalaya mountains, found both in Nepaul and Thibet. Its bark can be stripped off in broad flakes and layers, to the number of eight or ten – each almost as thin as common paper, and suitable for many purposes to which paper is usually applied.”

“Do you think it would do for a kite?” inquired Caspar, without waiting for Karl to finish his explanation.

“I am sure of it,” replied the botanist. “It would serve even better than the daphne paper; and had I believed there was a chance of finding it here, I should have preferred it to that. But I do not think we shall find it. I have observed no species of birch; and I know that this one, like most of the Betulaceae, affects a much colder climate than there is in this valley. Likely enough, it grows on the mountains above; but there it is out of our reach. Could we reach it there, we should not need to be robbing it of its manifold envelope. But let us not despair,” added Karl, endeavouring to appear cheerful; “perhaps it may be found growing down here; or, if not, we may still find another grove of the daphne trees. Let us proceed on and search!”

Karl was far from being sanguine in either conjecture; and it was as well for him that he was not: for after a minute and careful exploration of the valley – which occupied nearly three whole days – neither the wished-for birch, nor the desired daphne trees – nor any other material out of which a kite might be manufactured – rewarded their search.

It was of no use, therefore, to think any longer of a kite; and the subject was at length dismissed from their minds.

Chapter Forty Nine.

Aerostatics

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 a university?”

“You forget, brother Karl, that you yourself have been my instructor in these classical themes, as you call them. Though I must tell you that, with the exception of their occasionally lending a little ornament to my speech, I have derived not the slightest advantage from them; nor is it likely I ever shall.”

“Well, Caspar,” answered the botanist, “I am not going to stand up for the classics, as you are well aware. Although I have taught you a little of their lore, it was when I had nothing to do, and you were equally idle; otherwise I should have considered that both of us were wasting time. You already know my opinions on that subject – which are: that a knowledge of what is usually termed ‘the classics’ is of about as much use to a reasoning man as might be an equally profound knowledge of Chinese mnemonics. The time I have spent in the study of the dead languages has been sheer waste; and all I have learnt wont raise us a foot higher here. My knowledge of Jupiter and Juno is not likely to gain us the means of getting out of our difficulty, no more than my acquaintance with Mercury will help me to a pair of wings. So a truce to classical ideas, and let us see whether scientific ones may not serve us better just now. You have a quick invention, brother Caspar; can you think of anything – I mean anything within our reach – that would make the air-bag of a balloon?”

“But could you make the balloon, if you had the stuff?” inquired Caspar, still in doubt whether any other than an experienced aeronaut could construct so wonderful a machine.

“Pooh!” replied the philosopher, “the making of a balloon is almost as easy as making a soap-bubble. Any air-tight bag, filled with heated atmosphere, becomes a balloon. The question is, what weight it can be made to carry – including the materials out of which it may be constructed.”

“But how are you to get the heated air into it?”

“Simply by making a fire under an aperture left open below.”

“But would not this air soon become cold again?”

“Yes; and then the balloon would sink back to the earth from the air inside getting cooled, and becoming as heavy as that without. Of course,” continued the philosopher, “you are aware that heated air is much lighter than the ordinary atmosphere; and that is why a balloon filled with the former, rises, and will continue rising, till it has reached that elevation, where the rarefied atmosphere is as light as the heated air. Then it can go no further, and the weight of the balloon itself will bring it down again. A bladder of ordinary air sunk in water, or a corked bottle, will illustrate this point to your comprehension.”

“I comprehend it well enough,” rejoined Karl, rather piqued at being treated too much à l’enfant by his learned brother. “But I thought that, in a balloon, it was necessary to keep a fire constantly burning – a sort of grate or fire-basket suspended below. Now, even if we had the silk to make the great spherical bag, how could we make a fire-basket without iron?”

“We should not need the fire-basket you speak of. That is only required, when you design to keep your balloon some length of time in the air. If you only wish to make a short ascent, once filling the bag with hot air is sufficient; as it would be for us here. Even if we wanted a suspended grate, surely, brother, you have enough ingenuity to get over such a trifling difficulty as that?”

“Well, I’m not so sure that I could. How would you get over it?”

“Why, by making a common basket, and lining it with clay. That would carry fire, as well as a vessel of either cast or wrought iron – at least sufficient to serve for a short excursion such as we should care to make. Now-a-days, fire is not used for inflating balloons. Inflammable gas has been found to be far superior for this purpose; but as we have no such thing in stock, we should have to proceed on the old original plan – that employed by the brothers Montgolfier – the first inventors of the balloon.”

“You think, then, that the fire apparatus could be dispensed with, if we could only discover some material that would make the great globe-shaped bag to contain the heated air?”

“Ay,” replied Karl; “think of something to do that, and I promise to make you a balloon.”

Thus challenged, Caspar set his wits to work; and for a long while he sat in silence, as if buried in some very profound speculation. Probably, there was no material substance in that valley that did not pass in review before the retina of his mental vision; and all were considered in turn.

“It must be light, air-tight, and strong?” asked he, at length, as if there was something in his thoughts possessing these three requisites.

“Light, air-tight, and strong,” answered Karl, simply repeating his words.

“The two last I am sure of,” rejoined Caspar. “Of the first only have I my doubts.”

“What is it?” asked Karl, in a tone that betrayed his interest in what Caspar had said.

“Eel-skins!” was the laconic answer.

Chapter Fifty.

The skin balloon

“Eel-skins,” said Caspar, repeating the phrase, as he saw that Karl hesitated before pronouncing an opinion. “Don’t you think they would do?”

Karl had it on the tip of his tongue to cry out – “The very thing!” but something withheld him from making this unqualified declaration.

“They might – it is possible they might,” said he, apparently debating the question within himself – “just possible; and yet I fear – ”

“What do you fear?” asked Caspar.

“Do you think they would not be strong enough?”

“Strong enough,” replied Karl. “That’s not what I fear.”

“The air can’t pass through an eel-skin?”

“No – not that.”

“At the seams, perhaps? We can stitch them neatly; and then gum them over at the joinings. I’ll warrant Ossaroo can sew like a shoemaker.”

The shikaree could do all that. Karl knew it. It was not there the difficulty lay.

“The weight, then?” pursued Caspar interrogatively.

“Precisely that,” answered Karl; “I fear they will be too heavy. Bring one, Ossaroo; and let us have a look at it.”

The shikaree rose from his seat; and going into the hovel, returned presently – bringing back with him a long shrivelled object, which any one could tell to be a dried eel-skin.

There were many like it inside: for they had carefully preserved the skins of the eels they had caught, induced to do so by a sort of presentiment, that some day they might find a use for them. In this case their prudent providence was likely to prove of service to them.

Karl took the skin; and, holding it out on the palm of his hand, appeared to make an estimate of its weight. Caspar watched his brother’s countenance, and waited to hear what he would say; but Karl only expressed himself by a doubtful shake of the head, which seemed to show that his opinion was against the eel-skins.

“They might be made much lighter, I fancy,” suggested Caspar: “scraping would do a deal for them; and by the way, why would not boiling make them light enough? It would take all the fatty, oily substance out of them.”

“There’s something in what you say,” rejoined Karl, apparently impressed by the last suggestion. “Boiling might render them a good deal lighter. We can easily try it.”

As Karl said this, he proceeded to the boiling spring, and plunged the eel-skin under the water. There it was permitted to remain for about half an hour, when it was taken out; and, after being scraped with the blade of a knife, was spread upon a rock, under the sun, where it would soon get thoroughly dry.

They all waited patiently for the completion of this process. The result was of too interesting a character to allow of their occupying themselves with anything else.

In due time the eel-skin had become sufficiently dry, to be submitted to examination; and Karl, once more taking it up, balanced it upon his palm.

Tested, even in this inexact fashion, it was evidently much lighter than before; and, by the gratified look with which the philosopher regarded it, he appeared to be much better satisfied with its weight. Still, however, he was not sanguine: as his words testified. They were almost a repetition of what he had said before.

“It may do – it is just possible. At all events, there can be no harm in trying. Let us try it, then.”

To say, “Let us try it,” meant the same as to say, “Let us make the balloon.” The others understood that; and of course acquiesced in the determination.

As there was nothing to interfere with the immediate commencement of the work, they resolved to set about it at once; and in fact did set about it without farther delay.

The number of eel-skins on hand, though very considerable, would not be near enough for covering a balloon; and therefore Ossaroo went to work with his hooks and lines to catch a few hundreds more. Karl was able to tell how many it would take; or he could at least make an estimate sufficiently exact for the purpose. He designed a balloon of twelve feet diameter: for he knew that one of less size would not have power enough to carry up the weight of a man. Of course, Karl knew how to calculate the surface of a sphere whose diameter should be twelve feet. He had only to multiply the diameter on the circumference; or the square of the diameter on the fixed number 3.1416; or find the convex surface of the circumscribing cylinder; or else find four times the area of a great circle of the said sphere. Any one of these methods would give him the correct result.

On making the calculation, he found that a sphere of 12 feet diameter would have a surface of 452 square feet, within a trifling fraction. Therefore 452 square feet of eel-skins would be required to cover it. In other words, that quantity would be required to make the balloon.

As the eels happened to be of large size – most of them being over a yard in length, and full four inches in average girth – the skin of one when spread out would yield about a square foot of surface. Taking large and small together – and allowing for waste, the heads and tails that would have to be chopped off – Karl calculated that he would get nearly a square foot each out of the eels; and that about five hundred skins would make the balloon bag. But as they would have to be cut occasionally with a slant, in order to get the globe shape, perhaps a few more would be needed; and therefore Ossaroo was to keep his baits in the water, until the requisite number of eels should be hooked out of it.

Ossaroo had another department assigned to him besides catching the fish; and one that took up more of his time: since the baiting of the hooks, and looking after them, required only his occasional attention. Spinning the thread by which the skins were to be sewed together, was a much more delicate operation: since in these both strength and fineness were absolutely necessary. But as Caspar had said, Ossaroo was an adept with the distaff; and several large skeins of the finest twist were soon turned off from his nimble fingers.