as soon as they had hung the ibex-meat upon the curing strings, and pegged out the two skins for drying, they turned their attention to the making of the rope by which they were to be pulled out of their prison. by good fortune they had a large stock of hemp on hand all ready for twisting. it was a store that had been saved up by ossaroo—at the time when he had fabricated his fish-net; and as it had been kept in a little dry grotto of the cliff, it was still in excellent preservation. they had also on hand a very long rope, though, unfortunately, not long enough for their present purpose. it was the same which they had used in projecting their tree-bridge across the crevasse; and which they had long ago unrove from its pulleys, and brought home to the hut. this rope was the exact thickness they would require: for anything of a more slender gauge would scarcely be sufficient to support the weight of a man’s body; and considering the fearful risk they would have to run, while hanging by it against the face of such a cliff, it was necessary to keep on the safe side as regarded the strength of the rope. they could have made it of ample thickness and strength, so as to secure against the accident of its breaking. but then, on the opposite hand, arose the difficulty as to the strength of the eagle’s wing. should the rope prove too heavy for the bearcoot to carry over the top of the cliff, then all their labour would be in vain.

“why not ascertain this fact before making the rope?”

this was a suggestion of karl himself.

“but how are we to do it?” was the rejoinder of caspar.

“i think we can manage the matter,” said the botanist, apparently busying his brain with some profound calculation.

“i can’t think of a way myself,” replied caspar, looking inquiringly at his brother.

“i fancy i can,” said karl. “what is to hinder us to ascertain the weight of the rope before making it, and also decide as to whether the bird can carry so much?”

“but how are you to weigh the rope until it is made? you know it’s the trouble of making it we wish to avoid—that is, should it prove useless afterwards.”

“oh! as for that,” rejoined karl, “it is not necessary to have it finished to find out what weight it would be. we know pretty near the length that will be needed, and by weighing a piece of that already in our hands, we can calculate for any given length.”

“you forget, brother karl, that we have no means of weighing, even the smallest piece. we have neither beam, scales, nor weights.”

“pooh!” replied karl, with that tone of confidence imparted by superior knowledge. “there’s no difficulty in obtaining all these. any piece of straight stick becomes a beam, when properly balanced; and as for scales, they can be had as readily as a beam.”

“but the weights?” interrupted caspar. “what about them? your beam and scales would be useless, i apprehend, without proper weights? i think we should be ‘stumped’ for the want of the pounds and ounces.”

“i am surprised, caspar, you should be so unreflecting, and allow your ingenuity to be so easily discouraged and thwarted. i believe i could make a set of weights under any circumstances in which you might place me—giving me only the raw material, such as a piece of timber and plenty of stones.”

“but how, brother? pray, tell us!”

“why, in the first place, i know the weight of my own body.”

“granted. but that is only one weight; how are you to get the denominations—the pounds and ounces?”

“on the beam i should construct i would balance my body against a lot of stones. i should then divide the stones into two lots, and balance these against one another. i should thus get the half weight of my body—a known quantity, you will recollect. by again equally dividing one of the lots i should find a standard of smaller dimensions; and so on, till i had got a weight as small as might be needed. by this process i can find a pound, an ounce, or any amount required.”

“very true, brother,” replied caspar, “and very ingenious of you. no doubt your plan would do—but for one little circumstance, which you seem to have overlooked.”

“what is that?”

“are your data quite correct?” naïvely inquired caspar.

“my data!”

“yes—the original standard from which you propose to start, and on which you would base your calculations. i mean the weight of your body. do you know that?”

“certainly,” said karl; “i am just 140 pounds weight—to an ounce.”

“ah, brother,” replied caspar, with a shake of the head, expressive of doubt, “you were 140 pounds in london—i know that myself—and so was i nearly as much; but you forget that the fret and worry of this miserable existence has reduced both of us. indeed, dear brother, i can see that you are much thinner since we set out from calcutta; and no doubt you can perceive the like change in me. is it not so?”

karl was forced to give an affirmative reply to the question, at the same time that he acknowledged the truth of his brother’s statement. his data were not correct. the weight of his body—which, not being a constant quantity, is at all times an unsafe standard—would not serve in the present instance. the calculation they desired to make was of too important a character to be based upon such an untrustworthy foundation. karl perceived this plainly enough; but it did not discourage him from prosecuting his purpose to make the attempt he had proposed.

“well, brother!” said he, looking smilingly towards the latter, and apparently rather pleased at caspar’s acuteness; “i acknowledge you have had the better of the argument this time; but that’s no reason why i should give up my plan. there are many other ways of ascertaining the weight of an object; and no doubt if i were to reflect a little i could hit upon one; but as luck has it, we need not trouble ourselves further about that matter. if i mistake not, we have a standard of weight in our possession, that is just the thing itself.”

“what standard?” demanded caspar.

“one of the leaden bullets of your own gun. they are ounce bullets, i’ve heard you say?”

“they are exactly sixteen to the pound, and therefore each of them an ounce. you are right, karl, that is a standard. certainly it will do.”

the subject required no further sifting; and without delay they proceeded to ascertain the weight of two hundred yards of rope. a balance was soon constructed and adjusted, as nicely as if they had meant to put gold in the scale. twenty yards of the rope already in hand was set against stones—whose weight they had already determined by reduplicating a number of bullets—and its quantity ascertained in pounds and ounces. eight times that gave one hundred and sixty yards—the probable amount of cord they should require.

this being determined upon, the next thing was to find out whether the eagle could carry such a burden into the sky. of course, the bird would not have the whole of it to carry at first, as part would rest upon the ground; but should it succeed in reaching the top of the cliff—even at the lowest part—there would then be the weight of at least one hundred yards upon its leg; and if it ascended still higher, a greater amount in proportion.

it was natural to suppose that the bearcoot in going out would choose the lowest part of the precipice—especially when feeling his flight impeded by the strange attachment upon his leg; and if this conjecture should prove correct, there would be all the less weight to be sustained. but, indeed, by the cord itself they could guide the bearcoot to the lowest part—since by holding it in their hands, they could hinder him taking flight in any other direction.

considering all these circumstances, and rather cheered by the many points that appeared to be in their favour, they proceeded to make trial of the eagle’s strength.

it would not take long to decide; but conscious of the great importance of the result, they set about it with due deliberation.

a log of wood was procured, and chopped down, till it was exactly the weight of the rope to be used. to this the piece of twenty yards—already employed for a different purpose—was attached at one end—the other being tightly knotted around the shank of the eagle.

when all was ready, the bird was stripped of his other fastenings; and then all retired to a distance to give him space for the free use of his wings.

fancying himself no longer under restraint, the bearcoot sprang up from the rock on which he had been placed; and, spreading his broad wings, rose almost vertically into the air.

for the first twenty yards he mounted with a vigorous velocity; and the hopes of the spectators found utterance in joyful ejaculations.

alas! these hopes were short-lived, ending almost on the instant of their conception. the rope, carried to its full length, became suddenly taut—jerking the eagle several feet back towards the earth. at the same time the log was lifted only a few inches from the ground. the bird fluttered a moment, taken aback by this unexpected interruption; and, after recovering its equilibrium, again essayed a second flight towards the sky.

once more the rope tightened—as before raising the log but very little from the ground—while the eagle, as if this time expecting the pluck, suffered less derangement of its flight than on the former occasion. for all that, it was borne back, until its anchor “touched bottom.” then after making another upward effort, with the like result, it appeared to become convinced of its inability to rise vertically, and directed its flight in a horizontal line along the cliffs. the log was jerked over the ground, bounding from point to point, occasionally swinging in the air, but only for a few seconds at a time.

at length the conviction forced itself upon the minds of the spectators—as it seemed also to have done upon that of the performer—that to reach the top of the cliff—with a cord upon its leg, equal in weight to that log—was more than a bearcoot could accomplish.

in short, the plan had proved a failure; and, no longer hoping for success, our adventurers turned their disappointed looks upon each other—leaving the eagle free to drag his wooden anchor whithersoever he might wish.