Chapter XXXIV: Section II: Natural Science

To my Father's _natural science_, or original, almost intuitive, perception and application of scientific principles, I have already made repeated allusion. But this characteristic of originality, as well as superiority of mind, deserves, I think, more special consideration.

Having to deal with circumstances perpetually varying, and frequently presenting features entirely new, the profession to which he had devoted himself afforded almost the best possible opportunities for the development and application of this quality of mind. And, in a greater or less degree, every voyage he undertook as commander served to elicit this admirable characteristic. Those who understood him not, very naturally ascribed many of his novel proceedings to eccentricity, and these might be liable to run into this very usual extreme; but, for the most part, the apparent eccentricity was, in reality, a sound result of reflective, philosophical consideration. I might adduce some incidents, perhaps, in which the originality of conception was pushed into an extreme: yet I could recal, possibly, hundreds of others in which such conceptions resulted in proceedings at once admirable, in their fitness, and, as such, worthy of imitation.

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1. Take, for example, the process of _sallying_ the ice-bound ship for relieving her of any remediable pressure, and giving free action to the power of wind or "warps" for promoting her progress. And in this we have an adaptation of a previously unapprehended mean and provision, always at hand, possessing extraordinary capabilities as a mechanical force. It may not be uninteresting to elucidate this fact.

Suppose a ship, navigating the Arctic seas, to be held firmly on the sides by the contact of two large sheets, or numerous compacted pieces, of ice. The ice just a-head may be less compact, or there may be a proximate channel, available for "boring" or sailing, if the existing pressure could be relieved so that the ship might be free to move. For the relief of this _lateral_ pressure, no mechanical force, except the action of the wind on the sails when coming somewhat in the direction of "the beam," had heretofore been considered as available, or had been applied. But my Father's device afforded a novel, as well as a powerfully available, agency. In what degree powerful is easily estimated. The ship, in the case referred to, we will suppose is tolerably flat-sided (like the Resolution), and floats, ordinarily, at the depth of the greatest width. Now the power yielded by sallying may be considered as corresponding with that obtained by a wedge acted on by a heavy weight; the _wedge_, in this case, being the portion of the ship's side that becomes depressed, operating by virtue of the expansion of the ship's _width_ when heeling, and the _force_ acting on the wedge being the weight transferred from an even distribution with an upright position of the ship, to an accumulation of weight on one side, inducing a heeling position. Let the extent of heeling be considered as a "streak" of nine inches, in which case, as the opposite side will be proportionally and equally raised, the width of the line of flotation will be increased, altogether (in a main breadth of 26 feet), about half an inch, or a quarter inch on either side. The depressed side, then, in its progress under water, as far as nine inches, will have expanded a quarter of an inch in width, and the raised side an equal quantity; and both sides will act on the contiguous ices with the mechanical force of a wedge of nine inches long and a quarter-inch at the thick end,--exhibiting, on the ordinary mode of calculating the power of the wedge, a gain of power for either side in the proportion of twice the length of the wedge,[O] or 18 inches, to a quarter inch, or as 72 to 1.

The force acting on these wedges is that of the _weight_ of the men employed in sallying, when all are placed on one side of the deck right over the head or back of one of the wedges. In a whaler carrying fifty men, the weight available for this purpose, say that of forty-six or forty-eight of the crew, may be estimated at about three tons, one half of which only would act downward, the other half being expended in the resistance upward, of the opposite side.

Hence the mechanical force hereby derived, as represented by these data, would appear to be that of two wedges of a power of seventy-two to one, each acted on by a weight of a ton and a half, that is, a force of the weight of 108 tons acting towards the separation of the ice and ship on each side. But only half the amount of these two forces, it will be obvious, comes effectively into operation; for the wedges, being on _opposite_ sides of the ship, act antagonistically, thus spending one-half of their power against each other, in the compressing of the opposite sides of the ship together. The force really in operation, then, serving to push off the ice from each side, or tending to separate the compressing masses of ice, will be equivalent to two weights of fifty-four or altogether to a weight of 108 tons.

If there were no resistance either from the _friction_ of the ice on the ship's sides, or from the _stability_ of the ship, the estimated mechanical force, for the case assumed, would no doubt take effect. The resistance from friction cannot, it is evident, be determined; but that of the ship's stability might be easily represented. At the _commencement_ of the heeling position, however, the resistance from this source would be but trifling. In its actual influence, in ordinary cases, the stability might abstract, perhaps, a quarter or a third part from the entire force exerted, but still leaving a free action equivalent to the weight of seventy or eighty tons towards the separation of the ices, right and left.

But the force ultimately brought into operation, after a sallying motion is once obtained, becomes still greater and more effective,--acting now and then, in the nature of concussion from the momentum of a portion of the ship's weight, as thus may be illustrated:--

The weight of the crew, in the outset of the operation, being placed all on one side of the deck, and then suddenly transferred to the other, will, after the overcoming of the friction originally induced by the ice, cause the ship to heel, and, on the reversing of the action (by the men running back again across the deck) the direction of the heeling will be also reversed. The process being carried on with a strict attention to the adjustment of the moment of the running of the men (indicated by the word of command, "over") to the time of change in the natural oscillations of the ship,--these oscillations (supposing the ice to be gradually receding) will increase to a maximum, whilst the incidental concussions of the ship's sides against the contiguous ices will act as a "ram" on the wedge-like expansion of the width of her two broadsides. The additional force thus incidentally applied, it is evident, may be enormous. Hence the wonderful effects sometimes produced by my Father's ingenious device of sallying,--effects not less important and striking when "clawing" to windward of masses of ice in boring, when, by the mere action of the wind on the sails the ship may have come to a stand, as when stuck fast betwixt equally compressing ices on both broadsides at once. The moment the sallying is perceived, the ship realises such relief from both pressure and friction, as to start a-head as if acted on by a magical power!

It hardly requires, perhaps, to be explained, that our investigations of the operation of sallying in urging a path through encumbering ices, are, strictly, only illustrative. For the action of the ship's side which we have considered as that of a regular straight wedge is, in reality, curvilinear, and, ordinarily, would be unusually thin at the apex, thus giving, at the commencement of the heeling movement, a much higher degree of mechanical power. The _extent_ of the compression on the ship's sides, too, we could only consider in a particular case, such as one of thin ice, or ice touching the sides to no great depth. In case of compression from thick ice, having contact with the ship's sides to a considerable depth, the resistance to the sallying would, of course, be much increased, and, by consequence, the operation less effective.

It may just be added that the principle of sallying is evidently capable of still more powerful application by aiding the _weight_ of the men, in the first instance of movement, by auxiliary loads of guns, chains, casks, or other heavy bodies transferred to one side of the deck; or, in a still higher degree, by an auxiliary mechanical force derived from a "purchase" from the ship's lowermast, or top-mast head, to an anchor fixed in a distant part of the ice on either side. An enormous power, it is evident, might be derived from a leverage of this kind, sufficient almost to compress or squeeze in the very timbers of the hull.

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2. Another example of the application of the principles of natural science, may be adduced with respect to my Father's practice in the capture of certain harpooned whales. In the most usual habits of the mysticetus, when struck in the Greenland seas, it descends to a considerable depth, generally 600 or 700 fathoms, and, after an interval of about half an hour, or so, returns spontaneously to the surface for respiration. But sometimes, especially when a taught strain has been held on the line, the whale continues to press so determinately into the depths of the ocean that it dies by a process similar to drowning. In that case the heaving up of the capture becomes a matter of great labour and difficulty, and, because of the liability of the harpoon to draw, or of the lines to part, of much uncertainty as to the result. It is a matter, therefore, of much importance to avoid the possible contingency of a harpooned whale "dying down." The process ordinarily adopted for inducing the return of the fish to the surface, after the downward course is suspended, is to haul on the lines as soon as any impression can be produced, so as to stimulate to action and urge an ascending motion. In very many cases this process is effective, but by no means in all. For sometimes so desperate and continuous is the effort to get down that, when necessity might urge a return to the surface for respiration, the power to return no longer remains, and the helpless monster dies at its utmost depression.

My Father, with his peculiar felicity of consideration and device, assumed a measure of proceeding as _apparently_ unfitting as it was novel in its character. When the usual processes for the obtaining of the fish's return to the surface had failed, and no prospect remained but that it must die where it was, he would throw off the turns of his line round the stem or "loggerhead" of the boat, and allow an extent of fifty or a hundred fathoms more to run freely out and sink in the water.

The meaning of the device was this:--The entangled whale had no doubt descended deep in the water, as its ordinary mode of escaping from its natural enemies; but the attachment and restraint of the line it could not escape from. It was an instinct with it, therefore, as he conceived,--as in the case of some well-known quadrupeds, which may be driven but will not be led,--to resist the restraining force, and to struggle to distance the point from which the restraint proceeds. The untoward effect of this instinct, my Father supposed, might be diverted by rapidly slacking out a large extent of the entangling line, so that it might sink _below_ the place of the fish, and so _draw downward_; for the same instinct which had incited it so perseveringly to dive, might naturally be expected to urge it, under this change of circumstances, to an upward course.

The experiment on being tried proved, in different cases, successful. The whale, stimulated to a new course by a new direction being given to the restraining line, returned to the surface, where it was received by its waiting assailants, and, when deprived of its life, became a prompt and easy prize, instead of an uncertain, hard-earned object of pursuit!

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3. Besides the cases just recited of aptness in natural science, another occasion is before my recollection in which, during his varied adventures in the whale-fishery, this characteristic of mind, with my Father, was strikingly developed. A large whale had been "struck" on the borders of a vast sheet of ice, denominated a "field," which took refuge beneath the frozen surface, and, after suffering the deprivation of air for a period too considerable for its capabilities of endurance, died there.

After a long interval of patient waiting, on the part of the whalers, for the turning out of the expected capture (for the compactness of a firm field of ice generally obliges the whale to return to the outside for the purpose of respiration), they proceeded to haul on the line to try to facilitate their expectation. But when as much force had been applied as the line might safely bear, their efforts came to a stand. There was no reactive motion indicative of life in the whale, nor any progress towards its withdrawal, if dead.

Various repetitions of a similar effort, after slacking out a quantity of line to give some change to the direction of the tension, ended in the same discouraging manner; so that a doubt arose whether the harpoon were yet attached to the line, or whether it might have got entangled on some submerged irregularity of the ice.

My Father at length left the ship to give his personal attention to this difficult business. His first care was to examine the line at its fullest tension; but the exact direction was not discoverable because of the thickness of the verge of the ice. Slacking out, therefore, a considerable quantity of the line, he caused the boat to be backed off to a little distance, and, whilst it was kept off as much as possible by the oars of several boats attached, the line was hauled in, till, becoming nearly horizontal by tension, its direction beneath the ice could be clearly determined. By this direction he traced, by the eye, an imaginary corresponding line on the surface of the ice-field, which, by means of numerous irregularities and hummocks, he was enabled to do satisfactorily,--noticing particularly a very high and conspicuous hummock in this exact direction, and at about the distance to which the quantity of line run out might be supposed to reach. His next step, and that a truly scientific one, was to try to vary the line of direction, so that he might determine, by the intersection of lines, the position of the harpoon. This he effected by again slacking out the line, but to a much greater extent, and then causing the position of the boat to be changed by rowing slowly in a direction parallel to, and at some distance from, the edge of the ice, until the new direction might make a large angle with that previously determined. Time being allowed for the rope to subside into its position of rest, tension was given to it, as before, and another imaginary line traced by the eye on the ice. My Father now perceived that the point of intersection corresponded very nearly with the position of the remarkable hummock, almost a mile distant, before noticed, and that it must be immediately beyond it.

Taking a whale-lance in his hand he walked over the ice to the place, and _just beyond_ the hummock he found a thin flat surface of much younger ice. Striking his lance repeatedly into this, he gradually effected its perforation; when, to his no small delight and to the amazement of the men who had followed his steps, his lance struck against a soft and elastic substance beneath:--it was the back of the dead whale!

Aid of hands and instruments being now obtained, the thin sheet of ice was partly cut out and the fragments removed till the attached line could be got at. When effected, it was again slacked out of the boat, and the end firmly secured to the slender part of the body of the fish adjoining the tail. The two lobes of the tail were then partly cut off, so as to hang down in the water as sustained by a slight attachment, and thus by their gravity to help to sink the carcass whilst they no longer were calculated to catch the irregularities of the submerged surface of the ice, as the tail, when perfect in structure and position, had previously done. A considerable weight, I believe, in sand-bags, was also hung upon the "bight" of the line for helping to sink the fish clear of obstructions above, and, finally, the line being hauled on in the boat from whence the fish had been originally harpooned, it progressively yielded to the force applied, and in due time the loud and cheerful huzzas of the sailors announced the completion of the capture in its appearance outside!