« ForrigeFortsæt »
Heads of what has been done in the Voyage; with some Conjectures concerning the Formation of Ice-Islands ; and an Account of our Proceedings till our Arrival at the Cape of Good Hope.
I HAD now made the circuit of the southern ocean in a high latitude, and traversed it in such a inanner as to leave not the least room for the possibility of there being a continent, unless near the Pole, and out of the reach of navigation. By twice visiting the tropical sea, I had not only settled the situation of some old discoveries, but made there many new ones, and left, I conceive, very little more to be done even in that part. Thus I flatter myself, that the intention of the voyage has, in every respect, been fully answered; the southern hemisphere sufficiently explored, and a final end put to the searching after a southern continent, which has, at times, ingrossed the attention of some of the maritime powers, for near two centuries past, and been a favourite theory amongst the geographers of all ages.
That there may be a continent, or large tract of land, near the Pole, I will not deny; on the contrary I am of opinion there is; and it is probable that we have seen a part of it. The excessive cold, the many islands and vast Hoats of ice, all tend to prove that there must be land to the south; and for my persuasion that this southern land must lie, or extend, farthest to the north opposite to the southern Atlantic and Indian oceans, I have already assigned some reasons; to which I may add the greater degree of cold experienced by us in these seas, than in the southera Pacific ocean under the same parallels of latitude."
* After what has been said of the utter inutility of a southern continent to any human being, or even in the way of hypothesis to explain the constitution of nature, it may seem quite unnecessary to occupy a moment's attention about any arguments for its existence. As, however, a few renarks were hazarded respecting those of a mathematical kind, it may
be proper to say a word or two as to others of a physical nature. Two reasons for this supposition have been urged ; viz. the presence of rivers necessary to account for the large masses of fresh-water ice found in high southern latitudes; and the existence of firm and immoveable points of land round which these masses might form. The first of these is glaringly
In this last ocean, the mercury in the thermometer seldom fell so low as the freezing point, till we were in 600 and upwards; whereas in the others, it fell as low in the latitude of 54o. This was certainly owing to there being a greater quantity of ice, and to its extending farther to the
erroneous in point of principle and fact. In the first place, it is most cértain, that the waters of the ocean admit of being frozen, and that when so, they either do or do not contain the salts they held in solution, according to certain circumstances, which the argument does not require to be explained. And, secondly, it is absurd to imagine that lands in the vicinity of the Pole should have any rivers, as the snow-line, as it has been called, reaches so low down there as the surface of the earth, and as the tempe rature of the atmosphere, reckoning from what is known of it in high latitudes, can scarcely ever be above that point at which water becomes solid. The second argument is equally unsubstantial, and may be as readily invalidated. In fact, the principal thing requisite for the congelation of water in any circumstances of situation, is the reduction of the temperature to a certain point, to the effect of which, it is well known, the agitation of the water often materially contributes. It may be remarked also, that as the heat of the ocean seems to diminish in pretty regular progression from the surface downwards, so it is highly probable, that, even at considerable distances from the Pole, the lower strata may be in a state of congelation; much more probably, therefore, there may exist at and near the Pole, a mass of ice of indefinite size and durability, which, extending to greater or smaller distances according to different circumstances, may serve as the basis, or point d'appui, of all the islands and fields of ice discoverable in this region. Ice, in fact, is just as capable of a fixed position as earth is, or any other solid body, and may accordingly have constituted the substratum of the southern hemisphere within the polar circle, since the time that this planet assumed its present form and condition. So much then on the subject of a southern continent, which, after all, we see is not worth being disputed about, and appears to be set up, as it were, in absolute de rision of human curiosity and enterprise. Wise men, it is likely, notwithstanding such promissory eulogiums as Mr Dalrymple held out, will neither venture their lives to ascertain its existence, nor lose their time and tempers in arguing about it. Cook's observation, it is perhaps necessary to remark, as to the ice extending further towards the north opposite the Atlantic and Indian oceans than any where else, may be accounted for without the supposition he makes in explanation of it. Thus certain warm currents of water may be conceived to proceed from the north, towards those other parts where the ice has not been seen to extend so far, and to prevent the formation of it to the same distance; or again, there may be islands and rocks, to which the ice adheres, in the situations mentioned by Cook. Both causes, indeed, may operate, and there may be others also quite equivalent to the effect. But it is full time to leave this merely curious subject. Mr G. F. has somewhat wittily remarked, that the opinion of the existence of a southern concinent maintained by some philosophers, though much invalidated by this voyage, is nevertheless a proof of their great intelligence, considering the few data on which they could proceed. Some readers may incline, perhaps, to give as much credit to the writer, for hazarding, on about equal grounds, any opinion in opposition to it.-E.
north, in these two seas than in the south Pacific; and if ice be first formed at, or near land, of which I have no doubt, it will follow that the land also extends farther north.
The formation or coagulation of ice-islands has not, to my knowledge, been thoroughly investigated. Some have supposed them to be formed by the freezing of the water at the mouths of large rivers, or great cataracts, where they accumulate till they are broken off by their own weight. My observations will not allow me to acquiesce in this opi
because we never found any of the ice which we took up incorporated with earth, or any of its produce, as I think it must have been, had it been coagulated in land-waters. It is a doubt with me, whether there be any rivers in these countries. It is certain, that we saw not a river, or stream of water, on all the coast of Georgia, nor on any of the southern lands. Nor did we ever see a stream of water run from any of the ice-islands. How are we then to suppose that there are large rivers? The valleys are covered, many fathoms deep, with everlasting snow; and, at the sea, they terminate in icy cliffs of vast height. It is here where the ice-islands are formed; not from streams of water, but from consolidated snow and sleet, which is almost continually falling or drifting down from the mountains, especially in the winter, when the frost must be intense. During that season, the ice-cliffs must so accumulate as to fill
all the bays, be they ever so large. This is a fact which cannot be doubted, as we have seen it so in summer. These cliffs ac. cumulate by continual falls of snow, and what drifts from the mountains, till they are no longer able to support their own weight; and then large pieces break off, which we call ice-islands. Such as have a flat even surface, must be of the ice formed in the bays, and before the flat vallies; the others, which have a tapering unequal surface, must be formed on, or under, the side of a coast composed of pointed rocks and precipices, or some such uneven surface. For we cannot suppose that snow alone, as it falls, can form, on a plain surface, such as the sea, such a variety of high peaks and hills, as we saw on many of the ice-isles. It is certainly more reasonable to believe that they are formed on a coast whose surface is something similar to theirs. I have observed that all the ice-islands of any extent, and before they begin to break to pieces, are terminated by perpendis cular cliffs of clear ice or frozen snow, always on one or
more sides, but most generally all round. Many, and those of the largest size, which had a hilly and spiral surface, shewed a perpendicular cliff, or side, from the summit of the highest peak down to its base. This to me was a convincing proot, that these, as well as the flat isles, must have broken off from substances like themselves, that is, from some large tract of ice.
When I consider the vast quantily of ice we saw, and the vicinity of the places to the Pole where it is formed, and where the degrees of longitude are very small, I am led to believe that these ice-cliff's extend a good way into the sea, in some parts, especially in such as are sheltered from the violence of the winds. It may even be doubted if ever the wind is violent in the very high latitudes. And that the sea will freeze over, or the snow that falls upon it, which amounts to the same thing, we have instances in the northern heinisphere. The Baltic, the Gulph of St Laurence, the Straits of Belle-Işle, and many other equally large seas, are frequently frozen over in winter. Nor is this at all extraordinary, for we have found the degree of cold at the surface of the sea, even in summer, to be two degrees below the freezing point; consequently nothing kept it from freezing but the salt it contains, and the agitation of its surface. Whenever this lasť ceasethi in winter, when the frost is set in, and there comes a fall of snow, it will freeze on the surface as it falls, and in a few days, or perhaps in one night, form such a sheet of ice a's will not be easily broken up. Thus a foundation will be laid for it to accumulate to any thickness by falls of snow, without its being at all necessary for the sea-water to freeze. It may be by this means these vast floats of low ice we find in the spring of the year are formed, and which, after they break up, are carried by the currents to the north. For, from all the observations I have been able to make, the currents every where, in the high latitudes, set to the north, or to the N.E. or N.W.; but we have very seldomi found them considerable.
If this imperfect account of the formation of these extraordinary floating islands of ice, which is written wholly
2 Forster the elder, in his observations, has related many instances of this sort, and given some very ingenious remarks on the subject of the formation of ice in high latitudes; but it is impossible to do justice to them within the compass of a note, and perhaps most readers are of opiAion that the text is abundantly copious on this part of the voyage.-E.
from my own observations, does not convey, some useful hints to an abler pen, it will, however, convey some idea of the lands where they are formed: Lands doomed by Nature to perpetual frigidness; never to feel the warmth of the sun's rays; whose horrible and savage aspect I have not words to describe. Such are the lands we have discovered; what then may we expect those to be which lie still farther to the south? For we may reasonably suppose that we have seen the best, as lying most to the north. If any one should have resolution and perseverance to clear up this point by proceeding farther than I have done, I shall not envy him the honour of the discovery ; but I will be bold to say, that the world will not be benefited by it.
I had, at this time, some thoughts of revisiting the place where the French discovery is said to lie. But then I considered that, if they had really made this discovery, the end would be as fully answered as if I had done it myself. We know it can only be an island ; and if we may judge from the degree of cold we found in that latitude, it cannot be a fertile one. Besides, this would have kept me two months longer at sea, and in a tempestuous latitude, which we were not in a condition to struggle with. Our sails and rigging were so much worn, that something was giving way every
and we had nothing left either to repair or to replace them. Our provisions were in a state of decay, and consequently afforded little nourishment, and we had been a long time without refreshments. My people, indeed, were yet healthy, and would have cheerfully gone wherever I had thought proper to lead them; but I dreaded the scurvy laying hold of them at a time when we had nothing left to remove it. I must say farther, that it would have been cruel in me to have continued the fatigues and hardships they were continually exposed to, longer than was absolutely necessary. Their behaviour, throughout the whole voyage, merited every indulgence which it was in my power to give them. Animated by the conduct of the officers, they shewa ed themselves capable of surmounting every difficulty and danger which came in their way, and never once looked either upon the one or the other, as being at all heightened, by our separation from our consort the Adventure.3
3 « The sour krout, that excellent anti-scorbutic food, of which sixty large casks were put on board our ship, was now entirely consumed, and