"after well considering all you say, as well "Assuredly," wrote Sir John Herschel, as the common sense of the matter, and the experience of our hot water circulation-pipes in our greenhouses, &c., there is no refusing to admit that an Oceanic mere Heat, Cold, and Evaporation, as verœ circulation of some sort must arise from causa; and you have brought forward with singular emphasis the more powerful action of the Polar Cold, or rather the more intense action, as its maximum effect is limited to a much smaller area than that of the maximum of Equatorial Heat. The action of the Trade and Counter-trade Winds in like manner cannot be ignored; and henceforward the question of Oceancurrents will have to be considered under a twofold point of view"-namely, as he goes on to explain, the horizontal circulation produced by the action of Wind on the surface, and the vertical circulation dependent on opposition of Temperature. warmer sea around is cooled in its turn; the points bearing upon it. I have taken it then sinks, and goes down, down, down; the opinion of some of the most eminent and this colder and denser water creeps Mathematicians and Physicists of this gradually along the deepest parts of the country, with regard to the validity of the great Atlantic basin, and now and then, by principles I have advanced; and I am glad some peculiar conformation of the bottom, to say that I do not bring them forward it will come nearer to the surface, as it merely on my own authority, but am asdoes in this Lightning Channel. If we are sured that this doctrine will stand the test ever able to trace the Lightning Channel of very rigid inquiry. A short time before further north, it will be a most interesting the death of Sir John Herschel, I had the point to determine what it is that sends satisfaction of receiving a letter from him, up the cold water so much nearer the sur- fully accepting the doctrine I have proface there than it has been found anywhere pounded; and his acceptance is the more else in the same latitude. But we have a significant, since he had previously repudiparallel fact in the case of Gibraltar, where ated the doctrine of Captain Maury, that I have lately been able to prove very dis- an Oceanic Circulation (of which he retinctly that the water from the deeper por- garded the Gulf Stream as a part) is maintion of the Mediterranean basin is passing tained by the expansion produced by Equaas an under-current outwards through the torial heat. shallowest part of the Strait, beneath the surface-current that is continually flowing inwards from the Atlantic. Thus, then, you see what is the moving force. It is this constant reduction of temperature, which increases the density of the water and disturbs the equilibrium too. pose we had a Polar column of water of a Supcertain height at this end of the room, and an Equatorial column at the other end. As this Polar column is cooled down, it contracts and becomes denser; thus its level is lowered, and the water will flow towards its surface to bring up that level. When this column of dense Polar water has on the top of it the additional water which has flowed in to maintain the level of that column, it becomes considerably heavier than the corresponding Equatorial column at the other end. What is the consequence? Why, that a portion of the lower part of it must flow away. Thus there will be a tendency to a renewed lowering of the level, which must draw in water from the Equatorial region; and there will always be, as that water flows in and is cooled down, a tendency to the maintenance of a greater weight or downward pressure of water in the Polar area; so by these two influences the lowering of the level, and the increase of the density of the column- we have this constant disturbance of level and disturbance of equilibrium, producing an inflow from the Equatorial towards the Polar regions on the surface, and an outflow from the Polar towards the Equatorial area at the bottom. This is the doctrine of the General Oceanic Circulation to which I have been led. I say "I," because it has happened that I have been the member of the Expedition to whose share this part of the inquiry fell, and I have applied myself to all -- Society I was enabled, by the kindness of At a meeting of the Royal Geographical Dr. Odling, to exhibit an illustrative experiment, which was considered extremely satisfactory; and I think I can explain it to you in such a manner that you will easily understand its value. with plate-glass sides, about six feet long We had a trough, and a foot deep, and the sides not more than one inch from each other. At one end of this trough a piece of ice was wedged in between the two sides; that represented the Polar area. end we applied heat at the surface, not at At the other the bottom tions of the case the heat being applied -to imitate the exact condiby a bar of metal which was laid on the surface of the water, and then carried over the end of the trough and heated by a spirit lamp; that represented the Equato rial area. Then we put in some colouring which depends on the interruption of the Equatorial Current by the coast-line of Central America. But wherever there were deep seas, and the Polar water and Equatorial areas were in communication, there must have always been this vertical circulation. matter, red at the warm end, and blue at the cold end. What happened? The water tinged with blue put in at the surface of the Polar area, being chilled by contact with the ice, immediately fell down to the bottom; it then crept slowly along the bottom of the trough, and at the Equa- One very curious consequence of this torial end it gradually rose towards the vertical circulation, which I believe to be surface; and, having done so, it gradually very important in relation to the Life of returned along the surface to the point the ocean, is this-that by its means, if from which it started. The red followed this doctrine be true, every drop of water the same course as the blue, but started in the ocean will, in its turn, be brought from a different point. It crept along the from the bottom and exposed to the sursurface from the Equatorial to the Polar face. Now, in the Mediterranean there is end, and there fell to the bottom, just as no such circulation; and we found in the the blue had done, and formed another great depths of the Mediterranean an exstratum, creeping along the bottom and traordinary paucity of animal life, instead coming again to the surface. Each colour of finding the abundance which we enmade a distinct circulation during the half countered in the great depths of the Athour in which the audience had this exper-lantic. I will not say that this is the sole iment in view. - Now that was a very cause of the difference, but it has a good beautiful experiment; and I can myself deal to do with it. These depths are stagsee no flaw in the application of the argu- nant; there is nothing to change them; ment, that what is true on a small scale in for they are completely cut off from the this trough is true of a mass of water ex-depths of the Atlantic; and the only vertending from the Equatorial to the Polar tical circulation to which they are subject consists in the descent of water which has been concentrated by evaporation on the surface, and which, becoming heavier by concentration, will go down, but will soon diffuse its excess of salt, so as not to reach any great depth. Thus it is obvious that the condition of any "self-contained" basin, like the Mediterranean, must be extremely different Biologically, and therefore Geologically, from that of an Oceanic basin forming part of the great Watersystem of the globe. area. Lastly, let us return for a moment to the subject of Deep-sea Climates. You see that this vertical circulation is a great Cosmical matter-not a mere local phenomenon, and not confined to the present time as the Gulf Stream is. It is a phenomenon which must have had its place in all Geological history. The Gulf Stream, and the superficial Arctic current which brings its water back again, constitute a horizontal circulation, the continuance of NEW THEORY OF THE RATTLESNAKE. — It has long been urged as an objection to the theory of natural selection that the tail-appendage of the rattlesnake must be injurious to the animal by attracting to it the notice of its enemies. Professor Shaler has however observed that the THE American Journal of Science and Arts | gives an extract from a letter from Dr. Janssen to Prof. Newton, in which occurs the following interesting passage:-"My observations prove that, independently of the cosmical matter which should be found near the sun, there exists about the body an atmosphere of great ex-noise of the rattle is scarcely distinguishable from tent, exceedingly rare, and with a hydrogen the sound made by an American species of Cibase. This atmosphere, which doubtless forms cada; and he conjectures that the object of the the last gaseous envelope of the sun, is fed from rattle is to attract within reach of the snake the the matter of the protuberances which is shot birds which naturally feed upon the Cicada. up with great violence from the interior of the This he considers to be the explanation of the photosphere. But it is distinguished from the mode in which birds are seen to flutter round a chromosphere and the protuberances by a much rattlesnake, without calling into play the unreasmaller density, a lower temperature, and, per-sonable theory of fascination. A formidable obhaps, by the presence of certain different gases." jection to the universality of the principle of Janssen proposes to call this the "coronal at-natural selection is thus removed. Professor mosphere," as he considers it to produce a large Shaler's paper will be found in the American portion of the phenomena of the solar corona. Naturalist for January. Academy. From Blackwood's Magazine. THE MAID OF SKER. CHAPTER XLVIII. A BREATHLESS DISINTERMENT. By this time we were up to all the ins and outs of everything. A sailor has such a knowledge of knots, and the clever art of splicing, that you cannot play loose tricks, in trying on a yarn with him. Jerry Toms and I were ready, long before that day was out, to tie up our minds in a how-line knot, and never more undo them. Jerry went even beyond my views, as was sure to be, because he knew so much less of the matter; he would have it that Parson Chowne had choked the two children without any aid, and then in hatred and mockery of the noble British uniform, had buried them deep in Braunton Burrows, wearing a cocked for a shovel hat, purely by way of outrage.. On the other hand, while I agreed with Jerry up to a certain distance, I knew more of Parson Chowne (whom he never had set eyes upon) than to listen to such rubbish. And while we agreed in the main so truly, and thoroughly praised each other's wisdom, all the people in the house made so highly much of us, that Jerry forgot the true line of reasoning, even before nine o'clock at night, and dissented from my conclusions so widely, and with so much arrogance, that it did not grieve me (after he got up) to have knocked him down like a ninepin. However, in the morning he was all right, and being informed upon every side that the cook did it with the rolling-pin, he acknowledged the justice of it, having paid more attention to her than a married lady might approve, though parted from her husband. However, she forgave him nobly, and he did the same to her; and I, with all my knowledge of women, made avowal in the presence of the lady-housekeeper, that my only uneasiness was to be certain whether I ought to admire the more the behaviour on her part or on his. And the cook had no certainty in the morning, exactly what she might have done. This little matter made a stir far beyond its value; and having some knowledge of British nature, I proposed to the comitatus, with deference both to the cook and house-keeper, also a glance at the first housemaid, that we should right all misunderstanding by dining together comfortably, an hour before the usual time. Because, as I clearly expressed it, yet most inoffensively, our breakfast had been ruined by a piece, I might say, of misconstruction overnight between two admirable persons. And Heaviside came in just then, and put the cap on all of it, by saying that true sailors were the greatest of all sportsmen; therefore, in honour of our arrival, he had asked, and got leave from the gamekeepers, to give a great rabbiting that afternoon down on Braunton Burrows; and he hoped that Mistress Cockhanterbury, being the lady-housekeeper, would grace the scene with her presence, and let every maid come to the utmost. manner Heaviside's speech, though nothing in itself, neither displaying any at all, was received with the hottest applause; and for some time Jerry and I had to look at one another, without any woman to notice us. We made allowance for this, of course, although we did not like it. For, after all, who was Heaviside? But we felt so sorely the ill effect of the absence of perfect harmony upon the preceding evening (when all our male members of the human race took more or less the marks of knuckles), that a sense of stiffness helped us to make no objection to anything. And tenfold thus, when we saw how the maids had made up their minds for frolicking. These young things must have their way, as well as the nobler lot of us : for they really have not so very much less of mind than higher women have; and they feel what a woman is too well to push themselves forward. They know their place, and they like their place, and they tempt us down into it. Be that either way - and now unwomanly women waste their good brains upon a trifle of this kind - rabbiting was to be our sport; and no sooner was the dinner done, and ten minutes given to the maids to dress, than every dog on the premises worth his salt was whistled for. It would have amused you to see the maids, or I might say all the womankind, coming out with their best things on, and their hair done up, and all pretending never even to have seen a looking-glass. Madame Heaviside (as she commanded all people to entitle her) was of the whole the very grandest as. regards appearance. Also in manner and carrying on; but of this I have no time to speak. Enough that the former Naval Instructor thought it wiser to keep his own place, and let her flirt with the gamekeepers. We had dog3, and ferrets, and nets, and spades, and guns for those who were clever enough to keep from letting them off at all, and to frighten the women without any harm. There must have been five-and-twenty of came up, almost at a run, to a hill where Jerry Toms and I were sitting down, to look about a bit, and to let the young wo us in number all together, besides at least "What's the matter?" said I, not liking to be interrupted thus. "Matter enough," he panted out; "where is Madame? The Lord keep her away." "Madame is gone down to the cave in the sand," said Jerry, though I frowned at him, "together with that handsome fellow -I forget his name - underkeeper they call him." 66 Hurrah, my hearties!" cried Heaviside; "that is luck, and no mistake. Now lend a hand, every lubber of you. Her pet dog Snap is in the sand; with the devil to pay, and no pitch hot,' if we take long to get him out again." We knew what he meant; for several dogs of an over-zealous character had been smothered in and buried in the rabbitgalleries, through the stupidity of people who crowded upon the cone over them. Some had been dug out alive, and some dead, according to what their luck was. And now we were bound to dig out poor Snap, and woe to us all if we found him dead! Therefore we had the most wonderful fun, enjoying the wildness of the place, and the freshness of the river air, and the wilfulness of the sandhills, also the hideand-seek of the rushes, and the many ups and downs and pleasure of helping the young women in and out, also how these latter got (if they had any limbs they were proud of) into rabbit-holes on purpose to be lifted out of them, and fill the rosettes of their shoes, and have them dusted by a naval man's very best pocket-handkerchief together with a difficulty of standing on one foot while doing it, or having it done to them, and a fear of breathing too much out after onion-sauce at dinner-timewhich made their figures look beautiful. Enough that I took my choice among them, for consideration; and jotted down the names of three, who must have some cash from their petticoats. Let nobody for a I took the biggest spade, as well as the moment dream that I started with this in- entire command of all of them, and we tention. The rest of my life was to be de-started at quick step for the place which voted to the Royal Navy, if only a hot war Heaviside pointed out to us. He told us, should come again; of which we already so far as his breath allowed, that his small felt simmerings. But I could not regard brown terror Snap had found a rabbit of all these things, after so many years at sea, tender age hiding in a tuft of rushes. without some desire for further acquaint- Snap put all speed on at once, but young ance with the meaning of everything. At bunny had the heels of him, and flipped up sea we forget a great deal of their ways. her tail at the mouth of a hole, with an When we come ashore - there they are air of defiance which provoked Snap beagain! yond all discretion. He scarcely stopped to think before he plunged with a yelp into the hole, while another and a wiser dog came up, and shook his ears at it. For a little while they heard poor Snap working away in great ectasy, scratching at narrow turns, and yelping when he almost got hold of fur. Heaviside stood, in his heavy way, whistling into the entrance-hole, which went down from a steep ascent with a tuft of rushes over it. But Snap was a great deal too gamesome a dog to come back-even if he heard him. Meanwhile a lot of bulky fellows, who could do no more than clap their hands, got on the brow of the burrow and stamped, and shouted to Snap to dig deeper. Then of a sudden the whole hill slided, as a hollow fire does, and cast a great part of itself into a deep gully on the north of it. And those great louts who had sent it down so, This is a very childish thing for a man like me to think of. Nevertheless I do fall back from perfect propriety sometimes; never as regards money; but when my feelings are touched by the way in which superior young women try to catch me; or when my opinion is asked conscientiously as to cordials. And this same afternoon the noble clearness of the sun and air, and the sound of merry voices glancing where all the world (unless it were soft sand) would have echoed them, and the sense of going sporting which is half the game of it-these and other things, as well as the fatness of the rabbits' backs, and great skill not to bruise them, led the whole of us, more or less, into contemplation of Nature's beauties. We must have killed more than a hundred and fifty coneys, in one way and another, when Heaviside found it very hard (and never deserved) to | And then I thought of old Sir Philip, strid get their legs out. ing sadly along these burrows, for ever No wonder that Heaviside had made seeking something. "Dig away, dig away, such a run to come and fetch us. For Snap must be now many feet underground and the Naval Instructor knew what it would be to go home to Nanette without him. He stood above the slip and listened, and there was no bark of Snap; while to my mind came back strangely thoughts of the five poor sons of Sker, and of the little one dwelling in sand, forlorn and abandoned Bardie. my lads. Never mind the little dog. Let the maidens see to him. Under our feet there is something now, worth a hundred thousand dogs." All the people stood and stared, and thought that I was off my wits; and but for my uniform, not one would ever have stopped to hearken me. It was useless to speak to Heaviside. The whole of his mind was exhausted by anxiety as to his wife's little dog. No sleep could he Dig away, my lads, dig away!" I cried see before him for at least three lunar from force of memory, and setting exam- months, unless little Snap came round ple to every one; "I have seen a thing again. So I had to rely on myself alone, like this before; it only wants quick dig- and Jerry Toms, and two gamekeepers. ging." We dug and dug, and drove our All these were for giving up; bepit through several decks of rabbit-berths ; | cause I can tell you it is no joke to and still I cried " Dig on, dig on, my throw out spadeful after spadeful of this lads!" although they said it was hopeless. heavy deceitful sand, with half of it Then suddenly some one. struck some- coming back into the hole; and the thing hard, and cried "Halloa!" and place where you stand not steadfast. frightened us. We crowded round, and I And the rushes were combing darkly over took the lead, and made the rest keep us showing their ginger-coloured roots, back from me, in right of superior disci- and with tufts of jagged eyebrows threatpline. And thence I heaved out a beauti-ening overwhelmment. For our lives we ful cocked-hat of a British Captain of the worked away with me (as seems to be Royal Navy, with Snap inside of it, and not my fate) compelled to be the master-and quite dead! all the people looking down, and ready to revile us, if we could not find a stirring thing. But, we did not find a stirring thing, exactly as I will tell you. Such a cheer and sound arose (the moment that Snap gave a little sniff), from universal excitement and joy, with Heaviside at the head of it, that I feared to be hoisted quite out of the hole, and mounted on human shoulders. This I like well enough now and then, having many a time deserved without altogether ensuing it; but I could not stop to think of any private triumph now. The whole of my heart was hot inside me, through what I was thinking of. That poor honest fellow, who so eschewed the adornment of the outward man and carried out pure Christianity so as to take no heed of what he wore, or whether he wore anything whatever; yet who really felt for people of a weaker cultivation, to such an extreme that he hardly ever went about by day much, this noble man had given evidence such as no man, who had lost respect by keeping a tailor, could doubt of. In itself, it was perspicuous; and so was the witness, before he put up with a sack, in order to tender it. For suddenly my spade struck something soft, and which returned no sound, and yet was fine enough to stop, or at any rate to clog the tool. Although it was scarcely twilight yet, and many people stood around us, a feeling not of fear so much as horror seized upon me. Because this was not like the case of digging out poor bodies smothered by accident or the will of God, but was something far more dreadful; proof, to wit, of atrocious murder done by villany of mankind upon two little helpless babes. So that I scarce could hold the spade, when a piece of white linen appeared through the sand, and then some tresses of long fair hair, and then two little hands crossed on the breast, and a set of small toes sticking upwards. And close at hand lay another young body, of about the same size, or a trifle larger. At this terrible sight, the deepest breath of awe drew through all of us, and several of The whole force of this broke upon me the women upon the hill shrieked and now; while the others were showing the dropped and the children fled, and the men hat round, or blowing into the little dog's feared to come any nearer. Even my three nostrils, and with a rabbit's tail tickling or four fellow-diggers leaped from the hole him; because in a single glance I had seen with alacrity, leaving me all by myself to that the hat was our Captain Bampfylde's. "go on with this piteous disinterment. For |