as if

WILL it go any way towards calming Mr. Butler's zeal in the cause of literary honesty to remark that at any rate fifteen years ago, and it may have been further back, Mr. Darwin prefixed to "The Origin of Species' a historical sketch of the progress of opinion on that subject? In view of this it is at least very misleading on the part of Mr. Butler to quote the first sentence from the edition of 1859, and then to ask: "What could more completely throw us off the scent of the earliest evolutionists? in those days it would have made a pin's difference to him, or any one else whom he includes in the us, whether the scent of the earlier evolutionists lay strong or weak in the track. In these days he should know, if he knows anything of the history of opinion, that these predecessors of Mr. Darwin, with their great though varied merits, had been laughed down, and, for all popular estimation, might be said to have disappeared. To have relied in any way on their authority when Mr. Darwin's book was first published might well have increased the mountain of prejudice against his views without in any way relieving the weight of ridicule that lay upon theirs. When the whole scientific world had been stirred to its foundations and when the whole world almost

had been roused into paying attention to science by the awakening genius displayed in the new exposition de rerum naturâ, then, when it could best be done, Mr. Darwin turned ridicule into renown, and made all who could even remotely claim to have anticipated or shared his views participators of his fame. Not those who scatter seed at random, but those who cultivate it in chosen ground with indefatigable industry and prevailing skill should, I imagine, be considered the chief benefactors of mankind; and in like manner the fancy that may have fluttered uselessly through many brains becomes at last a fruitful hypothesis or a wide-stretching theory when it falls beneath the cultivation of undaunted genius. T. R. R. STEBBING

Tunbridge Wells, February 7

"Prehistoric Europe"

WILL you kindly allow me a few words in reply to certain statements made by Prof. Dawkins in his notice of my 'Prehistoric Europe." I shall not remark on the perplexing confusion which he gravely puts forward as an outline of my general argument further than to say, in all sincerity, that I fail to recognise in it any trace of what that argument really is. The few observations I have to make shall be confined chiefly to questions of fact.

1. Mr. Dawkins states that I ask geologists to believe that the mammaliferous gravels with Paleolithic implements, which overlie the chalky boulder-clay of East Anglia, were covered by an upper and younger boulder-clay, which latter "has been removed so completely that no trace of it is now to be seen.' Now I do not believe that the gravels in question ever were covered by boulder-clay, nor have I written anything which could justify Mr. Dawkins in attributing to me an opinion so absurd.

2. The account I have given of Victoria Cave was written after a careful perusal of all that has been said about it, and my proofs were submitted to Mr. Tiddeman, who reported on the explorations; and therefore I have every reason to believe that my description is correct.

3. The so-called Upper Pliocene deposits at Mont Perrier are described in detail by Dr. Julien, who shows that they are truly interglacial, being younger than the great "pumiceous conglomerate" with its striated stones and blocks, and older than the more recent moraines of the same neighbourhood. Dr. Julien remarks: "La période pliocène supérieure doit disparaître de la science." He correlates the interglacial beds of Mont Perrier with those of Dürnten.

4. The lignites of Leffe and Borlezza, according to Prof. Stopanni, who has carefully studied those closely adjoining districts, belongs without any doubt whatever to the glacial series; and his observations I have confirmed by a personal examination of the ground. They are generally admitted by Italian and Swiss geologists to be on the same horizon as the lignites of Dürnten.

5. I have not asserted the interglacial age of the so-called

Pliocene of Olmo. The newer deposits in the Upper Val d'Arno, which have usually been assigned by palæontologists to the Upper Pliocene, have been shown by Prof. Mayer, after an exhaustive analysis of the evidence (as well stratigraphical as palæontological) to belong to the Pleistocene; and as their mammalian fauna corresponds with the fauna of the lignites of Leffe and Borlezza, I have said that this fact is "significant,' meaning thereby that the beds in question may very likely be of the same age as those near Gandino.

6. Mr. Dawkins says that I deal with my subject not with the impartiality of a judge, but as an advocate, and that I have only called those witnesses which count on my side. I am probably as well acquainted with the literature of the subject as my critic, and after many years' careful reading and study must confess that I have not encountered any evidence that contradicts my views. Had it been my fortune to come upon such evidence I feel sure that I should not have been so weak and foolish, or so untruthful as to have ignored it. Doubtless I have met with many forcible statements of opinion by Mr. Dawkins that he does not agree with me; but I may remind him (and not for the first time) that mere expressions of opinion, however emphatic, prove nothing save, as a rule, the sincerity of him who utters them.

tion "is based on ice, and ice only." How very far this is from 7. My critic further ventures the statement that my classificabeing the case any candid person may see who shall take the trouble merely to run his eye over the "contents" of my book. Geologists rightly refuse to accept classifications which are based upon so narrow a foundation as a single series of phenomena, such, for example, as Mr. Dawkins's attempt to classify the Pleistocene by reference to the mammalia alone-a classification which, while it draws the line that separates Pliocene from Pleistocene at the base of the glacial deposits in England, would carry the same line, in France and Central Europe, through the middle of the glacial series. Or, to put it another forced to admit that the Glacial Period attained its climax in way, if we accepted Mr. Dawkins's classification, we should be France and Central Europe during Pliocene times, but that it did not begin in England until after the Pleistocene had commenced. And this is the classification which, as may be inferred from the tenor of my critic's remarks, I ought to have adopted.

Mr. Dawkins's remarks upon my views in regard to the evidence of climatic changes I am sorry to say I do not understand. All that I am sure of is that he has quite failed to grasp my meaning-that he has attributed to me opinions which I have done my best to refute-in a word, that he has strangely misrepresented me. But I need not attempt to set him right, as those who are sufficiently interested in the matter are not likely, after this repudiation, to accept his travesty for a reliable presentment of my views. JAMES GEIKIE Perth, January 7

On Dust, Fogs, and Clouds

A CURIOUS confirmation of Mr. Aitken's theory of fog was brought to my notice a short time ago. A friend of mine residing in Streatham, struck with the perfection of the heating arrangements in American residences, fitted up his house with a similar contrivance. In the basement was a furnace and boiler which warmed pure air that entered from without, and circulated at a regulated temperature throughout the house. A water-pipe that was connected with the boiler became stopped by frost; an explosion ensued, and the house was filled with so-called steam (hot fog, in fact) from top to bottom. Wherever a cold surface (clock faces, metal fixtures, &c.) was found, even in the topmost bed-rooms, the vapour condensed and left behind it black carbon dust. Nowhere else was this dust found.

Again, few persons who have read Mr. Aitken's paper can have noticed the dejected appearance of the late beautiful snow on the first morning of the welcome thaw without thinking of his theory. What on the previous evening was a clean dazzling mass of exquisite white became a sooty speckled heap of dirty snow. As the sparkling crystals liquefied into water which drained away, they left behind the dust and carbon, 'around which, according to Mr. Aitken, they originally formed, becoming by multiplication molar and visible. In the streets of London the masses of white snow rapidly became, as somebody remarked, like streams of cold café au lait. The whiteness rapidly disappeared and left behind mere dirt.

It may interest some of your readers to know that in 1537

Benvenuto Cellini was attracted to Paris from Florence in consequence of the much clearer and more beautiful atmosphere in the capital of France than in Italy! This fact is derived from the artist's autobiography. What a change now! Paris is rapidly becoming as bad as London. W. H. PREECE

February 5

IN NATURE, vol. xxiii. p. 195, I found an interesting abstract of a paper read to the Royal Society of Edinburgh, December 20, by Mr. John Aitken, showing "that dust is the germ of which fogs and clouds are the developed phenomena." It is not in the least the intention of this letter to diminish the value of the above-mentioned paper and experiments, but I wished to say that already, several years past, the same results were obtained by Messrs. Coulier and Mascart (1875) in France (Naturforscher, 1875, p. 400; Journal de Pharmacie et de Chimie, série 4, xxii. p. 165).

In my "Théorie cosmique de l'Aurore Polaire," p. 36, I have already pointed out the great importance of these results on the relation between aurora and clouds and the danger of measuring the height of auroral displays by means of superior cloudy apparitions (p. 35). In fact, if the invisible aqueous vapour is able to reach much higher regions than terrestrial dust, and if auroræ are in close connection with cosmical matter in a state of extreme division, like our theory attempts to prove, this cosmical matter is without any doubt enabled to form aqueous clouds in a much higher than the usual level. Moreover we have already, in 1873, in the German journal Gaca (Köln und Leipzig, E. H. Mayer), asked: "Welches wohl die weitere Rolle der Eisen- und anderen Dämpfe sei, welche nach der Verbrennung in den oberen Regionen der Atmosphäre schwebend bleiben und offenbar nach vollständiger Abkühlung einen Niederschlag von fein vertheiltem Eisenoxyd und anderen Stoffen bilden. Sollten diese Theilchen ... keine Veranlassung geben können zu den von deutschen Beobachtern so oft wahrgenommenen Polarbändern,' 1 deren Zusammenhang mit dem Nordlicht schon öfters dargethan ward, aber bisher unerklärt blieb. Noch würden wir hinzufügen können, mit Hinweis auf die Beobachtung Secchi's eines angeblichen Nordlichts bei Tage (NATURE, October 17, 1872), dass auch die bis jetzt ganz unerklärte, eigenthümliche Gestalt der Cirri, mit ihren ganz regelmässigen, auf ein gewisses Gesetz hindeutenden transversalen Verzweigungen, von Anwesenheit feiner Eisenstaubkerne in den Eisnadeln möglicherweise bedingt ist. Bekanntlich schweben diese Cirri in den höchsten Wolkenregionen."

der

It will further be generally known that microscopic meteorites have been found in the centre of hailstones (Comptes rendus, 1872, p. 683). H. J. H. GRONEMAN

Groningen (Netherlands), January, 1881

New Cases of Dimorphism of Flowers-Errors

Corrected

REVIEWING my notes and drawings of some years ago, I find the following new cases of dimorphism of flowers :

1. Syringa persica, L., cultivated in the garden of the Lippstädter Realschule, is gynomonoecious. In the same inflor. escence there are found a majority of hermaphrodite flowers of larger size and a minority of female flowers of smaller size. The hermaphrodite flowers are homogamous and short-styled, like Syringa vulgaris, L. (H. Müller, "Die Befruchtung der Blumen," P. 340, Fig. 125). The anthers of the female flowers, which are much reduced in size and never contain any pollen, are inserted sometimes above, sometimes beneath, but commonly in the same height with the stigma. In some few of the smallsized flowers the number of the petals is reduced to three.

2. Stellaria glauca, L., near Lippstadt, is gynodicecious, like St. graminea, L., as described by F. Ludwig (Bot. Centralblatt, No. vi. p. 28), some stems bearing small-sized flowers with very reduced anthers of white colour and greatly-developed stigmas, a vast majority of other stems bearing larger-sized proterandrous flowers with anthers of red colour.

3. Sherardia arvensis, L., near Lippstadt, is likewise gynodicecious, its hermaphrodite flowers being proterandrous and larger-sized, with a corolla of 3-4 mm. diameter, its female

Or "Polarbanden." My daily observations of these phenomena, beginning with the year 1875, are to be found in the German journal Wochenschrift, editor, Dr. Hermann J. Klein in Köln.

flowers possessing a corolla of only 2-3 mm. diameter, with extremely reduced anthers.

4. Asperula tinctoria, L., produces in Thuringia so frequently flowers with only three petals that in those stems examined by myself by far the greatest part of the flowers were threepetaled.

In my book "Alpenblumen Dr. Focke of Bremen has detected two errors of naming, which immediately ought to be corrected the flower described and illustrated on p. 171 is not Empetrum nigrum, but Azalea procumbens, like that of p. 377; Cerinthe, in pp. 264, 265, is not major, L., but glabra, Mill = alpina, Kit. HERMANN MÜLLER Lippstadt

Geological Climates

I HAVE read with much interest and attention the letters that have appeared in recent numbers of NATURE on the subject of "geological climates," and although it must appear presumptuous on my part to do so, I shall endeavour to show that each of the distinguished writers of these letters may be somewhat in error on at least one point, which-if I am rightmust materially affect the correctness of the conclusions they have come to.

I think that Mr. Wallace, whilst very justly giving the Gulf Stream and other currents which might exist were certain lands submerged, credit for great influence in ameliorating the rigour of climate, does not take into sufficient consideration the fact that the waters of the Gulf Stream, although warmer, are, in consequence of holding much more salt in solution, heavier than the colder and less saline Arctic current.

Some experiments show, as clearly as anything done on a very small scale can, that two waters brought as nearly as possible to the conditions of the Gulf Stream and the Arctic current do'not mingle when simultaneously poured into a long narrow glass trough; the Arctic water invariably taking its place on the surface.

Supposing then that these two currents meet somewhere about latitude 80 or 81° N., the Arctic water flowing south-if my experiments are of any value-will retain its position on the surface and the warm current pass underneath, and thus lose all its heating influence on the air over a Polar area about 1000 geographical miles or more in diameter.

We can have no stronger example of this effect of difference of density of ocean water than is shown by the two currents in and out of the Mediterranean Sea.

In NATURE, vol. xxiii. p. 242, Prof. Haughton says, "The thickness of this ideal ice-cap at the Pole is unknown, but from what we know of the Palæocrystic ice of Banks Land and Grinnel Land must be measured by hundreds of feet, and its mean temperature must be at least 20° F. below the freezing-point of

water."

With regard to both the above assumptions-which are in italics-I must beg to disagree entirely with the learned Professor. He appears to consider the so-called Palæocrystic ice as the normal state of the ice at.and near the Pole, and as a natural growth by the gradual freezings or increase of a single floe during a series of years; whereas I am of opinion that this mis-called Palæocrystic ice is the result of a number of floes being forced over and under each other by immense pressure caused by gales of wind and currents.

The western and northern shores of Banks and Grinnel Lands are peculiarly well suited for the formation of such ice-heaps, as they are exposed to the full force of the prevailing north and north-west storms, which pile up the ice in a wonderful manner on these shores and others similarly placed, for a distance of miles seaward. The whole of the west shore of Melvile Peninsula is so lined with rough ice of this kind that sledging is impossible.

It will wholly depend upon the form of land-if any-at or near the Pole, whether or not any floebergs are there. If there is no land it is probable there will be few or none, as the ice will meet with no great obstruction, as it is driven by winds and currents.

I have no authorities by me that give the thickness of ice formed in one season at or near the winter quarters of any of the Arctic expeditions, except my own in 1853-4 at Repulse Bay, latitude 66° 32' north.

The measurements of the ice-taken at some distance out in the

bay where there was very little snow-and the mean temperature of the air are given on next page.

January 24 February 25

April 25

14 in 35 days

7 feet of inch

8 feet 1 inch ... 8 feet 1 inch

16 in 32 days

123 in 59 days

... none 30 days

Monthly Mean Temp. F. -245 below zero

-30°6 -34 9 99

8°5 May 25 +24° above zero The above table shows that the ice ceased to increase in thickness some time between April 25 and May 25, after which it decreased rapidly; but I was unable to decide what proportion of this decrease was due to thaw and evaporation from the surface, and what amount from the lower part of the floe that was under water: no doubt by far the greater effect was produced by the two first causes.

Eight feet may perhaps be considered a fair or rather a high average of one winter's formation of new ice (not increase of an old floe) over the whole of the Arctic Sea, because Repulse Bay, although in a comparatively low latitude, was particularly favourable for ice-formation, there being no currents of any consequence. Where there are currents, one year's ice does not exceed three or four feet.

The winter's ice of 1875-6 at Discovery Bay, in latitude 81° 40′ N., did not exceed, if I remember correctly, six feet in thickness.

Even were these great compound floes, called Palæocrystic ice, found at or near the Pole, and of only the same thickness as those seen at Grinnel Land-instead of "hundreds of feet" -they would not probably have nearly so low an average temperature all the year round as 20° F. below the freezing-point of water, because only one-sixth of their mass would be exposed to very low temperatures for about six months of the year, the surface being during that time protected by a more or less thick covering of snow, whilst at least five-sixths of their bulk was under water, having a temperature for the whole twelve months at or above the freezing-point of the sea. The question is, how far the very low temperatures of an Arctic winter do pene. trate a mass of, say sixty feet of ice, the surface of which is covered with a foot of snow, and fifty feet or five-sixths under water of a temperature at or above the freezing-point of the sea?

From my experience on a much smaller scale, I do not believe that the atmospheric cold would, under the circumstances mentioned, penetrate to the lower surface of ice sixty feet thick ; and if it does not do so there would be no increase to its thickness during winter.2

An excellent example of formation of Palæocrystic ice, or floe-berg is afforded by the experience of the Austro-Hungarian Expedition under Weyprecht and Payer in the Barentz Sea in 1873-4. Their ship was lifted high out of the water by the pressure of the floes, which were forced over and under each other to a great thickness and extent in a very few days.

The ship and her crew were helplessly drifted about for many months, during which the floes were frozen together into one solid mass, and the inequalities of the surface in a great measure filled up with snow-drift. JOHN RAE

4, Addison Gardens, January 29

On the Spectrum of Carbon

IN addressing to you my former letter regarding Dr. Watts's experiments on the spectrum of carbon, it was not my intention to enter on any discussion concerning matters of opinion. The reference made in that letter to the difficulty of perfectly drying a gas so as to eliminate the ultra-violet spectrum of water had reference to gases at ordinary atmospheric pressure; and the expectation a gas will be dried "to all intents and purposes" by the use of a U-tube of phosphoric anhydride goes far to explain the origin of different experimental results. The cogent experimental evidence which Dr. Watts justly demands may, so far as the relations of carbon and nitrogen are concerned, be found in our complete papers on the spectrum of carbon compounds in the Proceedings of the Royal Society.

The supposition, which appears to be a difficulty to Dr. Watts's mind, that traces of nitrogen in hydrocarbons give with the spark the spectrum of nitrocarbons, and that traces of hydrogen in cyanogen give the hydrocarbon spectrum, is not only

able," but appears to me most consistent with the spectrum observations on the whole, and with the chemical regarding the formation and relations of acetylene and hydrocyanic acid. Cambridge, January 22 G. D. LIVEING

Vibration of Telegraph Wires During Frost

MR. T. M. READE asks for an explanation of this phenomenon. In Science Gossip for 1874, p. 254, there is a short article of mine on "Frost Phenomena," and one of those referred to is this curious vibration of telegraph wires.

The explanation there suggested, which was only a guess, is probably incorrect; but I think I can give the true one now, and it is, as usual in such cases, extremely simple.

Hoar frost is only deposited in air which is nearly at rest; a strong wind shakes it down as it forms. But there is nearly always a slight air-current in one definite direction, and the ice spicules are built up "in the teeth" of this current, that is on the windward side of the wire or twig.

They always point towards the wind. When they have attained a length of, say, half an inch, if the direction of the aircurrent slightly changes, it may strike the comb-like fringe no longer on the points, but on the side, and, obtaining thus a leverage upon the wire, will twist it round till the pressure is balanced by the torsion. If the pressure were absolutely constant the wire would perhaps remain in this position, but the very slightest variation of pressure would set up a vibratory motion, and this, I think, must be the true cause of the phenomenon. Birstal Hill, Leicester, February 5 F. T. MOTT

The Star Oeltzen, 17681

THE star Oeltzen, 17681, whose spectrum was announced by me to consist mainly of a yellow and blue band (NATURE, vol. xxii. p. 483), proves to belong to the same class as the three stars in Cygnus discovered by Wolf and Rayet in 1867 (Comptes rendus, vol. lxv. p. 292). A curious feature of these spectra is that they resemble each other without being identical, the relative brightness of the lines being very different. A further study of them is much to be desired. Cambridge, U.S., January 24

EDWARD C. PICKERING

Zeuglodontia

IN consequence of my letter in NATURE, vol. xxiii. p. 54, the sub-editor of the Graphic was kind enough to send me the number of that paper containing the engraving of the animal seen from the City of Baltimore (not City of Washington, as I had misunderstood), and which is that of April 19, 1879. The sketch from which this was taken was sent by Major H. W. J. Senior of the Bengal Staff Corps, with the following description, viz. :

"On January 28, 1879, at about 10 a.m., I was on the poop deck of the steamship City of Baltimore, in lat. 12° 28′ N. long. 43° 52′ E. I observed a long black object abeam of the ship's stern on the starboard side, at a distance of about three-quarters of a mile, darting rapidly out of the water and splashing in again with a sound distinctly audible, and advancing nearer and nearer at a rapid pace. In a minute it had advanced to within half a mile, and was distinctly recognisable as the veritable 'seaserpent.' I shouted out Sea-serpent! sea-serpent! call the captain!' Dr. C. Hall, the ship's surgeon, who was reading on deck, jumped up in time to see the monster, as did also Miss Greenfield, one of the passengers on board. By this time it was only about 500 yards off, and a little in the rear, owing to the vessel then steaming at the rate of about ten knots an hour in a westerly direction. On approaching the wake of the ship the serpent turned its course a little away, and was soon lost to view in the blaze of sunlight reflected on the waves of the sea. So rapid were its movements that when it approached the ship's wake I seized a telescope, but could not catch a view, as it darted rapidly out of the field of the glass before I could see it. I was thus prevented from ascertaining whether it had scales or not, but the best view of the monster obtainable when it was about three cables' length, that is about 500 yards distant, seemed to show that it was without scales. I cannot, however, speak with certainty. The head and neck, about two feet in diameter, rose out of the water to the height of about twenty or thirty feet, and the monster opened its jaws wide as it rose, and closed them again as it lowered its head and darted forward for a dive,

reappearing almost immediately some hundred yards ahead. The body was not visible at all, and must have been some depth under water, as the disturbance on the surface was too slight to attract notice, although occasionally a splash was seen at some distance behind the head. The shape of the head was not unlike pictures of the dragon I have often seen, with a bulldog appear. ance of the forehead and eyebrow. When the monster had drawn its head sufficiently out of the water it let itself drop, as it were, like a huge log of wood, prior to darting forward under the water. This motion caused a splash of about fifteen feet in height on either side of the neck, much in the shape of a pair of wings."

The italics in the foregoing and in the account of Capt. Cox are my own.

FIG. 1.-The Animal as seen from the City of Washington. The engraving being a large one, of which the foreground is formed by the deck of the steamer, I have copied and send with this that portion of it which shows the animal; and in this it should be observed that besides the splash rising round the neck "like wings," the separate splash at some distance behind the head is also shown, the position of which corresponds to that where the cetacean tail occurs in the figure sent by the captain of the Kiushiu-maru, which accompanied my first letter. The foam around the neck, I think, may be due to the splash of the humeroid paddles which a cetacean should possess.

FIG. 2.-The Animal as first seen from H. M.S. Dædalus.

The sub-editor of the Graphic has also been kind enough to obtain for me tracings from the three figures given in the Illustrated News of October 28, 1848, of the animal seen from the Dædalus. From two of these I have made the accompanying reductions to one-fourth (linear) of the originals; and the head portrayed in one of these (as seen when the animal passed close under the stern of the Dedalus) is evidently not reptilian, but mammalian; and it seems to bear out the " bulldog appearance of the forehead and eyebrow" which Major Senior describes in his case.

FIG. 3.-Head of the Animal as seen when passing passing under the stern of the Dædalus.

From the Times of September 24, 1879, I cut the following notice :

Capt. J. F. Cox, master of the British ship Privateer, which arrived at Delaware break water on the 9th inst. from London, says:-'On the 5th ult., 100 miles west of Brest (France), weather fine and clear, at 5 p.m., as I was walking the quarterdeck, looking to windward, I saw something black rise out of the water about twenty feet, in shape like an immense snake about three feet in diameter. It was about 300 yards from the ship, coming towards us. It turned its head partly from us, and went down with a great splash, after staying up about five seconds, but rose again three times at intervals of ten seconds, until it had turned completely from us and was going from us with great

speed, and making the water boil all round it. I could see its eyes and shape perfectly. Itwas like a great eel or snake, but as black as coal tar, and appeared to be making great exertions to get away from the ship. I have seen many kinds of fish in five different oceans, but was never favoured with a sight of the great sea-snake before."

In this account we have almost a duplicate of that of Major Senior in the dropping of the animal with a great splash into the water prior to its darting forward under it; while the boiling of the water around, which is so inconsistent with the motion of a snake in water (which I have more than once seen) evidently resulted from the strokes of the cetacean tail, and possibly also from those of the paddles, as in the case witnessed by Major Senior. The black colour also is described in both cases.

Capt. Drevar, the statutary declaration of whom and of several of his crew I quoted in my former letter, has written to me, and sent me a printed account (which he says he has circulated) of the conflict which he witnessed, and of the subsequent appearance of the animal rearing its long neck out of the water. This is satisfactory as showing that the declaration I quoted was no hoax, as I feared it might have been; but Capt. Drevar rejects with disdain my suggestion that the animal he saw was not a serpent, though I pointed out to him that nothing having the form of a snake would possess in its submerged portion the buoyancy necessary to enable it to elevate so great a proportion of its length out of water.

Judging from the figures which accompany this and my previous letter, it appears to me that the external form of the animal must resemble the well-known Pleisosaurus, if we imagine the hinder (femuroid) paddles of that Enaliosaurian to be absent, and a cetacean tail (which is their homologue), to be present in their stead. Since in the direction of the Porpesse the cetacean in external form so closely simulates the fish, so it may in another direction simulate this Mesozoic marine saurian, or the gigantic Elasmosaurus of the American Cretaceous formations, of which a nearly perfect skeleton is described by Prof. Cope as forty-five feet in length, the neck constituting twentytwo of this length.

Whether, through your circulation, any light on this subject, so far as the character of the skeleton of Zeuglodon cetoides is concerned, may be forthcoming from American paleontologists remains to be seen; but there ought, I submit, to remain no longer with naturalists any doubt that a hitherto unknown group of carnivorous cetaceans, with necks of extraordinary length, inhabit the ocean.

It seems to me also most probable that the conflicts which have been so often witnessed (and which Mr. Pascoe in his letter in NATURE, vol. xxiii. p. 35, says he himself twice witnessed), and referred to the Thresher, have been attacks by the animals in question upon whales. SEARLES V. WOOD

Martlesham near Woodbridge

Ice Intrusive in Peat

I HAVE just returned from a walk on the shore at Crosby, where I have been much interested in observing one of the effects of the late severe frost combined with the present thaw.

At the Alt Mouth is a submarine peat-and-forest-bed, and, lying over it, I was much surprised to see innumerable slabs of peat, which an examination showed in most cases contained interlaminations of ice. One slab measured 5 yards by 2 yards by about 8 inches thick, and right through its mass in a parallel plane with the surface, separating the peat into an upper and lower layer, was a slab of transparent ice, wedge-shaped, being 4 inches thick at one side, diminishing to I inch at the other. How the ice got there was the surprising thing, as the peat is very hard and compact, and about 18 inches thick. The holes or places from which the sea had quarried these frozen slabs were plainly to be seen, and I noticed round one of them that the edges or lips of the peat had been forced up by ice inserting itself between the laminæ.

A good deal of water ordinarily oozing through the sandhills flows or trickles over the surface of the peat, and as nearly six inches of rain fell in December last, and the two previous months were wet, the quantity of water would be abnormally increased. In some way or other it must have percolated along the peaty laminæ, and by gradual accretion the frozen water has forced up the layer of peat above it. This has occurred at neaps, and the late high tides, assisted by the thaw and the decreased specific gravity of the mass, has lifted the frozen slabs of peat and