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Hyperborean, Abaris, "the air-walker," to whom Pythagoras, the Miss Kilmansegg of antiquity, displayed his precious leg. In fact here, as elsewhere, Mr. Tylor has acted on the principle that the half is greater than the whole. He selects enough for his purpose, and resolutely declines to overburden himself with superfluous testimony. Fortunately there are two sides to the theory of survival. If on the one hand we have survivals of the type of modern spiritualism, we have on the other survivals of ideas, which, first broached in a stage of civilisation when they are considered foolish or mischievous, become in a higher stage the dominant influences which direct human opinion. To take a single case-It is now near upon two centuries since Balthazar Bekker, a D.D. of Amsterdam, corrupted, may be, by certain impious notions propounded by the arch-infidel Descartes, published his "Monde Enchanté," a crime for which he was at once deprived of his benefice; since, as a learned Englishman remarked in reference to the case :

Dæmonas ex mundo quisquis proscripserit audax,
Esse brevi nullum dicet in orbe Deum.

If the English reader of to-day will take the trouble to read this work-and it is worth the trouble-he can scarcely fail to be struck with the remarkable survival of the ideas contained in it, expanded, corrected, developed as they are in these chapters by Mr. Tylor. Not that Mr. Tylor has borrowed anything from Bekker, but simply that Bekker was the first, as Mr. Tylor is the last, to apply science systematically to the phenomena of sorcery, witchcraft, and spiritualism of his age. Survivals of this kind are indeed proofs as decisive of the vitality of civilisation as survivals of the other kind are of the vitality of barbarism.

In the following chapters on Language, emotional and imitative, Mr. Tylor makes out a strong case in favour of what Prof. Max Müller, with a felicity worthy of a better cause, has nicknamed the "pooh-pooh" and "bow-wow" theories. "It may be shown," he says, " within the limits of the most strict and sober argument, that the theory of the origin of language, in natural and directly expressive sounds, does account for a considerable fraction of the existing copia verborum, while it raises a presumption that, could we trace the history of words more fully, it would account for far more." Among other matters touched on in this inquiry, Mr. Tylor refers to the language employed in addressing beasts, particularly dogs and horses. Some curious samples of dog-language are to be found in the Book of St. Alban's, and, indeed, in almost every old treatise on hunting. Sir Tristram, however, the hero of the Arthurian cycle, who is generally considered the rédacteur en chef of this particular dialect, appears to have thought plain Norman French best adapted to the intelligence of greyhounds, and is very sparing in his use of mere "brutish interjections." Of horse-language one of the best examples is to be found in "The Enterlude of John Bon and Mast Person," a tract belonging to the middle of the sixteenth century. This is how John Bon addresses his team :

Ha, browne done! forth that horson crabbe! Ree, comomyne, garlde, with haight blake hab! Have agayne, bald-before, hayght ree who! Cherly boy, cum of, that whomwarde we may goo! One branch of inquiry into which Mr. Tylor partly

enters in these chapters and the following one on the Art of Numbers, appears to deserve closer attention than it has yet received. Considering the important part which gesture plays in all the lower languages, it is a fair hypothetical inference that, as language gradually became more and more developed, a number of words and phrases would creep into it, formed on the principle of translating gesture into phonetics. Thus, for instance, the universal gesture for "likeness " or " sameness" is to hold out both hands together. If, in several different languages, the words meaning "likeness" or "sameness" have an etymological connection with the word meaning "together," a strong presumption would be raised that they were translated from the gesture; and if any large number of correspondences of the same kind were detected, the presumption would be raised into a theoretical certainty. Whether such evidence exists of the translation of action into sound in general language, none could determine better than Mr. Tylor himself, whose essay on the gesture-language in one of his earlier works, forms really almost a complete handbook on the subject. That it does exist in language, as applied to numbers, is clearly shown in his chapter on the art of counting, where he traces the quinary, decimal, and vigesimal systems to their origin in the fact that the average man possesses five fingers on each hand, and as many toes on each foot. He perhaps, however, has not sufficiently noticed the further strong probability that the duodecimal system owes its origin to the circumstance that, in addition to his fingers and toes, a man possesses

two hands and two feet-a consideration not without its

bearing on the obscurity attending the numerals eleven and twelve in certain languages.

LEA'S UNIONIDE

A Synopsis of the Family Unionida. By Isaac Lea, LL.D. 4th edition. 4to. (Philadelphia, 1870.)

THIS work, by a veteran American conchologist, con

tains 184 pages, and is a memorial of his labour and zeal during a period of more than forty years. The Unionida are generally known as "fresh-water mussels." Their variability is notorious; for almost every river, lake, and pond yields different forms, which some writers call species and others call varieties.

Non nostrum est tantas componere lites.

But while giving Dr. Lea ample discretion to make as many species as he pleases, and full credit for his honest wish to keep down the number, it certainly strikes one as somewhat singular that he admits only seven or eight species of the family Unionide living in Europe," when he enumerates 720 species as North American, of which latter number he has himself described no fewer than 582! According to Kreglinger's catalogue, which is the newest on the land and fresh-water shells of Europe, fifteen species of this family inhabit Germany. We have but five, including one debateable species of Anodonta. The total number of living species recognised by Dr. Lea is 1,069, besides 224 unknown to him or doubtful. To distinguish varieties from species is one of the great difficulties which perplex the naturalist; but the rule which I have adopted may serve the purpose to a considerable extent, viz., "that all distinct groups of individuals living together and having a common feeding-ground, and which are not connected

or blended with each other by insensible gradations, are prima facie entitled to the rank of species." (British Conchology, vol. i., Introduction, p. xix). Now we may see several species of Rissoa living under the same stone between tide-marks, several species of Limnæa in the same stream or ditch, and more than one species of Helix feeding together on the same leaf. In such cases there is no fusion or confusion of species; each has its own definite limits, and retains its own peculiar characters. I say nothing of genera and more comprehensive groups which form communities in a still more diversified fashion, but are equally free from intermixture.

J. GWYN JEFFREYS

OUR BOOK SHELF

Echinides du Département de la Sarthe, considérés au point de vue zoologique et stratigraphique. Par Cotteau et Triger. (Paris: Bailliére, 1855-1869. London: Williams and Norgate.)

WE fear that some time must elapse before science will resume its place in unhappy France; but in the meantime its professors, who are innocent of the mischievous and insane acts which have caused so much ruin, demand our heartfelt sympathy. M. Cotteau, of Auxerre, whose work we are about to notice, is well known to English geologists, and is highly esteemed by them for his long and conscientious labours in the field of Mesozoic echinology. His coadjutor, M. Triger, died during the progress of the work. It consists of two royal octavo volumes, one containing an account of Echinoderms found in the Jurassic and Cretaceous formations in the Department of the Sarthe, the other having sixty-five wellexecuted plates of species, besides several charts to show their geological and stratigraphical distribution. It appears from the preface that this most creditable production of French palæontology was commenced in 1857, and finished in 1869. We therefore regret to observe that M. Cotteau was not aware of Dr. Wright's admirable monograph on British fossil Echinodermata, which was published by our Palæontographical Society in 1856, and which goes over a great deal of the same ground as M. Cotteau. Had the latter author consulted it, he would probably have avoided some mistakes, e.g. in attributing the specific name of Pseudodiadema hemisphæricum to Desor instead of to Agassiz. A comparison of the figures of this and other species given in both works is decidedly favourable to the British artist (Mr. Bone) as regards accuracy and completeness, although MM. Levasseur and Humbert are deservedly eminent in their style of lithography.

The Echinoderms found in the Jurassic and Cretaceous formations must have inhabited a soft bottom in seas of considerable depth, judging from the present habits of allied species; and their variability was not less in those remote periods of the world's history than it was in the epochs which preceded and followed.

LETTERS TO THE EDITOR

J. G. J.

[The Editor does not hold himself responsible for opinions expressed by his Correspondents. No notice is taken of anonymous communications.]

The Paris Observatory HAVING read only yesterday the agonising account written by M. Marie-Davy and countersigned by M. Delaunay, descriptive of the Communists having made the Paris Observatory one of their chief strategical points, of the domes of the observatory having five hundred bullet-holes through them, and of the rabid attempts made by the citizens in arms, before retiring on the ap.

proach of the Versaillists, to burn or blow up the whole building, I am not a little surprised to find in NATURE of June 8, received here this morning, a statement to the effect "that the Paris Observatory had suffered scarcely any injury up to the end of the second siege. No delegate of the Commune had presented himself either to take possession of it or to blow it up.' perhaps not without some intention of whitewashing the poor I presume that you wrote in ignorance of the real facts, and Communists from the exaggerated denunciations which have been poured on them since their fall; yet neither they nor you should object to true accounts of what they actually did while in power appearing before the world without menace and without favour. The mere showing of the Commune during this second siege, and still more its international organisation, seems to have surprised most persons; yet the character of the association, and its imminence under the feet of all the Governments of Europe, was duly noted in the section on Metrological Legislation of my report presented to the Board of Visitors of the Royal Observatory, Edinburgh, in June 1870; the association, though political, having obtained mention there on account of its having adopted the scientific metrical system of weights and measures, and professing to find it a most efficient agent for assisting in breaking down the barriers between nations, and rooting up traditional customs and beliefs. I must confess, however, that I was not prepared for these revolutionaries taking up so very early in their outward career, as this their first and just-concluded essay in Paris, the chronological department of the metrical system, thereby repudiating, as the order found on General Delescluze indubitably shows, both the Christian Era and the accustomed months, for decimal periods of days and the era of the first French Revolution. In my book, "Our Inheritance in the Great Pyramid," published in 1864, I did indeed remind that that most revolutionary method in chronology was originally a part of the metrical system, and though deposed under Napoleon Bonaparte, might be expected to reappear when the present promoters of French metrology in this country had acquired more boldness; but here is the accomplished fact upon us at this very moment, and it would be well for all those metrical agitators who were so loud at the British Association last summer in Liverpool in their outcries to Government to make the metrical system compulsory throughout this country, now to declare honestly whether they are inwardly with the Communists in desiring ultimately the abolition of the Christian era and the destruction of the week of seven days. 15, Royal Terrace, Edinburgh, June 9

C. PIAZZI SMYTH

Science Lectures for the People

It is all very well to say, Let our children be taught science in the schools; but that does not meet the need of a large section of the nation, the product of the schools of a former generation. Many hard-worked men who had no scientific teaching whilst at school, have now acquired the wish to know more of nature's mysteries, but know not whither to turn for aid. Books are plentiful, but it is very tiresome to wade through dry pages, scientifically dried of their sap by the use of terms which are not commonly understood-especially after the wearying labours of the day. Experimental lectures, like those at the Royal Institution, but a little more specialised, are wanted for popular use; the question is, How are we to get them? Are we to go to Government for aid, or shall we bestir ourselves and voluntarily endow these lectures?

Surely Huxley or Tyndall would be quite as much sought after as Spurgeon if they came forward and announced a series of lectures; St. James's Hall would be as crowded as the Tabernacle if they held a weekly lecture; pew-rents would be as certain of collection from scientific as from religious devotees. Those busily engaged professors can indeed hardly be asked to undertake such a task as this; but any competent man of science, able to explain the facts of science in popular language, might reckon on public support if he made such a venture as this. Let him, for example, give a series of twelve lectures on Biology, as it affects our daily existence; not wandering into the remote regions of extraordinary phenomena, but simply expounding ordinary life laws. Here would be a subject refreshingly new and interesting to thousands of City-born and bred toilers. The lectures, if on week days, must be after office hoursfrom nine o'clock to ten, say; and in some hall easily accessible, as St. James's. GEORGE FRASER

169, Camden Road, N. W.

The Eclipse Photographs

Ir would have given me much pleasure to have shown Mr. Winstanley the original negatives of the photographs of the late eclipse of the sun if he had called on me to see them, and by so doing he would have avoided falling into the mistakes which his letter contains.

At the time when the last photograph was taken the sky was perfectly clear, and unless Mr. Winstanley is in possession of exclusive information he has no right to assume that the American photograph was not taken under equally favourable conditions. Some of my photographs (which Mr. Winstanley cannot have seen) were taken through the edges of a cloud, the whole of which could be covered by the hand when held with the arm extended; and there was a perfectly cloudless sky near the sun excepting towards the east.

The imperfection in my No. 5 picture, which Mr. Winstanley's experienced eye detects, arose from the shaking of the telescope, caused by the high wind blowing at the time. Probably a single gust during the eight seconds while the plate was exposed caused the mischief, and this defect would never have been seen but for the extremely actinic power of the red prominences which leave their impression on the sensitive plate instantaneously. moon's limb is perfectly sharp, excepting where the red promi

nences appear.

The

Let it be clearly understood that this "indifferent definition" refers to the moon's limb only; the details of the corona do not appear to have suffered; after the gusts of wind the telescope has returned to its proper position, and Mr. Winstanley must know from experience that the image of an object giving off feeble light would not be materially injured by a slight blow given to a firmly mounted camera.

Mr. Winstanley says that "the identity of the coronal rifts in the Cadiz and Syracuse photographs is not satisfactorily conclusive." Assertion is not proof. In NATURE of March 9 I gave evidence which appeared to me to be conclusive (I need not here refer to the opinions of others who are equally satisfied), and up to the present time no counter-evidence has been pro duced.

It is not for me to defend the American photograph. In due time we shall know all about how that was produced. But has Mr. Winstanley failed to notice that the light on the moon's disc does not extend all round and all over it as it would do if caused by our atmosphere? It is chiefly on the east and west sides. We may expect the explanation of this defect when we hear how it happens that the corona in this photograph is cut off instead of extending as in all the other photographs.

I fail altogether to see the connection between the solar corona and a lunar halo-the phenomena bear no resemblance to each other. The solar corona comes close up to the perfectly black disc of the moon. I never saw a lunar halo close up to the moon's limb. When seen through a mist or in a "sky burdened with innumerable clouds," there can be no doubt that the lunar surface is obscured by the moisture in our atmosphere. A. BROTHERS

Ocean Currents

HAVING had occasion in the spring of 1868 to consider the subject of Ocean Currents as discussed by Captain Maury and Sir John Herschel, I was led to certain views respecting the origin of the oceanic circulation, which are briefly touched upon in a paper which appeared in the Student for July, 1868. At that time an experimental test of my theory (or rather of that portion of the theory I advocated, which was, as I judged, novel) occurred to me. The experiment might, I conceive, be very readily tried. It somewhat resembled that by which Dr. Carpenter illustrated lately at the Royal Institution his views respecting the influences of evaporation and polar cold; but as I wished specially to show how the westwardly equatorial current came about, the experiment was somewhat more complex. Let the circumference of a large and shallow cylindrical basin represent the equator and the central part the north polar regions. Within this cylinder let solid matter be so placed as to represent the northern halves of the continent, in such sort that the resulting configuration would correspond to that of a map of the northern hemisphere (say on the equidistant projection). Let sea-water be poured in to represent the northern portions of the terrestrial oceans. Now to represent the Arctic ice-fields, let lumps of ice be placed at the centre of the cylindrical vessel (they should be circled round by a wire-guard); and to represent the effects of equatorial heat, let

a stout iron ring round and above the rim of the cylindrical vessel be heated. In this state of things the process of circulation, which actually took place in Dr. Carpenter's experiment, would take place after such modified sort as the contour of the continent masses permitted. Now suppose that the cylindrical vessel is set in steady and somewhat slow rotation about its axis. It is clear that on the currents flowing from the pole and polewards, effects will be produced which precisely resemble those due to our earth's rotation. If I am right in regarding these effects as the true cause of the direction in which the equatorial currents, the Gulf Stream, and in fact all the currents in open ocean are observed to flow, abundant evidence to that effect will be obtained. If no such evidence be obtained, the westwardly direction of the equatorial currents must, I imagine, be ascribed to the trade winds, as Franklin and Sir J. Herschel have maintained.

In the summer of 1868 I suggested to Prof. Pepper that such a contrivance as the above, if it worked as I judged (and still judge) that it would, would form an interesting and instructive addition to the models exhibited at the Polytechnic Institution. Dr. Carpenter has already proved that the vertical circulation takes place in an experiment of this sort. If the eastwardly and westwardly circulation takes place as I expect, the experimental illustration of oceanic circulation would be singularly complete. The circulation in the southern hemisphere could be illustrated in like manner.

I may note here that the vast distance separating the polar from the equatorial regions must not be overlooked in theories respecting oceanic circulation. The influence of arctic cold may be paramount in very high latitudes; but equatorial evaporation must, it should seem, be the prime moving cause in tropical and sub-tropical regions. RICHARD A. PROCTOR

Brighton, June 6

Day Auroras

I HAVE read attentively the numerous letters which have ap peared in your columns on this subject; but so far as I can discern it seems not to have occurred to any of your correspondents that the auroral force, whatever it may be, affects every kind of cloud as well as the cirrus. On June 15, 1870, at 9 A. M., I witnessed here as complete a display of auroral motions in the cirrus cloud as ever I beheld in a midnight sky; and from that date I dismissed in my own mind all doubt as to the identity of auroral force, whether seen by day affecting the cirrus cloud or appearing as streams and rays of light at night. On Thursday and Friday last I witnessed a configuration of cirro-stratus cloud, evidently the result of magnetic polarisation, which I have no hesitation in characterising as auroral. There were on Thursday two poles, both in the line of the magnetic meridian; but on Friday night, at nine o'clock, only one pole in the direction of the true meridian. The phenomenon which I refer is of very frequent occurrence, especially before a track of fine warm weather; and without at present offering a theory on the subject of auroras, I venture to class polarisations of clouds, whether cirrus or not, as arising from the same cause as luminous aurora. The transverse or dia magnetic lines are generally as well marked in cloud auroras, and it is an interesting

to

task to watch the transformation of cirrus cloud from the meridional to the equatorial direction. I have also noted that when these auroral lines converge towards the magnetic pole, a steady barometer and fine weather ensue; but that when the transverse or equatorial lines predominate and continue long visible, rain soon follows. These transverse lines of cloud are always lower and seem to be dia-magnetic. D. Low Burntisland, May 22

PERHAPS you will allow me to add my mite to the discussion which has been going on in your pages on the question of the visibility of the aurora in daylight.

On the 3rd of September in last year, when at Nairn in the north of Scotland, I witnessed an aurora, such as I never heard or read of, or saw before; and strangely enough it was not noticed, as far as I am aware, in any of the newspapers. I had gone down to the beach at about 10 15 P.M., and immediately noticed what appeared at first to be a kind of haze over the whole sky, which slightly dimmed the light of the stars.

For a few minutes I thought no more about it, but, happening to turn my eyes towards the zenith, there was a sight I never shall forget. A number of sheets of whitish light were con

stantly darting with a flickering motion from the surrounding haze of similar light, and meeting in the zenith; the length of their course was as much as 15 to 18°; they appeared to proceed indiscriminately from all points in azimuth.

I immediately became aware that the whole sky, down to the very horizon, was illumined by a white, colourless aurora; but I was so fascinated by the incessant play of the streamers over. head, that for some time I could notice nothing else. At last I turned away in order to observe accurately the full extent of the aurora in all directions. I found that it reached quite down to the horizon all round, except in one place, viz., in the S.S. E., and at that point there was a symmetrical arc (of a great circle, as far as I could judge) the summit of which was about 7° or 8° above the horizon. This arc was perfectly well defined; within it was blue sky, and above and around, over the whole heavens, nothing but the auroral light, except in the gaps between the darting streamers in the zenith. I carefully took the bearings of this remarkable arc, and found by means of a compass the next day, that it was bisected by the magnetic meridian. The phenomena underwent no diminution during the time (an hour and a half) I was watching it. The sky appeared to be quite free from cloud.

I have often witnessed fine displays of aurora; one in the winter of (I think) 1848, in this county, the colours and streamers of which were magnificent, far finer than those I saw on the 24th and 25th of last October at Edinburgh; but I never before observed the stars to be so much dimmed as they were at Nairn in September, notwithstanding the light on that occasion was colourless. On other occasions, I have always thought the stars quite unaffected by the auroral light, both to the naked eye and in the telescope, but on this they were obviously dimmed as by a haze.

My impression is, that no aurora that I ever saw could be visible in daylight, with the exception perhaps of this last, and the only portion of this that could possibly be seen in daylight was the well-defined arc low down in the S.S.E. I think it is just possible that in a clear and cloudless sky such an arc as this might be visible. HENRY COOPER KEY

Stretton Rectory, Hereford, June 6

Red and Blue

I WAS much interested by the letter of Mr. T. Ward (NATURE, vol. iv. p. 68) describing the appearance of a blue colour when looking at white chalk marks on a black board while the sun was shining in the eyes, as I have frequently noticed a precisely complementary phenomenon.

While walking along the chalky roads of East Kent in bright sunshine, and reading under an umbrella, I have frequently noticed that the letters appear of a deep blood-red colour; the black colour of the type reappearing immediately on passing over the shadow of a tree on the ground, or on allowing the sun to shine directly on the book. This was so striking when first seen that I had to convince myself that the page was not printed in red ink. This is obviously the exact converse of the observation of Mr. Ward, who saw a blue colour from white marks on a black surface, while I saw a red colour from black marks on a white surface. A short time since I observed a precisely similar colour when looking down on the platform of a railway station with the setting sun shining on the eyes, the cracks between the boards also appearing red. HERBERT M'LEOD

Influence of Barometric Pressure on Ocean Currents A LOW barometric pressure and an increased height of the ocean was, I believe, first assumed to stand in the relation of cause and effect by Mr. Piddington. The abnormally high tidal waves that sometimes rushed up the Hooghly during Calcutta hurricanes were ascribed to the low pressures which accompanied them. There is no doubt that unequal pressure is a true cause of currents in the ocean. But I think it, as well as difference in specific gravity, may be regarded as infinitesimal in amount, compared to the influence of the winds.

The high tidal waves at the mouth of Hooghly are not experienced during the first stage of the hurricane, or so long as the wind blows from a northerly quarter. The waters in the Bay of Bengal are then propelled towards the south. It is only after the wind changes to the south and the barometer is rising that the waters are driven against its northern shores. It is when the

wind happens to change to the south at the time of the flow of the tide that great inundations occur in the Delta.

On the coast of the United States, however, there is apparently an intimate relation between low pressures and high tides. In general, so long as the barometer remains low, easterly winds are blowing on the coast and heaping up the waters in every bay. During the second stage of the storms the winds generally blow violently from the west or north-west, often at a right angle to the whole coast. These high westerly gales cause very low tides along the United States when the barometer is rapidly rising. But low tides are not experienced with high pressures if the air is calm.

High tides only occur on the coast of Europe after westerly winds have been blowing for some days in the Atlantic. It is a well-recognised fact among the fishermen on the east coast of Scotland that high tides are due to this cause. I think Hugh Miller was right in maintaining that the friction of the south-west winds on the wide surface of the Atlantic must be quite as powerful in maintaining the flow of the stream through the Florida Channel as the action of the Trade winds in forcing the tropical waters into the Gulf of Mexico.

Owing to the great rapidity with which barometric disturbances are propagated in our temperate latitudes, it is difficult to conceive how barometric pressure of itself can have an appreciable influence on the currents of the ocean. The rate of their propagation in winter is from thirty to sixty miles an hour. În the fourth number of the "Board of Trade Weather Report" an instance is given, in which the rate is affirmed to be upwards of seventy miles an hour. The velocity in this case, however, as I may try to show on another occasion, is estimated about ten miles an hour too high. But let us suppose that no winds accompanied these rapidly propagated depressions and elevations of the barometer. A difference of an inch of pressure existing between places on the ocean two or three hundred miles apart would create only a very slow moving current, even though the diminished area of pressure were stationary. But these low pressures pass so rapidly onwards that the vis inertia of the waters of the ocean would hardly be overcome before they were again subjected to the opposite influence of an increase of pressure. The effect of barometric pressure on the level of inland seas, like the Baltic and Mediterranean, must be still less than in the open ocean. Winds are often localised, but great depressions of the barometer extend over immense areas; in most cases far larger than the area of the Baltic. Any higher level from this cause would be brought about by the flow of the waters from either end, as the pressure might be assumed to be the same en The mere effect of changes of barometric pressure, it will be admitted, would be quite inappreciable in any inland lake in Britain. But any one who is in the practice of fishing in the smallest of our lakes may always observe that there is an under current or "drag" created when the wind blows strongly towards the shore, in consequence of the accumulation there of its waters. The Niagara is sometimes suddenly raised two feet by strong west winds blowing over lake Erie. It is long since M. Volney, as regards the Mediterranean, stated that east winds caused a rise or flood of from two to three feet in the harbour of Marseilles, and that westerly winds produced opposite effects. It was by a careful deduction of effects produced on a small scale that this acute observer was enabled to give a consistent outline of the causes which produced the ocean currents in general. The currents of the ocean may be regarded as coinciding very closely with the average force and direction of the winds over its surface. Since, however, Humboldt assures us that the surface water of the Gulf Stream in the Florida Straits is sometimes reversed by the force of the winter "northers," it does seem vain to attempt to trace permanent surface currents in any part of the North Atlantic, vexed as its surface is by winds so inconstant in their force and direction. Pilmuir, Leven, Fifeshire

both sides of that narrow sea.

St. Mary's Loch, Selkirkshire

R. RUSSELL

To the student of Nature it may seem easy to decide whether the water of any given lake is good for domestic uses. But as regards St. Mary's Loch, where the question has to be settled by dint of a squabble in the Auld Reekie municipality, with all its complementary dust, smut, and heat, the true aspects of Nature are liable to misrepresentation.

Although not resident in Edinburgh, nor subject to its prejudices and ratings, your correspondent has taken considers ble

interest in the subject as discussed both locally and in Parliament. Last week he visited St. Mary's Loch, and took pains to compare it with its very various reputation. He was prepared to find it an oozy swamp, fed by a moorland drainage of bogs and peat mosses.

A true poet is credited with seeing clearer and telling better than other people can, and in this case the credit is fairly earned by Sir Walter Scott, poet laureate of Scottish scenery. In the "Lay of the Last Minstrel" we read of "Fair St. Mary's silver Wave." In " Marmion,"

Nor fen nor sedge

Pollute the pure lake's crystal edge.
Abrupt and sheer the mountains sink
At once upon the level brink,
And just a line of pebbly sand

Marks where the water meets the land.

In plain prose your correspondent saw as follows:-St. Mary's Loch, a practically inexhaustible natural reservoir; in a district pastoral, not moorland. The surface of surrounding hills and flats, formed of loose rock, shingle, or gravel, with sprinkling of light earth, the very type of natural draining to prevent or exterminate bog, morass, and swamp. Not a trace of peat, except peat-reek odour from Tibbie Shiell's chimneys. Tibbie burns peats got from exceptional points high among the hills. The various feeders of the loch run in pure as water can be. That the loch, bedded in a shingly, gravelly flat, and surrounded with bare, smooth, lawn-like hill-slopes, should appear to contain brown-tinted water, arises from three concurrent causes. First, the extreme purity of the water; second, the tawny-brown hue of aquatic growths, enveloping the shingle under water, by transmission; third, the pipe-clay whiteness of the dry shingle on the beach, by contrast. From the first-stated cause the water varies in apparent tint according to the bottom hues. Aside from chemical analyses, the relative physical features at once decide St. Mary's Loch to excel the famous Loch Katrine as a water source.

The Edinburgh people are about to celebrate the centenary of Sir Walter Scott. His evidence, before cited, and the occasion, may serve to excuse the spontaneous testimony of A STUDENT OF NATURE

Sun Spots and Earth Temperatures

I NOTICED lately the deduction by Mr. Stone of a connection between Wolf's solar spot periods and the earth temperatures at the Cape of Good Hope: and now Professor Smyth, at Edin burgh, recalls to our attention the fact that his own investigations had, a year ago, led him to a similar conclusion.

Will you permit me to call attention to a further discussion of this subject, as contained in a short article, published in Silliman's "American Journal of Science." The compilations were mostly made in February, 1869, and afford interesting confirmation of the results, which I suppose to have been deduced by Messrs. Smyth and Stone.

Washington, May 6

CLEVELAND ABBE, Director Cincinnatti Observatory, Meteorologist to the Signal Office

Bessemer Bombs

ALLOW me through the medium of your columns to call the attention of scientific men to the significant inference which, it appears to me, is to be drawn from the formation of "bombs" in the Bessemer process, incidentally described by Mr. Williams in a recent number of NATURE.*

These "bombs" are minute hollow spherules; the smaller are for the most part perforated. These minute hollow spherules are formed of liquid incandescent matter, the smaller showing the true form-perforated spheres.

The point to which I wish to direct the attention of Mr. Williams and other scientific men is this:-May we not have here an experiment which supplements those ingenious ones of M. Plateau on revolving liquid spheres? Mr. Williams will perhaps kindly examine some of the most perfect of these bombs, and let us know whether he sees trace of revolution in their formation. I believe he will find such evidence, and that the revolution is about the perforation. C. E. Brighton

*See NATURE, vol. iii. p. 410.

THE STRASBOURG MUSEUM

A BRIEF notice of this Museum may not at this time be devoid of interest. It occupies ten large rooms in the Academy House of Strasbourg. Two rooms are devoted to Comparative Anatomy, and eight to the Zoological, Geological, and Mineralogical collections. One large hall is exclusively devoted to a collection of species indigenous to Alsace, and here its flora and fauna, both fossil and recent, will be found well represented. The large hall of Mammals contains about 2,000 specimens belonging to between 600 and 700 species, among which may be noticed a fine series of Felidæ, including two specimens of the rare Felis pardina of Portugal. Among the Ruminants are a grand specimen of the Ovis nivicola of Kamtschatka; four specimens of Tragelaphus from the mountains of Constantine, a large series in all stages of growth of the Antilope rupicapra from Switzerland, the Carpathians, and the Pyrenees; Capra semlaica of the Nilgherries; six specimens of C. agagrus from Kurdistan, of which two are magnificent adult males and the others females and young; C. walee from Abyssinia, male and female; nine specimens of C. hispanica from the Sierra Nevada; seventeen of C. ibex, representing it in all its ages and in all states of wool; not to mention excellent specimens of C. pyrenaica, C. caucasica, C. altaica, and C. sinaica; indeed, it may be doubted if there is in any Museum a more complete collection of this interesting group. Of the Antelopes the Museum also possesses a grand series, and the attention in this corner of the hall will be at once attracted by the case of Reindeer, containing eight perfect specimens, representing the wild race of Norway, the domesticated animal of Lapland, and the varieties from Siberia, Greenland, and Labrador. There are also beautifully stuffed specimens of the European and American Bison, and among the Cervidae we noticed a most interesting little variety from Corsica of Cervus elaphas.

Among the Rodents the Collection of Hares and Rabbits from all parts of the world is very fine. The Collection of Madagascar Lemurs is nearly complete. There are also fine specimens of Colobus ursinus and C. vallerosus from the Gaboon, and a skeleton of the female Gorilla; one of the largest specimens known of the Walrus, and an immense series of Phocidæ from the North Seas. We have omitted to mention two nice specimens of Chlamydophorus truncatus.

The

The Bird Galleries are very extensive, and contain upwards of 5,000 species and nearly 14,000 birds. Collection of Vultures is very rich; Gypatus_barbatus from Switzerland, Pyrenees, Sierra Nevada, the Atlas, and Abyssinia; Aquila pelagica from Kamtschatka. Of Strix there are about 200 specimens and 60 species. The Birds of Paradise are represented by perfectly fresh specimens of Semiophora Wallacei, Paradisea alba, Craspedophora magnifica, male and female; Astrapia nigra, male and female; good specimens of both species of Cephaloptera; Turacus giganteus; Anas Stelleri, male and female; Alca impennis, a very old specimen. Passing by the grand series of Pelicans, of Grouse we record magnificent specimens of Oreophatis derlyanus, Lophalector Macartneyi, male and female, Balœniceps rex, &c. The Reptiles and Fishes occupy two large halls.

The Entomological Collection is very fine; a portion of it is exposed to the public in one of the halls; but the greater part is kept in the Cabinet Room. Nothing can surpass the beauty and freshness of the collection of Alsace Insecta. The collection of Coleoptera numbers about 8,000 species.

The Palæontological Collection is arranged according to the geological formations; and one must remark a magnificent example of Teleosaurus Chapmani, 12 ft. long; a grand mass of Pentacrinus fascicularis, 5 ft. by 3, and containing 15 individuals established on a mass of oysters.

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