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frequently cut completely through the nSve and expose the rock beneath to the action of Irost. In such instances the rocks are in the best position possible to be acted upon by great changes of temperature. Dark bodies on high mountains absorb heat when exposed to the sun, although the air may be below 32° F.; and melting the adjacent snow, become saturated with water, which freezes as soon as they are in shadow. The blocks thus loosened fall away or are removed by the motion of the ni-vl. The tops of the cliffs, however, are protected by a covering of snow. There is frequently a space above the top of the neve' in summer which is exposed in like manner to the action of the atmosphere. These slopes recede by sapping through the action of frost, and precipices result. While the upper portions of the walls of depressions filled with neWsnow are being broken away by the tensions in the nh'c, and by atmospheric action, the snow on the lower slopes is under compression, and thus rendered capable of abrading the rocks over which it flows.

The ice, in descending the steep slopes from various sides, impinges with great force on the bottoms of the depressions it occupies, and tends to scoop out rock basins. The result of these combined agencies is seen when the n/vivs, removed, and we find amphitheatres with precipitous walls rising immediately above a rock basin lake. In other words, the resulting form is a cirque like those of the High Sierra.

So far as my observations extend, cirques are confined to mountains on which ice sculpture followed water sculpture. The topographic forms left after the disappearance of the ice are modifications of the antecedent forms due to the action of tain and streams.

In the vicinity of Mount St. Elias, Alaska, the mountain ranges are primarily monoclinal uplifts of geologically recent date, and do not bear evidence of having been deeply dissected by streams previous to the birth of the present glaciers. The ice drainage is largely consequent on the present orographic structure, and cirques are usually absent. One remarkable exception to this is furnished, however, by a fine cirque on the southern side of St. Elias, which is filled by neve snows and drained by a small glacier. Thousands of secondary and tertiary glaciers exist on the southern slopes of the mountains, but certainly very few, and so far as my knowledge goes none, of these have their origin in true cirques. On the north side of the mountaics, however, which are in general the gently sloping surfaces of orog'.'phic blocks, topographic forms inherited from former aqueous erosion are conspicuous, and cirques are abundant.

Glaciers exist about the summit of Mount Shasta, Mount Ranier, Mount Baker, and other high volcanic peaks in the Cascade Mountains, l>ut none of these, so far as known, originate in cirques. These mountains, like the uplifts about Mount St. Elias, are geologically young. They are volcanoes with fumaroles in their craters; and owing to their elevation, and the comparatively slight erosion they have suffered, it is reasonable to suppose that the first precipitation on their summits was in the form of snow. Glaciers were formed on unmodified slopes, but have not excavated cirques for themselves. The glaciers on these mountains, like many of the smaller ice streams in Alaska, occur on exposed slopes and not in depressions. The accumulations of snow and ice form prominent convex surfaces and frequently give a characteristic outline to the summits which they cover.

The probable origin of cirques which I have traced, together with the fact that they occur in thousands about the summits of mountains on which the glaciers followed water sculpture, together with their absence on unglaciated mountains like the Southern Appalachians, and also the fact that glaciers in themselves do not seem to have the power of excavating similar depressions, is seemingly cumulative evidence pointing to the conclusion stated above.

Cirques, alcoves, and possibly other forms, when considered simply as topographic features, may perhaps be classed together; yet, genetically, alcoves and cirques are distinct, the former owing their existence to aqueous sculpture, usually in horizontal rocks, and the latter to aqueous sculpture followed by ice sculpture, in rocks which may be heterogeneous or homogeneous, horizontal or inclined.

The generalization that "cirques are confined to glaciated regions, to which Mr. Bonney lakes exception, was reached from considering the distribution of typical examples, previous to the differentiation of cirques from other similar topographic forms. When they are recognized as distinct from alcoves, and

necessarily in part of glacial origin, the reason for their distribution becomes evident, as does also the further generalization that they "occupy localities where glaciers first appear."

In the Rocky Mountains the peaks and ridges on which cirques occur have an elevation of from 10,000 to 14,000 feet. The same is true also in the Sierra Nevada. In each of these regions the ancient neve" fields had generally about the same elevation, while the glaciers flowing from them descend to within 6000 or 5000 feet above sea-level. In Alaska, however, where the former glaciers descended into the ocean, cirques occur on peaks and ridges only 3000 or 4000 feet high, and examples may be found at elevations of less than 2000 feet. Their vertical, as well as their geographic range, therefore, appears to have been regulated by the climatic conditions which control the birth of local glaciers.

While "alcove" and "cirque" should have a definite sig nificance in geology, amphitheatre, recess, bowl, and other correlative words, may be considered as general terms applicable to more or less inclosed spaces without reference to their origin. The semicircular recesses made by winding streams in the sides of caiions and deep valleys, sometimes resemble alcoves. Craters frequently bear a close topographic similarity to cirques, but are readily distinguished when their origin is considered.

On looking over my account of the cirques of the High Sierra (Eighth Annual Report, 1886-87, U.S. Geological Survey), I fail to discern any reason for materially changing it, except, as indicated above, to state more definitely the differences between cirques and other topographic forms with which they might be confounded.

I remain very sincerely your friend,

Israel C. Russell.

Large Meteor of January 24, 1892.

It is to be hoped that further observations will be forthcoming of the brilliant meteor of January 24, ioh. 55m- (^e' scribed by Mr. T. Heath in your last number, p. 295), so that its real path may be computed. I think there is little doubt the meteor belonged to a shower of Draconids having a radiantpoint a few degrees south-east of the star (. On the same night (January 24) as that on which the fine meteor was observed, I saw a third magnitude shooting-star, at 7I1. 55m., with a path from 324° + 400 to 33oJ° + 31^", and this also belonged to the radiant in Draco. I discovered this shower on the nights of January 19 and 25, 1887, and determined the position of the radiant as at 261° + 63°. There are many other showers from the same point in the spring, summer, and autumn months.

Bristol, January 31. W. F. DENNING.

On the Relation of Natural Science to Art.

In Dr. du Bois-Reymond's interesting lecture, as published recently in Nature, there occurs the following passage (p. 226): "Flaxman" was "certainly mistaken in representing Polyphemus with three eyes—two normal ones which are blind, and a third in the forehead." Does not the recent discovery of a third (parietal) eye in some of the lizard and fish tribes (not to mention the tunicates !) diminish the force of this assertion? Flaxman's genius appears rather to have forestalled the discoveries of science in representing the human monster with three eyes, especially as Wiedersheim states that even in man nervefibre-* have been traced from the optic thalami to the pineal gland. W. Ainslie Hollis.

Brighton, January II.

Ice Crystals.

The following account of some very well defined ice crystals may be of interest.

On December 26, 1891, the thaw set in. On the 27th, I noticed on the surface of the ice on the lake at Drinkwater Park, near Prestwich, on the outskirts of Manchester, a large number of very distinct, hexagonal, tabular crystals. The surface of the ice was not very wet. These crystals varied from half an inch to three inches across, were raised about an eighth of an inch above the suiface of the ice, and in many cases bore a similar but much smaller crystal in the middle, raised about an eighth of an inch above the surface of the larger crystal. In some specimens the smaller crystal was rounded and indistinct. When it was absent, dark lines, following the direction of the lateral axes, were visible in some cases. Frequently an indistinct striation was present. GILBERT Rigg.

Manchester Museum, Mineralogical Department,
January 12.

A Tortoise inclosed in Ice.

I Should like to be allowed to record a case of a water-tortoise surviving an incarceration in ice, somewhat similar to that given in Nature (vol. xliv. p. 520).

In this instance, the tortoise has hibernated in a stone basin, in which there were about 6 inches of water and a quantity of dead leaves. The whole was, I believe, frozen into a solid mass. At any rate, when, on December 29, I examined a cake of ice and leaves, from 2 to 3 inches thick, which was floating in the basin after a thaw, I found the tortoise with its back embedded in the undir side of the mass, and with nearly 2 inches of porous-looking ice above it. The animal, though torpid, was alive, and I replaced it in the basin. Later on it put its nostrils up to the surface, and two days afterwards was seen with its head out of the water as usual. It remained in the pond, which has been again frozen over, in less than a week after this observation. Frank Finn.

31 Walton Crescent, Oxford, January 22.

Alpine Rubi.

In a footnote in Nature (vol. xlv. p. 10) it is staled that 41 The two highest-known species of Rubus are pinnatus and rigidus, at 5000-6000 feet. This is hardly correct, unless it is intended to refer to African species only. In South America, R. megallococcus, R. boliviensis, R. bogotensis, and A', roseus occur at 8000 feet, and R. rusbyi at 10,000. In Colorado I have found A', strigosus above 10,000 feet (see Bull. Torrey Bol. Club, 1890, p. 10; 1891, p. 169). In the Indian region, R. elliplicus goes to 7000, R. lasiocarpus to 8000, and R. biflorus and A\ rosifalius to 10,000 feet.

The name of the wild Zca is Z. canina, Watson (local name, "mais de coyote"), not nana, as given in Nature, vol. xlv. p. 39. T. D. A. Cockerell.

Institute of Jamaica, Kingston, Jamaica,
December 30, 1891.

UTILIZATION OF HOMING PIGEONS.

THE utilization of the homing instinct of the domesticated varieties of the blue rock pigeon, the Columba livia, for military purposes, has been effected by most of the Governments in Europe. In France, Germany, Austria, Switzerland, Italy, Spain, and Portugal the organization has been very complete. It has even extended to Russia, Denmark, and Sweden ; and Africa has been brought into communication with Spain by stations at Ceuta and Mellila. England alone, of all the great Powers, has neglected this important mode of communication, which is available under circumstances that preclude the employment of any other means.

It cannot be said that they have not been brought under the notice of the military and naval authorities. Nearly twenty years ago, on the occasion of the despatch of a flight of seventy-two birds from the Crystal Palace to Brussels, when the first birds arrived before the telegram which was sent to announce their departure, I wrote a letter to the Times of June 27, 1873, calling attention to their utility, and asking the question : " What would be the value of the birds, in the event of a war in which we may be engaged, that would convey messages to or from Guernsey, Jersey, and other places, when the sub,marine wires had been cut by the enemy ?"; and in a lecture delivered by me before the Royal Engineers' Institute at Chatham, on the use of pigeons for military purposes, I entered at some length into their mode of training and general utilization.

The employment of the Columba livia depends upon several conditions which are not without interest. In

the first place, this species is one of the comparatively few capable of domestication, a faculty which is totally distinct from, though frequently confounded with, the 1 facility of being tamed. A domesticated animal is attached to its home, and returns to it of its own will; a tame animal is merely familiar with man. These two states are admirably illustrated in the closely allied species, the fowl and the pheasant. Both were originally perfectly wild, but when domesticated the chickens invariably return home to roost, while the pheasants, though descended from numberless generations of birds bred in confinement, have no attachment whatever to the place of their birth or rearing.

In its natural habitat (the rocky cliffs of the sea-shore) I the blue rock pigeon has to fly long distances in search j of food, which, when breeding, it stores up in its crop and carries home to its young. This necessitates strong powers of flight and well-developed perceptive faculties, it being guided in its return solely by sight, and not, as is often supposed, by any special instinct.

The pigeons that are used for carrying messages are bred solely for that purpose. A process of artificial selection, as rigorous and remorseless as that of nature, is followed. The young birds, after acquiring their power of perfect flight, and learning the contour of the country in their circuits around their home, are taken in

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the direction in which it is desired that they should fly, and trained stage after stage until they know every locality over which they have to traverse. This training is absolutely necessary, if their return home is to be depended on. During its performance the inferior birds, those whose intelligence and determination are not well developed, are lost; and the best birds, only, retained. This loss, in the long-distance flights which are flown by the Belgians and by the best homing pigeon societies in England, is very severe. Old birds, that know large tracts of country well, may be taken in new directions, provided they are not too extended, with safety, but young birds that have not been trained would almost certainly be lost if carried many miles from their home.

Every homing pigeon flyer recognizes the hereditary character of this acquired faculty, and will give a very high price for birds descended from parents that have flown long distances, whereas he would not purchase another bird of precisely similar appearance were he not acquainted with the performances of its ancestors. The fancy varieties of pigeons, especially those which are called carriers in England, are perfectly useless for the purpose of flying distances.

The birds that are most valued are almost all descended

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Fig. ».'—Chart Showing The System Of Military Pigeon Posts In Ihe Continental Kingdoms.

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Brighton on the south, and all along the coast-line to Yarmouth on the north.

The homing-by-instinct theory is entirely disproved by the races which have taken place from Rome to Belgium, a distance of between eight and nine hundred miles, nearly half of which was over country entirely new to the birds. All the birds engaged in these races had been flown from the south of France to Belgium, whence they would have found their way back in one or two days, but of the hundreds liberated in Rome, not one returned before eleven days, and in the first race in a fortnight only four out of the number despatched. The country was new to them, and doubtless they circled about in search of some known landmark which would have directed their flight ; but the objects with which they were acquainted were hidden from them by the Alps, and it was only those few that, flying along the coast, succeeded in reaching the south of France, and then saw objects with which they were acquainted, that returned to their Belgian homes.

The first extensive practical application of the homing faculty of these birds took place when Paris was environed by the German army. During the siege, as is well known, balloons were continually despatched from Paris, carrying not only passengers, but bundles of letters, and the homing pigeons belonging to a few private individuals resident in Paris. In the first instance the despatches returned by these pigeons were photographed on paper and sent from Brussels into Paris. After a time a distinct pigeon post was organized from Tours, outside the German lines. This pigeon post was recognized by the English postal authorities, and letters at the cost of halfa-franc a word were sent from Tours into Paris with as great a degree of rapidity as the pigeons could be sent out by balloon, and conveyed from the places where thev descended to Tours, for the purpose of being renown into Paris. The letters, which were limited to twenty words, were set up in type, micro-photographed on thin films of collodion, inclosed in small quills, and attached to one of the tail feathers of the bird. So complete was this organization that one pigeon could have carried into Paris the whole of the many thousand letters that were sent in during the siege.

The Germans were not slow to utilize the services of the pigeons for military purposes, and at the present time every large fortress in Germany has its pigeon loft, and the birds are trained to fly back from the surrounding country for distances of many miles.

As will be seen by the accompanying map (Fig. 2), pigeons are trained to Berlin from all the large fortresses in the Empire, Strasbourg on the south to Koenigsberg on the north. Then, again, each fortress has its own loft of pigeons, which are trained to fly back to it, so that before a fortress is completely invaded by the enemy a number of birds can be sent out, or forwarded subsequently by balloon. On being liberated with despatches, these would return to the fortress, without the possibility of their being interfered with. A similar organization prevails in France, pigeons having been trained from Paris to all the military stations on the German frontier ; and it may be observed that in Italy, Austria, and even Russia the same system prevails. In our own country there is no definite organization of pigeons for military purposes. It is true pigeon flying has become a popular pastime with a large number of persons. There is scarcely a town in the kingdom where some good homing birds do not exist, which could be placed at the disposition of the military or naval authorities. One great use of the birds would be on the cruisers sent out to watch an enemy's fleet. It is obvious that each could readily take a number of pigeons on board, and, without leaving its post of observation, could send back day by day messages to the town from whence the pigeons were received.

It is doubtful whether any purely military organization

could take as good care of the pigeons, and could train them in a manner superior to that which is done by those who use them for racing purposes. No military or naval servant, unless he were a lover of pigeons, would train them with the same amount of interest and care that is done by the amateurs.

In this country, at the present time, there exists a verylarge number of pigeon-flying Societies. Their races extend from the midland counties in England as far as Cherbourg, and other parts of France. In actual practice the birds would not be, except under very rare occurrences, required to fly very long distances. Of course these long flights necessitate a considerable amount of risk, but good pigeons can be calculated on to return from fifty to a hundred miles with certainty.

On looking at the map it will be seen that no lines showing the military organization of pigeons appear in Belgium ; in fact, it is hardly thought necessary that any distinct organization should take place there, as it is supposed that there are in Belgium alone more than six hundred thousand homing pigeons belonging to private individuals, all of which are well trained, and would, in case of war, be placed at the disposition of Government.

W. B. Teget.meier.

NOTES.

The Committee which has been formed for the purpose of obtaining a portrait of Michael Foster, Secretary of the Royal Society, and Professor of Physiology in the University of Cambridge, has issued a second list of subscriptions. It is intended that the picture shall be presented either to the University or to Trinity College, as the subscribers may decide. The treasurer is Dr. Lea, Gonville and Caius College, and subscriptions may be paid either to him or to Messrs. John Mortlock and Co., Bankers (Limited), Bene't Street, Cambridge. Cheques should be made payable to the " Michael Foster Portrait Fund."

At the meeting of the Cambridge Philosophical Society on Monday, January 25, Prof. G. H. Darwin, President, in the chair, the following resolutions were proposed by Prof. Cayley, seconded byJDr. Lea, and passed unanimously :—"(1) That the Cambridge Philosophical Society desires to express its sense of the great loss sustained by the University and the Society by the death of Prof. Adams, who shed lustre on the Society by the brilliancy of his scientific career, and set an example to its members by the earnestness and simplicity of his life. (2) That the Society do now adjourn without transacting the business of the meeting, as a mark of respect for the memory of Prof. Adams, one of the benefactors of the Society. (3) That the President be instructed to convey the foregoing resolutions to Mrs. Adams."

We have heard at present of only one astronomer as candidate for the Professorship of Astronomy rendered vacant by the death of Prof. Adams; this is Mr. Turner, Chief Assistant at Greenwich. On the other hand, we hear of some mathematicians; it is not slated, however, what contributions to the science they have made.

The late Ferdinand Roemer, the well-known geologist and Professor at the University of Breslau, whose death on December 14, 1891, we have already recorded, intended to have celebrated on May 10 next his jubilee as a Doctor of Philosophy: and his friends, admirers, aud pupils were preparing to do him honour on the occasion. It is now proposed that a marble bust of Roemer shall he placed in the Minerr.logical Museum of Breslau, and an influential committee has been formed for the purpose of collecting subscriptions.

The Committees appointed bst year by the Royal Society and by the British Association for investigating ihe zoology of the Sandwich Islands have amalgamated, and at a meeting held one day last month "elected, from among the gentlemen who offered their services, Mr. Robert C. L. Perkins, B.A., of Jesus College, Oxford. Mr. Perkins will accordingly leave England in a few days, proceeding vi\i New York and San Francisco to Honolulu, where he will at once commence his researches into the fauna of the islands, and especially that part of it which is believed to be threatened with extinction; aided, it is hoped, by the Hawaiian Government, and some of the principal residents. Dr. David Sharp, F.R.S., Curator in Zoology in the Museum of the University of Cambridge, is the Secretary of the Joint Committee.

The annual general meeting of the Geological Society will be SeJd on Friday, February 19, at 3 p.m., and the Fellows and •heir friends will dine together at the Hotel Mctropole, Whitehall Place, at 7.30 p.m.

The new law on French Universities is soon to be discussed tiy the French Senate. The Committee appointed to report upon 'he Government's plan disapproves of many of its provisions.

M. Pierre Laffitte, the head of the "orthodox" PoutivisK. has been appointed professor, at the College de France, of the history of science.

!>■- Frihthof Naxsen is now in England, his object being

J fulfil a series of lecture engagements. The proceeds are .10 V devoted to the expedition to the North Pole on which he ■'■pes to start next year.

THE Joint Grand Gresham Committee has decided to cocerate with University and King's Colleges and the Medical '.-iQegei of the great hospitals of London in the establishment J the proposed University in and for London, on the under•-lading that it be called the Gresham University.

Da. Alfbed Carpenter, the well-known advocate of uaitary reform, died at Ventnor on January 27. He was the tiiftor of many works on sanitary subjects. In 1879 he was | teced President of the Council of the British Medical Associa

•*>, having been in the previous year orator of the Medical ^-oery of London.

PaciF. E. Ray Lankester will on Thursday next (February 11 . at the Royal Institution, begin a) course of three lectures a "Recent Biological Discoveries "; and Lord Kayleigh will a Saturday February 13) begin a course of six lectures on "Matter: at Rest and in Motion."

I'm. Noetli.ng, of the India Geological Survey, is now ttgaged in superintending the sinking of shafts at the amber aaetoo the Upper Irrawaddy.

Am index to the five yearly volumes of the h'ew Hnllelin, weady published, has now been issued as " Appendix IV.,

1(91.~ In an introductory note some interesting statements are aau« aa to the history of the Bulletin. It was originally in

eaded that a number should be issued only occasionally; but avaatMy publication was immediately found to be necessary, ~v! farther space has since been obtained by the printing of .-formation of a purely formal kind in appendices. The ••byecta treated have related almost entirely to economic t»ata»y. The results of investigations made by members of the staff at Kew and of kindred institutions at home and abroad on vegetable products and the plants producing them, have been carefully summarized and pretentcd in as concise and clear a T-anneT aa possible. In many cases the articles have been • Castrated by plates from original drawings or by those placed .t the disposal of the Director by the Hentham Trustees from the ■ Icooea Plantaxum." The ISulUtin has become a most con

venient mode of communicating information to persons at home, to the numerous correspondents officially connected with colonial and Indian botanical establishments, and to private persons interested in plant products in distant parts of the Empire. It has also been of service to members of the general public engaged in planting or agricultural business in India and the colonies.

The fourth part of the first volume (xxi. of the whole work) of the fourth series of Hooker's "Icones Plantarum " has appeared, completing this volume, which is devoted to the illustration, by Sir Joseph Hooker, of Indian orchids of a less conspicuous character than those commonly cultivated. The work is now published for the Hentham Trustees, and sold at four shillings per part by Dulau and Co., of London. The third series, consisting of ten volumes, containing 1000 figures of interesting plants, is on sale by the same firm, at £$ 'he set. Only a limited issue is printed, and when exhausted it will not be reproduced.

Mr. Ellsworth has offered to lend for exhibition at the "World's Fair," Chicago, a collection of orchids, including between 1500 and 2000 varieties.

The Chemical Institute of the Royal University, Rome, has printed a volume of reports on the researches carried on by its workers during the scholastic year 1890 91. Excellent service might be done 10 science if this example were followed by the laboratories connected with our own Universities.

The Director of the Colonial Museum at Haarlem has issued .1 circular notice to the effect that it is of the highest importance for the Museum to have in its library all recent treatises on tropical botany, zoology, products, and cultivation. He begs therefore that authors will send to the Museum a printed copy of their writings on these subjects in the publications of scientific Societies.

Thf. Times of Tuesday, February 2, contains an account of a very peculiar case of prolonged sleep which, on January 31, was occupying the attention of medical circles in Germany. It seems that a miner named Johann Latus, an inmate of the hospital at Myslowilz, in Silesia, has been there 4i months, and during that time all attempts that have been made to wake him have been fruitless. The doctor attending him, Dr. Albers, thinks that catalepsy is the real cause of his condition, although no previous record of so prolonged a sleep has ever been made in medic I science. The fact which has led Dr. Albers to this conclusion is that all the limbs are absolutely rigid. In other respects the appearance of the man betrays no sign of this. The body remains quite still, breathing takes place regularly, and the appearance of the face is quite normal, the cheeks being of a healthy colour. Lately the body has been less rigid and the patient has even made some slight movement, but the eyes have still been kept closed, and the condition of apparent sleep in no way disturbed. During this long sleep the hair on the head has increased in length, but the beaid has remained stationary. In order to supply the patient with food a tube has been inserted into the throat, and by means of it two or three litres of milk have been administered daily.

M. KoEBELK, who has been for the second time searching in Australia and New Zealand for "beneficial insects," has discovered that Onus chalybeus, a steel-blue ladybird, is a most important enemy of the red scale. According to /nstrt Lijt, he has found tbem by the hundred, and has observed the mature insects eating the scales. The trees were " full of eggs," and the larvae were swarming on all the orange and lemon trees infested with the red scale. M. Koebele has sent to America a large quantity of the eggs and many of the adult beetles.

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