been weathered out. In some places a third line runs alongside the two, but this is much less distinct and persistent. The double band resembles nothing more nearly than the hollow impression that would be left by double bars of iron placed closely together and neatly inserted in the rock for clasping some structure on it, if the iron were subsequently removed; or, as you suggest, the marks of a gouge driven by a carpenter across a board. The bands, when looked narrowly into, consist of very fine close hair-like lines, continuous and parallel to their sides, resembling very minute striæ left by glaciation, and look as if caused by some object drawn along the original red sand, before it became the present indurated rock.

"A similar double line runs parallel to this one, about two feet lower down, seven feet long, and a third parallel double line on the other or upper side, three feet long, both of the same breadth as the first. Besides those pointed out by you, which occur on the same flat of sandstone, other lines exist farther down, on the other side of the pool below this rocky flat, on a similar bed of sandstone, part of the same layer-one three feet in length, another six feet, running more or less parallel to those above. Indications of others may also be seen, and, no doubt, several more may be discovered on more careful examination.

"What they are I can scarcely even surmise, having seen nothing of the same kind elsewhere. They do suggest the possibility of their being the indentations of the caudal appendage of some huge creature, similar to the hollow tail-lines between the footprints on the sandstone at Tarbatness and along the shores of Morayshire-a suggestion strengthened by the fact of the existence, on both sides of the line, of numerous rounded hollow marks, very like the footprints on these reptiliferous rocks, occurring, as in them, at intervals. But the continuous even breadth and square section of the bands would seem to render this impossible. Then they might be the depressions left on the soft sand by the hinder portions of the shell of some large crustacean-a more likely cause, rendered more probable by the existence of very good ripple-marks on the same sandstone, in the same and neighbouring layers. The striæ-like lines of which the grooves consist would seem to point to some moving agent, organic or physical. They may, however, be the casts or impressions of some great land reed or sea fucoid, the hair-lines being the marks of the fine structure of its stem or the parallel veins of its leaves. It would be desirable to have the superincumbent layer of rock carefully removed where the bands in question disappear under the upper rock, which might shed some light on the nature of the strange marks. I was sorry I could not spend more time on their examination."

The impressions occur about 300 or 400 yards above the Victoria Falls, and immediately beside the last of three lesser waterfalls on the west side of the stream.

AN attempt has recently been made by Herr Graeve (Der Civil-Ingenieur, 1879, p. 591) to determine the amount of water in German rivers and its apportionment in different seasons, a question very important for navigation, and also of much scientific interest. His research comprehends the chief rivers of Germany, excluding the Danube, which begins to be navigable only outside of Germany, and including the Vistula and the Memel. He first calculated, from the mean heights of water, the quantities of water flowing out per second, and he adds a table in which the amount of outflow is shown in relation to the extent of the corresponding river territory. When the amount of outflow per 100 sq. km. of the region of precipitation is calculated the following values are obtained:-(1) the Rhine at Coblentz above the Moselle mouth delivers per 100 sq. km. of land 1070 cub. m. of water in a second; (2) the Weser at Minden, o'826 cub. m.; (3) the Elbe at Sorgau, o ̊579; (4) the Elbe at Barby, o'554; (5) the Oder at Steinau, 0'460; (6) the Oder below the Warta mouth, 0°413; (7) the Warta near its mouth, o'344; (8) the Vistula at Montau Spitz, o'538; (9) the Memel at Tilsit, o'600.

From these numbers it appears (a) that the average outflow of different rivers, from equal portions of their territory, differs much more than is usually thought, for in the Middle Rhine it is about three times, in the Middle Weser two and a half times, and in the Middle Elbe, as also in the Lower Vistula and Memel, more than one and a half times as much as in the Lower Warta.

On the whole, it decreases from the Rhine to the Warta, and from the latter increases again to the Memel. (b) In one and the same river the quantity from equal portions of land seems as a rule to decrease down stream. (c) All calculations of quantity of outflow in streams, based merely on extent of the region of precipitation, must as a rule give incorrect results.

It was important to try and determine the relations of the quantity of outflow to the rainfall of the corresponding regions, and Herr Graeve, doing so by a method which he describes, obtained the following percentage numbers, corresponding to the above series of rivers :-(1) = 38°5 per cent. ; (2) = 37 p.c.; (3) 30 p.c.; (4) = 28.5 p.c. ; (5) = 27′2 p.c. ; (6) = 21°4 p.c. ; = 21 p.c.; (8) = 29 p.c.; (9) = 32'5 p.c.

=

(7) =

From this the following conclusions (briefly) are drawn :— (a) The percentage proportion of the amount of outflow to the rainfall differs very considerably in these several rivers, though far less than the amount of outflow from equally large regions of these rivers; hence the differences of the latter can be due only in part to differences in the rainfall.

(b) The percentage decreases from the Rhine to the Warta, and increases again from the latter to the Memel. In one and the same river a decrease is perceptible down the stream, at least so far as the phenomena in the Oder and the Elbe are general.

(c) Since in a mountainous region a greater part of the atmospheric precipitates is carried off by rivers than in the plain, the steady decrease in the percentage proportion of outflow to rainfall in the direction from the Rhine to the Warta must be primarily attributed to the increasing flatness of the region; so too must the decrease of the percentage down stream. influence of more or less wood on the land could not be precisely determined.

The

(d) The marked increase of the percentage in the direction from the Warta to the Memel cannot be explained by the orographic conditions of the region of precipitation, because this region in the case of the Memel is not at all hilly, and in that of the Vistula only a little more hilly than that of the Warta, but since the amount of the evaporated part of atmospheric precipitates is considerably influenced by the mean temperature of the region of precipitation, and this in the region of the Vistula and the Memel is lower than in that of the Warta, the increase of percentage in question from the Warta to the Memel must mainly be attributed to climatic conditions.

(e) While the percentage in question must be chiefly governed by orographic and climatic conditions, there can be no doubt that other factors also act, e.g., the relative amount of moisture in the air, which influences the degree of evaporation, and in general must decrease from the rainy Rhine region to the dry region of the Warta; further, the amount of plantation, which in the regions of the Vistula and Memel is larger than in those of all other German rivers; lastly, the nature of the ground, allowing more or less passage to the precipitates; the influence of all these factors, however, cannot be proved with the same certainty as the orographic and climatic conditions.

A comparison of the amounts of outflow in different years shows that in individual rivers more important differences occur than are generally supposed, that these differences in rivers of different character and unequal force are very different in amount, and that in the same river they decrease down stream.

With regard to the difference in amount of outflow in the various seasons and months, the following average values were obtained. The amount of outflow in winter (from the beginning of November to the end of April) is to that of summer, at the parts of the stream examined, in the Rhine as I : 0'922, in the Weser as 10'434, in the Elbe as 1:0'467, in the Oder as I: 0°525, and further down stream as I: 0'522, in the Vistula as I: 0 486, and in the Me el as I: 0.389. A better idea of the regularity of the quantities of outflow is given by the relations of these for the drye-t and the wettest month of the year; in the case of the Rhine this ratio is I: 1'458, in the Weser I: 4, in the Elbe 1: 5'238, in the Oder I : 4'5, and further down 1 : 3'68; in the Vistula 1 : 4'19, and in the Memel 1 : 4°51.

The causes of the difference in the ratio of the largest and least monthly amounts of outflow must chiefly be sought in the presence or absence of collecting basins, as also in the orographic and climatic conditions. In the Rhine all those factors com ine which affect the regularity of outflow. possesses in the Swiss la es large reservoirs; its river-region comprises mountains of various height, and plains, so that the

It

melting of the snow must occur at very different times of the year. The Memel also possesses reservoirs in its marshes, and its region is perhaps better wooded than that of the other streams of Germany, but the long and hard winters cause an accumulation of large masses of ice and snow which melt suddenly and almost simultaneously in the whole region.

Herr Graeve takes up various other points, which have a practical bearing on navigation, but for these we must refer the reader to his memoir. He remarks in concluding on the desirability of comparing the conditions of outflow of German rivers with corresponding data for other European rivers, though at present the scanty and incomplete character of the data at hand render such inquiry scarcely practicable.

SCIENTIFIC SERIALS

THE Journal of the Russian Physical and Chemical Society, vol. xii. fascicules 5 and 6, contain, besides the minutes of meetings of the Society, the following papers :-In fascicule 5: On the dosage of chromium, by M. Th. Willm.-On the composition of the hydrate of peroxide of barium, by M. E. Schöne. On the distribution of naphtha on the peninsula of Apsheron, by M. S. Goulichambaroff.-On the oxidation of ketones, by M. Gold. stein. On the products of oxidation of erythrite, by M. S. Przibytek.-A necrology of Prof. Nicolas Zinin, by MM. Borodin and Boutleroff.-On the magnetisation of liquids, by M. Ziloff.— On hail, by M. Schwedoff.-Notes by M. Latchinoff on specific heat, on a new dynamometer, and on electrical light.-In fascicule 6: On chlorocamphoric oxide, by M. Latchinoff.-On the action of heat on phosphorites, by M. Beletzky.-On tetrolic acid, by M. Lagermark.-On the solidification and evaporation of drops of liquid, by M. Sloughinoff.-On the dosage of mercury and arsenic in corpses; and an analysis of the artesian wells of Staraya Rousia.

Revue internationale des Sciences biologiques, July, 1880.J. L. de Lanessan, on the protozoa (a chapter with illustrations from the author's forthcoming "Manuel d'Histoire Naturelle médicale).-A. Hovelacque, on the inferior races of mankind.M. Debierre, man before and on the threshold of history.-Proceedings of the Academies of Paris, Belgium, and Amsterdam. August.-J. L. de Lanessan, the coloration and the colouring. matters in plants.-M. Moniez, on the cysticers of Tania.-M. Debierre, man before and on the threshold of history.-Proceedings of the Academies of Paris, Belgium, and Amsterdam. September.-M. Vulpian, physiological study of poisons: curare.-M. J. L. de Lanessan, the saccharomycetes and the fermentations caused by them.-Prof. W. H. Flower, on the comparative anatomy of man (translated from NATURE).-M. R. Moniez, on cestoid worms and helminthologists.-Proceedings of the Academy of Paris.

SOCIETIES AND ACADEMIES

LONDON

Chemical Society, November 18.-Prof. H. E. Roscoe, president, in the chair.-It was announced that a ballot for the election of Fellows would take place at the next meeting (December 2). The following papers were read:-Notes on the oxides of manganese, by Spencer Pickering. Various samples of oxides were procured and heated to various temperatures, until their weight was constant; in some cases they lost weight, in others they gained, whilst in some the weight remained constant. On aluminium alcohols, by J. H. Gladstone and A. Tribe. When aluminium foil and iodine are heated with alcohol the latter is decomposed, two new organic aluminic compounds being formed, alumini: iodoethylate (C2H5O), I, Al, and aluminic ethylate Al,(CHO). The authors have applied this reaction to other alcohols, and have thus prepared aluminic methylate, ethylate, propylate (isopropylate could not be obtained), isobutylate, amylate, cetylate, phenylate, cresylate, and thymolate. -Mr. W. H. Perkin then gave an account of the artificial production of indigo by A. Baeyer, and prepared some before the Society. The steps in the process are: toluene C-HO, dichloride of benzyl CH CHCI,, cinnamic acid C,H ̧O,, orthonitrocinnamic acid C,H,(NO)O,, orthonitrodibromhydrocinnamic acid C,H,BrO2(NO); by the action of caustic potash orthonitrophenylpropiolic acid C,H,(No)O, is formed, which on reduction in alkaline solution with grape sugar furnishes indigo C16H10NO.-On the synthetical production of new acids of the pyruvic series, by E. Moritz.-On the old alum well at Harrogate, by R. H. Davis. The author gives an analysis of the mineral constituents in the residue.-On the

absorption spectrum of ozone, by W. N. Hartley.-On the probable absorption of the solar rays by atmospheric ozone, by W. N. Hartley. The author has photographed and measured the absorption spectrum of ozone; he suggests that the shortening of the solar spectrum at the violet end is due to the presence of ozone in the atmosphere, also that the blue colour of the sky may be ascribed to the same cause.-On peppermint camphor, by M. Moriya of Tokio. The author has studied carefully the physical characters of this substance; he has also investigated the action of chromic acid, nitric acid, and bromine thereon.

Zoological Society, November 16.-Prof. Huxley, F.R.S., vice-president, in the chair.-Mr. W. K. Parker, F.R.S., read a paper on the development of the skull in the Urodele Batrachians. Mr. Parker described the skull of the adult Gigantic Salamander (Sieboldia maxima), the Siren and the Menopoma, and compared their structure with that of the various stages of the skull of the common newt.-Mr. G. E. Dobson, C.M.Z.S., exhibited and made remarks on the head of a partridge (Perdix cinerea) with an extraordinary prolongation of the intermaxillary bones. -Mr. W. A. Forbes, F.Z.S., made some remarks on the shed ding of the horns of the Prong-buck (Antilocapra americana), as recently observed in the specimen living in the Society's Gardens. Mr. Harting, F.Z.S., exhibited a specimen of Bartram's Sandpiper, recently killed in Lincolnshire.—Mr. Sclater exhibited the skin of the Guinea Fowl, lately described in the Society's Proceedings as Numida Ellioti. Further investigation had induced him to believe that this bird was the same as Numida puckerani of Hartlaub, the inaccurate colouring of the head in Mr. Elliot's figure of that species having prevented its identification. Mr. G. A. Boulenger read a paper on the Palearctic and Ethiopian species of Bufo, of which he recognised ten species: four in the Palearctic, five in the Ethiopian region, and one found in both regions.-A communication was read from Dr. Otto Finsch, C.M.Z.S., in which he gave a list of the birds of the Island of Ruk, in the Central Carolines. -A second communication from Dr. Finsch contained the descriptions of some new or little-known species of pigeons from the Caroline Islands.-A communication was read from Mr. Edgar A. Smith, containing an account of the shells of the genus Myodora of Gray.-A communication was read from Mr. Martin Jacoby, in which he gave the descriptions of a collection of Phytophagous Coleoptera made by Mr. Buckley at Eastern Ecuador. The collection contained a good many new and interesting species, of which a great part were not alone inhabitants of Ecuador, but had been found either in Peru or the Amazonian region.-A paper by Messrs. F. D. Godman and O. Salvin was read, in which they gave the descriptions of some supposed new species of butterflies collected by Mr. Andrew Goldie in the interior of the district of Port Moresby, New Guinea.

Physical Society, November 13.-Prof. W. G. Adams in the chair.-Mr. Bosanquet, of St. John's College Physical Laboratory, Cambridge, read a paper on the nature of the sounds which occur in the beats of consonance. From mistimed octaves and twelfths he found that when the beats of the harmonics are cleared away each beat consists entirely of variations in the intensity of the lower notes. He gave the mathematical theory of these beats, and likewise of the curves given by the harmonograph. He also described an ear-tube for using in connection with a resonator. It is difficult to get definite results with a resonator unless the passage from the latter to the ear is closed to sound. The ear tube consists of a copper pipe bent into a sickle shape to gird the face, so that the ends may enter the ears, into which they are screwed, plugging them close. The sound is led from the resonator to the middle of the bent pipe by a flexible india-rubber tube, and thence to the ears.— Mr. Brown read a paper on action at a distance. He drew attention to the fact that though Newton disbelieved in action at a distance, he did not pronounce whether the medium was material or immaterial. Mr. Brown showed that the hypothesis of a material medium was encumbered with difficulties, since, among other reasons, direct contact could not explain gravity, projection of small particles from one body to another could not explain attraction, and Lesage's theory of corpuscles (as modified by Mr. Tolver Preston) required an enormous degree of porosity in masses of matter. The nature of magnetism and vibrations was also discussed by the author.-Mr. J. Macfarlane Gray read a paper on the mechanical nature of the forces called attraction, and gave grounds for attributing them to the pressures of a universal material ether of a gaseous nature. The paper was long, and had to be in part left unread. The hypothesis held by Mr. Gray

is remarkably confirmed by numerical results obtained by him.— Prof. Cottrell threw some doubts on Mr. Gray's results on the score that numerical coincidences were not always safe ground for basing theoretical deductions on. Mr. Gray stated that in the parts of the paper which had to be skipped Prof. Cottrell's objections were answered. He also pointed out that Mr. Brown in his criticism of the gasiform ether had not taken into account the important condition that the particles of ether have volume. Professors Perry and Ayrton read a note on the contact-theory of Herr Exner recently brought before the Academy of Sciences of Vienna. They showed that Exner's experimental results disagreed with the concordant results of several independent experimenters, namely, Kohlrausch, Hankner, and Ayrton and Perry. They concluded that Herr Exner's experiments were inaccurate. They further argued that Exner's second and later paper, so far from being a disproof of the contact theory of electromotive force as now received, is in reality a proof of it. Dr. Wright stated that he will read a paper on this subject soon; and Prof. Reinhold said that Herr Exner had sirce corrected some of the results of his early papers on contact electricity.Prof. Minchin of Cooper's Hill Engineering College exhibited a new photo-electric cell. This consists of a vessel of water containing a little acid, carbonate of calcium, and two tinfoil plates. When a beam of lime light was allowed to fall on one of the plates, a powerful current was set up in the cell, as seen by the deflection of a galvanometer connected in circuit with the plates. When a red glass screen intercepted the beam, the effect was very slight. Prof. Minchin had begun his experiments with fluorescence, but found "hard" water containing this salt of lime do equally well. The cell possesses this advantage: that the current it gives soon decreases in the light. When first the light falls on it, the exposed plate is positive, but it soon changes to negative. Prof. Minchin had tried the cell in place of a selenium one in the photophone, but with unsatisfactory results.

In

Anthropological Institute, November 9.-Edward B. Tylor, D.C.L., F.R.S., president, in the chair.-A paper was read on anthropological colour phenomena in Belgium and elsewhere, by J. Beddoe, M.D., F.R.S. Within the last few years the numerical method had been extensively applied to the determination of ethnological colour-types, the Anthropometric Committee of the British Association having set the example. The Continental nations were, however, now far ahead of us. Germany Prof. Virchow had procured the tabulation as to the colour of the eyes and hair of all the school population, with the exception of Hamburg. In Switzerland Dr. Guillaume, of Neuchâtel, had obtained school statistics. For Belgium an elaborate monograph had been written on the subject by Prof. Vander Kindere, who, by the aid of the National Geographical Society, had induced the Minister of Public Instruction to include questions on the colour of the children's eyes and hair in the educational census. The results obtained have been of considerable importance, and bring out a remarkable contrast between the Flemish and Walloon provinces of Belgium.-Mr. J. F. Rowbotham read a paper on different stages in the development of the art of music in prehistoric times. Musical instruments, though their varieties may be counted by hundreds, are yet readily reducible under three distinct types: 1. The drum type. 2. The pipe type. 3. The lyre type. And these three types are representative of three distinct stages of development through which prehistoric music has passed. Moreover, the stages occur in the order named. That is to say, the first stage in the development of instrumental music was the drum stage, in which drums, and drums alone, were used by man. The second stage was the pipe stage, in which pipes as well as drums were used. The third stage was the lyre stage, in which stringed instruments were added to the stock. The three stages answer respectively to rhythm, melody, and harmony. And as in the geological history of the globe the chalk is never found below the oolite, nor the oolite below the coal, so in the musical history of mankind is the lyre stage never found to precede the pipe stage, nor the pipe stage to precede the drum stage.-A paper was read on neolithic implements in Russia, by Prince Paul Poutiatine. From the evidence of certain finds on his estate the author came to the conclusion: 1. That the Sclave-Scythians existed there in the stone period. 2. That they possessed instruments resembling those of the Celt-Scythians, and burned their dead. 3. That the old iron period of that neighbourhood was a continuation of the stone period. 4. That they supported them. selves partly by hunting. 5. That they understood corn-growing.

Meteorological Society, November 17.-Mr. G. J. Symons, F.R.S., president, in the chair.-The following gentlemen were elected Fellows: G. Corden, E. T. Dowson, F. Hepburn, B.A., C. M. Hepworth, J. Mulvany, M.D., R.N., F. H. G. Newton, Capt. M. Parry, E. P. Phillips, and H. L. Roth.—The papers read were: Table of relative humidity, by Edward E. Dymond, F.M.S.-Rainfall in South Africa, by John G. Gamble, M.A., M. Inst. C. E., F.M.S. The author gives the monthly totals of rainfall from 103 stations for the thirteen months, December 1878 to December 1879, and also the monthly means from all stations in South Africa from which a record of five years or upwards could be obtained. It is shown that the Cape Peninsula, the South-West and the West Coast, have winter rains with a dry summer, characteristics of what is called the subtropical region, the rains coming with the north-west wind or anti-trade; while Natal, Aliwal north, and in a less degree Queenstown, have the tropical features of a wet summer and dry winter. On the South Coast the rainfall appears to be more equally distributed throughout the year, though there seems to be an October maximum at Port Elizabeth and Uitenhage. In the Central and. Northern Karroo the maximum of the very scanty rainfall occurs in February and March. These rains generally fall in thunderstorms; each storm seems to come from a westerly direction, but it is a more or less well-ascertained fact that these rains do not fall up country until the south-easters have set in on the South and South-West Coasts. In the southeast of the colony the transition towards tropical features may be noticed, both Grahamstown and King Williamstown showing a winter minimum in June.-On the meteorology of Mackay, Queensland, by Henry L. Roth.-Thermometrical observations on board ship, by Capt. W. F. Caborne, F.M.S.

VIENNA

Imperial Academy of Sciences, November 18.-Contribu butions to general nerve and muscle physiology, by Dr. Biedermann. On rhythmic contractions of striped muscles, produced by chemical stimulation, by the same.-On some platino-cyanide compounds, by Herr Scholz.-On resorcin colouring matters, by Drs. Wesselskyund and Benedikt-On the formation of carboxylnatron acid from Brenz, catechin, and the constitutional formula of benzol, by Prof. v. Barth.-Note on mononitropyrogallol, by the same.-The distribution of rainfall over Austria in the period August 11-15, 1880, and its relation to distribution of air-pressure, by Herr Hann.

too, American writers are dismissed without notice, save a passing allusion to F. A. Walker. Carey's theories are occasionally referred to in connection with other names, but no specific account is given of them, nor are other American authors, orthodox or heterodox, better treated. Even a general history ought not, one would think, to have omitted notice of such writers as Lord Lauderdale (whose treatment of Demand and of the Functions of Capital has not received the attention it deserves), R. Jones (whose essay on the Early English Economists might also have been noted in its proper place), Jacob, Stirling (the translator of Bastiat and author of an excellent but well-nigh forgotten work, "Philosophy of Commerce"), Bernhardi (the author of a remarkable treatise on Large and Small Landed Properties), Hübner, H. Thornton, Baumstark, Skarbek, Cieskowski, SaintChamans, Esmenard de Mazet, Louis Say, Schön, Canard, and Cazeaux. Dureau de la Malle's work might have been noted in connection with the political economy of the Romans, and De Tracy's name should not have passed without reference to his commentary on Montesquieu.

The translation appears to us generally excellent, and the translator, who is evidently well acquainted with the subject, deserves much credit for the clear and concise English into which she has rendered Prof. Cossa's work.

OUR BOOK SHELF

Avis préliminaire d'une nouvelle Classification de la Famille des Dytiscide. Par D. Sharp. (Extrait des Comptes rendus de la Société Entomologique de Belgique, Séance du 4 septembre, 1880.)

DR. SHARP is well known to have been long occupied on a work on the water-beetles of the world (at any rate on those of this particular family). The author announces it as ready for the press, and has forwarded to the Belgian Entomological Society a sketch of his ideas of the limits of the family and its classification, from which we learn that about 80 genera are recognised. One of the most important characters, as separating true Dytiscidæ from Carabidæ | and from all other Coleoptera, appears to consist of the condition of the metathoracic episternum in connection with the intermediate cotyloid cavities. The family as a whole is divided into two great divisions, termed "fragmentati", and "complicati,” the latter being headed by the anomalous genus Amphizoa, the position assigned to which will perhaps not find universal favour. No one can doubt that the book, when it appears, will mark an era in this department of entomology. It is a great pity therefore that Dr. Sharp should throw himself open to the shafts of ridicule in his choice of terms wherewith to designate some of his new genera. We need only allude here to such terms as Huxelhydrus (presumably a misprint for Huxleyhydrus), Darwinhydrus, and Tyndalhydrus !!! We all revere the honoured names that form the prefixes, and fail to realise the watery connection suggested; if we mistake not, the bearers of them are not disciples of Sir Wilfrid Lawson.

Aid to the Identification of Insects. Edited by Charle Owen Waterhouse. Lithographs by Edwin Wilson. Small 4to, Part I. (London: E. W. Janson, 35, Little Russell Street, W.C.)

MR. WATERHOUSE, whose duties in the zoological department of the British Museum have probably continually caused him to feel the want of some such work as that which he now commences under the above title, has conceived the idea of issuing, at intervals of a month or six weeks, a series of hand-coloured drawings of insects of all orders not previously figured. Every working naturalist knows that a good pictorial representation con

veys a more accurate and ready perception of a species than the most elaborate verbal description; and we can knowledge of the arcana of science than this. Each part imagine no more ready way of widely disseminating a is to contain eight or nine plates, each representing a single species, with its generic and specific names, the name of its describer, and a reference to its locality and place of description. The plates can be classified on the completion of a volume (twelve parts), when a title-page and index will be issued.

The first part, just issued, contains some well-executed figures of Coleoptera, Hemiptera, and Lepidoptera. The whole idea is unconsciously a repetition of Prof. McCoy's "Prodromus of the Zoology of Victoria," but with no Government money to back it up.

LETTERS TO THE EDITOR

The Editor does not hold himself responsible for opinions expressed

by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts. No notice is taken of anonymous communications.]

The Editor urgently requests correspondents to keep their letters as short as possible. The pressure on his space is so great that it is impossible otherwise to ensure the appearance even of communications containing interesting and novel facts.]

Geological Climates

I HAVE read with much interest Mr. Starkie Gardner's letter in NATURE, vol. xxiii. p. 53.

It is not necessary for me to discuss the question whether I am right in requiring an increase of 20° F. mean annual temperature at Bournemouth in Eocene times, or whether he is right in demanding an increase of only 14° F. to 15°, for I am able to show that the one increase is as impossible as the other, on the principles held by Lyell and his followers.

Mr. Starkie Gardner's ideas on the subject of oceanic circulation and its effects upon climate are expressed in the following words:

"The general cooling effect of incessant oceanic circulation between the North Pole and the Tropics is, I think, scarcely taken into sufficient account; and although it may be contended that conversely the northerly flow of the Gulf Stream mitigates climate, I think that its action in Europe is chiefly in fending off the ice-laden currents from our coasts," &c., &c.

This statement, to my mind, involves so complete a misapprehension not only of the physical causes of oceanic circulation, but also of the whole problem of geological climate, that I shall ask your permission to lay down a few elementary propositions on the subject, which are capable of demonstration.

1. The Gulf Stream of the North Atlantic, so far from

acting the part of a policeman in "fending off" imaginary cold water streams from the Polar regions, is the cause of their existence. If there were no Gulf Stream there could be no Labrador current of cold water running south. The same statement is true of the Kuro-Siwo of the North Pacific, of the Brazilian current of the South Atlantic, and of the Mozambique curren of the Indian Ocean.

2. If the globe were covered with water, or in the condition of an archipelago pretty uniformly distributed, there would be no exchange of currents between the Tropics and the Poles, and consequently no effect upon climate. Within the Tropics there would be a broad, slow current of warm water moving from east to west, and producing no effect upon climate. In the temperate zones there would be in the northern hemisphere a feeble interchange of south-westerly and north-easterly currents, and in the southern hemisphere a similar interchange of northwesterly and south-easterly currents, both incapable of affecting climate to any sensible degree.

3. If a north and south barrier be constructed to the westward of a locality like the West of Europe; such a barrier as North and South America affords, a gulf stream is, at once, formed, and a corresponding Labrador current running in the opposite direction. The effect of the Gulf Stream is to raise the temperature of the West of Europe to its maximum, and the effect of the Labrador current is to depress the temperature of the east coast of North America to its minimum.

4. It is impossible to suggest any rearrangement of land and water which shall sensibly raise the temperature of the West of The earth's rotation compels the Gulf Stream to impinge on the west coast of Europe, and the Polar current on the east coast of North America.