was just about to hop into it when it caught sight of the caterpillar, and stood jerking its head from side to side, but did not venture to enter. Another bird soon came, and behaved in a precisely similar manner; then a third, and a four h; others settled on the perch over the trough, and a flock of ten or twelve were finally perched around. They all stretched their heads and looked into the trough, but none flew into it."

On removing the caterpillar the birds again assembled, and at once entered the trough to feed. Fowls were also frightened at first, and would draw back just as they were going to peck at the caterpillar. At last, after several had tried, and even made ineffectual attempts to peck, one more courageous than the rest would actually touch it, and after a time, finding nothing disagreeable, the insect would be swallowed. In the genus Deilephila, however, there are uneatable caterpillars, and these have strongly contrasted black and white or yellow spots combined with the habit of fully exposing themselves upon their food plants. Dr. Weismann experimented with two species (D. galii and D. euphorbia) and found that they were refused by birds, though the latter was eaten by lizards. It is to be noted however that the experiments were made with a South European species of lizard, not that of Germany, so that the result has not a direct bearing on the point.

The general conclusion at which Dr. Weismann arrives is, that all the varieties of colour and marking occurring in the Sphingidæ have a distinct biological value, and can in every case be traced to the action of natural selection and correlation of growth.

ment.

The next essay is not quite so interesting or important. It is an endeavour to prove, by a distinct line of inquiry, that the markings of the larvæ are not due to a "phyletic vital force" or to general laws of growth and developThe different groups of Sphingidæ are minutely examined and compared in their three stages of larva, pupa, and imago, and it is shown that the changes that occur from species to species in each stage are to a great extent independent of the changes in the other stages. Numerous examples of this want of phyletic parallelism are given, and it is hence argued that the modifications which occur must be due to an adaptation to the special conditions to which the insect is exposed in one or other of its states, not to any innate law of variation and development, which, it is argued, would affect all the stages pari passu and produce a "phyletic parallelism" which does not actually exist. The same general facts are shown to prevail, not only among Lepidoptera generally, but among all insects and crustacea-or generally among all organisms which undergo a metamorphosis.

This instalment of the work has been admirably translated and edited by Mr. Meldola, who, in a series of valuable notes and an Appendix, has brought up the information on every branch of the inquiry to the latest date. The six coloured plates of larvæ in their several stages are very well executed, and serve to illustrate the somewhat complex discussion in a clear and effective ALFRED R. WALLACE

manner.

OUR BOOK SHELF

The Wandering Jew. By Moncure Daniel Conway. (London: Chatto and Windus, 1881.)

THIS last volume of Mr. Conway's is a study, not only of the legend of the Wandering Jew, but with it of the large

group of analogous myths of undying men who from age to age wander over the earth, or sleep in caverns, or are translated from among men into divine regions, whene however they come back and show themselves still living men. The interest of these stories in the history philosophy lies in their keeping up men's early ideas of life and death. One of Mr. Conway's purposes in dis cussing them is to draw attention to their being relics of the primitive period when men were still so far from definitely realising the nature of death, that they had to having only departed for a while from among them, difficulty in regarding kings, heroes, and prophets : return in a future age to rule and protect their expect nations. In comparative mythology this group of stor has some importance. They show the beliefs of vari races running curiously into one another, as where the Lancashire peasant still hears in the cry of the plover wail of the Wandering Jew, or in the Harz Mountains his myth has got mixed with that of a grander wandere the Wild Huntsman, who courses with his storm-cl across the sky. The storm-demon whom mythic imagines rushing through the air is often called a cabee, and Mr. Conway points out why he has this pane It is because of a verse in the Second Book of Mar personal forms taken by the fancy of an excited peo bees, chap. v., which, by the way, is a good instance "And then it happened, that through all the city, for space almost of forty days, there were seen horsene running in the air, in cloth of gold, and armed with ans like a band of soldiers." Unfortunately some other er mologies made or quoted by Mr. Conway are not reasonable as this. When the names of biblical pers ages, Herod and Ahasuerus, find their way into Europe myths, it may not be easy to explain how they gett but at any rate it is better to leave them alone tha make up imaginary and even impossible German their presence. It would be easy to take exceptions : Scandinavian forms, Haar-Rote, As-Vidar, to account many of the arguments in this volume, but at any ra there are many interesting points in it.

scatter

A Short Sketch of the Geology of Yorkshire. By Chane Bird, B.A. (Univ. Lond.) (London: Simpkin, Marsh and Co.; Bradford: Thomas Brear, 1881; pp. and Map.) Geological Map of Yorkshire. By the same (Edinburgh and London: W. and A. K. Johns.. Bradford T. Brear, 1881.) IN the preface of this book, written by way of dedicat it is represented to be a "small and cheap volume su to the general reader' and tourist." It is impossible say that it is not a useful and interesting one. So ood work has been done on the county, though through very various publications, that a short cannot fail to be of value; but there are books and ba and if we measure this by what it might have been poor indeed. It resembles, in fact, geologically spea a kind of boulder clay, full of fragments of solid r brought from a distance-we will not say to be depos in mud-but certainly scratched and rubbed in the In the beginning of the volume is a list of surrounding mountains whence the boulders have be derived, but it is not a complete one; and the sourt. each fragment is not indicated in the body of the Its great defect is that it is unstratified; in other wor the extracts are not duly digested, but thrown together out sorting, and with very little alteration; so little ins that it would not be difficult to trace them to their so Thus under the head of "The Carboniferous Period have a brief explanation, from a popular lecture, from the general mineral character of a rock the circ stances under which it was formed can often be predicate Then under the head of "Salt water deposits' we have twelve pages on the origin and contents of the Victor

cess.

ave, which ought surely to belong to the chapter on the Recent Geological History of Yorkshire," only that the tter happened to be written by one who confined himelf to the Holderness drift. Under the head of "The ermian Rocks" there is an exposition of the views of hose who would reintroduce the old (not recently sugested) name Poikilitic to include the Trias. It was a ity the author was not acquainted with any recent papers n the series above the Lias, for there are no good boulders a this part of the book. Mr. Hudleston's admirable apers on the Yorkshire Oolites seem to have been written n vain, and there have been modern papers also on the Yorkshire Chalk. It was perhaps excusable for our uthor to conclude that the third edition of Prof. Phillips'

"Yorkshire Coast" contained all the most recent information, though every East-Yorkshire geologist knew that t did not. In examining a work on local geology it s always well to see where the author lived, for the surrounding country will be the best described. So it is here; the best part of the book is the description of the Middle and Upper Coal-measures, which are well deveoped in the neighbourhood of Bradford. For East Yorkshire and the coast the book is of little value.

The topography of the map requires no other guarantee than the name of the constructors for its excellency. The south-western part of the geological colouring derived From the Geological Survey maps is also very good. Nor can we complain when lack of published material prevents accuracy elsewhere, though it is a reason for regretting the slow publication of the Geological Survey maps which have been long ago completed; but when the whole of the Vale of Pickering is coloured Neocomian, and a patch of the same is placed in the south near Cave, scarcely an acre of rocks of that age being discoverable in the former, and none in the latter locality, one is led still more to regret that the author's map should be spoiled by his not knowing Mr. Hudleston's papers and relying on Prof. Phillips. But he has surely introduced a little mistake of his own, which will be very serious to visitors to the popular watering-places of Scarborough and Filey. The Castle Rock and Filey Brig are coloured -one Lower Oolite and the other Neocomian, whereas they are both what the author would call "Middle Colite"! It will take more than Mr. Bird to write a good "Geology of Yorkshire."

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.] Leaves Injured at Night by Free Radiation FRITZ MÜLLER, in a letter to me from Sta. Catharina in Brazil, dated August 9, supports the view which I have advanced with respect to leaves lacing themselves in a vertical position at night, during their so-called sleep, in order to escape being chilled and injured by radiation into the open sky. He says: "We have had last week some rather cold nights (2° to 3° C. at sunrise), and the e have given me a new confirmation of your view on the meaning of the nyctitropic movements of plants. Near my house there are some Pandanus trees, about a dozen years old; the youngest terminal leaves stand upright, whereas the older ones are bent down so as to expose their upper surfaces to the sky. These young leaves, though of course the most tender, are still as fresh and green as before; on the contrary, the older ones have suffered from the cold, and have become quite yellowish. Again, the leaves of Oxalis sepium were observed

THE account in NATURF, vol. xxiv. p. 431, of a pink rainbow cer from Mr. Tennyson's house, recalls to me a rainbow which Ive sed in July 1877 over the Lake of Lucerne from the prende in front of the Schweitzerhof. The low in question a peared at sunset, when the whole sky, east and west, was lit up with ruddy tints; and just before it faded cut, the bow itself, which was a very brilliant one, showed only red and orange colours in place of its usual array of hues. No fewer than five supernumerary arcs were visible at the inner edge of the primary bow, and these showed red only. I fancy that the phenomenon cannot be very rate, from the circumstance that in pictures of the rainbow red and yellow are frequently the only colours set down by the artist. A few months ago Mr. C. Brocke Branwhite of Clifton showed me a very beautiful sketch in oils by his father, the late Mr. Charles Branwhite, a colourist of no mean power, in which a beautiful and exquisitely pellucid rainbow was drawn with red and yellow tints only. It may also be mentioned that in the copy of Rafael's "Madonna di Foligno" in the Dresden Gallery, there is a semi-circular red and yellow rainbow. I have not seen the original Foligno Madonna in Rome; and should be interested to know whether in this also red and yellow are the only tints accorded by the colourist. Haslemere House, Clifton SILVANUS P. THOMPSON

ALTHOUGH I am not an "eminent" authority, perhaps you will excuse my troubling you with the following extract from a paper read by me before the Philosophical Society of Glasgow in November, 1875, a copy of which paper I posted to the Editor of NATURE:-"I have long been of opinion that the most probable hypothesis of the crigin of atoms is that there is only one kind of matter-ether or its constituents-and that atoms are merely congeries of units of ether circling at enormous speeds round each other, differently grouped, in different numbers, at different velocities, and at different distances, even as the different members of our sun systems. . . The numbers of units in each similar atom need not be always the same; a few dozens more or less will not be appreciable by us. On the other hand, if a so-called element show a plurality of spectroscopic lines or hues, I do not think it at all doubtful that there is a plurality of units moving to produce these, since they thus show effects of different modes of moving of bodies; all our different states of sensual consciousness of colours are necessarily dependent on differences in the modes of moving of the agents that excite in us such plurality of lines and hues. As the motions of atom, or rather of groups of atoms, excite in us sensations of sound, so the motions of unit-, or rather of course the lower-pitched movements of dark heat. Then of groups of units, excite in us sensations of colour, and again, we may hold that the more lines that persist in a spark or a sun, the less easily reducible are the portions of the elements showing them, as far as these lines' constitue. ts are concerned the lines being still undissociated material." (Proc. Phil. Soc. of Glas., vol. x. p. 61.)

Cambuslang, August 26

HENRY MUIRHEAD

Luminous Phenomena on Rupture of Sea-Ice IN my diary for January 20, 1881, occurs the following but am certain it was not caused by any reflection of the lights passage. I make no attempt to account for the phenomenon, on board the vessel :

"Started from Christiania at about 2 a.m. in the Nyland steamer bound for Christiansand. At Krujero the steamer forced its way through the ice for half an hour till within about a mile of the land, where sleighs met it on the ice. The passengers and cargo were discharged or taken up on the ice, out of which we backed in close proximity to the Kong Hacon, which steamer had followed us in. A beautiful sunset and Arctic winter view, clear air, and rich sky, also a distant ship fast in the ice. The Nyland stopped at Arendal for the night, having got to the quay through much ice. We observe often phosphorescence or phosphorescence-like sparks and flashes in the ice as it is broken up by the steamer."

I think that the average thickness of the ice might have been about eight inches. I cannot give the temperature, but on the previous day at Christiania the thermometer indicated about 8° or 10° below zero Fahrenheit (about 40° Fahrenheit of frost). The diary from which the above extract is taken was kejt jointly by myself and my travelling-companion, Mr. Winter, of the Indian Civil Service, who of course also saw the flashes referred to. I should like to have been able to talk the matter over again with him, but he is now in India. J. ALLEN ALLEN

[The question raised in this letter is a very interesting one. The phenomenon is possibly analogous to the electric flashes which are produced when loaf-sugar is crushed or when mica is rapidly split. It appears very improbable that it can be due to phosphorescent creatures in the water under the ice.-ED.]

Tidal Currents versus Wind Waves

IN NATURE, vol. xxiv. p. 286, a writer on "sea-shore alluvion" positively asserts that the travelling of sea beaches is due to wind-waves, and not to tidal currents, and calls a writer in the Engineer to task for having stated the latter. Notwithstanding this assertion, I would suggest that the writer in the Engineer is right. Twenty-five years ago, when an engineering student, I was taught that sea-beach travelling was due to wind-waves. Afterwards, while 1nocking about during fifteen years in the vicinity of the south and west coasts of Ireland, I noted facts that went to show that such a theory was not universally correct. This led me to study wind-action on the sea and lakes, also all I could find that had been written on the subject; the result being that as good evidence was so contradictory, no opinion could be come to from the evidence of others. But it was not till about ten years ago, when I was so circumstanced that I could properly study wave-action, and after six years' careful observation on the south-east coast of reland, that I found that tidal currents were the principal motive power; and on again reading what had been written on the subject, that I found that nearly all the advocates for the driftage of sea beaches by wind-waves had studied on beaches where the most continuous and powerful winds acted in conjunc'ion with the flow-tide current. As the results of my observations have been published in the Proceedings of the Royal Irish Academy, English and Irish Institutions of Civil Engineers, the Geological Societies of London, Dublin, &c., during the last six or eight years, it is unnecessary to repeat them here. I would, however, point cut that when there are only wind-waves and no tidal currents, the beaches as a general rule are banked up, but do not travel (the writer in NATURE seems to have observed this, but does not appear to see the importance of it). This may be seen in the tideless Mediterranean, as pointed out by the late Dr. Ansted in his paper on the Lagoons at the Delta of the Rhone; it may also be seen in Malcombe, or any other bay where there is a "head of the tide" but no tidal current; and in the different freshwater lakes, when the wind-waves are the only motive power. But wherever there are tidal currents acting on a coast the beach must travel. Such tidal currents are those that most perplex the erectors of groynes. If there was only the travelling augmented by wind-waves, the erection of groynes would be very simple; but, as a general rule, they are most necessary where there are strong tidal currents (or conflicting currents) due to the regular "flow" tide, "half counter" tides, or "on-shore" tides; which conflicting currents, combined with the action of wind-waves, let them be direct or as "ground swells," make up all the “cutting-out tides.” The greater the complications the greater the "cutting out," and the more ingenious have to be the groynes. "Fulls" accumulate with the wind-waves, but rapidly disappear when the wind ceases. I presume the writer of the article in question is aware that the greatest rise of tide and the least current is at the "heads of

the tides," while the least rise and greatest current is at the "nodal or hinge lines"; and I would be interested to k where permanent beaches accumulate in the latter localities a from what I have seen those that form rapidly disappear whe the wind ceases. G. H. KINAHAN H.M. Geological Survey

Glaciation

IN NATURE, vol. xxiv. p. 364, I see a notice of a paper Dr. Woeikoff on the glacial climate, in which it is shown t "the difference of man temperature at the lower ends of glac (in different parts of the world) reaches fully 20." This be expected. The extent of glaciation depends not at al mean or on winter temperature, but chiefly on summer tem rature. Perpetual snow means summer snow, so that star temperature is what determines the extent of the snow tal remaining unmelted in the summer, and consequently of glaciers which are fed by the snow-fields. The extent of g tion is also much influenced by the amount of snow-fall. A this is stated in Forbes's "Norway and its Glaciers." JOSEPH JOHN MURPHY

Old Forge, Dunmurry, Co. Antrim

Yellow Glass in Fog

SOME years ago I was staying at an hotel on the Lake Constance. One morning a fog came on which com obscured the opposite shore, but looking through a s yellow glass, which formed the border of the window, 1 =. able, to my surprise, to see it distinctly. I presume the ye glass choked the blue rays reflected by the fog, just as a N prism, held at the proper angle, chokes the rays reflected the glass and enables us to see clearly the picture lehind a. f) my way home I stopped in Paris, and, happening to call on t of the principal opticians, mentioned the circumstance to He forthwith showed me a naval telescope provided with 15 at the eye end containing a yellow glass, which could be re at pleasure, I should like to know if the same simple trivance has ever been used in our own navy.

The New Museum of Natural History IN your article on "The New Museum of Natural His (NATURE, vol. xxiii. p. 549 et seq.) it is stated that the men of Archeopteryx macrura in the British Museum is he Will you permit me to draw attention to a nodule projecting t the slab in which the fossil lies, which bears a striking rese blance to the cerebral portion of a bird's skull? It is one since I visited the museum, but I recollect feeling satisfied a “ time that the nodule was the missing head, and worth disinterring from its surrounding slate. E. H. PRINC

Calicut, July 31

[The nodule referred to by our correspondent is well k and has been frequently criticised. Mr. John Evans, DC.L F.R.S., drew attention to it in an article published by the Natural History Review, 1865, PP. 415-421: “0 tions of a cranium and of a jaw in the slab contain fossil remains of the Archeopteryx." Although these f which occur in the slab in question undoubtedly belong to d pteryx, yet, as stated in our article, vol. xxiii. p. 551, original specimen described by Prof. Owen is headless," w the newly-discovered Berlin specimen has the head entire trunk.-ED.] fairly well preserved, and still attached by the neck t

On the Velocity of Light

IN view of the experiments of Young and Forbes velocity of light, and of the article published by Lord Ray on the subject, it may not be out of place to state 25 19 which seemed at the time too evident to require special pe in my paper "On the Velocity of Light," that if the velared and of blue light in air differed by as much as one-te I per cent., the image of the slit which served as the sou light, instead of being white, would be spread out into 25 trum which could not fail to be observed. The total dis ment in these experiments amounted to 133 millimetres; fore, a difference of velocity of the red and the blue rays of per cent. would necessitate a spectrum 2.4 millimetres in les

It is needless to say that no spectrum was observed. These facts appear to be utterly irreconcilable with the conclusion drawn by Messrs. Young and Forbes. ALBERT A. MICHELSON

Schluchsee, Prussia, August 28

Salmon in Preserved Rivers

HAVING resided for some time lately near one of our salmon rivers which is at present preserved by a club, I have at different times had conversations with men who knew it before its socalled preservation. They all say that when they were allowed to fish when and how they pleased, the supply of fish was much better in regard both to size and quantity. They account for it in the following manner :-Firstly, when the river was free, the people living near used to make spawning-beds for the fish, by placing large stones across the river and throwing gravel where deficient, and where gravel was naturally they used to loosen it with forks and remove the large stones. Secondly, they used to watch the fish at spawn n tim, and catch and kill all very large fish, say about 1 to 301 s. wegh, after they had partially or wholly finished spawng, as they say the large fish destroy the salmon fry. Neither this nor the formation of spawning-beds is done at present. Would the above reasons account for the diminution in the size ad number of salmon caught in our rivers? The diminution, in the river I speak of, cannot be accounted for by pollution, as the number of hou es near enough to send their drainage into the river is too small to affect it, and as the river has a very quick fall and rocky bed, it is subject to such very rapid rises and falls in quantity of water that would prevent any settlement of noxious sediment. F. C. S.

New Seismometer

IN NATURE, vol. xxiv. p. 113, there is a notice of a new seis mometer which has several advantages claimed for it. Might I suggest what seems an obvious and important improvement? As a rule pendulums cannot record vertical or oblique motions, and yet these are often the most necessary and valuable to record. I. To do this, and yet as easily allow of lateral regi-tration, I would say, support a heavy (leaden) ball of some 100 lbs. by a 30 or 40 feet spiral or rubber spring of suitable strength. It will be found that a very considerable amount of vertical play can take place, especially vertical effort, ere the ball can be affected, and that lateral play of the support will produce very little effect indeed, unless, as is most unlikely, the motion is prolonged and is continuous in one direction. 2. Around the sphere, and at a very short distance from its surface, radial rods actuated like the key-plugs of a cornet are supported, say at every 30° all over the surface, contact with any one of which will electrically record time, and the pencil attached to the plunger record distance of stroke on revolving paper attached to plunger-tube. Asam, July 6

S. E. PEAL

THE BRITISH ASSOCIATION ΤΗ HE actual number of persons who attended the York Meeting of the British Association, as announced at the last meeting of the General Committee, was 2556; divided between 272 old life-members, 27 new life-members, 312 old annual members, 175 new annual members, 1232 associates, 514 ladies, and 24 foreigners. The seven previous occasions on which this number has been exceeded were:-Newcastle-on-Tyne, 1863 (3335); Manchester, 1861 (3138); Liverpool, 1870 (2878); Bath, 1864 (2802); Glasgow, 1876 (2774); Dublin, 1878 (2578); Aberdeen, 1859 (2564). The number fell below 1000 at Cambridge, Plymouth, Southampton, Ipswich, Hull, and Swansea. 1280l. were paid out by the Council for scientific purposes after the last meeting, a larger sum than on any occasion since 1873; while between 1873 and 1861 that sum was always exceeded, and at Norwich, in 1868, it amounted to 1940/.

The following foreigners were present at the meeting:-Professrs Barker of Pennsylvania; Bergeron, Paris; Bojanowski; Carbonnelle, Brussels; Chemin, Paris; Craig, Johns Hopkins University, U.S.; Dohrn, Naples; Eads, St. Louis, U.S.; Gariel, Paris; Dr. Asa

Gray, Harvard University; Halphen, Paris; Dr. Edwin Hall, Baltimore, U.S.; Hubrecht, Leyden; Prof. W. W. Johnson, Annapolis, U.S.; Prof. O. C. Marsh, Yale College; Moser, Berlin; Prof. H. A. Rowland, Baltimore; Stephanos, Paris; Sturm, Münster, Westphalia; Prof. H. M. Whitney, Beloit College, Wisconsin, U.S.A.

We ought to have stated in our report of the doings of the Association in our last number, that Prof. Huxley's lecture on Palæontology, which we gave in the same number, was delivered on the evening of Friday the 9th.

Nearly 350 papers or reports were read before the several sections. Of these the Physical and Mathematical Section received 89; the Chemical Section 49; Geology 59; Biology 79; Geography 16; Economic Science and Statistics 26; and Mechanical Science 29. Of the papers in Section A 23 related to Electricity; 21 were Mathematical; Optics claimed 12; Micteorology 11; Astronomy and Physical Geography 12; Heat 5; and subjects of interest were electric lighting, electric meamiscellaneous physical subjects 5. Of course prominent surements, and Faure's cells. Such subjects were tho roughly ventilated by discussions both in Section and Committee, and more intimately during the thousand and one opportunities for interchange of ideas which occurred in the afternoon and evening. Again, the storage of energy, the nature of meteoric dust, the existence of intra-Mercurial planets, the lunar disturbance of gravity, the nature of colours, and the contact theory were each severally discussed. Among the 49 Chemical papers several theoretical matters were introducedspecially the atomic theory, chemical nomenclature, vapour densities, molecular weights, Mendeleeff's law, and molecular attraction; processes of analysis and technical operations were described, and new experiments were explained. Of course a good deal of the geological work bore reference to Yorkshire, especially to the evidences of glacial action which it presents. The geological papers were of a very general and interesting character, and embraced every branch of the subject, from the vulcanology of Japan to the minerals found at Laurium, and from the Cheshire salt beds to the evolution of the Plesiosaurus. Section D furnished a larger number of papers than any other Section except A, but we must bear in mind that it really consists of three sub-sections, devoted respectively to Zoology and Botany, Anatomy and Physiology, and to Anthropology. The latter subject has developed extraordinarily, more than half the papers contributed to the Section were read before this Sub-Section. The report of the Anthropometric Committee, which evoked a good deal of discussion, was read in the Section of Economic Science and Statistics. In this section Mr. Grant Duff delivered a very able address, which was warmly received. A tendency to introduce matter which has a political bearing and which may be discussed from a political standpoint is sometimes apparent in this section, and should be carefully guarded against by the Committee. The Mechanical Section furnished some important reports on patent laws, wind pressure, tides in the English Channel, and the steering of screw steamers. Here also were papers on the different forms of electric lamp, the electrical transmission of force, and the illumination of lighthouses.

Thus it will be seen that all the prominent subjects of science have received their share of attention, and at the hands of one or other of the sections have been either expanded or discussed. The interchange of ideas has been incessantly going on, and many men have become acquainted who might otherwise have remained unknown to each other for years. Some 500 scientific men have been gathered together from various parts of the British Islands; and some 2000 persons have been brought face to face with the burning scientific questions of the day, and have had new interests awakened, or old knowledge resuscitated. There can be little doubt as to the

expediency of continuing the work of the Association, if it keep at all near to the standard of the York meeting. The German Society, founded nine years before our Association, and its prototype, still continues to meet annually; and scientific congresses are becoming more and more general every year in Europe.

Canada has been proposed as the place of meeting for 1885. The difficulties of time and place and expense are far less formidable than they appear at the outset. Great facilities would be put in our way by steamboat companies; and, once arrived, the Colony would receive us with open arms. Again, the Americans wish us to join their Association on some convenient occasion, and apropos of this a practical American observed a few days since, "From the moment you set foot on American soil to the moment of departure, you should not put down a cent." One other fact remains to be noticed in regard to the York meeting. Thirty-four local societies and institutions were represented at the meeting by forty-nine delegates ; and the Council have under consideration the conditions under which these delegates were present, and their object in attending. Cannot the Association do something for them? Cannot some organisation be introduced to influence the local societies through the Association, and cannot a committee of delegates be appointed to discuss matters connected with their respective institutions?

REPORTS

Report of the Committee, consisting of Dr. J. H. Gladstone' Dr. W. R. E. Hodgkinson, Mr. W. Carleton Williams, and Dr. P. P. Bedson (secretary), appointed for the purpose of inves tigating the Method of Determining the Specific Refraction of Solids from their Solutions.-Mr. P. P. Bedson, D.Sc., read the Report, and stated that the object of this report was to submit to further examination the method proposed some years ago by Messrs. Gladstone and Dale. According to this method the specific refraction of a solid may be deduced from that of a solution containing it, provided the specific refraction of the solvent is known, as also that of the solution and the composition of the solution. The experiments, of which an account is given in the report, appear to confirm this statement of the abovementioned authors. The first case examined was that of liquid phenol. Its specific refraction for a ray of light of infinite wavelength was determined at 40° and 45°. The values obtained for the specific refraction of liquid phenol at 40° and 45°, viz., 4850 and 4848, are closely approximate to that obtained by Brühl (Fourn. Chem. Soc., abst., 1880, p. 782) for phenol at 20°, viz., 4862. Further, these results agree very well with the mean of the specific refractions obtained from the alcoholic and acetic acids solutions. The specific refraction of rock-salt in the solid state has also been determined and compared, with its specific refraction as deduced from its aqueous solutions; and it was found that the specific refraction obtained from the aqueous solution is substantially the same as that obtained from a prism of rock-salt. Further, the specific refractions of fused borax and boric acid have been determined, and in these cases also the specific refraction obtained from their aqueous solutions was found to be approximately the same as the specific refractions of fused borax and boric acid. The indices of fused borax and of fused boric acid were determined by means of prisms of these materials, which were cast in a mould of silver plates and afterwards ground and polished.

Report of Committee on Meteoric Dust, by Prof. Schuster.This Committee was appointed for the double purpose of examining the observations hitherto recorded on the subject of meteoric dust and of discussing the possibility of future more systematic investigations. With regard to the first point we note at in a paper presented to the Royal Astronomical Society in 1879, Mr. Ranyard has given what appears to be a pretty com. plete account of the known observations as to the presence of meteoric dust in the atmosphere. It appears that in the year 1852 Prof. Andrews found native iron in the basalt of the Giant's Causeway. Nordenskjöld found particles of iron which in all probability had a cosmic origin in the snows of Finland and in the ice fiel of the Arctic regions. Dr. T. L. Phipson, and more recently Tissandier, found similar particles deposited by

the winds on plates exposed in different localities. Finally, Mr. John Murray discovered magnetic particles raised from deposits at the bottom of the sea by H.M.S. Challenger. These particles were examined by Prof. Alexander Herschel, who agreed with Mr. Murray in ascribing a cosmic origin to them. For fuller details and all references we must refer to Mr. Ranyard's paper. There cannot be any doubt that magnetic dust, which in all probability derives its origin from meteors, has often been ob served, and the question arises, in what way we can increase our knowledge on these points to an appreciable extent. A further series of occasional observations would in all probability lead to no result of great value, unless they were carried on for a great length of time in suitable places. Meteoric dust, we know, does fall, and observations ought if possible to be directed rather towards an approximate estimate of the quantity whist falls within a given time. Difficulties very likely will be found in the determination of the locality in which the observation should be conducted. The place ought to be sheltered as mad as possible against any ordinary dust not of meteoric origin. The lonely spots best fitted for these observations are generally accessible to occasional experiments only, and do not lend the selves easily to a regular series of observations. Nevertheles experiments continued for a few months at some elevated spet the Alps might lead to valuable results. The Committee woald like to draw attention to an instrument which is well fitted fr such observations. It was devised by Dr. Pierre Miquel for the purpose of examining, not the meteoric particles, but organic and organised matters floating about in the air. A description, wh illustrations, will be found in the Annuaire de Montsouris for 189 Two forms of the instrument are given. In the first form, which is only adapted to permanent places of observations, an aspiraz draws a quantity of air through a fine hole. The air impinge on a plate coated with glycerine, which retains all solid mate By means of this instrument we may determine the quantity solid particles within a given volume of air. The second, portable, form does not allow such an accurate quantitative analysis. The instrument is attached to a weathercock, and th is always directed against the wind, which traverses it, and d posits, as in the other permanent form, its solid matter glycerine plate. An anemometer placed in the vicinity serves t give an approximate idea of the quantity of air which has pas through the apparatus. These instruments have been calle aeroscopes by their inventor. It is likely that the second f given to the apparatus will be best fitted for the purpose wh

the Committee has in view.

Seventh Report of the Committee on Underground Water Saf ply, consisting of Prof. E. Hull, the Rev. H. W. Crosskey, Car Douglas Galton, C.B., Mr. James Glaisher, F.R.S., Pr Pengelly, Prof. J. Prestwich, Mr. James Plant, Mr. You A. Lebour, Mr. W. Molyneux, Mr. G. H. Morton, Mr. W. Parker, Mr. T. Roberts, Mr. S. Stooke, Mr. G. 7. Sy Mr. IV. Whitaker, was read by Mr. C. E. de Rance, of II.M. Geological Survey, the Secretary.-The Committee was Prof. Hull, LL.D., F.R.S., as Chairman, and Mr. De Rance pointed in 1874 at the Belfast Meeting of the Association, wi F.G.S., as Secretary and Reporter; its six published re investigations of the Committee show that the Permian, Tras occupy 125 pages of the Society's Proceedings, and the results of and Jurassic formations of England and Wales are capable d absorbing from five to ten inches of annual rainfall, giving daily average yield of from 200,000 to 400,000 gallons p square mile per day. The area occupied by these formati is, in round numbers, Permian and Trias, 8600 square mi and Oolites, 6600 square miles, capable of yielding 1720 lions and 1320 million gallons respectively, at the lowest rate: absorption, or, united, a supply for 100 million people, at thi gallons a head. Mr. De Rance then described the water-bearing condition of the Yorkshire area, and stated that the investigat would now be extended to all the porous rocks of South Brian Report on the Earthquakes of Japan, by Prof. John MilneThe author arrives at the following conclusos:-I. That the actual back and forth motion of the groun!) a few millimetres (usually not equal to I.), even thoug chimneys have fallen. gently, but is very irregular. 3. The number of vibrations per 2. The motio. usually commences second usually vary between three and six. 4. During shock its direction of motion may be irregular. 5. East and west vibrations, as recorded in Yedo, have in some cases been shown by time observations to have travelled up from the south. 6. Many of the shocks which visit Yedo appear to have come

eldom more tha