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THE Paris correspondent of the Times reports that earthquake shocks were experienced at about 2 a.m. on April 29 over the whole of the Jura, the Rhone valley between Lyons and Valence, and the eastern portion of the Central Massive. All the shocks appear to have occurred simultaneously, and were accompanied by sudden and violent squalls, as well as by rumblings like distant thunder. An earthquake shock, lasting eight seconds, was recorded also at Chamonix. Subsequently the shocks recurred, though in a mitigated degree. At this place a new spring suddenly gushed from the ground as the result of the seismic disturbance, and the waters of the river Arve were swollen in consequence. The shock was felt at 2.45 a.m. at Turin and Domodossola. The seismographs at the observatories of Pavia, Padua, Ferrara, Modena, Ischia, and other towns also recorded disturbances. At Heidelberg Observatory the seismograph registered a decided earthquake of short duration at 2.49 a.m.

ATTENTION was recently directed in these notes (vol. lxxi. p. 492) to a statement made in the Times that the Tower of Galileo on the hill of Arcetri, near Florence, has been practically destroyed in the course of recent building operations. Prof. A. Ricco, having been led by our note to make a special inquiry at Florence, now writes to point out that the so-called Torre del Gallo cannot in any way be considered as associated with the name of Galileo.

Such an association was first suggested comparatively recently and purely gratuitously by the late proprietor of the tower, but no evidence in support of it can be traced either in the numerous letters or writings of Galileo. This was clearly pointed out by Gebler in 1878 in an article in the Deutsche Rundschau, and the most recent examination of Galileo's writings made on the occasion of the publication of the "national edition" of his works has given support to the same opinion. It may perhaps be surmised that a confusion of names has occurred, Torre del Gallo, literally the Cock's Tower, being wrongly regarded as a corruption of Torre di Galileo.

IN one of his recent articles on Stonehenge (vol. lxxi. p. 391, February 23) Sir Norman Lockyer referred to the interesting fact, pointed out to him by Colonel Johnston, director of the Ordnance Survey, that the solstitial line in 1680 B.C. passes through not only the present centre of Stonehenge, but also through Sidbury Hill to the northeast, and the earthworks at Grovely Castle and Castle

Ditches to the south-west. This continuation of the solstitial line from Stonehenge to other ancient structures is of great interest; but an even more remarkable relation found by Colonel Johnston is that Stonehenge, Old Sarum, and Grovely Castle occupy the points of an equilateral triangle each side of which is exactly six miles in length. A very definite connection is thus shown to exist between the various primitive works in the neighbourhood of Stonehenge. We notice that Mr. J. H. Spencer describes these relationships in an article in the April number

of the Antiquary, but he does not mention that the credit of the discovery of the connecting lines between the various monuments belongs to Colonel Johnston.

We learn from the Journal of the Society of Arts that funds have been placed at the disposal of the council of the Society of Dyers and Colourists for distribution in the form of prizes for the solution of technical problems. The now offered :-(1) 20l. for a satisfollowing prizes are factory systematic tabulation of the reactions of dyestuffs on the fibre, and a comprehensive scheme for their identification on dyed fabrics; (2) 10l. for a trustworthy method of distinguishing between unmercerised and mercerised cotton of various qualities, and for the estimation of the degree of mercerisation without reference to lustre; (3) 20l. for a full investigation of the causes of the tendering of cotton dyed with sulphide blacks, and the best means of preventing such tendering; (4) 20l. for a satisfactory standardisation of the strength and elasticity of cotton yarns of various qualities and twists in the grey and bleached conditions; (5) 20l. for a full investigation of the average degree of tendering brought about in cotton yarn of various qualities by-(a) cross dyeing with acid colours; (b) dyeing aniline black; and (c) various other dyeing processes, with the object of fixing standards for the trade. Further information can be obtained from the hon. secretary, Mr. E. T. Holdsworth, Westholme, Great Horton, Bradford.

SATISFACTORY progress and general prosperity form the key-note of the report of the Zoological Gardens at Giza for the past year. The report is illustrated by the reproduction of a most interesting photograph of an aard-vark, or ant-bear, slightly marred by the effect of a shadow by the side of the nose.

IN a communication published in the Anales of the Buenos Aires Museum (vol. F. xii. pp. 1-64), Dr. Ameghino gives reasons for concluding that the single facet by which the astragalus of marsupials articulates inferiorly with the calcaneum is a specialised feature, derived from the more common type in which there are two such facets.

THE April issue of the Proceedings of the Royal Irish Academy is devoted to a list of Irish Coelenterata, inclusive of the Ctenophora, by Miss Stephens. The list includes about 250 species, but since the north-west coast of Ireland has not yet been thoroughly worked, it cannot be regarded as complete.

Museum News is the title of a periodical issued by the Brooklyn (N.Y.) Institute of Arts and Sciences to replace the Children's Museum News, and intended to deal with matters connected with both the Central and the Children's Museum in that city. Special attention will be devoted to informing the public with regard to new exhibits and

additions to the collections.

ACCORDING to its seventy-first report, Bootham School (York) is making a vigorous push in the direction of encouraging the study of natural science, and the natural history club has entered a period of renewed life and vigour. The report is illustrated with reproductions from two excellent photographs, one showing the nest and eggs of a black-headed gull, and the other the same eggs in the process of hatching.

THE seals frequenting Killala Bay and the Moy Estuary. in Mayo, form the subject of an article by Mr. R. Warren in the April Zoologist. Both the common and the grey seal frequent and breed in this district, the young being apparently born in most cases in caverns difficult of access

The largest grey seal ever killed weighed 560 lb., but specimens scaling 740 lb. and 770 lb. are recorded from the Farne Islands, on the Northumberland coast.

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"DIE SOGENNANTEN RIECHSTÄBCHEN DER CLADOCEREN is the title of a paper in vol. xii. of Ploner Forschungsberichte, in which the author, Mr. D. J. Scourfield, of Leytonstone, discusses the function of the so-called olfactory sete in this group of minute crustaceans. From the stronger and more numerous development of these bristles in the males, it is inferred that their sensory functions are more acute in this sex than in the females. As regards their probable function, the author is of opinion that while they are largely concerned in the perception of taste, yet that they may also serve in the recognition of other senses which may be as far removed from taste as is the latter from hearing.

THE Journal of Hygiene for April (v., No. 2) contains a number of interesting and important papers. Dr. Petrie discusses the relationship of the pseudo-diphtheria and diphtheria bacilli, and Dr. Boycott the relative seasonal prevalence of these two organisms. Dr. Petrie also describes trypanosomes observed in rabbits, moles, and certain birds. Dr. Savage, as the result of experiments made to ascertain the degree of sewage pollution of tidal waters, considers that mud samples yield more trustworthy evidence of the degree of contamination than either water or oyster samples. Other papers are by Dr. Hamilton Wright on preventive measures against beri-beri, Drs. Newsholme and Stevenson, and Dr. Hayward on statistical methods applied to birth-rates and life tables, and Dr. Mackie on a handy method of determining the amount of carbonic acid in air.

PART i. of the reports of the commission appointed for the investigation of Mediterranean fever under the supervision of the advisory committee of the Royal Society has just been issued. The first two reports, by Major Horrocks, R.A.M.C., deal with the problem of the saprophytic existence of the causative organism (the M. melitensis) outside the human body. It is found that the organism will retain its vitality in sterilised tap water for thirty-seven days, in dry soil for forty-three days, and in moist soil for seventy-two days. The same observer was able to isolate the micrococcus from the urine, but not from the faces, sweat or breath of patients. A series of experiments was instituted which showed that the microCocus is absorbed by, and gives rise to the disease in, monkeys exposed to dust, or given food containing it. Staff-Surgeon Gilmour, R.N., and Dr. Zammit detail experiments on the isolation of the M. melitensis from the blood, and Staff-Surgeon Shaw, R.N., writes on the same subject and on experimental work in relation to animals.

A interesting article on polished stone axes in history until the nineteenth century, by Dr. Marcel Baudouin and Lionel Bonnemère, will be found in the Bulletin de la Secute d'Anthropologie de Paris (5e. sér., tome v., p. 496). Examples are given of their use at the present day as charms against lightning, storm, and other evils, and also they are credited with therapeutic efficacy. The βαίτυλος of the Greeks was a polished stone implement; from classical times onwards these stones were supposed to have fallen from heaven, and at the present day this belief is current from western Europe to Malaysia.

VARIOUS folk-tales and other items of folklore will be found in the Journal of the Asiatic Society of Bengal; in vol. I., part iii., p. 99, Mr. S. C. Mitra records a new

accumulation-droll or cumulative folk-tale from Bihar; in vol. Ixxi., part iii., p. 4, in the same Journal, Mr. H. P. Shastri describes a form of tree worship at Naihati; a female deity is supposed to reside in a date palm, when clods of earth are thrown at the tree as offerings to her, she at once pacifies children crying at the home of the devotee. Ten years later the author re-visited the spot, and found that sweets were then offered as well, that various other boons were prayed for, and a myth had grown up about the tree. The marriage customs of the Khonds are described by Mr. J. E. F. Pereira, from which it appears that they are gradually Hinduising their


THE ideal forestry college forms the subject of an article in the Indian Forester (February); the suggestions made are based upon a selection of the advantages observed at various institutions, all of which, it is hardly necessary to state, lie outside the British Isles. College gardens and forests are mentioned as the most important adjuncts to laboratories and museums, and in these particulars the forestry school at Tharandt, Saxony, is well provided. In the matter of getting wider experience than can be obtained in the college forests, the students of the St. Petersburg Institute have the advantage of inspecting and completing a final course in some of the great forest areas of Russia.

JUDGING from the account by Mr. J. W. White published in vol. xxii., part iv., of the Transactions and Proceedings of the Botanical Society of Edinburgh, the Balearic Islands offer many attractions to the botanist who is contemplating a holiday. Not only do the islands lie outside the general track of tourists, but the flora is unusually rich, and a considerable number of the plants are endemic or confined to one of the neighbouring countries. Amongst the rarer curiosities a fragile vetchling, Vicia bifoliata, Lepidium Carrerasii, and a curious little shrubby Daphne velloeoides were obtained in Minorca, and in Majorca Pimpinella Bicknelli, which grows in splendid isolation, and a delicate rock-sheltered labiate, Salvia Vigineuxii, were discovered.

A RECORD of the progress of the Albatross Expedition to the eastern Pacific is given in a letter from Prof. Alexander Agassiz dated January 6 (Amer. Journ. Science, April). The influence of the Humboldt current on the marine life west of Callao was investigated. As far as 800 miles from the mainland, it affected both the surface and bottom fauna. Towards Easter Island, the surface fauna first became less abundant, and at a distance of from 1200 to 1400 miles from South America the trawl hauls were absolutely barren. The bottom of the greater part of the line was covered with manganese nodules on which were found attached a few siliceous sponges, an occasional ophiuran, and a few brachiopods and worm-tubes. The pelagic and intermediate fauna from Easter Island to 12° south latitude, in the direction of the Galapagos, was very poor, and indicated that the region was to the westward of the great Humboldt current. Beyond this limit the marine fauna was again rich and abundant, and great changes were noted in the temperature of the water between 50 and 300 fathoms. Soundings made eastward of the Galapagos and Easter Island indicate a gradual deepening of the ocean bed towards the Continent, as observed during the Challenger Expedition. On Easter Island some time was spent in examining the prehistoric monuments and the great quarries from which colossal images had been cut. Sculptured rocks were noted, and it was remarked that some of the cyclopean stones used in the ancient buildings exhibited excellent workmanship.

GEOLOGICAL and petrographical researches on the northern Urals have for some years been carried on by Prof. Louis Duparc and Dr. Francis Pearce. Their latest work (Mém. Soc. de Physique et d'Hist. nat. de Génève, xxxiv., fasc. v.) embraces a description of the eruptive rocks of the chain of Tilai-Kanjakowsky-Cérébriansky, in the Government of Perm. This range is composed of basic igneous rocks, of pyroxenites passing into koswites, which form the principal axis of the chain, with bordering gabbros elsewhere prominent; there are diorites, norites which are intercalated locally in both gabbros and pyroxenites, and dunites which are massive in places and also send veins into the gabbros and pyroxenites; and there are other eruptive rocks. All these are described in considerable detail and illustrated. Continuing their observations eastwards, the authors describe the quartzites and crystalline conglomerates of Aslianka and of Tépil, with, in the latter region, Devonian strata and various igneous rocks; and finally they deal with the crystalline schists and intrusive rocks of Koswinsky-Katéchersky-Tilai. The memoir is illustrated by pictorial views of the topographic features, by longitudinal sections, and by microscopic sections of the rocks.

THE report of the observatory department of the National Physical Laboratory for the year 1904 shows, as usual, a large amount of useful work; it is published separately, as appealing to a different class of workers from that interested in the engineering and physics departments. The work of the observatory deals with magnetic, meteorological, and seismological observations (separately), experiments and researches, verification of instruments and watches (separately), and miscellaneous commissions for inland, colonial, and foreign institutions, &c. It is observed that the electric trams have interfered with part of the magnetic work; the mean declination for the year was 16° 37'9 W. The tabulations and automatic records of the meteorological observations are sent to the Meteorological Office for publication in detail; the Kew report contains monthly and yearly summaries of the results. The seismological observations are published in the report of the British Association; the largest disturbance recorded during the year took place on April 4, when the maximum amplitude exceeded 17 mm. The verification of instruments, exclusive of watches and chronometers, amounted to 25,797, of which 15,903 were clinical thermometers.

DURING a thunderstorm it has often been noticed that some flashes of lightning appear to "flicker," while others seem to leave a glow in their paths which lasts a second or two before entirely disappearing. In the first case the apparent trembling of the light is due to the fact that the observer is actually watching the passage of more than one flash following the same route. In multiple or intermittent lightning flashes there are sometimes as many as five or six separate flashes in a very brief interval of time, and the impression on the retina is an apparent flickering of a single flash. In the Comptes rendus (April 10) M. Em. Touchet directs attention to those particular flashes which leave a glow in their wake, and gives an illustration of a photograph of one he secured with a moving camera on April 12 of last year. The object of the communication is to point out that this glow is attributable to the incandescence of the air; but it seems to us that this is a fact already very well known. In photographing very bright lightning flashes with movable cameras it is a very common occurrence to get trails on the plate of the brighter portions of the flash, and if the plate and lens be very rapid it should be the rule rather than the exception.

There are numerous examples of flashes which have been photographed showing this peculiarity, and it is a simple matter to differentiate between those due to multiplicity and those due to the incandescent air resulting from the original flash. Anyone interested in this question will find some typical photographs published by L. Weber (Sitz. d. k. Preuss. Akad. d. Wiss., vol. xxxviii., 1889), Ladislaus von Szalay (Met. Zeit., vol. xxxviii., 1903, p. 341), and B. Walter (Jahrbuch d. Hamburgischen Wiss. Anstalten, vol. xx., 1903). As M. Touchet refers to Dr. Hoffert's paper on intermittent lightning-flashes (Phil. Mag.. August, 1889), reference is there made to "streaks of light, showing that a very considerable residual illumination remains between the discharges," which indicates that the writer was quite familiar with the incandescence of the air due to the flash and its effect on the photographic film.

AN installation for the production of high-tension electricity, on view at Messrs. Isenthal and Co.'s, 85 Mortimer Street, Cavendish Square, W., has been examined by a representative of NATURE. The original source of the energy is an ordinary uni-directional current, and an important feature of the apparatus is a commutator which does away with the necessity for an interrupter. In the main circuit is a condenser of very large capacity, and the commutator breaks the circuit when the condenser is charged, so that no sparking is produced. The condenser employed is not large, and owes its compactness to the use of thin layers of aluminium oxide, prepared electrolytically, as the dielectric. The commutator has the appearance of a piece of engineering work, and should not require much attention. Oscillatory currents, with a frequency of about a thousand per second, are set up in the primary of an induction coil, and it is claimed that the impulses in the secondary are much stronger in one direction than in the other. The apparatus is also intended for the production of alternating currents, and some very interesting experiments are shown. An alternating current is sent through the coil of an electromagnet, the core being vertical; a sheet of paper is placed over the upper pole, and on the paper is scattered some iron dust (not filings); the dust forms itself into little spiked heaps which move and dance about. When the paper and iron dust are removed, and the forehead is placed near the pole of the magnet, the light of the room appears to fluctuate in intensity.

MESSRS. A. BROWN AND SONS, LTD., will publish during this month a work by Mr. J. R. Mortimer entitled "Forty Years' Researches in British and Saxon Burial Mounds of East Yorkshire, including Romano-British Discoveries and a Description of the Ancient Entrenchments on a Section of the Yorkshire Wolds."

THE report of the council of the Hampstead Scientific Society and the proceedings for 1904 have been received. Fifty-six new members were elected during the year, and the number of members is now 333. The number of meetings held in 1904 was thirty-three, and in addition there were four Christmas lectures to children and a course of six lectures on nature-study. Among lectures delivered at general meetings of the society may be mentioned one by Prof. S. P. Thompson, F.R.S., on Japanese magic mirrors, and one by Prof. W. Boyd Dawkins, F.R.S., on the incoming of the Brythons into Britain.

MESSRS. S. RENTELL AND Co., LTD., have published a fifth edition of The Telegraphists' Guide to the Departmental and City and Guilds Examinations in Telegraphy,' by Messrs. James Bell and S. Wilson. The contents have

been revised thoroughly, the chapters re-arranged, and much fresh matter introduced. The extra pages supply a description of Wheatstone's ABC instrument, a more detailed reference to batteries, single-needle working, duplex and Wheatstone automatic systems, repeaters, test cases, concentrator switch, wireless telegraphy, and other subjects.

No. 5 of the Central-the magazine of the Central Technical College is very good, and may be regarded as even constituting an advance on its predecessors. It contains an account by Mr. R. Freeman of the design and Construction of the steel-work of the bridge over the Zambezi at Victoria Falls, a continuation of the series of articles by Prof. Armstrong on the mechanism of combastion, and a description of the Klingenberg carriage switchgear by Mr. J. D. Griffin. The magazine is well and copiously illustrated.

WE have received from Mr. Geoffrey Martin a copy of a paper on the theory of solution, published in the Journal

Physical Chemistry (vol. ix. p. 149), giving a detailed account of views already briefly stated in a letter to NATURE (vol. Ixx. p. 531). An attempt is made to explain The fundamental facts that for all substances there is a limit of solubility in each solvent, that the solubility increases as a rule with the temperature, and that molecules often dissociate on passing into solution.

AMONG the popular science lectures to be delivered at the Royal Victoria Hall, Waterloo Bridge Road, during May are the following:-May 9, fishes old and new, Dr. Smith Woodward, F.R.S.; May 23, some summits of the lost continent Atlantis, Mr. H. Ling

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first of the two articles he enumerates the requirements of the site of such an observatory, and then discusses in detail the meteorological conditions, the seeing, the transparency of the atmosphere, and the instruments available at Mount Wilson.

In the second article the author describes the foundation, the equipment, and the programme of the observatory, and illustrates his description with photographs and diagrams of the site and of the various instruments and houses already erected or in course of erection.

ANOMALOUS DISPERSION AND "FLOCCULI."-In No. 3, vol. xxi., of the Astrophysical Journal, Prof. Julius advances the theory of anomalous dispersion to explain the varying appearances of the flocculi on spectroheliograph photographs. The "dark flocculi" of Prof. Hale are explained by the incurvation of the direct rays producing an excess of light in the bright flocculi, and therefore a deficit elsewhere, hence the dark regions naturally ensue.

The differences between the H, (calcium) and HB (hydrogen) pictures obtained by Prof. Hale are explained by the supposition that the HB rays are less strongly incurvated, and therefore rays of more varied refractive indices pass through the secondary slit, thereby producing a less dark and less defined image. On this assumption Prof. Julius states that the hydrogen photographs would show the fine details seen on the K, photographs if the dispersion employed were greater, or if the secondary slit were used narrower. Without requiring any other hypothesis, Prof. Julius explains by this theory all the anomalies seen on the spectroheliograms.

In the same journal, the same author also discusses the "dispersion bands " seen in the spectra of 8 Orionis and Nova Persei, and, inter alia, arrives at the. conclusion that the former star is not a spectroscopic binary.

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ASTRONOMICAL SOCIETY OF AMERICA.-Abstracts of sixteen of the numerous papers read at the sixth meeting of the Astronomical and Astrophysical Society of America, held at Philadelphia last December, are given in No. 533 of Science by Mr. Frank B. Littel. The various titles are too numerous to mention here, but amongst them we may notice "The Constant of Aberration," by Prof. C. L. Doolittle, in which the author obtains the value 20":540 ± 0.0055 from a series of zenith telescope observations made between December, 1889, and December, 1903; "The Reflex Zenith Tube," by the same author; "Variation of the Bright Hydrogen Lines in Stellar Spectra," by Miss Annie J. Cannon; Planetary Spectrograms and The Canals of Mars, by Mr. Lowell; "The Coordination of Visual and Photographic Magnitudes,' by Mr. J. A. Parkhurst ; and "Recent Researches of the Henry Draper Memorial,' by Prof. E. C. Pickering. AND

DISCOVERY OF A TENTH SATELLITE TO SATURN.-A teletam from the Kiel Centralstelle announces the discovery nt a tenth satellite to Saturn by Prof. W. H. Pickering, who, it will be remembered, also discovered Phoebe, the ninth satellite.

The newly discovered satellite is very faint, being reported as three magnitudes fainter than Hyperion, the seventh satellite, which has a magnitude of about 17; its period is given as 21 days, and its orbital motion is direct. THE ALLEGED IDENTITY OF COMETS" BROOKS 1889 LENELL-An abstract of a paper by Dr. Charles L. Poor, wherein he discusses the identity of Brooks's 1889 comet with the object known as Lexell's comet, is given in No. 4, vol xiii., of Popular Astronomy. After mentioning the discovery and subsequent history of each body, he discusses the various perturbations to which each has been subjected, and then gives the results obtained from a re-computation of the orbit of Brooks's comet, using the observational data secured during the re-appearance of 1903. Finally, he arrives at the conclusion that the objects are not identical, although further evidence will be necessary before the question can be settled definitely.

ANCIENT DRAWINGS OF CELESTIAL PHENOMENA.-Parts xiii and xiv. of the current volume of Das Weltall contain an interesting article by Dr. W. Lehmann, of Berlin, in which the ancient Mexican accounts of solar eclipses, romets, &c., are discussed. The article is freely illustrated by drawings of eclipses, comets, the moon, planets, &c., taken from the old accounts, and these drawings are most interesting as depicting the old Mexican ideas of these phenomena. For instance, the first is a contemporary drawing of the total solar eclipse of 1531 A.D., and shows plainly immense prominences and coronal wings.

MOUNT WILSON OBSERVATORY.-In No. 2, vol. xxi., of the Astrophysical Journal, Prof. Hale gives an account of the conditions of solar research at Mount Wilson, Calitornia, where he has recently established the Solar Observatory of the Carnegie Institution of Washington. In the

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IN the paper referred to below the author deals very fully

with the various colour variations observable in the species of the genus under notice, and a very interesting account is given of the variability in colour-pattern, and of its gradual development in the nymphal and imaginal stages, illustrated by coloured plates i. and ii. A chemical analysis of the nature of the pigments is also given, and illustrations of the layers in which the pigments are located. Coloured plates iii. and iv. give figures of several of the different species of the genus-besides these plates there are excellent maps, showing the distribution of the various forms, and elaborate diagrams are provided, indicating the variations observable. The author has evidently spared no pains to render the treatment of the subject as exhaustive as possible, and as a study of colour variation this treatise seems to leave little to be desired. The problem attacked in this work, viz. "an inquiry into the nature and probable causes of specific differentiation in the genus Polistes," is one which is both difficult and perplexing.


The author commences at once by saying, apart from differences in size, the characters used to separate the species are based almost exclusively on colour; accordingly, this in1 "Coloration in Polistes." By Wilhelmine M. Enteman. Pp. 88 6 plates. (Carnegie Institution of Washington, November, 1904.

vestigation resolves itself into a study of coloration in the genus.' The conditions which make for variation in the different species are well indicated, as the author points out that, even where the inmates of a single nest are examined, the following points have to be considered :-First, that two or three females may work together for the good of one community, and may be very differently coloured; secondly, that each may be fertilised by several males, which again may be differently coloured; thirdly, that intruders from other nests may be present as they "are not always so certainly driven away from strange nests as has been affirmed for other social Hymenoptera.'

In these circumstances, the attempt to distinguish the species by colour characters seems to be almost hopelessa point, however, which seems to the present writer to have been overlooked is the possibility of the presence of unobserved plastic characters which might serve as better and more satisfactory guides to classification. That such characters exist among the palæarctic species has been demonstrated by F. F. Kohl in Ann. K.K. Naturh. Hofmuseum, Wien, xiii., heft i., pp. 87-90, taf. iii., who shows that five forms of the males can be easily separated by well-defined characters in the form of the clypeus and genæ, the grooves of the face, and the shapes of the subapical joints of the antennæ, and although their respective females and workers have not been satisfactorily identified, it is not improbable that careful investigation may yet disclose characters to associate the sexes of the different species together; as also it is quite probable that all the species would vary in colour in more or less parallel directions-any investigation into the distribution of the species, unless conducted with special reference to these characters of the males, would be very liable to lead to wrong conclusions. One conclusion especially to which one would like to apply the male character test is summed up in the following words :-" It is hardly probable that we have in P. variatus a primitive species which has differentiated in two directions, but, as we shall see from the study of the geographical distribution of the species, aurifer and pallipes are two originally distinct species which, from the course of their migration northwards, have come together in the Mississippi valley, and by their commingling produced a species having, in some measure, the characters of both." These remarks are made with no wish to depreciate, even if it were possible, this very careful attempt to investigate a most difficult problem, but merely to point out that there are characters in our Palæarctic species of Polistes which might be well looked for in those of the other hemisphere.

observed are such as to be rightly described as cleavagethey have rather the character of fractures, depending on the application of the forces which produce them, as well as on the intimate structure of the material.


It is unfortunate that no attempt is made to collate the results of the experiments with actual examples of cleaved rocks. As the author remarks, the position of the strainellipsoid affords a crucial test. On the Sharpe-Sorby theory the principal diametral plane of the ellipsoid must coincide with the cleavage-plane; on Dr. Becker's hypothesis it should be inclined at some angle of less than 45°. Now there are many slates in which the strain-ellipsoid is actually presented in deformed spherical concretions colour-spots. The "birdseye" slate of Westmorland and the green-spotted purple slates of Llanberis are examples familiar to every English geologist. In every case the orientation of the ellipsoid is that which agrees with the received theory. Moreover, the spots are elliptic in the cleavage-plane itself, being elongated, as Dr. Sorby pointed out fifty years ago, in the line of cleavage-dip. If the cleavage-plane were a plane of shearing, it would correspond with a circular section of the ellipsoid.

We might object further that, since there are two directions of circular section, or of shearing, there should, on Dr. Becker's hypothesis, be always two directions of cleavage, perpendicular to one another with incipient cleavage and making an acute angle in well cleaved slates. Our author endeavours to meet this difficulty in discussing his shearing experiments. One direction of shearing is parallel to a fixed face of the block undergoing deformation, while the other is continually changing, so that any one set of particles undergoes maximum tangential strain along these planes only for an infinitesimal time." Even assuming such conditions to be realised in nature, which cannot be the general case, we should still suppose that the cleavage-property (as distinguished from fractures set up in the process of deformation) will depend on the actual structure of the rock, not on the manner in which that structure has been arrived at.

It will be apparent from the foregoing criticism that, while recognising the intrinsic value of these experiments and the clear manner in which the author's views are set forth, we do not find in them anything which assails successfully the generally accepted interpretation of the cleavage structure. A. H.


THE memoir described below contains an account of experiments undertaken to test the author's theory, propounded some years ago, of the cause of the cleavage property in slates. Dr. Becker's theory, substantially the same as that put forward earlier by the Rev. O. Fisher, is that cleavage-planes are planes of maximum tangential strain, or in other words shear-planes. This is opposed to the theory of Sharpe (or, as we might say, of Sharpe and Sorby), which makes the cleavage-planes perpendicular to the maximum compression. The author has misunderstood Dr. Sorby's position, having apparently overlooked the earlier papers of that writer. The question whether heterogeneity in the rock is necessary for the production of cleavage seems to be beside the mark, since all rocks (other than glasses) are heterogeneous in this sense. Both Tyndall's wax and Dr. Becker's ceresin, being crystalline bodies, are heterogeneous, and their behaviour must depend on the orientation of the minute component crystals.

The experiments described were carried out with ceresin, a substance of the paraffin series, and some also with clay. These were submitted in one series of tests to simple compression, and in another series to shearing by means of a machine devised for the purpose. In the small masses dealt with the strains developed vary greatly from point to point, and the resulting structure is of a complex kind. We must confess that we are not convinced that the effects 1 "Experiments on Schistosity and Slaty Cleavage." By George F. Becker. Pp. 34 7 plates. Bull. No. 241 of U.S. Geological Survey. Washington, 104.)


CAMBRIDGE. By direction of the Board of Geographical Studies, part ii. of the examination for the diploma in geography will be held on June 21 and two following days. No person is qualified for admission to part ii. who has not previously passed part i. (or the special examination in geography for the ordinary B.A. degree). The names of intending candidates, together with the subjects they propose to take up, should be notified to the registrary not later than May 24. The fee for admission to the examination is, for members of the university, 31.; for persons not members of the university, 51. The fee must be paid to the registrary not later than June 15. The subjects are regional geography, surveying and mapping, geomorphology, oceanography and climatology, the history of geography and anthropogeography. Copies of the schedules defining the range of examination may be obtained by application at the registry.

The council of the Senate has recommended that the University of Queen's College, Kingston, Ontario, be adopted as an institution affiliated to Cambridge University. It is understood that the syndicate for considering the studies and examinations of the university, the report of which in favour of the abolition of compulsory Greek in the previous examination was thrown out last term, will continue to meet. It is proposed to add to the syndicate Mr. E. S. Roberts, master of Gonville and Caius College: Dr. Adam, one of the tutors of Emmanuel College; Mr S. H. Butcher, late professor of Greek at Edinburgh University; and Mr. G. H. Hardy, of Trinity College. These gentlemen were on the "non-placet " side at the

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