was not re-ignited; the bulk of the nitrogen was nearly five minutes in boiling off, after which a smouldering splinter dipped into the mouth of the test-tube burst into flame.

Between the poles of the magnet all the liquefied air went to the poles; there was no separation of the oxygen and nitrogen. Liquid air has the same high insulating power as liquid oxygen. The phenomena presented by liquefied gases present an unlimited field for investigation. At 200° C. the molecules of oxygen had only one-half of their ordinary velocity, and had lost three-fourths of their energy. At such low temperatures they seemed to be drawing near what might be called "the death of matter," so far as chemical action was concerned; liquid oxygen, for instance, had no action upon a piece of phosphorus and potassium or sodium dropped into it; and once he thought, and publicly stated, that at such temperatures all chemical action ceased. That statement required some qualification, because a photographic plate placed in liquid oxygen could be acted upon by radiant energy, and at a temperature of 200° C. was still sensitive to light.

Prof. M'Kendrick had tried the effect of these low temperatures upon the spores of microbic organisms, by submitting in sealed glass tubes blood, milk, flesh, and such-like substances, for one hour to a temperature of 182° C., and subsequently keeping them at blood heat for some days. The tubes on being opened were all putrid. Seeds also withstood the action of a similar amount of cold. He thought, therefore, that this experiment had proved the possibility of Lord Kelvin's suggestion, that life might have been brought to the newly-cooled earth upon a seed-bearing meteorite.

In concluding, the lecturer heartily thanked his two assistants, Mr. R. N. Lennox and Mr. J. W. Heath, for the arduous work they had had in preparing such elaborate demonstrations.

SCIENTIFIC SERIALS.

IN the Journal of the Royal Agricultural Society of England third series, vol. iv. pt. 1) there is an interesting paper on the home produce, imports, consumption, and price of wheat over forty harvest years, 1852-3 to 1891-2, by Sir J. B. Lawes and Dr. J. H. Gilbert. This paper, extending to fifty-five pages, contains a general review of the produce of the experimental plots at Rothamsted, from which they have annually calculated the wheat crop of this country.-The first of the official reports is that of the Royal Veterinary College on investigations conducted for the Royal Agricultural Society during the year 1892. An interesting case of actinomycosis is related; a heifer with tongue badly diseased was put under Thomassen's treatment. Potassium iodide administered at first in doses of one drachm, twice daily, and the doses gradually increased to three drachms, effected a complete cure in about ten weeks.-Experiments have lately been made at the Veterinary College with Koch's tuberculín. The results in the case of seventy-two animals inoculated and afterwards killed show that "the tuberculin pointed out correctly the existence of tuberculosis in twentyseven animals and wrongly in five, and it failed to indicate the existence of the disease in nineteen. In only three of the twentyseven animals in which the tuberculin correctly pointed out the existence of tuberculosis could á positive diagnosis have been made by any other means." Experiments have also been made with Kalning's mallein, and "the results warrant the statement tuar mallein is an agent of greater precision than tuberculin, and that it is likely to render most important service in any attempt to stamp out glanders."

Wiedemann's Annalen der Physik und Chemie, No 4.-On electric discharges; the production of electric oscillations, and their relations to discharge tubes, by H. Ebert and E. Wiede mann. The influence of electric oscillations of given frequency producing glow in vacuum tubes without electrodes was investigated by means of Lecher's wire system. The oscillations in the primary circuit were produced by means of an influence achine throughout. The terminals of the machine were connected to the primary condenser, consisting of four plates, to the further two of which the two Lecher wires, copper wires or thick metal tubes, were attached, running parallel for distances arving from 2 to 14 m., and ending in another condenser of variable capacity. The sensitive tubes were placed in various positions between or near the plates of the secondary condenser.

It was found that wide tubes, not too short, glowed most readily. Nodes along the wires were discovered by means of wire bridges, which were moved along the wires until the tube glowed, or, if it was glowing already, until it reached a point where the glow became more intense and uniform. It was found that the position of the nodes was independent of the pressure in the tube, but that as evacuation proceeded the limits within which the tube would glow grew wider. Hence the most accurate method for finding the nodes, was by finding them for the highest possible pressure of gas in the tube.-On the comparison of intensities of light, by the photoelectric method, by J. Elster and H. Geitel. Apart from the dissipation of an electric charge from a negative zinc pole by ultra-violet radiation, it is also possible to measure the intensity of optically active light by an electric method. If a clean surface of potassium is joined to the negative pole of a battery, and a platinum or aluminium electrode to the positive pole, and the two electrodes are placed in a vacuum cell, the illumination of the potassium surface will allow a current to flow whose strength will be proportional to the intensity of the light source, and can be measured by means of a galvanometer. That this is really the case was proved by measuring independently in this way the intensities of two luminous sources, and then combining them, when the resultant reading was found to be equal to the sum of the other two, within the limits of constancy of the sources themselves. The greatest effect is produced by the blue rays. Also papers by Messrs. Bjerknes, Zahn, Voigt, Richarz, Ambronn, Christiansen, Goldhammer, and Oberbeck.

Meteorologische Zeitschrift, March. - Iridescent clouds, by H. Mohn. The paper contains observations made at Christiania during the years 1871-1892, together with a detailed investigation of the formula recently employed. During this period iridescent clouds were only visible on forty-two days; in some years the phenomenon failed entirely, and was not observed during the whole lustrum 1876-80. The great majority of cases occurred in December and January, but a few occurred frequently at sunset than at sunrise or mid-day, but the difference in summer; the phenomenon was also seen somewhat more is so small as to make it appear that its occurrence is independent of the time of day. The height of the clouds varied from about fourteen to more than eighty miles, the lower level being about twice the height at which ordinary cirrus clouds are usually seen at Christiania. The phenomenon appears to have some connection with the state of the weather, as an during the prevalence of stormy weather in the North Atlantic examination of the synoptic charts showed that it mostly occurred and over Northern Europe, and when the air was dry and warm at Christiania. On the determination of wind force during gusts of a Bora storm, by E. Mazelle. From an investigation of the anemometer observations at Trieste for the ten years 1882-1891, hourly values give little idea of the violence of individual gusts, the the greatest hourly velocity recorded was seventy miles. But as author adapted an ingenious electrical arrangement to the anemometer, by which he could record the number of revolutions of the cups in each second. During a storm on January 16 last, the gusts during the space of a few seconds reached the velocity equivalent to 100 to 140 miles an hour. Presuming the instru ment to have been a large-sized anemometer, this high velocity is not unlikely, as in a paper read before the Royal Meteorological Society on May 18, 1881, by R. H. Curtis, a velocity at the rate of 120 miles an hour at Aberdeen is quoted as recorded in gusts lasting two minutes, while shorter intervals, if they could be measured, would no doubt show higher velocities; and at Sydney a velocity of 153 miles an hour was recorded during one or two minutes. In all these cases the factor 3 has been used for the ratio of the movement of the cups to that of the wind, but this factor has been shown to give a velocity which is nearly 30 per cent. too high.

Bulletin de la Société des Naturalistes de Moscou, 1892.-(No. 1.) The chief papers are:-The development of the gemmulæ in Ephydatia fluviatilis, by W. Zykoff.-Catalogue of Kazan Lepidoptera, continued, by L. Kroulikovsky.-Analogy between the solution of a gas and of a salt in indifferent solutions of salts, by I. M. Syetchenoff. The author's law, which was found ), holds good within certain limits, for the solution of salts in the same solutions; but the latter must only be taken either weak or of medium strength.New plants and insects from Sarepta, by Alex. Becker. -On a

or carbon dioxide (

= ae

The action upon the circulatory, muscular and nervous systems, therefore, closely resembles of that strophanthin.

April 27. The Electric Organ of the Skate. Note on an Electric Centre in the Spinal Cord." By J. C. Ewart, M.D., Regius Professor of Natural History, University of Edinburgh. Communicated by Prof. Sir W. Turner, F.R.S.

Having considered the development and structure of the electric organ of the Skate, it appeared to me desirable, by way of making my work more complete, to reinvestigate the nervous apparatus of the organ, and more especially to ascertain whether, as in Torpedo and Gymnotus, there is an electric centre. In Torpedo the electric organs are developed from a limited number of myotomes, and innervated by afferent fibres, belonging to a limited number of cranial nerves, which proceed from two large collections of cells-the electric lobes-situated in the region of the medulla. In Gymnotus the nerves for the electric organs proceed from two well-marked cellular tracts which extend along the greater length of the spinal cord, one at each side of the central canal. In the case of the Skate the question at the outset is, granting the existence of an electric centre, is it, as in Torpedo, situated in the brain or, as in Gymnotus, in the spinal cord? Sanderson and Gotch (Journal of Physiology, vol. x. No. 4), made out that in the Skate reflex centre is situated in the optic lobes," but, notwithstanding this, these lobes in the Skate in no way differ histologically from the corresponding structures in Acanthias and other Selachians anprovided with electrical organs.

66

a

The development of the Skate's organ from portions of the caudal myotomes, and its innervation by afferent fibres from certain caudal nerves, point to the electric centre being situated in the spinal cord rather than in the brain, and to its being, as in Gymnotus, on a level, and all but coextensive, with the electric organ.

Having observed, when working at the develop. ment of the electric organ, a number of large nerve-cells in the caudal portion of the spinal cord, the sections of Skate embryos made some years ago were first examined. It soon became evident that in sections from the middle of the tail on a level with the electric organ certain cells of the anterior horn of the cord were very much larger than in sections through the root of the tail, and further that in late embryos and very young Skate there was an electric centre, resembling in many respects the electric centre in Gymnotus.

the same lenses were used in each case-objective D and ocular 2, Zeiss. It will be noted that, though the cell from the Skate is much smaller than the Torpedo cell, it is decidedly larger than the one from Gymnotus.

It did not, of course, follow that the electric nerve-cells persisted into adult life. They might degenerate, and thus the supposed feebleness of the Skate's organ might be accounted for. The fact that the Skate's organ increases in size as the fish grows larger led me, however, to expect that large nerve cells would be found in the caudal region of the spinal cord in well-grown fish. In this I was not disappointed, for, though there was at first some difficulty in demonstrating the presence of electric nerve-cells in large fish, on obtaining perfectly fresh material their position, size, and relations were easily made out, and the remarkable difference in the appearance of sections of the cord at, and in front of, the root of the tail, from sections on a level with the electric organ, was at once evident. From the observations already made, it appears that the electric centre in the Skate closely resembles, from a morphological point of view at least, the electric centre in Gymnotus. The electric tract is, however, much shorter in the Skate than in the Electric Eel, and the cells are relatively fewer in number. On the other hand, the cells in the Skate sre larger than in Gymnotus, and this is true not only of Kaia batis but also of R. radiata, in which the organ is extremely small and poorly developed. Nerve cells from the electric centres of Torpedo, Gymnotus, and Raia are represented in the accompanying figures. Fig. 1 represents a cell from the electric centre of the Skate (a R. batis two feet in length); Fig. 2 a cell from the electric centre of a wellgrown Gymnotus; and Fig. 3 a cell from the electric lobe of a large Torpedo. All three figures are camera drawings, and

In sections of the Skate's cord on a level with the electric organ, small, as well as large, cells are usually visible in the anterior horn. The small cells are in connection with the fibres which supply the untransformed caudal muscles. They agree exactly with the cells in the anterior horn throughout the entire length of the spinal cord lying in front of the electric organ region. One of these unenlarged motor cells is represented in Fig. 4. It was drawn from section of the cord (of the same fish from which Fig. I was taken), about six inches in front of the electric organ. It closely resembles, except in size, the electric cell (Fig. 1), and it also resembles the large motor cells of the Mammalian cord. A motor cell from the spinal cord of a Mammal, drawn to the same scale as the other cells given, is represented in Fig. 5. This cell, smaller than the electric cell of the Skate (1), and still smaller than the cell from

O

3. Torpedo.

5.

1

2. Gymnotus.

1. Raia.

4.

Torpedo (3), is about the same size as the electric cell of Gymnotus (2).

With the help of sections through a series of embryo Skate, for most of which I was indebted to Dr. Beard, I have been able to study the development of the cells in the Skate's electric centre. This part of the subject, together with the condition of the electric cells in large fish, will be dealt with in a subsequent communication. It may, however, be stated now: (1) That in R. batis embryos under 5 cm. in length none of the motor cells in the caudal region had undergone enlargement. (2) That in an embryo 5.8 cm. in length, although the muscular fibres seemed still unchanged, certain cells in the anterior horn of the caudal portion of the cord were distinctly larger than similarlyshaped cells in their vicinity. (3) That in an embryo 15.5 cm. For the use of the section from which Fig. 5 was drawn I am indebted to Sir William Turner, F.R.S.

in length, in which the electrical elements were already well developed, the electric nerve-cells were large and conspicuous, so that sections through the cord in the region of the electric organ presented quite a different appearance from sections through the root of the tail, where no change had taken place in the cells of the anterior horn.

By

May 4.-"On the Differential Covariants of Plane Curves, and the Operators employed in their Development." R. F. Gwyther, M.A., Fielden Lecturer in Mathematics, Owens College, Manchester. Communicated by Prof. Horace Lamb, F.R.S.

"On the alleged Increase of Cancer." By George King, F.I.A., F.F.A., and Arthur Newsholme, M.D., M.R.C.P. Communicated by Dr. J. S. Bristowe, F.R.S.

The general result is that the supposed increase in cancer is only apparent, and is due to improvement in diagnosis and more careful certification of the causes of death.

Chemical Society, April 20th.-Dr. Armstrong, president, in the chair. The following papers were read :-A contribution to the chemistry and physiology of foliage leaves, by H. T. Brown and G. H. Morris. This paper deals with the occurrence, relations and physiological significance of the starch, diastase and sugars contained in foliage leaves. The first part relates to the starch and diastase of leaves, and the second treats of the sugars of the leaf. A bibliography of the subject is appended. The work originated in an attempt to discover the explanation of the conditioning effect of "dry-hopping;” viz., the addition of a small amount of dry hops to finished beer. This was ultimately traced to the presence in the hop strobiles of a small, but appreciable, quantity of diastase, sufficient to cause slow hydrolysis of the non-crystallisable products of starch-transformation left in the beer, and to reduce them to a condition in which they can be fermented by the yeast. The authors were then led to enquire into the first formation of starch in the chloroplasts of the foliage leaf, the mode of its dissolution and translocation in the plant and the nature of the metabolised products; the results obtained are antagonistic to the assumption made by Sachs, that all the products of assimilation at some time take the form of starch. Only a small portion of the assimilated material exists at any one time as starch. The fluctuations in the amount of starch in leaves under various conditions were also determined. Wortmann's recent denial that diastase plays any part in the dissolution and translocation of starch in leaves is incorrect; the authors prove that, instead of leaves containing little or no diastase every leaf examined by them contained sufficient diastase to transform far more starch than the leaf can have contained at any one time. The difference between the author's and Wortmann's results is chiefly due to the faulty method of examination employed by the latter. The products of the hydrolysis of starch by leaf diastase are identical with those formed by malt-diastase, maltose having been directly separated from the leaves; leaf-diastase is not able to convert maltose into dextrose, but the leaf contains an enzyme capable of inverting cane-sugar. The amount of diastase present varies greatly in different plants, and within narrower limits even varies in the same plant at different times; it is very high in the case of the Leguminosa. Any conditions which favour a decrease in the leaf-starch result in an increase of the leaf-diastase; thus a marked increase in diastatic activity is observed with leaves kept in darkness. Contrary to Wortmann's statement, leaf-diastase can attack the starchgranule under certain conditions; no evidence could however be obtained of the disappearance of starch in killed leaves under the influence of the contained diastase, and the authors are led to the conclusion that the first stage of dissolution of the starch-granule in the leaf is in some way or other bound up with the life of the cell. From experiments on the leaves of Tropaolum the authors draw the following conclusions :Cane-sugar is the first sugar to be synthesised by the assimilatory processes. This sugar accumulates in the cell-sap of the leal-parenchyma whilst assimilation is proceeding vigorously, and when the concentration exceeds a certain point starch commences to be elaborated by the chloroplasts at the expense of the cane-sugar. This starch forms a more stable reserve material than the cane-sugar, and is only drawn on when the latter more readily metabolised substance has been partially used up. Cane-sugar is translocated as dextrose and levulose and the starch as maltose. From the invert-sugar derived from the cane-sugar, the dextrose is more readily used up for

CS

the respiratory processes, and possibly also for the new tissuebuilding, than is the levulose; hence in a given time more levulose than dextrose must pass out of the leaf into the stem. The reading of this paper was followed by an interesting discussion in which the President, Mr. Thiselton Dyer, Dr. D. H. Scott, Prof. Green and Dr. Lauder Brunton took part.-The interaction of alkali cellulose and carbon disulphide: cellu. lose thiocarbonates, by C. F. Cross, E. J. Bevan and C. Beadle. The maximum number of hydroxyl groups in alkali cellulose appears to be four, expressing cellulose as CH20O10 By the interaction of alkali cellulose and carbon disulphide, cellulose thiocarbonates result; these products, when treated with water, swell enormously and regenerate cellulose. From a study of a large number of these thiocarbonates the authors are led to assign to them the formula OX where X is the cellulose residue, a radicle of variable SNa dimensions. The thiocarbonates yield solutions of extraordinary viscosity.-Sulphocampbylic acid, by W. H. Perkin, jun. On heating Walters' sulphocamphylic acid, a monobasic acid, C9H140, distils; on dissolving this in sulphuric acid sulphocamphylic acid seems to be regenerated. By oxidation with permanganate the latter yields a dibasic acid, CHO,, which on reduction gives another dibasic acid, C18H2O6. The substance of the composition C18H2O, yields, on hydrolysis, hydroxymetaxylenecarboxylic acid (CO,H: Me: Me: OH = 1:24:5). A number of salts and derivatives of the above substances are described.-Magnesium diphenyl, by Lothar Meyer. In reference to a recent note by Hodgkinson (NATURE, this vol., p. 22) the author states that magnesium diphenyl has been recently prepared in his laboratory; it is a voluminous powder and is spontaneously inflammable. The formation of pyridine derivatives from unsaturated acids, by S. Ruhemann. Ethyl methyldicarboxyglutaconate yields methylmalonamide and ethyl amidoethylenedicarboxylate with aqueous ammonia; with phenylbydrazine it gives ethyl methylmalonate and the ammonium compound of CO.C.COOEt the pyrazolon PhN

NH.CH

Ethyl methylglutaconate

gives B-methyl-aa'-dihydroxypyridine with aqueous ammonia and B-picoline on reduction with zinc dust. Similar reactions hold in the cases of the higher homologues of these two substances. Chlorinated phenylhydrazines, Part II., by J. T. Hewitt. Orthochlorophenylhydrazine does not yield a urazole when heated with biuret; both the meta- and para-isomerides give urazoles and their hydrochlorides yield semicarbazides with potassium cyanate. A number of other compounds are described.-The oxidation of tartaric acid in presence of iron, by H. J. I Fenton. On adding a small quantity of hydrogen peroxide to a solution of tartaric acid containing a trace of ferrous salt, a yellow colour is produced which changes to violet on adding alkali. The substance which gives the colour with ferric salts seems to be represented by the formula C,H,03; it is crystalline and behaves as a powerful reducing agent. The author is still engaged in its examination-The inertness of quicklime, by V. H. Veley. The author is still making experiments on the velocity of reaction between lime in various states of hydration and sulphurous and carbonic anhydrides at different temperatures. The products of the interaction of tin and nitric acid. by C. H. H. Walker. This investigation is a continuation c the work of Veley on the conditions of the interactions of metals and nitric acid. The whitish substance formed by the action of fairly concentrated nitric acid on tin seems to have the composi tion Sn(NO3)(OH), -Interactions of thiourea and some haloid derivatives of fatty acids, by A. E. Dixon. Thiourea reacts with dichloracetic acid, yielding thiohydantoic acid and ultimately thiohydantoin in accordance with the following equaS--CH,

tion :

2CSN ̧H ̧ + CHCI.COOH = NH: CNH.CO, HCI

+ HCl + S + H2O + CN.NH..

a-monochlor (or brom) propionic acid interacts similarly with thiourea, giving methylthiohydantoin; on boiling this substance with hydrochloric acid it yields B-methyldioxythiazole

Mathematical Society, May 11.-Mr. A. B. Kempe, LS., president, in the chair.-The following communicais were made:-On the collapse of boiler flues, by A. E. H. re. The problem consists in discovering the conditions of a apse of a thin cylindrical shell under external pressure, en the ends are coʻstrained to occupy fixed positions. Since problems of collapse depend on the geometrical possibility inite displacements accompanied by only infinitesimal strains, ppears at the outset that unless the shell can receive a discement of pure bending without stretching of the middle face collapse is impossible. The assumed condition of no ninal displacement is equivalent to closing the ends of the Il, and, since a closed surface cannot be bent without stretch, this condition apparently precludes the possibility of lapse. On the other hand it is well known that, if the ernal pressure exceeds a certain value, an infinitely long indrical shell of given small thickness and given diameter I collapse under the pressure. The critical pressure has been ermined by Bryan and Basset, who find the same result. It herefore to be expected that, if the cylinder is of sufficient gth, the extensional displacement which must be superposed on the displacement of pure bending in order to satisfy the i conditions will be practically unimportant, except in the ghbourhood of the ends. The problem is thus reduced to covering the order of magnitude of the length of the shell in ler that it may be treated as infinite when the thickness is all. For this purpose consider the case where the pressure is t equal to the critical pressure, and the displacement of pure nding in the infinite cylinder is consequently of the form v = A cos 20, u = 0, T = A sin 20, ere A is a small arbitrary constant. The displacement u is rallel to the generator, v is along the circular section, and along the radius outwards. By means of displacements of s form the equations of equilibrium can be satisfied, but the undary conditions at the ends cannot. Now take the case of infinite cylinder with an end x = 0, at which v and w must nish, and seek a displacement involving both flexure and tension of the middle surface to be superposed on the disicement given by the above form, such displacement to satisfy e equations of equilibrium and the boundary conditions:) that the new and to are equal and opposite to those above ven at x = 0; (2) that the new u, v, z vanish at x= oo. The quired solution can be determined and is of the form

is the thickness and d the diameter of the shell. If a be ken equal to the reciprocal of m is about 546 of the mean oportional between the thickness and the diameter, and it llows that whenever r is great compared with this quantity e influence of the end is unimportant, and the displacement proximates to one of pure bending. To make the tendency - collapse occur in practice, it would be necessary that the half ngth of the flue be great compared with -, and the praccal conclusion would be that for a flue of length / stability ould be secured if

} < n/m, or ? < NJ (dt),

here N is a considerable number. It is customary in staonary boilers to make the flues in detached pieces connected y massive flanged joints, so that the effective length of the e is the distance between consecutive joints. If the number be taken equal to 12 we have the rule that the distance tween the joints must be not greater than twelve times the ean proportional between the thickness and the diameter. he value N = 12 accords well with what has been found safe a practice, but the rule as to spacing the joints is new.on some formulæ of Codazzi and Weingarten in relation to the oplication of surfaces to each other, by Prof. Cayley, F. R.S.on the expansion of some infinite products, by Prof. L. J. ogers. On a theorem for bicizcular quartics and for cyclides rresponding to Ivory's theorem for conics and conicoids, by Mr. . L. Dixon. Using a form of the equation to these curves and

surfaces (in quadricircular and pentaspherical co-ordinates) already studied by Darboux and Casey, the writer deduced that the ratio of the distance of any two points to the product of the lengths of the tangents from them to a fixed focal circle or sphere is the same as for the pair of corresponding points. He also showed how the theorem for the Cartesian oval could be derived from its equation in terms of elliptic functions.A supplementary note on complex primes formed with the fifth roots of unity, by Prof. Lloyd Tanner. The author investigates a method of determining whether a complex number is prime or composite. The process takes two distinct forms, one of which was established, on different grounds, by Tchébicheff. The other appears to be new, and is convenient in testing the sets of complex integers described in the author's previous communication on the subject. The discussion is based upon a certain classification of complex integers according to the "orders" of their complexity, and this conception facilitates the direct factorization of complex numbers. The theory is restricted to the case of 5, but seems to be quite general. On the linear transformations between two quadrics, by Mr. H. Faber. In Creile's Journal, vol. v. (also Phil. Trans., 1858), Cayley gave a representation of the automorphic linear transformation of the unipartite quadric function in the notation of the theory of matrices. In the present paper the author extends Cayley's method to the determination of the general linear transformation of a given quadric into another given quadric, and applies the results to the determination of the general real linear transformation between two equivalent quadrics and to the reduction of a quadric to a sum of squares. The determination by this method of the general linear transformation between two quadrics depends upon the solution of an algebraic equation of the nth degree, to which the problem as it originally presents itself-viz., the solution of a system of n quadratic equations in n variables, is thus reducible. On maps and the problem of four colours, by Prince C. de Polignac.-On Fermat's proof of the problem that primes of the form 4n+ I can be expressed as the sum of two squares, by Mr. S. Roberts, F. R.S.

Entomological Society, May 10, Mr. Henry John Elwes, President in the chair.-Mr. R. McLachlan, F. R.S., exhibited for Dr. Fritz-Müller, of Blumenau, Santa Catarina, Brazil, specimens of larvæ and pupe of a dipterous insect, and read a letter from Dr. Fritz-Müller on the subject. The writer stated that the larvae were similar to those exhibited by Mr. Gahan, at a meeting of the society in October, 1890, and which were then thought by Lord Walsingham, F. R.S., and Mr. McLachlan, to be allied to the Myriapoda.-Mr. S. G. C. Russell exhibited specimens of Hesperia alveolus, including one of the variety Taras, taken by him at Woking in April last.-Mr. J. M. Adye exhibited a long series of Moma orion, Eurymene dolo. braria, Amphidasis betularia, Cloephora prasinana, and a few specimens of Notodonta dodonea, N. chaonia, and N. trepida, Acronycta alni, and Selenia illustraria, all bred by him in March and April last, from larvæ obtained in the autumn of 1892 in the New Forest.-Mr. H. Goss read a copy of a letter received by the Marquis of Ripon, at the Colonial Office, from the Governor of the Gold Coast, reporting the occurrence of vast swarms of locusts at Aburi and Accra, West Africa, about the middle of February last. The writer stated that at Accia the swarm extended from east to west as far as the eye could see, and appeared to occupy a space about two miles wide and from a quarter of a mile to a mile in height.-Colonel Swinhoe stated that some years ago he had been requested by the Indian Government to report on plagues of locusts. He said he had witnessed swarms of these insects far larger than the one just reported from the Gold Coast, and mentioned that many years ago, when going up the Red Sea in one of the old P. and O. paddle boats, the boat had frequently to stop to clear her paddle-wheels from locusts, which had settled in such swarms as to choke the wheels and stop their action.Mr. E. C. Reed, of Valparaiso, Chili, communicated a paper entitled "Notes on Acridium paranense, the migratory locust of the Argentine Republic." Colonel Swinhoe, Mr. Champion, Mr. Elwes, Mr. McLachlan, and Mr. Merrifield took part in the discussion which ensued.-Prof. L. C. Miall, F. R. S., communicated a paper entitled "Dicranota; a Carnivorous Tipulid Larva."-Dr. T. A. Chapman communicated a paper entitled "On a Lepidopterous pupa (Micropteryx purpurella) with functionally active mandibles." Mr. McLachlan said he thought Dr. Chapman's observations were of great value, and