June 23, 1898] 



NATURE 



i^i 



capsule whilst attached to the inner wall of the coenoecium, and 

 results in the form of a larva segmented into two parts by an 

 annular constriction. — Mr. Malcolm Laurie gave a description 

 of anew Silurian scorpion from the Pentland Hills, the fourth that 

 had been found in Silurian rocks. Regarding certain structures 

 on the abdominal segments, the hypothesis was advanced that 

 the new form was a water-breathing animal. A description was 

 also given of some new Eurypterids, of which no fewer than 

 twelve species had been found in this particular Pentland bed. 

 — Dr. Masterman also communicated a paper on the theory 

 of archimeric segmentation, considered in relation to the 

 classification of the Ca-lotnata. This was a following up of 

 a suggestion made in a recent paper that in the morphology of 

 the Calomata there are two distinct types of segmentation : («) 

 a primitive or archimeric type, having in its constitution 

 evidences of a radial origin, and {b) a secondary or metameric 

 segmentation superposed upon the former, and bearing evidence 

 of a bilateral origin. 



Mathematical Society, June lo.— Dr. Mackay in the chair. 

 — The following papers were read : — Notes on permutations, 

 &c., by Mr. R. F. Muirhead. — Extension of the method of 

 displacement-sequence, by Mr. R. F. Muirhead. — Converse 

 theory of binomial theorem, by Mr. Sita Noth Chokrobarthy.— 

 Elementary notes, by Mr. W. J. Butters. 



Dublin. 



Royal Dublin Society, May i8.— Prof. D. J. Cunningham, 

 F.K.S., in the chair. — Dr. F. T. Trouton, F.R.S., communi- 

 cated a method of measuring the surface tension of liquids which 

 depends on the rate at which a column of liquid fills, or empties 

 itself out of a tube of fine bore. The tube is placed horizontally 

 and has one end bent downwards into a vessel of the liquid. By 

 altering the level of the liquid it can be either arranged to 

 measure the rate the tube fills, in which case the capillary forces 

 draw the liquid up, or the rate it empties, the capillary forces 

 retarding Were the flow viscous the distance traversed would 

 be proportional to the square root of the time. This was shown 

 to be approximately true. Experiments were described using an 

 inclined tube with a wide bent-down portion attached to the 

 lower end. The rate of emptying could be made constant by 

 making the height of the liquid in the wide part equal to the 

 capillary elevation in the fine tube. Experiments were also 

 described made with liquids such as soap solution, where surface 

 tension varies with time. — The Rev. H. O'Toole exhibited and 

 described a new hydrometer, whicli consists of a stem at the 

 lower end of which is a weighted bulb, as in any of the common 

 forms of hydrometer ; higher up on the stem is another bulb, 

 which causes the instrument to float, and at the top is a dish in 

 which weights may be placed. Between the floating bulb and 

 the dish there is another bulb, which may be called the standard 

 bulb. The method of use is as follows : the apparatus is im- 

 mersed in a given liquid, and weights added to make it sink to 

 a marked point between the floating and standard bulbs ; addi- 

 tional weights are then added to immerse the standard bulb to 

 ?nother marked point near the dish ; these additional weights 

 ire evidently the weight of a volume of the liquid equal to the 

 volume of the standard bulb. The weight of the same volume 

 of water may be similarly found, and thus the specific gravity 

 determined.^ — Prof. D. J. Cunningham, F. R.S. , and Mr. Joseph 

 Welland exhibited an apparatus foj lantern-photography of 

 microscopic objects. This is of intei-est as afl^ording a means of 

 using an ordinary optical lantern, with or without a microscopic 

 projector, for making enlarged photographs of transparent micro- 

 scopic objects, the precise degree of enlargement wished for being 

 readily obtained. It has been employed chiefly for photo- 

 graphing large sections «f the brain, ajnd it is. particularly well 

 adapted for this purpose. ' Further, by means of this apparatus, 

 transparencies reproducing the diflferent colours of stained and 

 injected tissues can be readily obtained by the Joly process. Slides 

 showing a section through a kidney injected in two colouris (red 

 and blue) and a picrocarmine specimen of hair follicles were 

 exhibited. — Mr. Richard J. Moss exhibited an apparatus for 

 drying bodies in vacuo at various temperatures. Steam or other 

 vapour is passed through a flat coil of pipe in an inverted beU- 

 jar, closed with a glass plate and rubber ring, and attached to a 

 water vacuum pump. A flat-bottomed platinum capsule con- 

 taining the substances to be dried rests on the coil of pipe, and 

 any desired desiccant is placed in a tray above it. 



NO. 1495. VOL. 58] 



Academy of Sciences, June 13.— M. Wolf in the chain- 

 Liquid air, by M. d'Arsonval. An account of the Lirjde pro- 

 cess of liquefying air. An expenditure of rather less than three 

 horse-power gives a litre of liquid air per hour.— Spectroscopic 

 researches on atmospheric air, by M.M-' H. Mdissah and H. 

 Deslandres. A sealed note deposited May 11, 1896.— ftemarjcs 

 by M. H. Moissan on the above. — On the direct measurement 

 of a quantity of electricity in electromagnetic units ; application 

 to the construction of a current meter, by M. R.' Blondlot. A 

 coil in the form of a ring is hung, on a- vertical axis inside a 

 long horizontal bobbin, the same current passing round both 

 coils. The product of the intensity of the current ftito the time 

 of oscillation, that is, the quantity of electricity which traverses 

 any given section of wire during one swing, i$ a consta,9t 

 quantity, depending only on the construction, of tHe two 

 bobbins. By the application of a device fdr counting the vibra- 

 tions of the small coil, a practical coulomhm'eter is obtained, 

 which works equally well with continuous and alieritating 

 currents.— On differential equations cTf the second order at fixed 

 critical points, by M. Paul Painleve. — On the prqbletn of in- 

 tegration from the point of view of real variable's, by M. R. 

 Baire. — On mixtures of gases, by ^L Daniel Berthelot. A 

 discussion of Dalton's Law of mixed gases. Starting with the 

 assumption that the law of Avogadro is only true in the 

 limiting case of infinite volume, an expression is developed 

 for the constants in the Van der Waal equation to the mixture. 

 The results found experimentally by M>L Leduc and Sacerdote 

 are in perfect agreement with the theory. — On the study of 

 the radiations of mercury and the measurement of their wave- 

 lengths, by MM. Ch. Fabry and A. Perot. A comparison of 

 the green line and two yellow lines of mercury with the cadmium 

 lines by means of the interferential spectroscope described in 

 previous papers. — On the electrical resistance of steel, by 

 M. n. Le Chatelier. The steels were examined in the form 

 of well annealed bars, 20 cm. long and i sq. cm. in section. 

 The resistance increases with increasing percentage of carbon, 

 and similarly with silicon, i per cent, of the latter having double 

 the efi"ect of the same amount of carbon. Steels containing 

 manganese, nickel, chromium, tungsten, and molybdenum were 

 also examined. — Entoptic vision, and sensibility in the 

 yellow spot, by M. Aug. Charpentier. — On the atomic weight 

 of nitrogen, by M. M. Vezes. From the densities of nitrogen 

 and its compounds M.Daniel Berthelot has deduced an atomic 

 weight of 14-005 for nitrogen, whilst the figure given by Stas 

 is I4'044. This discrepancy cannot be accounted for, as M.M. 

 D. Berthelot and Leduc have assumed, by the systematic error 

 introduced by oxygen di.ssolved in the silver, as M. Stas has 

 himself carefully reconsidered the whole of his work in the light 

 of this objection of Dumas, and has .shown that the effect is 

 practically negligible, the atomic weight in question being only 

 lowered from I4'044 to 14O40. The cause of the difference 

 still remains to be explained. — On the atomic weight of 

 tellurium, by M. R. Metzner. The tellurium employed in this 

 research was prepared by the decomposition of tellurium hy- 

 dride at 500° ; it is certain that this metal must be free from 

 antimony and bismuth. The reactions chosen were the conver- 

 sion of the metal into its sulphate, and the reduction of tellurous 

 acid with carbon monoxide. The mean result is 127 "9. — Action 

 of sodammonium in excess upon red phosphorus, by M. C. 

 Hugot. — On the preparation and properties of ajiew carbide of 

 tungsten, by M. Percy Williams. The carbide ^ produced by 

 the interaction of tungstic acid, carbon, and iron at the tem- 

 perature of the electric furnace. Its formula is WC, and is dis- 

 tinguished from the carbide WjC, discovered by M. Moissan, in 

 not being attacked by chlorine. — New method of separating 

 geraniol and citronnellol, by MM. J. Flacau and H. Labbe. 

 The essence is converted into phlhalic ethers by heating with 

 benzene and phthalic anhydride, and these separated by means 

 of ligrpin. The ethers are described in detail. — Oh the con*- 

 position of fish, Crustacea, and molluscs, by M. Ballard. De- 

 terminations of water, nitrogen, fat, extractives, and ash for a 

 large number of fish, Crustacea, and molluscs. — On the crystal- 

 line forms of quartz from Meylan, by M. Ferdinand Gonnard. 

 — On the direct fertilisation in some plants in which the flowers 

 would appear to be adapted to cross fertilisation, by M. C. 

 Gerber..— On a remarkable fault between Brives, P^rigueux and 

 Angouleme, by M. Ph. Glangeaud.— On new sources of petro- 

 leum in the Caucasus, by M, Venukoff. Naphtha-bearing sand 

 has been found near Anaclie, in the Eastern Caucasus. — 



