4/8 



NA TURE 



[March i6, 1899 



lo ihe primary of an induclinn coil through a Wehncit inlerrupter 

 produced only about half the effect of the corresponding direct 

 current — apparently, only half the alternations got through. But 

 if two interrupters were connected in parallel circuits it was 

 possible so to arrange them that one took one-half and the other 

 the second half of the alternations. Il might, therefore, be 

 possible to design an[induction coil with two jirimary windings to 

 correspond to the two interrupters, so as to give an additive 

 effect. The induction coil he had used had suffered no damage 

 from the currents employed in the experiments exhibited ; there 

 was extremely little heating of the secondary. He could not 

 with his apparatus restore the working condition by any 

 mechanical disturbance of the inlerrupter. Hydrochloric acid 

 failed, but a saturated .solution of potassic bichromate gave fair 

 results. The President, in proposing thanks, said he did not 

 agree with Mr. Campbell Swinton's remarks as to the chances 

 of improving Hertzian telegraphy by the use of these inter- 

 rupters. The rate of interruption with this apparatus was some- 

 thing like 1000 per second, but the vibrations corresponding to 

 Hertz waves were of the order 100,000 per .second. The wave- 

 trains from oscillators excited by the new interrupter would 

 still be a series of damped vibrations ; the amplitudes would not 

 lie maintained. It might be advantageous to have sparks 

 following one another so rapidly, but he doubted it. For 

 Hertzian telegraphy, the spark at the oscillator should 

 "crackle"; to produce the best effect, the air about the 

 <i';cillator should be in a non-electric condition. — A paper by 

 Mr. A. (Jriftiths, on an apparatus for the determination of the 

 rate of diffusion of solids dissolved in liquids, was then read. 

 The apparatus consists of a cylindrical glass vessel subdivided 

 about midway by a horizontal non-porous partition, into which 

 are fitted a numljer of vertical tubes. The lower section of the 

 vessel is filled with a liquid, such as an aqueous solution of 

 cupric sulphate, and the upper one contains pure water. 

 The method consists in determining by chemical analysis 

 the quantity of cupric sulphate transmitted up the tubes. The 

 jiaper gives the theory of the method, with very few experi- 

 mental results. Ordinary diffusion observations are affected by 

 the flow of liquid in the tubes due (I) to charges of temper- 

 ature of the apparatus as a whole; (2) to differences of tem- 

 perature throughout the liquid ; (3) to local variations in volume 

 produced by the process of diffusion ; (4) to inequalities in the 

 lengths of the tubes. Equations are given for determining the 

 magnitudes of the sources of error, and certain numerical cases 

 are worked out.— The same author also contributed a note on 

 the source of energy in diffusive convection. Diffusion tends 

 to produce local changes of density, causing gravitational cur- 

 rents, which currents can be made to do work. By "diffusive 

 convection," the author means these gravitational currents. The 

 heat equivalent of the work done is determined in a particular 

 case, i.e. for a subdivided vessel, as in the above paper, having 

 two tubes of unequal length. He points out that the heat ab- 

 .sorbed, owing to diffusion through one of the tubes, is indepen- 

 dent of the mechanical motion of the liquid in that tube, and 

 it is also independent of the length of the tube.— The President 

 proposed a vote of thanks, and in doing so described an ap- 

 paratus he had used for a thermostat. A double-walled cylinder 

 of copper sheet, with a little water in the inter-space, is ex- 

 hausted at atmospheric temperature until the water boils. It 

 is then sealed. Water-vapour is a powerful equaliser of tem- 

 perature, and a vapour-jacket of this kind is very efficient when 

 it is required to maintain uniform temperature — not constant 

 teiTiperature. Mr. Watson described the inethod of Mr. V.. H. 

 Criffiths, who used lap-water as a negative source, and a gas- 

 flame as a positive source, with extremely good results as a 

 thertnostat for constant and for uniform temperature.— The 

 meetine then adjourned until March 24. 



Entomological Society, March i.— Mr. G. H. Verrall, 

 I'resident, in the chair. —Mr. J. J| Walker exhibited a specimen 

 of a rare British beetle, Qiicdius lon^icornis, Ivtz., recently 

 taken at Cobham I'ark, Kent. Mr. M. Jacoby exhibited a 

 Halticid beetle from Sumatra, of the genus Chalocnus, Westw., 

 and called attention to the remarkable position of its eyes, 

 these organs being placed at the end of two very distinct 

 lateral processes of the head, somewhat resembling the stalked 

 eyes of crabs and other Crustacea. He said this character was 

 peculiar to the male sex, and was very exceptional in Cole- 

 optera, not being met with in any other genus of I'hytophaga, 

 and only occurring in a few Anthribida.-, and in isolated cases 

 in one or two other families. He also showed a beetle from 



^"O. 1533. VOL. 59] 



Peru, which was sent to him in a collection of Phytophaga, 

 and, superficially, was very like certain members of that group ; 

 but from the structure of the antenna and other characters, it 

 appeared to be out of place in the Phytophaga, and probably 

 belonged to some other family. Mr. Gahan remarked that this 

 beetle, to whatever family it might prove to belong, was very 

 interesting, not only from its structural peculiarities, but 'also 

 from the fact that it had the colour and markings characteristic 

 of certain species of Galerucidse, a family to which it undoubtedly 

 was not in any way closely related. This fact seemed to show 

 that it was a mimetic form, and thus helped to explain the 

 present obscurity surrounding its affinities. — -Mr. G. J. Arrow 

 contributed a paper " On Sexual Dimorphism in beetles of the 

 family Kutelijac," and sent for exhibition a series, including 

 both sexes, of six species of Anomala, selected to illustrate the 

 subject of his paper. 



Chemical Society, March 2. — Proi. Dewar, President, in 

 the chair. — The following papers were read : — Bromomethylfur- 

 furaldeh'yde, by H. J. H. Fenton and M. Gostling. The sub- 

 stance which gives rise to the purple coloration when ketohexoses 

 are treated with hydrogen bromide in ethereal solution is a . 

 bromomethylfurfuraldehyde of the constitution 



ClI : C^CHO 



I >0 ; 



CH : C/ CH.,Br 

 it has a golden yellow colour and seems only to be produced 

 from ketohexoses or substances capable of yielding them by 

 hydrolysis. — The reaction of alkyl iodides with hydroxylamine. 

 F'ormation of alkylated hydroxylamines and oxamines, by W. R. 

 Dunslan and E. Goulding. The hydriodide of trimethyloxamine 

 (CH^IjN : O, is obtained by the action of methyl iodide on 

 hydroxylamine ; the base yields the iodide of trimethylmethoxy- 

 ammonium by treatment with methyl iodide. The reactions of 

 these substances are described, and also the products of the 

 interaction of hydroxylamine with other alkyl iodides — Deriva- 

 tives of aa'-dibromocami)horsulphonic acid, by A. Lapworth. 

 On heating ammonium o-bromocamphorsulphonate with 

 bromine and water an aa'-dibromocamphorsulphonic acid, 

 CioHijBrjO . SO3H, is formed; its acid bromide loses sulphur 

 dioxide on healing, yielding aa'T-tribromocamphor, CiuHuBrjO. 

 — Ethylic j85 dimethylpropanetetracarboxylatc, by W. T. 

 Lawrence. Ethylic /8S - dimethylpropanetetracarboxylate, 



CMe.i[CH(COOEt)J.j. is obtained by the interaction of ethylic 

 isopropylenemalonatc with ethylic sodiomalonate ; on hydro- 

 lysis with potash it yields i8«J-dimethylpropanetricarboxylic 

 acid. — The action of metallic thiocyanates on certain substituted 

 carbamic and oxamic chlorides ; and a new method for the 

 production of thiobiurots, by A. E. Dixon. — A reaction of some 

 phenolic colouring matters, by K. G. Perkin. A number of 

 metallic derivatives of colouring matters containing hydroxyl 

 groups in relatively ortho-positions are described. — Note on the 

 optical activity of gallotannic acid, by O. Rosenheim and P. 

 Schidtowitz. 



Royal Microscopical Society, February 15.— Mr. E. M. 

 Nelson, President, in the chair. —The President called the 

 attention of the Fellows to a beautifully made micro.scope by the 

 late Andrew Ross, which had been presented to the Society by 

 Messrs. Watson and Sons. It had a rotating foot, into which 

 the standard was fixed eccentrically ; this was not, however, an 

 original idea, having been used by Cuff in 1760. — .Mr. Beck 

 exhibited a very ingenious and compact reversible compressorium 

 designed by Mr. 11. U. Davis. Dr. Tatham said that being 

 made chiefly of ebonite, it was comparatively light, and in his 

 ojiinion would be found a useful accessory by the naturalist. — 

 Messrs. Walson and Sons exhibited a new model of their \"an 

 Ileurck microscope, designed to give complete rotation to the 

 stage, a feature which the President described as a step in the 

 right direction, the great desirability of which he said had been 

 insisted upon by l)r. Dallinger and Mr. Michael. Messrs. 

 Watson also exhibited a new cover-glass clip devised by Mr. 

 Pake.s, of Guy's Hospital, for making blood lilms. Dr. Hebb 

 thought it likely to be of use, especially as the technique of the 

 blood was coming more and more into notice. ^The I'resident 

 referred lo the .Martin microscope presented to the Society 

 last year ; he had come to the conclusion that it was 

 not made by Benjamin Martin, but it was a very good 

 imitation, probable date about 1S50. — The President read 

 a letter he had received from Mr. Keeley, of Philadelphia, 

 with a slide of diatoms mounted on edge, and some photo- 



