June 30, 1892J 



NATURE 



21 



field in C.G.S. lines. To vary the sensitiveness in known 

 proportions, resistances are employed. Referring to the improve- 

 ments made in movable coil instruments since January 1890, 

 when a paper on " Galvanometers" was read before the Society 

 by Dr. Sumpner and the present authors, Prof. Ayrton said Mr. 

 Crompton had greatly increased the sensitiveness of Carpentier's 

 instruments by suspending the coils with phosphor-bronze strip. 

 Mr. Paul had brought out a narrow-coil instrument which com- 

 bined the advantages of portability, dead-beatness, quickness, 



and sensibility. Specimens. i uments were exhibited. 



The narrow coils are inclosed in silver tubes, which serve to 

 (lamp the oscillations. Such a coil is suspended within a brass 

 tube which also forms the mirror chamber, and slides down 

 between the poles of a circular magnet fixed to the base. To 

 clamp the coil, a plug mounted on a slotted spring passes 

 through a hole in the brass tube. A tube can be taken out and 

 replaced by another containing a coil of different resistance in a 

 few seconds. An instrument of this kind, with a coil of 300 ohms, 

 ijave 95 divisions per microampere, and the damping on open 

 circuit was such that any swing was ^V of t^ie previous one. On 

 comparing recent instruments with those mentioned in the paper 

 on galvanometers above referred to, a distinct improvement is 

 apparent, for their sensitiveness is, for the same resistance and 

 periodic time, as great as that of Thomson instruments. Prof. 

 Perry remarked that the forces dealt with were extremely small. 

 Mr. Swinburne thought that ballistic galvanometers mi^ht be 

 legarded as instruments indicating the time integral of E.M.F. 

 rather than quantity. Illustrating his meaning by reference to 

 dynamos, he said that if two machines arranged as dynamo and 

 motor were joined by wires, then, if the armature of the dynamo 

 were turned through any angle, that of the motor would move 

 through the same angle, supposing friction, &c., eliminated. 

 Speaking of figures of merit, he pointed out that the power con- 

 sumed was the important factor. Prof. S. P. Thompson inquired 

 what was the longest period yet obtained with narrow-coil instru- 

 ments. The decay of magnetism in large dynamos was so slow 

 that very long periods were required. He himself had used a 

 weighted coil for such measurements. He also wished to know 

 why the figures of merit were expressed in terms of scale divisions 

 on a scale at 2000 divisions distance, instead of in angular 

 measure or in tangents. Mr. E. W. Smith asked what was the 

 length of strip required to prevent permanent set when the 

 deflection exceeded a revolution. Mr. A. P. Trotter thought 

 that, in testing magnetic fluxes by the workshop ballistic instru- 

 ment, the test coil might be left in circuit instead of putting in 

 another coil. He wished to know what error was introduced 

 by the change of damping caused by the resistance of the circuit 

 not being quite constant. In his reply. Prof. Ayrton said Mr. 

 Hoys had pointed out that the scientific way to lengthen period 

 was not by weighting the coils or needles, but to weaken the 

 control. Periods of 5 seconds had been obtained. At present 

 it was not easy to obtain longer periods owing to difficulties 

 in obtaining sufficiently thin strip, and to the magnetism of 

 materials. 



Zoological Society, June 14.— Prof. W. H. Flower, C.B., 

 I. R.S., President, in the chair. — The Secretary read a 

 report on the additions that had been made to the Society's 

 Menagerie during the month of May 1892, callmg special 

 Ttention to a pair of the rare and beautiful Passerine bird the 

 ey Coly- Shrike {Hypocolius ampelinus) from Fao, Persian 

 ilf, presented by Mr. W. D. Gumming. He also made some 

 < iiiarks on the most interesting objects observed during a recent 

 visit to the Zoological Gardens of Rotterdam, the Hague, 

 Amsterdam, and Ant»Aerp» — A communication from Mr. T. D. 

 A. Cockerell contained particulars of the occurrence of a species 



NO. I 183, VOL. 46] 



of Jacana (Jacana spinosa) in Jamaica.— Dr. John Anderson, 

 F. K.S., exhibited and made remarks on some specimens of the 

 Mole-Rat {Spa/ax typhlns) from Egypt.— Prof. Romanes gave 

 an account of some results recently obtained from the cross- 

 breeding of Rats and of Rabbits, and showed that it did not 

 follow that a blending of the characters of the parents was the 

 result of crossing two different varieties.— Prof. Howes exhibited 

 and made remarks on some photographs received from Prof. 

 Parker, of Otago, New Zealand, illustrative of Sea- Lions, 

 Penguins, and Albatrosses in their native haunts.— Dr. Dawson 

 made remarks on the Fur-Seal of Alaska, and exhibited a 

 series of photographs illustrating the attitudes and mode of life 

 of these animals.— Mr. Sclater called attention to the habits of 

 a South African Snake {Dasypeltis scabra) as exhibited by an 

 example now in the Society's Gardens.— Mr. Sclater also read 

 some extracts from a letter addressed to him by Mr. H. H. 

 Johnston, C.B., announcing the despatch of a consignment of 

 natural history specimens illustrative of the fauna and flora of 

 the Shire Highlands.— Mr. W. Saville Kent exhibited and made 

 remarks on some photographs of a species of the genus Podargus, 

 showing the strange attitudes of these birds in a living state.— 

 Mr. F. E. Beddard read a paper on the brain and muscular 

 anatomy of Atiiacodus.—MT. Gerard W. Butler read a paper 

 on the subdivision of the body cavity in Snakes, being a con- 

 tinuation of the subject treated of in a memoir on the subdivision 

 of the body-cavity in Lizards, Crocodiles, and Birds, previously 

 read before the Society. — Mr. J. W. Grci^orv gave an account 

 of his researches on the British Palaeogene Bryozoa, of which 

 he recognized thirty species, represented in the National Collec- 

 tion by about 750 specimens. — Mr. Sclater gave an account of a 

 small collection of Birds from Anguilla, West Indies, made by 

 Mr. W. R. Elliott, one of the collectors employed by the Com- 

 mittee for the exploration of the Lesser Antilles.— Prof. G. J. 

 Romanes, F. R. S., read a paper on a seemingly new diagnostic 

 character of the Primates, which was that the terminal joints of 

 both hands and feet in all species of this Order are destitute of 

 hairs. This rule did not apply to the Lemurs.— Mr. O. Thomas 

 read a paper on the genus Echinops, of the order Insectivora, 

 and gave notes on the dentition of the allied genera Ericuhis 

 and Centetes. — Mr. G. A. Boulenger gave an account of the 

 Reptiles and Batrachians collected by Mr. C. Hose on Mount 

 Dulit, North Borneo. Amongst these was a fine new Lizard 

 of the genus Varanus, proposed to be called V. heteropholis. 

 Two new Batrachians were also described as Khacophortis 

 dulitensis and Nectophryne hosii. — A paper was read by Lieut. - 

 Colonel H. H. Godwin-Austen, F.R.S., on new species and 

 varieties of the Land-Molluscan genus Diplomtnatina, collected 

 by himself, and more recently by Mr. W. Doherty. in the Naga 

 and Munipur Hill ranges. The author described twenty-seven 

 supposed new species, the most remarkable being D. unicrenata, 

 with a peculiarly formed peristome. ^ — A communication was 

 read from Mr. B. B. Woodward on the mode of growth and the 

 structure of the shell in Velales conoideus, l.amk., and in other 

 Neritidie. The mode of growth and the structure of this shell 

 were described as follows : Up to a certain point the growth 

 is normal ; a change in the direction of growth afterwards takes 

 place, and the test is enlarged by the addition of fresh shelly 

 matter on the exterior of the under side, and by the removal of 

 previously-formed layers on the inner surface. The internal 

 septum that serves the purpose of a myophore was shown to 

 have originated in the paries, which, in the course of growth, 

 had been replaced by the septum. In this respect Velales 

 conoideus epitomized in its life-history conditions which are 

 found in distinct recent species of the closely-allied genus 

 Neriiina. The relations of the paries and septum in this last 

 genus were also described in this paper. — This meeting closes 

 the present session. The next session (1S92-93) will com- 

 mence in November 1892. 



Paris. 

 Academy of Sciences, June 20.— M. d'Abbadie in the 

 chair. — Phenomena of the residual life of muscle taken from the 

 living being : physiological action of the muscular bases, by 

 MM. Arm. Gautier and L. Landi.— On the influence of 

 mineral filters on liquids containing substances produced by 

 microbes, by M. Arloing. — On the sanitary system adopted by 

 the Venice Conference to prevent cholera from penetrating into 

 Europe through the Isthmus of Suez, by M P. Brouardel. 

 Four previous conferences for the reform of the quarantine sys- 

 tem having failed, that convened at Venice in January 1892 has 

 at last adopted a system chiefly advocated by the French dele- 



