94 



NA TURE 



[May 



1907 



of tellurium to ninety-nine parts of selenion at a tempera- 

 ture of 360° C. The sublimate contains certainly less 

 than one-tenth per cent, of tellurium, and probably less 

 than one-fortieth per cent., the extreme limit of analytical 

 discrimination. 



A thorough investigation showed that tellurium cannot 

 be detected in presence of selenion in quantity by spectro- 

 scopic analysis. Details as to the method of carrying out 

 Ekman's and Petterson's purification are given. The 

 purified product was tested for arsenic with constant refer- 

 ence to check and blank trials, and it was found that 

 arsenic was present to the extent of 000038 per cent. 

 Mercury was sought for by the method suggested by 

 Marcel, and also by Dr. Sand with a special electrolytic 

 apparatus, but none was found. 



The remaining difficulty in regard to a possible solubility 

 of selenion dioxide in selenion was not entirely overcome, 

 though it is shown that by distillation of a mi.xture of 

 selenion and selenion dioxide in an inert gas nearly, if 

 not all, the dioxide can be separated, but there does not 

 seem to be any perfectly satisfactory criterion as to the 

 complete absence of dioxide. This uncertainty prevented the 

 subject of the conductivity of really elemental selenion from 

 being undertaken, but the highly purified material obtained 

 was examined by Messrs. Vonwiller and Mason with re- 

 spect to its specific inductive capacity. The material 

 employed by these observers was returned to the author 

 for re-examination, and it is shown that no material 

 amount of impurity was introduced during the necessary 

 meltings and treatment which it had undergone. 



Royal Microscopical Society, April 17. —Mr. G. C. 

 Karop in the chair. — The Podura scale : E. M. Nelson, 

 The author traced the efforts of previous observers to 

 interpret the markings on the scales, giving figures — 

 which were drawn to an enlarged size upon the board — 

 to illustrate the various interpretations, including the 

 result of his own observations. — The root bacteria of 

 pulse : Dr. Antonio Rodella. 



Zoological Society, April 23. — Dr. J. Rose Bradford, 

 F.R.S., vice-president, in the chair. — The ears of the 

 African elephant as a race character : R. Lydekker. To 

 illustrate this paper, a large number of photographs and 

 several specimens were exhibited. The author considered 

 that there must be many more local races than those 

 already named by Dr. Matschie, although, with the pre- 

 sent material, he hesitated to give separate designations 

 to several of these. He ventured, however, to propose new 

 names for the elephant of the eastern side of Cape Colony ; 

 for that of Mashonaland, as typified by a head in the 

 Imperial Institute; for that of the Lake Rudolf district, 

 as represented by a head presented to the British Museum 

 by Mr. H. S. H. Cavendish ; and for the Somali elephant, 

 as typified by a head in the collection of S.A.R. le Due 

 d 'Orleans at Wood Norton, this last race being character- 

 ised by the very small ears, which, however, were quite 

 dilTerent in shape from those of E. a. knochenhaueri. 

 The author also directed special attention to a skull from 

 the Albert Nyanza district, for which he had previously 

 suggested the name E. a. albertensis. Differing in many 

 points from those of other African elephants, this skull 

 showed a remarkable resemblance to that of the extinct 

 Indian E. planifrons, thus suggesting the descent of the 

 African elephant from that species. — Descriptions of three 

 new species and five new subspecies of Siberian birds : 

 S. A. Buturlin, — A list of small mammals obtained in the 

 islands of Saghalien and Hokkaido by Mr. M. P. Anderson 

 for the Duke of Bedford's exploration of eastern Asia : 

 Oldfield Thomas. Fourteen species were recorded from 

 Saghalien and thirteen from Hokkaido. The faunas of the 

 two islands proved to be very similar to each other, 

 although in some cases subspecific differences between the 

 representative forms in each were perceptible. In one 

 genus only, Micromys, the relationship of Hokkaido 

 seemed to be with the main island of Japan rather than 

 with Saghalien. — A list of the cold-blooded vertebrates of 

 Saghalien : G. A. Bouleng^er. — Notes on hybrid bears : 

 H. Schercen. The author referred to cases that had 

 occurred in the society's gardens, the long series bred by 

 Herr Nill in his zoological garden at Stuttgart (now broken 

 up), and a recent case in the garden at Halle-an-dcr- 



NO. i960, VOL. 76] 



.Saale. Reference was also made to cases said to have 

 occurred at Cologne and Hanover, but for these the 

 evidence was not conclusive. — Some new species of earth- 

 worms of the family Eudrilida;, belonging to the genera 

 Polytoreutus, Neumaniella, and Eminoscolex from Mt. 

 Ruwenzori : F. E. Beddard. — South .American pseudo- 

 scorpions of the family Cheliferida; in the collections of the 

 British and Copenhagen Museums : C. J. With. 



Physical Society. April 26. — Prof. J. Perry, F.R.S., 

 president, in the chair. ^ — Electrical conduction produced 

 by heating salts : .\. E. Garrett. The experiments de- 

 scribed are divided into two series. The first, of a pre- 

 liminary nature, consisted in testing a large number of 

 inorganic compounds up to a temperature of 360° C. 

 Several compounds, chiefly halogen salts, were found to 

 produce easily detected conductivity when heated. In the 

 case of zinc iodide, conductivity could be detected at the 

 ordinary temperatures of the laboratory. The second series 

 was confined to special cases in order to ascertain the 

 causes of the increased conductivity. It was found that 



in all the cases trie<l a fnniiula of the form I=o6^<,' ', 

 where I = saturation current, a and b constants, and 8 the 

 absolute temperature, represents with fair accuracy the 

 connection between the saturation-current anU the absolute 

 temperature. — Solenoids which will move under the action 

 of the earth's magnetic field : \V. B. Croft. In showing 

 Ampere's experiments, it is not very easy to complete the 

 theory of magnetism by making a solenoid point to the 

 north. Many years ago Ritchie made a solenoid with an 

 iron core, which acted as a motor with the help of a 

 mercury commutator. A copper solenoid without core was 

 shown which had been made to rotate in this manner. 

 The method is unsatisfactory and uncertain, owing to the 

 rigidity assumed by the skin on the surface of mercury in 

 certain conditions. The ampere mercury contacts cause 

 no difficulty when a wire rotates on its own a.xis, but 

 there are strong hindering forces when the wire is pushed 

 through the mercury, partly from the skin and partly from 

 amalgamation. The best pattern for a solenoid is sug- 

 gested by the moving coil of an electrodynamometer. Two 

 of such were shown, which were conveniently worked by 

 four dry cells in series. Each of these was hung with very 

 thin metal strip by bifilar suspension, the threads about 

 5 inches long and I'loth inch apart. The bifilar control 

 makes the movements manageable ; it is convenient to set 

 the -coils N. and S., or the axis of the corresponding 

 magnets E. and W., so as to make these swing up to the 

 meridian when a current is sent through the coils. — The in- 

 fluence of pressure upon convection currents, and a criticism 

 of J. Stark's relation between kathode fall of potential and 

 temperature : W. S. Tucker. Stark employed as kathode 

 a wire mounted radially in a globe-shaped vessel. The 

 wire was heated electrically, and its resistance, and hence 

 its temperature, determined. He refers to the weaknesses 

 of the method : — (i) the conduction of heat away from the 

 wire by its leads causes the observed mean temperature 

 to be too low; (2) the error made in assuming the kathode 

 dark space temperature to be that of the heated kathode. 

 The author's apparatus was devised to show how seriously 

 these weaknesses affect Stark's results. — A simple 

 apparatus for mechanically illustrating the tangent and 

 sine laws : J. A. Tomkins. 



Geological Society. May I. — Sir Archibald Geikie,Sec.R.S., 

 president, in the chair. — The xerophytic character of coal- 

 plants, and a suggested origin of coal-beds : Rev. Prof. 

 George Henslow. It is held that the characteristic feature 

 of the great coal-forests was xerophytic, and the vegetation 

 appears to be of an upland type. Illustrations are given 

 from recent and Carboniferous plants to show the 

 characters of leaf, root, and stem which separate these 

 classes of plants. The position of coal-seams is accounted 

 for by the action of earth movements in late Carboniferous 

 times ; these threw the forest-bearing surface into shallow 

 waves and troughs, which became gradually accentuated, 

 the latter being gradually filled with sediment, upon which, 

 during intervals of rest, new forest growth took place. — 

 Petrological notes on the igcnous rocks lying to the south- 

 east of Dartmoor : H. J. Lowe. The rocks described are 



