February 28, 1895] 



NATURE 



43 i 



sekten Deutschlands " some sixteen years ago, and as he was 

 engaged on a cla'isification of the Coleoptera of the world, he 

 included a considerable number of these exotic species in his 

 work. — Mr. G. F. Hampson read a paper entitled "Descrip- 

 tions of New Heterocera from India." 



Mineralogical Society, February 5. — Dr. Hugo MiiUer, 

 F. R. S., in the chair. — Prof. Judd read a paper on some simple 

 crys'alline rocks (massive minerals) from India and Australia. 

 From specimens supplied by Mr. T. II. Holland, of the Geo- 

 logical Survey of India, Mr. P. Bosworth Smith, Lite Govern- 

 ment Mineralogist at Madras, and Mr. C. Harrington Brown, 

 the author was able to make known some new types of rocks. 

 Two remarkable forms of corundum-rock were noticed, one 

 from Pipra, S. Rewah, first brought to the knowledge of 

 mineralogists by Mr. F. R. Mallet, and the other from Hunsur 

 Talug, in the Mysore State. A fibrolite rock, derived from the 

 same district as the last, was also noticed. A new variety of 

 tourmaline (schorlj-rock with a fibrous texture, having a wide 

 distribution in India, was likewise described, and an analysis, 

 together with a descrirition of the optical properties of the 

 mineral, was given. From the Bingera district in New South 

 Wales, two dykes were described as traversing masses of serpen- 

 tine, one heing composed of a green garnet-rock (urossularite?) 

 yielding gold, and the other of picolite, the chrome-spinel. 

 — The Earl of Berkeley read a paper on an accurate 

 method of determining the densities of solids, in the 

 course of which it was shown that by taking suitable 

 precautions with a pyknometer having a thermome'er stopper 

 and a capillary at the side, re>u!ts accurate to 003 per cent, 

 could be obtained. The actual values for different crops of 

 rubidium alum were 1-8884, 1-8885, I 8885 and 1-8889. '1 he 

 chief point of the communication was that the evaporation of 

 the lir|uid used in the ol>serva'ions (CCI4) from the him formed 

 between the stopper and the neck of the pyknometer, instead of 

 lieing a source of error, is utilised to bring the level of the 

 liquid into coincidence with the mark on the capillary. — Prof. 

 Church made a communication on the derermina'ion of mineral 

 densities. Three points were specially referred to : The em- 

 ployment of dilute alcohol instead of water was recommended 

 as enabling full advantage to b; taken of the sensitiveness of 

 an assay balance ; the results quoted for specimens under two 

 grams in weight were probably correct to -003. A method of 

 removing interstitial air by first replacing it with carbon di- 

 oxide, and then absorbing this gas by an alkaline solution or 

 byboiled water was descritaed. An account was next given of a 

 method of determining relative densities by means of mercury, 

 the volume of mercury displace 1 by the mineral being weighed. 

 Although no novelty was claimed for these methods, special 

 precautions ill their conduct were nam<d, and illustraiions ad- 

 duced of their application to the determination of mineralogical 

 problems. 



Cambridge. 



Philosophical Society, February 11. —Prof. J. J. Thomson, 

 President, in the chair. — On a method of determining the con- 

 ductivities of badly conducting substances, by Prof. J. J. 

 Thomson. A sphere of the substance the conductivity of which 

 is to be determined is placed inside a coil A through which 

 very rapidly alternating currents are passing. The currents 

 induced on the sphere react on those in the coil. K small coil 

 H placed in series with A contains a highly exhausted bulb in 

 which a ring discharge is produced by the alternating currents. 

 .\ny change in the intensity of the currents through A produces 

 a change in the brightness of the discharge through the bulb 

 inside B. The effect produced by the sphere inside A is 

 measured by the change in the brightness of the discharge 

 within B, and as the elfect produced by the sphere depends on 

 its conductivity, the observaion of changes in the brightness of 

 the discharge makes it possible to compare the conductivities of 

 different substances. The paper contains applications of this 

 method to the study of the conductivity of electrolytes under 

 very rapidly alternating currents, of rarefied gases, of gases 

 when entermg into chemical combination, of (lames, and 01 the 

 effect ol the formation of drops of water from aqieous vapour. — 

 Note on the calinraiion of the wire of a Wheaistone bridge, by 

 Mr. li. 11. Griffiths. 



Berlin. 



Physiological Society, January 4, — Prof, du BoisReymond, 

 President, in the chair. — In the discussion on Prof. Waldeyer's 

 discourse (of December 2!, 1S94), Dr. Benda and Dr. Rawitz 



NO, 1322, VOL. 51] 



laid stress on the anatomical difficulties which stand in the way 

 of the generalisations of Golgi's school, and Prof. Gad made 

 his protest from the physiological point of view. Prof. 

 Waldeyer recognised the propriety of the objections made 

 against the newer views as to the minute anatomy of the 

 nervous system, views due to those recent methods of re- 

 search which have led to a very distinct advance in knowledge. 

 Dr. Ziegenhagen communicated the results of his researches on 

 the development of the blood-vessels in trout-embryos, based 

 on observation of the living object, on injections by Wert- 

 heim's method, and on photographs. 



January 18. — Prof, du Bois Reymond, President, in the chair. 

 — Dr. Benda explained the preparations he exhibiied of 

 nerve-endings in muscles made by Prof. Sihler, of Cleveland. 

 — Dr. Rawitz described a new method of staining cells with 

 aniline dyes, which consists in first mordanting the tissues, 

 harrtened in P'lemming's fluid, with tannin and tartar emetic, 

 and then treating them with the dye. By this method of 

 " adjective "staining, only the protoplasm of the cell is coloured, 

 not the nucleus. The same speaker next described some results 

 of his method as applied to resting-cells of salamander testis. 

 The nucleus shows the brown-coloured chromatin filaments ; 

 the linin network and the distinct nuclear membrane are of 

 a pale red colour. In the middle of the protopKasm, at some 

 distance from the nucleus, is the dark-red attraction sphere 

 with the centrosome in its midst. Close-set meshes of the net- 

 work of red fibrils, which permeate the protoplasm, and are in 

 other pans less close-se-, join on to the periphery of the 

 sphere, and are in direct communication with the nuclear 

 membrane and the linin filaments. Occasionally the attraction 

 spheres of two neighbouring cells a'e joined together by a dark- 

 red filament. — Dr. Cohnstein described experiments on the 

 action of intravenous injections of sodium chloride on the com- 

 position of lymph and blood, and showed that the observed 

 variations of quantity and of the amount of water and salt in 

 the lymph, as also the changes in the amount of salt in, and 

 concentration of the blood, could be adequately explained by 

 the purely physical processes of diffusion and filtration. 



Meteorological Society, January 8. — Prof. Hellmann, 

 President, in the chair.^Dr. L. A. Bauer discoursed on the 

 secular changes of terrestrial magnetism. From the observa- 

 tions available at an extended series of stations he had deter- 

 mined the declination and dip of a magnetised needle freely 

 suspended at its centre of gravity, and had compared the curves 

 of secular change thus obtained with the corresponding formulas. 

 Taking older compass-charts additionally into consideration, he 

 found that the curves of secular change must contain loops. 

 If one imagines a magnetised needle, freely suspended at its 

 centre of gravity, to be carried round the earth along a given 

 parallel, one obtains the momentary curve of terrestrial 

 magnetism for that parallel, and this curve corresponds to the 

 curve of secular variation. This curve further shows a distinct 

 loop, as, for example, for the parallel 40' N. In the discussion 

 which followed, the President drew attention to the fact that 

 the statements of the oUler travellers as to compass bearings 

 cai.not well be used for determining the components of terres- 

 trial magnetism, since each compass was specially arranged in 

 order to show the astronomical north-pole, and hence it is 

 necessary, first of all, to know what this special arransjement 

 was before their indications can be used. — Dr. Kassner de- 

 scribed a "fohn" wind in the Riesengebirge, which was very 

 marked on Novcjjber I and 2 last, on the north fall of the 

 mountain, and caused by the high temperature and excessive 

 dryness. The dryness and great transparency of the air was 

 observed as far as Breslau, a distance of 100 kilometres. 



Physical Society, January 11. — Prof, du Bois Reymond, 

 President, in ihe chair. — Dr. .-Mtschul made communications 

 from the Raoul Piclct Institution, dealing first with the 

 influence of intense cold (-70° to -200" C.) on along series of 

 chemicil processes, and in the next place on physical processes, 

 such as phosphoresence, &c. He then reported upon experi- 

 ments on the behaviour of bodies at the critical temperature. 

 The disappearance and reappearance of the meniscus .v as found 

 to take place always at the same temperature as lung as the 

 warming of the substance was uniform. It was found that the 

 critical temperature is a better criterion of the chemical purity 

 of a liquid than are its melting point and boiling point, and a 

 number of instances were cited where minute impurities altered 

 the critical temperature by many degrees. Solutions of solids 

 when heated above the critical temperature gave no precipitate. 



