May 28, 1896J 



NA TURE 



95 



studied. — Preparation and properties of uranium, by M. II- 

 Moissan. — The significance of an axis of symmetry in 

 plants, by M. A. Chatin. — On the transformation of fat into 

 carbohydrate in unfed animals, by M. A. Chauveau. During 

 hiljcrnation it has been noticed that the animal may in- 

 crease in weight. This can be accounted for by the partial 

 oxidation of the stearin to glucose, carbon dioxide, and water. 

 If this is really the case the respiratory constant should be about 

 o 27. — On the integration of the difierential equation of the 

 radiui vector of a certain group of small planets, by M. O. 

 BacKhmd.— On a family of left-handed curves, by M. Jules 

 .-^ndrade.— The area of parabolas of higher order, by M. P. H. 

 Sclioute.— On some properties of the .\-rays penetrating ponder- 

 able media, by M. C. Malteros. A mathematical proof that 

 if the X-rays be regarded as hyperultra-violet rays, the 

 difleient absorptive power of various substances may be ex- 

 plained by supposing that the index of refraction is not 

 exactly unity, but a number very near this value, and depend- 

 ing on the density. — On the application of the formula of 

 Clapyron to the melting point of benzene, by M. R. Demcrliac. 

 .\n experimental study of the lowering of the melting point of 

 ben/ene by pressure. The manometer used had been calibrated 

 against a mercury column directly, and the alterations in tem- 

 perature were measured to •001° by the changes in resistance of 

 an iron wire forming an arm of a Wheatstone's bridge. The 

 alteration in melting point for an additional pressure of one 

 atmosphere calculated from Clapyron's formula is 0° '02936 ; the 

 experimental figure is '0294, the difference being less than the 

 erri>rs of observation. — Remarks on the reply of M.M. Benoist 

 and Hurmuzescu, by M. Aug. Righi. — Observations on the .\- 

 rays, byM. T. Argyropoulos. — On a new ozone generator, by 

 .M. G. Seguy. — On a new apparatus for electrolysis, by M. D. 

 Tommasi. In the apparatus described the advantages claimed 

 are the suppression of polarisation, that the deposited metal is 

 removed from the oxidising action of the bath, and that the 

 electrical resistance of the bath is considerably reduced. — Re- 

 searches on nickel cyanide, by M. Raoul Varet. A thermo- 

 chemical study of nickel cyanide and its double salts. The 

 thermal data show that the compounds undissociable by dialysis, 

 may be looked -upon as salts of a complex acid, hydronickel- 

 ocyanic acid, differing only from ferrocyanides in stability. — On 

 a crystallised tetrachromite of barium, by M. E. Dufau. — On 

 the chloraloses, by M. Hanriot. Galactose forms a compound 

 with chloral similar to the chloraloses previously prepared. The 

 acetyl and benzoyl derivatives and the acid obtained on oxidising 

 with potassium permanganate are described. The corresponding 

 reactions with levulose were also examined. — On some aromatic 

 symmetrical derivatives of urea, by .M.M. P. Cazeneuve and 

 Moreau. Carbonate of guiacol serves as the starting point 

 for these compounds, aniline giving diphenyl-urea, paratolu- 

 idine, di-paratolyl-urea, andortho-toluidine, diorthotolyl-urea. — 

 On the ratios which exist between the chemical constitution of 

 organic compounds and their oxidisability under the influence 

 of laccase, by .M. G. Bertrand. The degree of oxidation of 

 the aromatic polyphenols studied appears to depend upon the 

 facility with which they can be transformed into quinones. — 

 Characterisation and separation of the chief vegetable acids, by 

 M. L. Lindet. For the separation of citric and malic acids 

 advantage is taken of the different sohiljility in methyl alcohol 

 of their acid quinine and cinchonine salts. — On the internal 

 appendages of the female genital organs of the Orthoptera, 

 by M. A. Fenard. — On tlie general relation connecting the 

 degrees of sensation and luminous intensity, and on the laws of 

 simultaneous contrast of lights and tints, by M. C. Henry.— On 

 the browning of the cuttings of the vine, by MM. P. Viala and 

 L. Ravaz — Researches on the carpellary venation in the bi- 

 carpellary (lamopetala; of Bentham and Hooker, by M. Paul 

 Grelot. — On the siphons of springs and undergrounil rivers, by 

 M. E. \. Martel.— The Cadurcolhcrium, by M. Marcellin 

 Boule. — Measurements of the variatinn m length of glaciers in 

 the French region, by Prince Roland Bonaparte. — Method for 

 defining the po.sition of the surface of emission of the X-rays, 

 by M. Stchcrbakof. 



Berlin. 



Meteorological Society, April 14.— Prof. Bornstein, 

 President, in the chair. — Dr. Schwalbe spoke on the investigation 

 and most important theories of atmospheric electricity, and added 

 'in account of experiments he had made on the dissipation 01 

 i lectricity by vapour. A metal plate insulated, charged to ten 

 volts and connected with a Thomson's quadrant electrometer, 



NO 1387. VOL. 54 1 



discharged itself in exactly the same time when dry as when 

 wetted with water or other easily vaporised fluid. Sprinkling 

 with finely pulverised quartz greatly hastened the discharge ; 

 coarsely powdered glass to a less extent. The time of discharge 

 was the same for a rough as for a iiolished plate. He considered 

 that these experiments had settled the fact that vapour does not 

 discharge an electrified body, but that fine powders do. 



Physical Society, .April 17. — Prof Warburg, President, in 

 the chair. — Prof. Konig spoke on the number of visual units 

 existing in the human retina. The acuteness of vision was 

 measured by the distance at which a grating made of regular 

 rectilinear wires begins to appear wavy. Starting at the fovea 

 it diminishes towards the periphery, and in such a way that the 

 curves of equal visual acutene.ss form concentric ellipses. The 

 area of each retinal field by svhich two wires are seen as two, 

 increases towards the periphery. If such a field be called a 

 vi.sual unit, then their total number for the whole retina is 50,000. 

 If it be assumed that each unit can perceive three kinds of colour, 

 of which the resulting impulse is conveyed to the brain by a 

 separate nerve fibre, then there must be 150,000 fibres in the 

 optic nerve. As a matter of flict, histologists give them as 

 400,000 to 500,000 in number, lie further discussed the experi- 

 ments he had made in conjunction with Dr. Zumpf, which had 

 .shown that objects of different colour must be perceived 

 at different depths in the retina. The difference of these 

 depths for red and blue rays was found to be so great, 

 that one lay in the pigment layer, which must hence be re- 

 garded as a sensory organ. As a matter of fact, quite 

 recently an English anatomist has described the existence of 

 spherules in this layer united to a nerve-plexus from the rods 

 and cones. He finally gave an historical retrospect of Purkinje's 

 phenomenon, in which two coloured (red and blue) fields of 

 equal luminosity as seen by daylight appear unequally luminous 

 at twilight, the red disappearing much .sooner than the blue. 

 After this phenomenon had been studied by a whole series of 

 observers, and its importance insisted upon, Prof. Hering had 

 quite recently found that it is really an exceptional phenomenon. 

 It can only be observed in dark surroundings ; in daylight and 

 bright surroundings the diflerently coloured fields remain equally 

 luminous, while the intensity of their illumination is reduced 

 down to a point at which colour perception ceases. Prof. 

 Konig had satisfied himself of the truth of the above observa- 

 tion, so that Purkinje's phenomenon has now lost all its supposed 

 significance. 



May I.— Prof, von Bezold in the chair.— Dr. du Bois spoke 

 on the magnetising and hysteresis of various kinds of steel and 

 iron, basing his remarks on experiments made in conjunction 

 with Mr. E. T. Jones. The discrimination of different samples 

 of iron by means of their hardness has now lost all its import- 

 ance ; the real criterion is rather hysteresis, coercitive power, 

 residual and maximal magnetisation, which had been determined, 

 together with other magnetic properties, for a large series of 

 samples. Chemical composition is of less importance than the 

 mode of treatment during manufacture from ore to metal. The 

 magnetic constants of the material are of importance to phy- 

 sicists and technologists. The speaker then gave the results of 

 his measurements for three kinds of iron with maximal, and 

 three with minimal hysteresis. As a general rule hardening 

 increases hysteresis and coercitive intensity, whereas residual 

 magnetism is lessened. Krupp's cast-iron is distinguished by 

 its low hysteresis and small coercitive intensity. 



PHII-ADELPHIA. 



Academy of Natural Sciences, April 14.— In connection 

 with the presentation of a collection of recent and fossil 

 Strombidie, Mr. H. A. Pilsbury discussed the ancestry of 

 Strombus costata and Meloiigcna sukoronata, their relations 

 fossil species being illustrated by large suites of intermediate 

 forms.— Mr. James Willcox commented on the influetice of 

 environment on the species as illustrated by the specimens 

 presented. It was apparent that those from the southern coasts of 

 Florida swept by the Gulf Stream were all of a dwarfed type.— 

 Dr. Benjamin Sharp related the plentiful occurence of a Cteno- 

 phore, Mueopsis Leidyi in a fresh-water pond near Nantucket. 

 The embryos had been swept in by an accession of salt water, 

 and had accustomed themselves to their new environment. The 

 species did not, however, persist in the pond, in consequence 

 probably of the severity of the winter. Specimens of the species 

 referred to were beautifully preserved in a 2 per cent, solution 

 of formaline.- Mr. Pilsbury announced the finding by Mr. 



