May 20, 1897] 



NATURE 



71 



and they may partly explain the " inductoscripts " of Mr. F. J. 

 Smith. Dr. S. P. Thompson said he did not know of any other 

 example of an anode being more active, mechanically, than the 

 kathode, except the electric arc. He was surprised that the film 

 should appear on the positive surface. Mr. Shelford Bidwell 

 thought selenium presented, in some of its actions, an example 

 of the anode being thus active. Prof. Ayrton said that if a 

 vessel containing a substratum of mercury amalgam was filled 

 up with water in which gold crushings were washed, the 

 gold descended into the amalgam. This, however, might be 

 due partly to gravity, and partly to simple electrolysis. Mr. 

 Appleyard said he had no definite views as to the formation of 

 the films. He believed it to be a secondary effect of electro- 

 lysis, aided by electric osmosis. The experiments of Mr. C. 

 K. Falkenstein upon the electric tanning of leather, and the 

 early results of M. Perret, helped the idea of electric osmosis ; 

 they were not sufficient, however, to justify that theory without 

 further research. A careful chemical analysis of the deposits 

 left in the folds of filter-paper would be the best guide. 



Edinburgh. 

 Royal Society, May 3— Prof. Chrystal in the chair— A 

 paper on Dschabir Ben Hayyan and the chemical writings 

 ascribed to him, by Prof. Ferguson. — The seasonal changes in 

 the pressure and temperature of the atmosphere from May to 

 June, and November to December, by Dr. Buchan. — Dr. W. 

 W. J. Nicol read a paper on supersaturation. After a short 

 reference to his previous papers on supersaturation, in which the 

 author showed that supersaturated solutions differ in none of 

 their properties from ordinary solutions, if only the tempera- 

 ture be not allowed to fall below a certain point (depending 

 upon the nature of the salt in question, and the concentration of 

 the solution), and contact with the solid salt or with an iso- 

 morphous salt be carefully prevented, he repeated his statement 

 that there is really no such thing as a supersaturated solution, 

 that such solutions are in reality satuiated or non-saturated 

 solutions of what may be termed the anhydrous salt ; that is to 

 say, they contain the salt to which the whole of the water is 

 similarly related, no distinction existing in solution between the 

 water organically present as water of crystallisation, and the 

 solvent water. The author proceeded to explain that he was 

 forced into premature publication of his recent work on the sub- 

 ject, by the appearance of a paper by Ostwald in the last number 

 of the Zeitschrift fiir Physikalische Chemie (see pp. 61-2.) In 

 this paper, Ostwald was apparently on the verge of coming to the 

 same conclusions as those at which the author had arrived as 

 the result of his more recent work, thus no other course was 

 open to him than the publication of the work in an incomplete 

 form. The conclusion at which the author has arrived is as 

 follows. Whenever, under the conditions of experiment, two 

 allotropic forms of the dissolved or fused substance can exist, 

 then supersaturation or superfusion, as the case may be, is also 

 possible. In other words, allotropy is the cause of super- 

 saturation. The term allotropy is used in a wider sense than 

 usual ; here it includes different crystalline or amorphous forms 

 of a body brought about by the presence or absence of foreign 

 molecules, and the statement is therefore applicable to cases of 

 supersaturation involving hydrated salts, and also double salts. 

 The experimental evidence in favour of the above, though in- 

 complete, is already fairly large. The law is found to hold 

 good not only with hydrated salts, but also with salts crystal- 

 lising usually without water and with numerous organic com- 

 pounds. Thus, allotropic forms have been found, and super- 

 saturated solutions prepared, in the case of potassium nitrate, 

 ammonium nitrate, silver nitrate, acetonilid, hydroquinone, 

 acetamide, malonic acid, mandelic acid, resorcin, tartaric acid, 

 citric acid (four modifications), and sodium chlorate, this last 

 observed first by Ostwald. The author intimated his intention 

 to examine further as to the limits, and to investigate the border 

 region in which supersaturation can be terminated by shock or 

 other mechanical means. — A paper on the geometrical investi- 

 gations of the circular functions of 36 and 56, by Prof. Anglin. 

 — On some nuclei of cloudy condensation, by John Aitken, 

 F.R.S. It has been claimed, the author said, by Helmholtz 

 and Richarz, that "ions" were active in producing condensation 

 in supersaturated vapour, and that these, along with dust, 

 produced the ordinary cloudy condensation in the atmosphere. 

 In an experiment by the author to test this conclusion, hydrogen 

 was burned in filtered air, when it was found that, if precautions 

 were taken to have the hydrogen pure and the air absolutely 



NO. 1438, VOL. 56] 



dust free, the ions lost their power of producing cloudy conden- 

 sation as soon as they were cooled. The products of combustion 

 remained free from condensed particles, when expanded, and 

 when the products were tested by means of steam near the 

 combustion-chamber, while they were still hot, they showed 

 very little power of condensing. It had been shown in a previous 

 paper that sunshine gave rise to a great increase in the number 

 of particles under certain conditions, and experiments, recently 

 made, were described in which it was shown that, though sun- 

 shine has no effect in producing nuclei in ordinary air, yet, if 

 any of the so-called impurities in the atmosphere be present 

 there in the gaseous condition, the sunlight produces a great 

 number of nuclei. It was found that if ammonia, peroxide of 

 hydrogen, nitric acid, nitrous acid, or sulphurous acid, were 

 present in the air, sunlight caused the formation of a great 

 number of nuclei of condensation, showing that if any of these 

 gases are present in the air, clouds would be produced, though 

 there was no dust present, if the air became saturated. 



Academy of Sciences, May 10.— M. A. Chatin in the 

 chair. — The President announced the losses the Academy had 

 sustained by the deaths of M. Des Cloizeaux and Mgr. le due 

 d'Aumale. — Explanations of some experiments of M. G. Le 

 Bon, by M. Henri Becquerel. Experimental evidence is given 

 showing that vulcanite is transparent to the red and infra-red 

 rays, which, although without action upon an unexposed plate, 

 are capable of continuing the action of the actinic rays upon a 

 plate which has been exposed for a very short period of time. 

 These red rays are also capable of destroying the phosphor- 

 escence of zinc sulphide, and their passage through the vul- 

 canite affords a complete explanation of the observations of M. 

 G. Le Bon, the assumption of the existence of a special kind of 

 light, " dark light," being unnecessary. — On solutions of acetone 

 and their explosive properties, by MM. Berthelot and Vieille. 

 This paper is a lengthy one, and gives the pressures of acetylene 

 dissolved in acetoneat different temperatures and concentrations, 

 theconditions under which dissolved acetylene explodes ; and also 

 acetylene gas in contact with its solution in acetone.— Remarks 

 on the explosive decomposition of solutions of acetylene, by 

 MM. Berthelot and Vieille. In the explosive decom- 

 position of solutions of acetylene in acetone, the latter 

 is also broken up into carbon, hydrogen, water, and 

 the two oxides of carbon. — On some conditions of propa- 

 gation of the decomposition of pure acetylene, by MM. 

 Berthelot and Vieille. It was found to be impossible to obtain 

 a critical pressure below which the propagation of the explosive 

 wave did not take place, as in a series of experiments at a given 

 pressure the wave was sometimes produced and sometimes not. 

 : — On the employment of four-dimensional space in the study of 

 algebraic surfaces admitting several series of conies, by M. 

 Eugene Cosserat. — On an analytical formula relating to certain 

 integrals of elliptic functions with respect to their modulus, by 

 M. F. de Salvert. — On the algebraic integration of linear 

 differential equations of the third order, by M. A. Bou- 

 langer. — On the solubility of liquids, by M. A. Aignan. 

 The method of Alexejew for the study of the mutual solubility 

 of liquids is criticised, and a new method suggested which leads 

 to a different definition of the coefficient of solubility. The 

 formulae deduced are applied experimentally to the case of ether 

 and water. — On multiple resonance, by M. L. Decombe. The 

 experiments cited entirely confirm the theory of resonators put 

 forward by Poincare and Bjerknes. — On the diurnal variation 

 in the direction of the wind, by M. Alfred Angot. In order to 

 get rid of the disturbing effects of surrounding buildings, the 

 observations were carried out at the top of the Eiffel Tower. — 

 Basic salts of cadmium, by M. Tassilly. — Researches on 

 strontium sulphide, and on the method of obtaining it highly 

 phosporescent, by M. Jose Rodriguez Mourelo. The sulphide 

 is prepared by heating a mixture of strontium carbonate, 

 sulphur, sodium carbonate, sodium chloride, and bismuth 

 sub-nitrate. — Thermal study of the sodium derivatives of 

 acetylene, by M. Camille Matignon. — Contribution to the 

 study of the preparation of ordinary ether, by M. L. 

 Prunier. Some sulphonic acids are always present in addition 

 to the sulphate and ethyl sulphate previously noted. — Action of 

 chloral hydrate upon phenylhydrazine. Diphenylglyoxazol 

 and its derivatives, by M. H. Causse. — On the effect of man- 

 ganese in the oxidations, induced by laccase, by M. Gabriel 

 Bertrand. The presence of a manganese salt increases the 



