456 



NATURE 



[September io, 1891 



due to the erosion of the zinc by the chlorides present in the 

 solution in which the brass has been pickled, and in the water 

 in which it is afterwards washed, care not being always taken to 

 prevent such chlorides from drying on before rolling. 



A. P. Laurie described the experiments he has made to deter- 

 mine the electromotive forces of various alloys with a view to 

 establishing the existence of definite compounds among them. 

 His earlier experiments will be found in the Journ. Chem. Soc, 

 1888, p. 104. His recent work leads him to conclude that a 

 compound of gold and tin of the formula AuSn exists, a sudden 

 rise of electromotive force being observed when the proportion 

 of tin in the alloy exceeds that required by the above formula. 

 Compounds do not appear to exist among the alloys of zinc, 

 cadmium, lead, and tin. 



Prof. Roberts- Austen exhibited and described his self-re- 

 cording pyrometer. In this instrument, thermal junctions of 

 platinum and platinum containing lo per cent, of rhodium are 

 connected with a galvanometer. The spot of light from the 

 mirror of this is caused to fall on a slit before which a photo- 

 graphic plate passes at a given rate, by which means a curve is 

 traced, corresponding to the variations in temperature of the 

 heated thermal junction. The other junction is kept at a con- 

 stant temperature by immersion in water. Temperatures up 

 to the melting-point of platinum can be determined with an 

 accuracy of io°. The curves of cooling of several alloys have 

 been determined. The alloy of gold and aluminium differs 

 from others, such as that of platinum and lead, in that there is 

 no break in the curve at the point of solidification of the alloy. 



A paper by A. Vernon-Harcourt and F. W. Humphery was 

 entitled " The Relation between the Composition of a Double- 

 Salt and the Composition and Temperature of the Liquid in 

 which it is formed." The authors have obtained a large number 

 of double chlorides of ammonium and iron by crystallizing from 

 solutions containing varying amounts of ferrous and ammonium 

 chlorides, and maintained at different temperatures. The com- 

 position of the salts varied, according to conditions, from two to 

 twenty-one molecules of ammonium chloride combined with one 

 of ferrous chloride. The salts could be obtained well crystal- 

 lized, and varied considerably from each other in their crystalline 

 habit. The authors suggest that similar complex compounds 

 may exist in other cases. 



Prof. Dunstan, in the discussion which followed, described 

 a series of double cyanides of zinc and mercury, of complex 

 composition, which he had obtained by precipitation. 



In a preliminary account of some experiments he is making 

 on the action of oxide of cobalt in causing the evolution of 

 oxygen from hypochlorites. Prof. M'Leod showed that, on 

 boiling an alkaline solution of a hypochlorite alone, some oxy- 

 gen is evolved and chlorate formed, so that the action is probably 

 somewhat complex in presence of oxide of cobalt. 



In the absence of Prof. Armstrong, Dr. Morley read the 

 Report on the Isomeric Naphthalene Derivatives. The study of 

 the dichloronaphthalenes has been completed. Of the twelve 

 reported to exist, only ten could be obtained. This number is 

 that required by theory. Of the fourteen theoretically possible 

 trichloronaphthalenes, thirteen have been obtained. The com- 

 pound containing the chlorine atoms in the positions i : 2 : i' is 

 missing. These results put it beyond question that naphthalene 

 has a symmetrical structure. Its exact inner configuration has 

 yet to be dealt with. Experiments have been made with a view 

 to determine the manner in which substitution takes place. 

 It appears probable that an addition product is always first 

 formed. 



Prof. Rucker gave an account of the experiments made by 

 Prof. Roberts-Austen and himself to determine the specific heat 

 of basalt. The experiments were performed with the aid of the 

 self-recording pyrometer above-mentioned. The results obtained 

 when the substance was heated in a platinum crucible in a gas 

 furnace agreed well together. The specific heat increases regu- 

 larly up to the melting-point, which is not very definite. About 

 this point there is considerable absorption of latent heat. The 

 mean specific heat between 20° and 470° was found to be "199 ; 

 between 470° and 750°, '244 ; between 750° and 880°, '626 ; 

 and between 880° and 1190", '323. 



Prof. F. Clowes described an apparatus for testing safety- 

 lamps which permitted economy in the marsh-gas used. It con- 

 sisted essentially of a large wooden box, rendered gas-tight by 

 paraffin, in which the mixture of fire-damp and air could be 

 made, the safety-lamp being afterwards introduced. A lamp 



NO. 114 1, VOL. 44] 



was exhibited which would indicate in this apparatus "25 pe^ 

 cent, of fire-damp. 



Prof, C. M. Thompson described the results he has obtained 

 on repeating the experiments of Kriiss and his colleagues on the 

 rare earths, which caused them to announce the probable exist- 

 ence of about twenty new elements. Although he has worked 

 on material from the same locality and of the same appearance 

 as that used by the above-named workers, he has entirely failed 

 to confirm their results, at any rate with regard to the didymium 

 fraction. He considers that the absence of certain lines noticed 

 by them in the didymium spectrum may be due simply to dilu- 

 tion, and do not indicate a splitting up of that element. On 

 making his solutions sufficiently strong, he was able in all cases 

 to obtain the lines. 



Prof. Ramsay drew attention to the remarkable properties 

 which are exhibited by the liquids obtained by passing excess of 

 hydrogen sulphide into solutions of certain metals, and after- 

 wards expelling the excess of hydrogen sulphide by hydrogen. 

 Mercuric sulphide treated in this way dissolves to a dark-brown 

 solution. Antimony and arsenic sulphides also dissolve. On 

 examining the mercury solution under the microscope, brown 

 particles are seen in a state of rapid motion. With antimony 

 solution, particles are not visible, but a sort of granular move- 

 ment is to be seen. With arsenic solution, nothing is visible. 

 On dialysis of the solution, none of the metal diffuses if the 

 solution is pure ; in the case of the antimony, diffusion takes 

 place if tartaric acid is present. These solutions are readily 

 precipitated by the addition of certain salts, but, although the 

 antimony solution becomes nearly solid on precipitation, no 

 accompanying rise of temperature can be noticed. Also, no 

 depression of the freezing-point is observed with such a solution. 

 The specific gravity of the solution, however, is higher than that 

 of water. The experiments show the power of the solvent to 

 bring about extremely fine mechanical division of a substance, 

 and suggest the possibility of further atomic or ionic separation. 

 The particles of quasi-dissolved substance are believed to be in 

 a state of rapid but circumscribed motion. 



One of the few papers on organic chemistry was read by J. J. 

 Sudborough, on the action of nitrosyl chloride on unsaturated 

 carbon compounds. He has examined the action of nitrosyl 

 chloride on ethylene, propylene, amylene, and cinnamene, 

 crotonic, oleic, erucic, and cinnamic acids. Of these, ethy- 

 lene is chlorinated, and forms the dichloride C2H4CI2 ; pro- 

 pylene is practically unacted upon; amylene forms a nitroso- 

 chloride, CsHjqNOCI, melting at 152° ; and cinnamene a 

 similar compound, CgHgNOCl, melting at 97°. Crotonic acid 

 is unacted upon, even when heated to 90°, while oleic and erucic 

 acids readily form definite nitrosochlorides, the former melting 

 at 86° and the latter at 92°. Cinnamic acid is unacted upon 

 when cooled, but forms the dichloride CgHgOaCij when heated 

 to 100°. Up to the present the author can find no laws 

 regulating the action of nitrosyl chloride on various carbon 

 compounds. 



A paper was read by C. G. Moor, on a new method for the 

 disposal of sewage. This consists in the application of a method 

 invented by Mr. Rees Reece for obtaining tar, ammonia, &c,, 

 from peat, to the recovery of similar products from sludge cake. 

 A kind of lime-kiln is employed, with a forced draught, con- 

 nected to a series of condensers. The operation is conducted in 

 such a manner that the material in the lower part of the furnace 

 is kept in active combustion ; its heat distils the material directly 

 above, and this in its turn gradually descends to serve as fuel 

 for the succeeding charge. Eighty per cent, of the theoretical 

 yield of ammonia has been obtained. In order for the process 

 to be commercially successful, it seems that the use of lime in 

 pressing the sludge should be avoided at all costs, as, if much 

 lime is present, the ash obtained in the furnace has a very low 

 value, and clinker is apt to be produced. The author suggests 

 the use of carbonized sludge in powder, mixed with salts of 

 alumina and iron, in place of lime. 



A. H. Allen described a curious reaction he had noticed on 

 treating glycerides with alcoholic potash. If the quantity of 

 potash or soda present is insufficient to completely saponify the 

 glyceride, an ethyl salt of the acid is obtained. Thus in the 

 case of butyrin large quantities of ethyl butyrate pass over on 

 distillation. In the case of acetin it was found that no action 

 took place on boiling sodium acetate, acetin, and alcohol to- 

 gether ; but, on the addition of a trace of potash, 80 per cent, 

 of the theoretical yield of ethyl acetate was obtained. 



