074 'fKANSACiTIONS of SECTlOJJ fi. 



folliiwino; inetals have hitherto been studied. First the meta'i? of the silver and 

 copper orpoaps and zinc, i.e., silver, mercury, copper, bismuth, lead, cadmium, and 

 zinc. These metals have all been deposited singly, separated from each other 

 and also separated when all present in the same solution. In the last-named case 

 the quantity of each metal taken varied between 010 and 0'15 gram, and the 

 time for the deposition of each between about ten and fifteen minutes.' Secondly, 

 new metliods have been elaborated for the determination and separation from 

 each other of antimony and tin. A considerable number of determinations have 

 been carried out in which the metals taken in varying rntios weighed together 

 approximately one gram. The time lor the deposition of the antimony was 

 iisuilly about twenty minutes, that for the tin about eighty minutes. Lastly, the 

 possibility of securing a purely electroanalytical method for the analysis of an 

 alloy consisting of copper, antimony, lead and tin has been examined, and all the 

 separations required for such an analysis have been carritd out. 



6. Studies on the Electro-deposition of Metals. 

 By W. E. Hughes and Dr. F. M. Perkin. 



7. Transparent Silver and other Metallic Films. 

 By Professor Thomas Turner, M.Sc. 



Thin gold-leaf, when mounted on glass, becomes transparent when heated to 

 about 550° 0. The lig-ht transmitted is white, and the etlect does not depend upon 

 the supporting material or the gaseous atmo-iphere. 



Thin silver-leaf becomes transparent if heated in air or oxygen. The light 

 transmitted is white, and the ert'ect is not produced in vacuo or in a reducing 

 atmosphere. Though oxygen is necessary it is not apprecinbly absorbed, and the 

 etiect is only noticed with thin sheets. Silver xtj^^jj of an inch in thickness is 

 too thick to show the effect. 



Thin sheet-copper when heated in air or oxygen to about 200° C. gradually 

 passes in'o a transparent substance which transmits yellow-green light quite 

 freely. With further heatiuEr the colour darkens until at length it becomes black. 

 No effect is produced in a reducing atmosphere. 



Thin sheet-alumhiium does not become transparent when heated. For further 

 particulars the original paper may be consulted.- 



8. Report on Wave-length Tables of the Spectra of the Elements. 



See Reports, p. 119. 



TUESDAY, SEPTEMBER 8. 

 The following Papers and Reports were then read : — 



1. Discussion on Problems of Fermentation. 



(i) T}ie Factors which influence the Rate of Alcoholic Fermentation. 

 By Arthur Slatok, Ph.D., D.Sc. 



The transformation of glucose into alcohol and carbon-dioxide by the action of 

 yeast is probably not a single chemical reaction but a series of reactions. If one 

 reaction of the series proceeds relatively much mare slowly than the others, then 

 the velocity of the transformation is determined by the rate of this slow reaction. 



» Trans. Chem. Sue, 11)07, 91, 373. * Proc. Royal Sou., May 1908. 



