284 Augmentation of the Chemical Activity of Aluminium, 

 Thus, finally, the solution is 



12 "1 



where N 4 , N 6 , N 8 , . . . are functions of e determined by (15). 



Yacht ' Lalla Rookh/ 

 Largs, August 14, 1875. 



XXXII. The Augmentation of the Chemical Activity of Aluminium 

 by Contact with a more negative Metal. By J. H. Gladstone, 

 Ph.D., F.R.S., Fullerian Professor of Chemistry in the Royal 

 Institution, and Alfred Tribe, Esq., Lecturer on Chemistry 

 in Dulwich College*. 



HAVING had occasion to employ aluminium for effecting 

 certain decompositions, we were induced to determine 

 whether covering its surface with more-negative metals would 

 so augment its chemical activity as to enable it to decompose 

 water below or at 100° C. 



According to DevilJe, the metal alone does not decompose 

 water except at a white heat. 



The following experiments were made. 



(«) 0*43 grm. of metallic copper was deposited upon 6 grms. 

 of aluminium-foil (126 centims. long, 5 centims. wide) in a two- 

 ounce flask by immersion in very dilute copper-sulphate solution 

 very slightly acidulated with hydrochloric acid. The couple so 

 obtained was completely freed from sulphate and chloride by 

 washing with pure water. 



(b) 0*2214 grm. of platinum was deposited upon a similar 

 quantity of aluminium-foil by immersion in dilute platinic chlo- 

 ride and was washed as in the former instance. 



The flasks containing these preparations were filled with water 

 and allowed to stand at the temperature of the air for twenty- 

 two hours, when they were heated to 100° C. Hydrogen gas 

 was evolved. 



The results obtained were as follows : — 



* Communicated by the Authors, having been read before the British 

 Association at Bristol, August 1875. 



