ALUMINUM. 179 



Series B. 



6.9617 grm. AlBrg ^ 8.4429 gim. Ag. 82.456 



II. 2041 " 13-5897 " 82.445 



3.7621 " 4.5624 " 82.459 



5.2842 " 6.40S5 " 82.456 



9-7338 " 11.8047 " 82.457 



Series C. 



9-3515 grm- AlBi-3= 11.3424 grm. Ag. 82.447 



4-4426 " 5-3877 " 82.458 



5.2750 " 6.3975 " 82.454 



Mean, 82.455, dz .001 



Hence Al = 26.916. 



The experiments to determine the amount of hydrogen evolved by the 

 action of caustic soda upon metallic aluminum were conducted with pure 

 metal, speciall}" prepared, and with caustic soda made from sodium. 

 The soda solution was so strong as to scarcely lose a perceptible amount 

 of water by the passage through it of a dry gas at ordinary temperature. 

 As the details of the experiments are somewhat complex, the original 

 memoir must be consulted for them. The following results were obtained, 

 the weight of the hydrogen being calculated from the volume, reckoned 

 at .089872 gramme per litre. 



Wt. Al. Vol. H. Wt. H. At. Wi. 



Mean, 26.S90, i .0034 



The closing series of experiments was made with larger quantities of 

 aluminum than were used in the foregoing set. The hydrogen, evolved 

 by the action of the caustic alkali, was dried by passing it through two 

 drying tubes containing pumice stone and sulphuric acid, and two others 

 containing asbestos and phosphorus pentoxide. Thence it passed 

 through a combustion tube containing copper oxide heated to redness. 

 A stream of dry nitrogen was employed to sweep the last traces of hy- 

 drogen into the combustion tube, and dry air was afterwards passed 

 through the entire apparatus to reoxidize the surface of reduced coi:)per, 

 and to prevent the retention of occluded hydrogen. The water formed 

 by the oxidation of the hydrogen was collected in three drying tubes. 



