ALUMINUM. 



179 



6.9617 grm. AlBr a 

 11.2041 " 

 3.7621 

 5.2842 

 9.7338 



Series B. 



8.4429 grm 



13.5897 



4.5624 



6.4085 

 11.8047 



Ag. 



82.456 

 82.445 

 82.459 

 82.456 

 82.457 



9-35I5 S rm - 



4.4426 



5.2750 



Series C. 



AlBr 3 i= 1 1. 3424 grm. Ag. 



5.3877 

 " 6.3975 



82.447 

 82.458 

 82.454 



Mean, 82.455, .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, specially 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 



3697 

 3769 

 .3620 



7579 

 73*4 



7541 



Vol. H. 

 458.8 

 467.9 

 449-1 

 941-5 

 907.9 



936.4 



Wt. H. 



.041234 

 .042051 

 .040362 

 .084614 

 .081595 

 .084156 



At. Wt. 



26.898 

 26.889 

 26.907 

 26.872 

 26.891 

 26.882 



Mean, 26.890, .0034 



'he 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 copper, 

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

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



