GALLIUM. 181 



Hence for aluminum we have — 



From (l) Al ^ 27.311, ± .0270 



From (2). 

 From (3) , 

 From (4). 

 From (5). 

 From (6) . 



;= 26.952, ± .0037 

 ^ 26.916, ± .0201 

 ;= 26.890, zb .0034 

 ;= 26.867, =t .0046 

 = 26.858, ih .0113 



General mean Al = 26.906, ± .0021 



With = 16, Al = 27.111. The rejection of Dumas' data only lowers 

 the result to 26.903. 



GALLIUM. 



Gallium has been so recently discovered, and obtained in such small 

 quantities, that its atomic weight has not as yet been determined with 

 much precision. The following data were fixed by the discoverer, 

 Lecoq de Boisbaudran : * 



3.1044 grammes gallium ammonium alum, upon ignition, left .5885 

 grm. Ga^Oj. 



Hence Ga = 69.595. If = 16, Ga = 70.125. 



.4481 grammes gallium, converted into nitrate and ignited, gave 

 .6024 grm. Ga.Os. 



Hence Ga = 69.171. If = 16, Ga = 69.698. 



These values, assigned equal weight, give these means : 



With H= I, Ga = 69. 383. With O = i6, Ga = 69.912 



* Journ. Chem. Soc, 1878, p. 646. 



