ATOMIC WEIGHTS 299 



.053 



Hence Tli = 233.98. 



In 1882, jSTilson's determinations appeared.' This chemist studied 

 both the anhydrons snlphate, and the salt with nine molecules of water, 

 using the usual calcination method, but guarding especially against the 

 hygroscopic character of the dry Th(S04)2 and tlie calcined ThOo. The 

 hvdrated sulphate gave results as follows : 



Th(S0,)„.9H,0. ThO,. Per cent. ThO,. 



2.0549 .9267 45.097 



2.1323 .9615 45.0^2 



3.0017 1.3532 45.081 



2.7137 1.2235 45.086 



2.6280 1.1849 45.088 



1.9479 .8785 45.099 



Mean, 45.091, ± .0019 

 Delafontaine found, 45.062, ± .0332 



General mean, 45.090, ± .0019 



Hence Th = 233.64. 



The anhydrous sulphate gave data as follows : 



ThiSOJ.. ThO.,. Per cent. ThO,. 



1.4467 .9013 62.300 



1.6970 1.0572 62.298 



2.0896 ■ 1.3017 62.294 



1.5710 .9787 62.298 



Mean, 62.297, ± .0009 



Hence Th = 232.59. 



The last four determinations appear again in a paper published five 

 years later by Kriiss and Nilson,^ who, however, give four more made 

 upon material obtained from a different source. Tlie new data are sub- 

 Joined : 



Th(SO^),. no.. Per cent. ThO,. 



1.1630 .7245 62.296 



.8607 .5362 62.298 



1.5417 .9605 62.301 



1.5217 .9479 62.292 



Mean, 62.297, ± .0013 

 Hence Th = 232.59. 



iBer. Deutsch. chem. Gesell., 15, 2519. 1882. 

 -Ber. Deutsch. chem. Gesell., 20, 1665. 1887. 



