THORIUM. 217 



who published a single analysis of the lower hydrated sul- 

 phate, as follows : 



ThOj 52.87 



SO3 32.11 



HjO 15.02 



Hence, from the ratio between SO 3 and ThO 2 , ThO 2 ^ 

 263.030. Probably the SO 3 percentage was loss upon calci- 

 nation. 



The latest, and probably also the best determinations, are 

 those of Cleve,* whose results, obtained from both the sul- 

 phate and the oxalate of thorium, agree admirably. The 

 anhydrous sulphate, calcined, gave the subjoined percent- 

 ages of thoria : 



62.442 



62.477 



62.430 



62.470 



62.357 

 62.366 



Mean, 62.423, ± .014 



Hence ThO, = 265.380, ± .123. 



The oxalate was subjected to a combustion analysis, 

 whereby both thoria and carbonic acid could be estimated. 

 From the direct percentages of these constituents no accu- 

 rate value can be deduced, there having undoubtedly been 

 moisture in the material studied. From the ratio between 

 CO 2 and ThO,, however, good results are attainable. This 

 ratio I put in a fourth column, making the thoria propor- 

 tional to 100 parts of carbon dioxide : 



