298 SMITIISONIAX MISCELLANEOUS COLLECTIONS VOL. 54 



Delafontaine was soon followed by Heriiumn,' who published a single 

 analysis of the lower liydrated sul])liatc, as follows: 



ThO, 52.87 



SO3 32.11 



H.O 15.02 



100.00 



Hence, from (he ratio between SO., and 'I'hO.,, Th=:231.()T. Probably 

 the SO;j percentage was loss upon calcination. 



Botli Hermann's results and tbose of Delafontaine are affected by one 

 serious doubt, namely, as to the true composition of the lower hydrated 

 sulpbate. The latest and best evidence seems to establish the fact that 

 it contains four molecules of water instead of four and a half,' a fact 

 which tends to change the resulting atomic weight of thorium consid- 

 erably. In the final discussion of these data, therefore, the formula 

 Th(S04)2.4H^0 will be adopted. As for Hermann's single analysis, bis 

 percentage of ThOo, 52.87, may be included in one series w*ith Delafon- 

 taine's, giving a mean of 52.535, ±.0473. Hence Th = 229. 



The next determinations to consider are those of Cleve,^ whose results, 

 obtained from both the sulphate and the oxalate of thorium, agree ad- 

 mirably. The anhydrous sulphate, calcined, gave the subjoined per- 

 centages of thoria : 



62.442 



62.477 



62.430 



62.470 



62.357 



62.366 



Mean, 62.423. ± .014 



Hence Th = 234.01. 



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 accurate value can be deduced, there having 

 undoubtedly been moisture in the material studied. From the ratio 

 between CO, and ThOz, however, good results are attainable. This ratio 

 I put in a fourth column, making the thoria proportional to 100 parts of 

 carbon dioxide: 



' .Jouin. piakt. Chem., 93, 114. 



'^ See Hillebrand, BulL 90, U. S. GeoL Survey, p. 29. 



= K. Svenska Vet. Akad. Handling., Bd. 2, No. 6, 1874. 



