THORIUM. 215 



From Acetate. From Formate. From Oxalate. 



67.31 68.06 65.87^ Two results 



95 J by Berlin. 

 75 

 13 

 54 

 85 



66.59 67.89 65 



67.27 68.94 65 



67.06 65 



68.40 Mean, 68.297, i .219 66 

 65 



Mean, 67.326, ±z .201 



Mean, 65.85, ± .12^ 



We may fairly assume that these figures were calculated 

 with = 8, C'= 6, and S := 16. Correcting by the values 

 for these elements which have been found in previous chap- 

 ters, ThOj becomes as follows: 



From sulphate ThO.^ = 268.584, d= .803 



" acetate " = 268.735, =b .805 



" formate " = 272.586, ± .877 



" oxalate " = 262.804, ± -493 



The single result from the double potassium sulphate is 

 included with the column from the ordinar}' sulphate, and 

 the influence of the atomic weight of potassium is ignored. 



Chydenius was soon followed by Marc Delafontaine, whose 

 researches appeared in 1863.* This chemist especially stud- 

 ied thorium sulphate ; partly in its most hydrous form, partly 

 as thrown down by boiling. In Th(S04),.9H2 0, the follow- 

 ing percentages of ThOa were found : 



45.08 

 44.90 

 45.06 



45-21 

 45.06 



Mean, 45.062, d= .0332 



Hence ThO, == 263.637, ± .256. 



The lower hydrate, 2Th(SO4)2.0H.O, was more thoroughly 

 investigated. The thoria was estimated in two ways ; first, 

 (A,) by precipitation as oxalate and subsequent ignition ; 

 second, (B,) by direct calcination. These percentages of 

 ThOj were found : 



* Arch, des Sci. Phys. et Nat., (2,) 18, 343. 



