I 9°5\ Davis — Atomic Weight of Thorium. 55 



water, thus showing- that all the oxide had been converted 

 into sulphate. 



Two determinations of each, carolinium, thorium and ber- 

 zelium were run at the same time and subjected to the same 

 conditions as nearly as possible. The sulphate of each was 

 heated at 350°C. to constant weight. The platinum bath 

 already described was used and also some larg-e porcelain 

 crucibles with a platinum ring- suspended in the center to hold 

 the crucibles. The crucible with the sulphate was placed 

 on this ring-, the large crucible covered with a punctured 

 clock g-lass, and a thermometer suspended through the hole 

 in the g-lass just above the sulphate inside the small crucible 

 containing- it. The results obtained are given below. 



The oxides of the three fractions were different in appear- 

 ance. The carolinium invariably was gray with pink ting-e, 

 the thorium slightly greenish, and the berzelium a little more 

 pronounced green. The sulphates of all are pure white when 

 cold, but that of the thorium is yellow while hot. 



The following are the results from the determinations: 



(1) Carolinium. 







Oxide. 



Sulphate. 



At. Wt. 



1.559290 



2.434914 



255.5 



0.524254 



0.819365 



255.9 



0.549331 



0.854810 



255.6 



(2) Thorium. 







Oxide. 



Sulphate. 



At. Wt. 



0.425456 



0.694936 



220.62. 



0-740052 



1.210405 



220.1 



(3) Berzelium. 







Oxide. 



Sulphate. 



At. Wt. 



0.306778 



0.507505 



213.6 



0.320618 



0.530890 



212.0 



From this it seemed that we were accomplishing- the sepa- 



