440 



McCoy and Ross — Thorium Compounds. 



solution and titration with permanganate* after separation as 

 phosphate by the method of Brearley.f 



The activity of films of thorium minerals can be corrected for 

 the effect of the emanation according to the formula applied 

 to films of pure ThO„. In calculating a from a 15 the approxi- 

 mate value of & 1? as found from the uncorrected activity of the 

 thinner films, was used. This procedure involved no appre- 

 ciable error. 



The results are given in Tables V to IX. The significance 

 of the symbols has already been given. The curves for all the 

 minerals were smooth. It is not necessary to reproduce them 

 here. 





Table V. 



Orangite, 



No 



. 1. 





w 



Ctl 



a 





w 

 a 



E 



2400 



52-29 



47-2 





•02628 



5-8 



3415 



45-01 



44-1 





•00775 



1-5 



2259 



39-24 



38-8 





•00583 



1-0 



1212 



28'46 



28-3 





•00428 



tC««) 



0526 



14-85 



14-8 





•00355 



(•24) 



\«/o 



■00310 



(!).=- 



Table VI. Thorite, No. 



•1825 

 •3243 

 •2339 

 •1349 

 •0904 



50-51 

 43-03 

 39-37 



29-74 

 22-61 



47-1 

 42-4 

 39-0 

 29-6 

 22-6 



( 



w \ 



— ] = -00301 

 a 



, 



•02511 

 •00765 

 •00600 

 •00456 

 •00400 



E 



3-90 

 1-16 



•88 

 (•53) 

 (•34) 



26 



Table VII. Monazite, No. 3. 



•0587 

 •2825 

 •2059 

 •1094 

 •0476 



4'70 

 3-96 

 3-43 

 2-36 

 1-23 



4-55 

 3-94 

 3-42 

 2-35 

 1-23 



•233 



•0717 



•0602 



•0466 



•0387 



E 



•17 



•04 



(•03) 



(•02) 



(•01) 



(t)- 



® = 



6-2 



0332 



Chem. Soc, xxiii, 685, 1901 ; Pulman, this Journal, 



* Kern. J. Amer 

 xvi, 229, 1903. 



f Analytical Chemistry of Uranium, 1903. 



% The values of E in parenthesis are calculated from E = w 



/(w 



/ \E 



