Perkins — Molecular Weight of Radium Emanation. 471 



The exponential character which the curve assumes after 

 the 14th collection will be noted. That the curve is expo- 

 nential, after vapor alone remains in the diffusion chamber, is 

 well shown in the following tables, which contain the results 

 of an experiment in full, made at 250° C. with about 0*4 grs. 

 of mercury in the diffusion chamber ; and the results for k, 



So 

 7Q 

 Co 



20 

 io 



7o 



-O 



3 v «r & j g 



f te // n t& if /<r /(> 77 



Collections. 



calculated from the data given by similar experiments at 

 250° C. ; also at 275° C, using 07 grs. : 



Time of 



collection 



in min. 



20 

 20 

 20 

 20 



20 



20 



20 



Wt. after 



collection 



in grs. 



44-9167 

 47-3115 

 44-9109 

 47-3074 



44-8938 



47'2629 



44-8519 



Wt. of tubes 

 empty 

 in grs. 



44-S390 

 47-2366 

 44-8393 

 47-2381 



44-8393 



47-2367 



44-8393 



Amt. of Hg 

 diffusing 



•0777 

 •0749 

 •0716 

 •0693 



•0545 



•0262 



- -0126 



Calcul ation 

 for k 



0545 _ 20& 

 0262~ 6 

 -. £=-0366 

 0262 _ 20& 



0126 _ 



-. A-=-0366 



