THE YTTRIUM GROUP. 241 



•3379 g''"^- SCoOj gave .9343 grm. Scji'SO^"!.. 36. 166 per cent. 



.3015 " .8330 " 36.194 " 



.2998 " .8257 " 36.187 



.3192 " .8823 " 36.178 " 



Mean, 36.181, ± .004 



Hence Sc = 43.980, dr .015 ; or, if = 16, then Sc = 

 44.081. If SO 3 = 80, then Sc = 44.032. These values are 

 doubtless very nearly correct. 



YTTRIUM. 



For yttrium we need consider only the determinations 

 of Popp, Delafontaine, Bahr and Bunsen, and Cleve. 



Popp* evidently worked with material not wholly free 

 from earths of higher molecular weight than yttria. The 

 yttrium sulphate was dehydrated at 200°; the sulphuric 

 acid was then estimated as barium sulphate ; aifd after the 

 excess of barium in the filtrate had been removed, the 

 yttrium w^as thrown down as oxalate, and ignited to yield 

 oxide. The following are the weights given by Popp : 



Eliminating water, these figures give us for the percent- 

 ages of Yt^.Og in Yt2(S04)3 the values in column A. In 

 column B I put the cpiantities of Yt.Og proportional to 

 100 parts of BaSO^ : 



A. B. 



51-237 36.075 



51.226 36.064 



51. 161 36.058 



51-209 36.055 



Mean, 51.20S, ih .011 Mean, 36.063, d= .003 



From B, Yt = 101.880. The values in A will be com- 

 bined with similar data from other experimenters. 



* Ann. Chem. Pharm., 131, 179. 



16 



