OF ARTS AND SCIENCES. . 269 



ing nearly the same atomic masses, and then applying the method of 

 separation to these. 



Other applications of the method give, as I will now show, substan- 

 tially similar results. The next substance examined was a mixture of 

 oxides received from Dr. Shapleigh. and obtained from residual mother 

 liquors of cerite and monazite salts. The oxide was dissolved in chlor- 

 hydric acid, and purified by a current of sulphydric acid. Of the 

 mixed oxalates, — 



(69) 0.5622 gr. gave 0.1715 gr. C 2 3 = 30.50 per cent. 



(70) 0.4782 gr. " 0.1458 gr. " =30.50 



(71) 0.4355 gr. « 0.1326 gr. " =30.17 " 



(72) 0.6100 gr. « 0.2778 gr. R 2 O s = 45.55 « 



(73) 0.6904 gr. " 0.3141 gr. " =45.50 « 



Atomic mass 137.25. 



I also determined the mean atomic mass after separating the cerite 

 earths by means of sodic sulphate in the usual manner. Of course 

 some yttria went down with the double sulphates. 



(74) 0.2440 gr. gave 0.0946 gr. C 2 8 = 38.77 per cent. 



(75) 0.2438 gr. " 0.0946 gr. " = 38.80 



(76) 0.4597 gr. " 0.2146 gr. R 2 3 = 46.68 



(77) 0.3570 gr. " 0.1668 gr. « =46.72 " 



Atomic mass 106.05. 



The oxides with atomic mass 106.05 were then treated by the oxy- 

 chloride process. 



Portion B t Left. 



(78) 0.4027 gr. gave 0.1505 gr. C 2 8 = 37.38 per cent. 



(79) 0.5204 gr. " 0.1943 gr. " =37.35 



(80) 0.6947 gr. " 0.3250 gr. R 2 3 = 46.78 



(81) 0.9233 gr. " 0.4323 gr. « =46.82 



Atomic mass 11 1.3. 



Portion B 2 Left. 



(82) 0.4127 gr. gave 0.1464 gr. C 2 3 = 35. 19 per cent. 



(83) 0.3215 gr. " 0.1142 gr. " =35.51 



(84) 0.5885 gr. " 0.2668 gr. R 2 3 = 45.33 



(85) 0.6205 gr. " 0.2814 gr. " =45.35 



Atomic mass 113.95. 



