268 



PROCEEDINGS OF THE AMERICAN ACADEMY 



The followinoj diagram enables us to take iu all the results at a 



glance. 



Lefi. 



107.05 Rirjht. 



It must be noted that in the above and on the diagram, Bi, Bg, B3, 

 etc. denote basic or oxychlorides ; Ai, Ag, A3, etc., neutral or rela- 

 tively acid chlorides. The analyses were not pursued further because 

 the material taken was exhausted by the separations accomplished. 

 The examination of the results obtained in this particular case by the 

 basic chloride process leads to interesting conclusions. In the first 

 place, it will be remarked that the atomic masses of the insoluble 

 basic chlorides increase with each successive separation into basic and 

 acid chlorides, while the neutral or relatively acid chlorides give di- 

 minishing atomic masses. In the cases of these last, three successive 

 operations give a nearly pure yttria, with atomic mass 89.5. The 

 rate of increase of the atomic masses of the successive portions Bi, 

 B2, B3, is about 5.3 units for each operation. The rate of decrease of 

 the portions Ax, A2, A3, is about 2.6 units for each operation. It is 

 inot to be expected that jDerfectly uniform results will be obtained 

 even when the process is applied to the same mixture of oxides, be- 

 cause the amount of separation into basic and acid chlorides by each 

 operation must depend very much upon the temperature of the muffle 

 and the length of time during which the heat is applied. In the sec- 

 ond place, it must be noted that, while a very nearly pure yttria is 

 obtained in three operations, this does not represent the whole quan- 

 tity of the earth in the compound. It will also be seen that a decided 

 advantage must be secured by making mixtures of the products hav- 



