232 THE ATOMIC WEIGHTS. 



Bi Taken. Bi^O-^ Found. Per cent. Bi. 



25.0667 - 27.9442 89.703 



21.0691 23.4875 89.7035 



27.2596 30-3922 89.693 



36.5195 40.7131 89.700 



27.9214 31-1295 89.6944 



32.1188 35-8103 89.692 



30.1000 33-5587 89.694 



26.4825 59-5257 89.693 



19.8008 22 0758 89.695 



Mean, 89.696, ± .0009 



Hence, if = 16, Bi = 208.92, or, reduced to vacuum standards, 208.90. 



Classen's paper was followed by a long controversy between Schneider 

 and Classen,^ in which the former upheld the essential accuracy of the 

 work done by Marignac and himself. Sclmeider had started out with 

 commercial bismuth, and Classen found that the commercial bismuth 

 which he met with was impure. Schneider, by various analyses, showed 

 that other samples of bismuth were so nearly })ure that the common 

 modes of purification were adequate ; but Classen replied that the original 

 sample used by Schneider in his atomic weight investigation had not 

 been reexamined. Accordingly, Schneider published a new series of 

 determinations t niade by the old method, but with metal which had 

 been scrupulously purified. Results as follows : 



Bi. Bi^O.^. Percent Bi. 



5.0092 5.5868 89.661 



3.6770 4.1016 89.648 



7.2493 8.0854 89.659 



9.2479 10.3142 89.662 



6.0945 6.7979 89-653 



12.15S8 13.5610 89.660 



Mean, 89.657, ± .0015 



Hence with =: 16, Bi = 208.05, a confirmation of the earlier deter- 

 minations. 



Although the results so far are not final, a combination of the data 

 relative to bismuth oxide is not Avithout interest. 



1. Lagerhjelm 89.865, ± .0650 



2. Schneider, 185 1 89.655, dr .0034 



3. Marignac 89.682, ± .0036 



4. Lowe -. . . 89.648, =b .0040 



5. Classen 89.696, d= .0009 



6. Schneider, 1894 89.657, db .0015 



General mean 89.681, zb .0007 



* Journ. fiir Prakt. Cheni. (2), 42, 553 ; 43, 133 ; and 44, 23 and 411. 

 t Journ. fiir Prakt. Chem. (2), 50, 461. 1S94. 



