RICHARDS AND BAXTER. — ATOMIC WEIGHT OF COBALT. 369 



Thus the last of Professor Winkler's criticisms is sufficiently answered. 



After necessarily dwelling at such length upon disagreements, it is a 

 pleasure to emphasize other points in which we agree with Professor 

 Winkler. The evidence of our work, together with Dr. Cushman's, 

 strongly supports Winkler's contention that nickel and cobalt, as we 

 knew them of old, cannot contain more than an infinitesimal amount of 

 any unknown element. Several radically different methods of prepara- 

 tion and many fractionations invariably led us to constant atomic weights, 

 within a reasonable limit of experimental error ; and we are forced to 

 conclude that the familiar properties of these common and useful metals 

 are to be ascribed to elements as definite as any of the seventy-five. It 

 is needless to point out also that we agree with Professor Winkler in 

 assigning to cobalt a higher atomic weight than to nickel, in spite of the 

 conflict of periodicity with rhodium and palladium. According to our 

 results, the atom of cobalt, weighing almost exactly 59.00, is very nearly 

 half of one per cent heavier than that of nickel. 



Cambridge, October 29, 1898. 



VOL. XXXIV. — 24 



