98 JOURNAL OF THE 



RECALCULATIONS OF THE ATOMIC WEIGHTS. 



F. P. VENABLE. 



Within the last five years several attempts have been made by 

 chemists of prominence to recalculate the many atomic weight 

 determinations upon a uniform basis and by uniform methods, 

 and so secure, if possible, a trustworthy table of these most im- 

 portant constants of nature. Our better knowledge of these ele- 

 ments and the iucreased accuracy of modern methods promised 

 favorably for the success of such an undertaking. That such a 

 revision was called for a glance at the text-books of the time 

 will abundantly show. The greatest variance was shown in the 

 tables of atomic weights given. They seemed to be chosen most 

 arbitrarily. No single authority was recognized, and in many 

 cases it would have been difficult to trace the source of the num- 

 bers given. Especially were the differences notable in text-books 

 of different nationalities. Taking two nearly contemporaneous 

 text-books widely used in England, America and Germany — 

 Watts (1878) and Richter (1881)— I find that out of 64 elements 

 37 per cent, only have the atomic weights the same in both; 22 

 per cent, differ by from .10 to .25; 20 per cent, differ from .25 to 

 .50; 10 per cent, differ from .50 to 1.00, and 11 per cent, differ 

 by more than 1, the difference in several cases ranging from 25 

 to 40. 



To call such a list a table of constants seems ridiculous, nor 

 does it speak well for chemistry as a science that these, the very 

 foundation stones on which its building is reared, should be so 

 unstable and little trustworthy. Analyses calculated by num- 

 bers so different, as in these two tables, must give very different 

 results, one or the other, or perhaps both, of which must be 

 erroneous. 



The evil was and is a crying one and demands the best ener- 

 gies of the wisest chemists to rectify. 



