638 I'UOCEEDINGS OF THE AMERICAN ACADEMY. 



NOT E. 



SiNXF. the jqjpearance of this table last year, the Committee of the Ger- 

 jiian Chemical Society, Messrs. Landolt, Ostwald, and Seubert, have made 

 their interesting report upon the subject, and have invited the chemists of 

 the world to join them in deciding upon one standard to be used everywhere. 

 The fulfilment of this very desirable end must necessarily be a matter of 

 many months ; hence the present table is republished this year in accordance 

 with the original iilan. Jt is to be distinctly understood that the repub- 

 lication is not in any way an attempt to compete with or to foi-estall the 

 International Committee ; it is merely an expression of opinion, which may 

 be of temporary service. The fact that none of the other recent tables 

 follow the accepted scientific usage concerning significant figures seems to 

 afford an additional reason for reprinting this one. 



The investigations of the past year have pointed to a change in four 

 values given in the table of 1898. Calcium is made 40.1 instead of 40; for 

 recent experiments (as yet unpublished) in this Laboratory indicate that 

 last year's estimate was too low. Neo- and praseodymium were oddly 

 transposed by their discoverer, and the more accurate values of Jones * and 

 others are substituted. Lastly, Lenher's f careful investigation upon sele- 

 nium seems to show that this element has a higher atomic weight than was 

 formerly supposed to belong to it. For,the present a compromise number, 

 79.2, is recorded above. 



* Am. Chem. Journ., XX. 345 (1898). 



t Journ. Am. Chem. Soc, XX. 555 (1898). Compare Clarke, Ibid., XXI. 200 

 (1899). 



