264 Wells $ Foote — One Hundred Years of Chemistry. 



which dealt with most of the common elements, were 

 accepted with much confidence by chemists everywhere. 



Stas reached the conclusion that there could be no real 

 foundation for Prout's hypothesis, since so many of his 

 atomic weights varied from whole numbers, and this 

 opinion has been generally accepted. 



The first accurate atomic weight determination pub- 

 lished in the Journal was that by Mallett on lithium (22, 

 349, 1856; 28, 349, 1859), showing a result almost identi- 

 cal with that accepted at the present time. Johnson and 

 Allen's determination (35, 94, 1863) on the rare element 

 caesium was carried out with extraordinary accuracy. 

 Lee, working with Wolcott Gibbs, made good determina- 

 tions on nickel and cobalt (2, 44, 1871). The work of 

 Cooke on antimony (15, 41, 107, 1878) was excellent. 



Concerning the more recent work published elsewhere 

 than in the Journal, attention should be called particu- 

 larly to the investigations that have been carried on for 

 the past twenty-five years by Richards and his associates 

 at Harvard University. Richards has shown masterly 

 ability in the selection of methods and in avoiding errors. 

 His results have displayed such marvelous agreements 

 among repeated determinations by the same and by dif- 

 ferent processes as to inspire the greatest confidence. 

 His work has been very extensive, and it is a great credit 

 to our country that this atomic weight work, so superior 

 to all that has been previously done, is being carried 

 out here. 



It may be mentioned that for a number of years the 

 decision in regard to the atomic weights to be accepted 

 has been in the hands of an International Committee of 

 which our fellow countryman F. W. Clarke has been 

 chairman. In connection with this position and pre- 

 viously, Clarke has done valuable service in re-calculat- 

 ing and summarizing atomic weight determinations. 



Analytical Chemistry. 



Analysis is of such fundamental importance in nearly 

 every other branch of chemical investigation that its 

 development has been of the utmost importance in con- 

 nection with the advancement of the science. It attained, 

 therefore, a comparatively early development, and one 

 hundred years ago it was in a flourishing condition, par- 

 ticularly as far as inorganic qualitative and gravimetric 



