221 



Upon most carefully revising the determinations at hand, 

 for the completion of this fourth part, I had to drop several 

 elements for which the standard atomic weights seemed 

 reasonably well determined, such as Pd, Sr. 



We need thoroughly independent analytical work for 

 such elements. Keiser is too much given to " confirm " 

 what is current, and Richards is too much in the wet way, to 

 attach real value to their determinations for these metals. 



Ag=108. SILVER. MAUMENE, 1846. 



The true atomic weight of silver was determined more 

 than half a century ago, by E. Matiment ; his admirable 

 determinations were published in the Annales de Chimie et 

 de Physique, T. 18, pp. 57-61 ; 1846. See also Sebelien, pp. 

 81-82, and especially my True Atomic Weights, 1894, pp. 

 195-199. 



The silver acetate he prepared in "very beautiful crys- 

 tals" (Nos. 1,2); of which a large lot he recry stall ized with 

 extreme care for determinations, Nos. 3, 4, the purest he 

 was able to obtain. No. 5 was made on a small scale from 

 silver chloride. 



The process used in the determination is analytically and 

 atomically the sharpest we know; namely, by combustion, 

 the carbon is determined as carbon dioxide, as in the noted 

 combustion of the diamond by Dumas, while metallic silver 

 remains as residue; in this case without loss by volatiliza- 

 tion, the combustion being effected at a comparatively low 

 temperature. 



The presence of a trace of occluded water in these crys- 

 tals will have no influence on the result, as is perfectly 

 evident. This was one of the determining reasons for 

 selecting this process of analysis. 



It is passing strange that this in every manner excellent 

 work has been almost ignored for half a century; in Clarke's 

 Constants, the weighings are given, but the spirit is omitted, 

 hence the record is a barefaced misrepresentation of the 

 real facts, as we shall see. 



