144 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



weight of lithium by an analysis of the sulphate, and had found a value 

 not far from 6.5, thus confirming the results of Berzelius and of Hagen, 

 who had employed the same method. But Diehl showed that the BaS04 

 precipitated from LijSO^ always retained traces of Li, which were recog- 

 nizable by spectral analysis, and which accounted for the error. In the 

 later paper Troost made use of the chloride and the carbonate of lithium, 

 both spectroscopically pure. The carbonate was strongly ignited with 

 pure quartz powder, thus losing carbon dioxide, which loss was easily 

 estimated. The subjoined results were obtained : 



.970 grm. LijCOs lost .577 grm. COj. 59.485 per cent. 



1.782 " 1.059 " 59.427 



Mean, 59.456, ± .020 



Hence Li =7.003. 



The lithium chloride employed by Troost was heated in a stream of 

 dry hydrochloric acid gas, of which the excess, after cooling, was ex- 

 pelled by a current of dry air. The salt was weighed in the same tube 

 in which the foregoing operations had been performed, and the chlorine 

 was then estimated as silver chloride. The usual ratio between LiCl 

 and 100 parts of AgCl is given in the third column : 



1.309 grm. LiCl gave 4.420 grm. AgCl. 29.615 



2.750 " 9.300 " 29.570 



Mean, 29.5925, ± .0145 

 Hence Li = 6.959. 



Xext in order is the work of Stas/ which was executed with his usual 

 care. In three titrations, in which all the weights were reduced to a 

 vacuum standard, the following quantities of LiCl balanced 100 parts 

 of pure silver: 



39.356 

 39.357 

 39.361 



Mean, 39.358, ± .001 



Hence Li =7.0110. 



In a second series of experiments, intended for determining the atomic 

 weight of nitrogen, LiCl was converted into LiNOg. The method was 

 that employed for a similar purpose with the chlorides of sodium and 

 of potassium. One hundred parts of LiCl gave of LilSTOg : 



162.588 

 162.600 

 162.598 



Mean, 162.5953, ± .0025 

 Hence Li = 6.956. 



1 Oeuvres Completes, 1, 710-716. 



