GOLD 163 



4.1445 grm. KjAuCljgave .S185 gmi. KCl and 2.159 ?.^^- ^"- 263.775 



Still a third series of experiments by Berzelius * may be 

 included here. In order to establish the atomic weight of 

 phosphorus he employed that substance to precipitate gold 

 from a solution of gold chloride in excess. Between the 

 weight of phosphorus taken and the weight of gold ob- 

 tained it was easy to fix a ratio. Since the atomic weight 

 of phosphorus has been better established by other methods, 

 we may properly reverse this ratio and apply it to our dis- 

 cussion of gold. 100 parts of P precipitate the quantities of 

 Au given in the third column : 



• 



.829 gnn. P precipitated 8.714 grm. Au. 1051.15 



.754 " 7-930 " 1051.73 



Mean, 1051.44, dr .196 



Hence Au = 195.303, ± .589. 



Levol's t estimation of the atomic weight under considera- 

 tion can hardly have much value. A weighed quantity of 

 gold was converted in a flask into AuClg. This was reduced 

 by a stream of sulphur dioxide, and the resulting sulphuric 

 acid was determined as BaS04. One gramme of gold gave 

 1.782 grm. BaSO,. Hence Au = 195.794. 



If we give this single experiment and Berzelius' single 

 result with mercury each equal weight with one analysis in 

 the potassio-auric chloride series, and include respectively 

 the probable errors appertaining to Hg and to BaSO^, we 

 may combine all the data as follows : 



*Lehrbuch, 5 Aufl., 3, 1188. 



f Ann. d. Cliim. et d. Phys., (3,) 30, 355. 1850. 



