OF ARTS AND SCIENCES. 



53 



* Columns (a), (b), and (c) contain the results of a supplementary series of 

 experiments, made merely to control the results given in columns (4) and (5). 

 {Vid. infra.) 



t The solution of this fine silver in nitric acid became blue when neutralized 

 with ammonia. The filtrate from the mixed precipitate of sulphate of lead and 

 gold (see p. 56) contained a decided trace of copper and a fainter trace of iron. 

 The solution of sulphate of soda, from which the sulphuric acid of col. (3) was 



