54 



Transactions. 



be filtered in 1 such an arrangement in a remarkably short 

 space of time. 



To suction 

 pump 



The precipitate, which remains in a, is washed with a 

 small quantity of a solution containing zinc-sulphate and 

 ammonium-nitrate, in which it is practically insoluble. 



The liquid which collects in b is then transferred to a 

 graduated flask of 100 c.c. capacity. It saves time, however, 

 if the liquid is filtered directly into a measuring-flask to which 

 a side tube is attached (Fig. 2). 



After dilution 10 c.c. of the solution is treated with an 

 equal volume of decinortnal silver-nitrate, and n, sulpho- 

 cyanide added until a red colour is developed with ferric sul- 



