456 Penfield and Bradley — Precipitates on Asbestos. 



Antimony in Japanese stibnite was precipitated by hydrogen 

 sulphide after dissolving the mineral in hydrochloric acid. The 

 Sb„S 3 was ignited in C0 2 gas. 



Stibnite taken (VI 385 



Sb 2 S 3 weighed 0-1384 



Error 0-0001 — 



Bismuth in pure Bi„0 3 was precipitated by hydrogen sul- 

 phide after dissolving the oxide in the least possible amount 

 of dilute nitric acid, and diluting largely before precipitation. 



Bi 2 S 3 was ignited in C0 2 and weighed. 



Bi„0 3 taken 0-3047 



Bi~0 3 determined 0*3046 



Error 0-0001 — 



Thanks are here expressed to Dr. ~W. E. Ford, who kindly 

 furnished the results of the last two determinations. 



Filter tubes such as here described have been in use for 

 many years in our laboratory, and have frequently been 

 employed in the estimation of potassium as platinic chloride ; 

 on subsequent ignition in hydrogen gas the salt may be 

 decomposed, the alkali chloride extracted with water, and 

 tested spectroscopically for caesium and rubidium. 



Mineralogical Laboratory of the Sheffield Scientific School 

 of Yale University, New Haven, Conn., March, 1906. 



