MancJiester Memoirs, J^ol. xlv. (igoo), No. "Z. 



S 



material which it was possible to bring over at any par- 

 ticular velocity was collected in a large cylinder. On 

 standing, the solid matter was allowed to settle, the 

 accompanying water was then decanted and the residue 

 dried at ioo*^C. 



0'2 gram of each fraction was weighed, shaken for 

 one hour with 200 cc. of a 0'25 per cent, solution of 

 hydrochloric acid, allowed to settle for one hour and then 

 filtered. Sulphuretted hydrogen was passed through 

 100 cc oi the filtrate, and the lead sulphide which 

 separated was filtered off, ignited with a drop of nitric 

 and sulphuric acids, and weighed as lead sulphate. 



The results obtained with this fritt are indicated under 

 the heading A in the table, and are accompanied by a 

 second series of results obtained in the same manner from 

 another fritt B, supplied to us, already ground, by Mr. W. 

 Burton, and the solubility of which, as determined by the 

 Home Office, was 5 "06 per cent. 



