284 PROCEEDINGS OP THE AMERICAN ACADEMY 



water. When exposed to the air it slowly effloresces, and loses its 

 water readily over sulphuric acid or when heated to 100°. 



I. 0.7880 grm. of salt dried by short exposure to the air gave 

 0.4246 grm. BaSO,. 

 II. 0.6729 grm. air-dried salt gave 0.3631 grm. BaSO^. 



III. 1.5568 grm. air-dried salt lost at 100° 0.2547 grm. HgO. 



IV. 1.1932 grm. air-dried salt lost over HoSO^ 0.1935 grm. HjO. 



Calculated for Found. 



PaCoUClSO,., . 4 H2O. I. II. m. IV. 



Ba 31.60 31.63 31.72 



H2O 16.61 16.36 16.22 



I. 0.6958 grm. salt dried at 100° gave 0.4477 grm. BaSO,. 

 II. 1.0371 grm. salt dried over HgSO^ gave 0.6678 grm. BaSO^. 



Calculated for Found 



BaCsHClSOs I. 11. 



Ba 37.89 37.83 37.86 



The solubility of the salt in cold water we determined in the usual 

 way. 



I. 15.6246 grm. solution saturated at 20° gave 0.1888 grm. BaSO^. 

 II. 17.2519 grm. solution saturated at 20° gave 0.2084 grm. BaSO^. 



The solution saturated at 20° therefore contained the following per- 

 centages of the anhydrous salts : — 



I. II. 



1.87 1.87 



Plumbic fi-Chlor-h-Sulphopyromucate, PbC^HClSOg . 4 HgO. 



The lead salt is readily soluble in hot water, more sparingly soluble 

 in cold water, and crystallizes when its hot aqueous solution is cooled 

 in thick rhombic prisms which contain four molecules of water. The 

 salt effloresces slowly when exposed to the air, loses the greater part of 

 its water over sulphuric acid, and becomes anhydrous when heated 

 to 125°. 



I. 0.7342 grm. air-dried salt gave 0.4416 grm. PbSO^. 

 II. 1.7839 grm. air-dried salt lost at 125° 0.2552 grm. H,0. 

 III. 0.7343 grm. air-dried salt lost at 125"" 0.1045 grm. H.A 



III. 

 14.23 



