OP ARTS AND SCIENCES. 311 



The air-dried salt, therefore, contains seven molecules of water of 

 crystallization, five of which it gives up in vacuo, while a heat of 160° 

 is necessary to remove the whole of its water. The very high result 

 of the first water determination was undoubtedly due to hygroscopic 

 moisture in the air-dried salt. 



0.6976 gr. of the salt dried at 160° gave, after precipitation with 

 ammonic oxalate and ignition over the blast-lamp, 0.085 gr. of CaO. 



Calculated for (C 7 H B CiS0 3 ) 2 Ca. Found. 



Calcium 8.87 8.70 



It forms rhombic crystals so nearly square that they look like flat- 

 tened cubes, freely soluble in water. 



The Copper Salt, (C 6 H 4 ClCH 2 SO ; ,) 2 Cu . 2H a O, was made by warm- 

 ing the aqueous solution of the acid with pure cupric carbonate, and 

 concentrating the filtrate on the water-bath ; the crystals thus obtained 

 were recrystallized from water. 



0.7400 gr. of the salt dried in vacuo lost when heated to 160° 

 0,0525 gr. 



Calculated for (C 7 H 6 ClS0 3 ) 2 Cu . 2H 2 0, Found. 



Water 7.08 7.05 



0.5000 gr. of the salt dried at 160° gave by precipitation with 

 sodic hydrate 0.0833 gr. of CuO. 



Calculated for (C 7 H 6 CISO g ) 9 Cu. Found. 



Copper 13.37 13.30 



It crystallizes in pale green needles grouped in bundles, and is 

 readily soluble in water. 



The neutral Lead Salt, (C 6 H 4 ClCH 2 S0 3 ) 2 Pb . H 2 0, was made by 

 treating an aqueous solution of the acid with plumbic hydrate not in 

 excess, the solution was evaporated in vacuo, and the crystals washed 

 with a little water to free them from the acid. It is probable from 

 the resemblance in crystalline form, that the precipitate formed on 

 adding a strong solution of the sodium salt to plumbic acetate consists 

 of this salt. 



0.8695 gr. of the salt dried in vacuo lost when heated to 100° 

 0.0261 gr. 



0.1910 gr. lost at 100° 0.0056 gr. 



0.1900 gr. of the salt dried in vacuo gave, after precipitation with 

 dilute H 2 S0 4 , 0.0902 gr. of PbS0 4 . 



