310 Mr Graham on Water as a Constituent of Salts. 



it is attempted to form it by double decomposition from the bi- 

 sulphate of soda, in general a large quantity of sulphate of soda 

 and of sulphate of copper are separately deposited before the 

 double salt appears. It is then deposited in a crust, consisting 

 of small but distinct crystals, which are slightly deliquescent, and 

 appear to contain two proportions of water. This salt is easily 

 made anhydrous, and thereafter fuses at an incipient red heat 

 without loss of acid, and remains of a blue colour when cool. 

 The fused salt does not split into thin scales in the progress of 

 cooling, as the corresponding sulphate of copper and potash does. 



Sulphate of Manganese with Saline Water : MnSH-f-H 4 . 



phate of Manganese. 



Sul- 



The water in this salt was found to be reduced from five ato- 

 mic proportions to little more than one, by drying the crystals 

 in open air at 238°, while one entire atomic proportion was re- 

 tained at 410°. Flesh-coloured crystals, dried in vacuo in warm 

 summer weather, without artificial heat, lost somewhat more 

 than three proportions of water. 





Anhydrous 

 Salt. 



Water. 



Anhydrous 

 Salt. 



Water. 





28.42 



17.07 



100 



60.06 



Do. dried at 238°, 



21.53 



2.92 



100 



13.05 



A portion of last, afterwards dried for onel 

 hour between 380° and 410°, . . . j 



9.54 



1.12 



100 



11.74 



A portion of same, dried for one hour between 1 

 415° and 468°, J 



10.90 



0.56 



100 



5.14 



Crystals dried for nine days in vacuo over^ 

 sulphuric acid, thermometer 64° to 72°, > 

 but had lost nothing the last two days, J 



8.62 



11 



100 



20.88 



Composition of sulphate of manganese with ) 

 one atom of water (by theory), . . . ) 





... 



100 



11.88 



Composition of do. with five atoms of water, 





... 



100 



594 



A crystalline crust of sulphate of manganese, deposited from 



