1 824.] On the Crystalline Forms of Artificial Salts. 117 



Article IX. 



On the Crystalline Forms of Artificial Salts. 

 By H. J. Brooke, Esq. FRS. 



(Continued from p. 22.) 



Sulphate of Nickel and Copper. 



The primary form of this salt is an oblique rhombic prism, with 

 an imperfect cleavage parallel to its lateral planes. 



PonM,orM' 100° 15' 



Pone' 117 30 



M on M' 83 30 



I received these crystals from Mr. R. 

 Phillips, and having dissolved some of 

 them in distilled water for the purpose of 

 obtaining others with more perfect planes, 

 I found that the first crystals deposited 

 from the solution were sulphate of' cop- 

 per ; the next, sulphate of nickel and 

 copper similar to those which had been 



dissolved : these were removed, and were succeeded by a crop 

 of the same crystals intermingled with a few others of the 

 rhombic sulphate of nickel; and crystals of both these salts con- 

 tinued to be deposited together until the fluid was nearly all eva- 

 porated. 



There were not any crystals of sulphate of copper deposited 

 from this solution after the double salt began to crystallize, but 

 the solution at Mr. P.'s, from which the crystals I received had 

 been obtained, had subsequently produced crystals of sulphate 

 of copper. It would appear from these circumstances that the 

 double salt would only be produced in uncombined portions of 

 both of the single ones. 



Sulphate of Ammonia and Magnesia. 



The primary form of this salt is an oblique rhombic prism. 



P on M, or M' 104° 45' 



Pone, ore' 154 40 



Pong 135 40 



Pone' 115 30 



MonM' 109 30 



M on k 125 15 



The crystals of this and the following I 

 have received from Mr, R. Phillips. 



