18 



quadrilateral acicular prisms, having a deep ruby or garnet-red 

 colour, with a bluish-violet or light purplish reflexion-tint ; it is 

 sometimes deposited in thin flat plates, or long, flat, acicular prisms ; 

 these, when thin, transmit a pure yellow colour, but in thicker 

 plates it becomes reddish, with a tinge of brown. 



There is scarcely any appearance of double absorption in this 

 salt ; the thicker crystals alone exhibit it, when their usual tint be- 

 comes darkened on analysis with a Nichol. 



This salt requires 31 parts of boiling spirit, and 121 parts at 62 

 to dissolve 1 ; water precipitates it as a cinnamon-brown powder. 



Its deep marone-coloured large aciculse had a specific gravity of 

 17647 at 62. 



These large crystals, exposed whole to a temperature of 212, de- 

 crepitate afterwards on exposure to the air, but dried at 212, they do 

 not appear to lose further water after prolonged exposure to the 

 drying bath. 



The author having supplied Dr. Sheridan Muspratt with a 

 quantity of this salt, has been most obligingly furnished with the 

 results of his examination ; from which it will be seen that those 

 previously obtained by the author have been confirmed in the most 

 satisfactory manner by that experienced analyst. 



100-000 100-000 100-000 

 The formulae derivable from these analyses are the following : 



