MINERALOGY. |gg 



it ferments in a ftill greater degree, when it 

 is melted with the microcofmic fait. 



5. It does not excite any effervefcerioe with the 

 fpirit of nitre : aqua regia, however, extra&s 

 the colour out of the black, and difiblves 

 likewiie a great deal of it, which, by means 

 of an alcali, is precipitated to a white 

 powder. 



6. Such colours as are communicated to glafTes 

 by manganefe, are eafily deftroyed by the 

 calx of arfenic or tin : they alfo vanifh of 

 themfelves in the fire. 



7. It is commonly of a loofe texture, fo as to 

 colour the fingers like foot, although it is of 

 a metallic appearance when broke. 



SECT. CXIV. 



Manganefe is found, 



A Loofe and friable, Magnefia friabilis terri- 

 forms. 



a. Black, feems to be weathered or decayed 

 particles of the indurated kind, from Eng- 

 land. 



SECT. CXV. 



B. Indurated, Magnefia indurata. 



1. Pure, in form of balls, whofe texture 



con Mils of concentric fibres, Magnefia pur a 



f-phterica radiis concentratis, 



a. White, Magnefia alba ftrifte fie difta^ 



is very fcarce. 1 have feen a fpecimen of 



this kind in a collection from an unknown 



place in Norway •, and by examining a 



piece of it, I found that it differed from 



the 



