FROM BURDWAN. 175 



No. 7. 

 DESER GERH. 

 Sp. Gr. 3645. 



Blowpipe — becomes magnetic, and assumes the metallic tarnish ; 

 with borax on charcoal, a dark coloured enamel studded with bright gold 

 spots, resembling avanturine : the fragments translucent and of a bright 

 golden green. 



CONSTITUENTS. 



Water, .... 

 Silex, .... 

 Lime, .... 

 Alumine, 



Phosphate Iron, , 

 Oxide Manganese, 

 Peroxide Iron, 



99 13 



NOTE. 



The very beautiful appearance produced by the blowpipe, may probably be owing to the 

 conversion of Pliosphate of Iron into Phosphuret of Iron, by the combustion of the charcoal support. 



6 



3 75 



50 



50 



90 



1 50 



86 00—60 Iron. 



The process used in the foregoing analysis differs from those indicat- 

 ed by the books ; I have therefore subjoined a memorandum of it for the 

 satisfaction of the scientific chemist. 



1. — Weigh the pulverised ore at the temperature of the atmosphere, 

 and calcine at a low red heat, the loss indicates the water, and if there is 

 change of colour (from yellow to deep red brown) probably of carbonic 

 acid. 



2. — For 100 grains of the ore take 1]- oz. muriatic acid, boil it gently 

 over a lamp in a covered vessel for twenty minutes, add four ounces of 

 water, and boil again for a few minutes ; this dissolves every thing- 

 except 



