Intelligence and Miscellaneous Articles. 67 



NATIVE PHOSPHATES OF MANGANESE AND IRON. 



M. Dufre'noy has analysed two varieties of the above-named mine- 

 ral. The first, to which the name of Huraulite is given from its 

 occurring in the Commune des Hure'aux, was originally found by M. 

 Alluan in the granite near Limoges. The characters of this mi- 

 neral are, that it is crystallized, the crystals being of the size of a pin's 

 head j the primary form is an oblique rhombic prism. It shows no 

 cleavage, its fracture is vitreous, it is transparent, has a reddish yel- 

 low colour, scratches calcareous spar, but is scratched by steel j its 

 sp. gr. is 2'27. It fuses very readily, and gives with the blowpipe a 

 black button with a metallic lustre j when heated in a matrass it gives 

 water. It is composed of 



Phosphoric acid. . . . 38'0 



Oxide of iron 11-1 



manganese. . 32*8 



Water 18'0 



99-9 



The other phosphate of manganese is called Hdteposite j it has 

 been found only in lamellar masses, presenting a three- fold cleavage ; 

 the primary form appearing to be an oblique rhombic prism : it has 

 but little lustre, and it is greasy like that of phosphate of lime 5 its 

 colour is greenish gray, or blueish : when it has been long exposed 

 to the air the colour is a fine violet, and the vitreous lustre is changed 

 to semi-metallic. Its sp. gr., when it has not changed by exposure, 

 is 3-524, but when it has, it is 3'390. It dissolves in acids, except a 

 little silica ; and by the blowpipe it fuses into a brown enamel, with 

 a semi-metallic lustre. It is composed of 



Phosphoric acid . . . . < 41 '77 



Oxide of iron 34'89 



Red oxide of manganese. 17*57 



Loss by heat 4*40 



Silica ' -20 



98-83 



The double phosphate, analysed by Berzelius, gave 

 Phosphoric acid .... 32-80 

 Protoxide of iron .... 31 '90 



manganese 32'60 



Phosphate of lime . . 3'20 



100-50 



It appears, therefore, that these three minerals are composed of 

 different atomic proportions of their constituents. Ann. de Chimie, 

 xli. 347. 



ON OXAM1DE. BY M. DUMAS. 



Oxamide is a new product formed during the distillation of oxalate 

 of ammonia ; its name is derived from the compound which produces 

 it, and which it reproduces. When oxamide is treated with pot- 



K 2 ash, 



