Mr. Phillips on a new Oxide of Manganese ; Sfc. 211 



being then suffered to enter, the space unoccupied by it indi- 

 cated the quantity of oxygen gas remaining in the retort. 

 There were left undissolved 7*8 grains of peroxide of man- 

 ganese and silica; consequently, allowing one grain for the 

 sulphuret of copper, 191 "2 of the oxide were decomposed by 

 the acid. 



The capacity of the retort was 1 8 cubic inches, of which 

 the acid and oxide occupied 5; by deducting 13 from the 

 contents of the air-jar, amounting to 83*5 cubic inches at 60°, 

 we have 70'5 of oxygen gas, to which are to be added 5'5 

 inches left in the retort, giving 76 cubic inches as the whole 

 of the oxygen gas, yielded by 191*2 of the oxide of manga- 

 nese. On repeating this experiment, I procured 76*7 inches 

 of oxygen from 192'5 of the oxide; the mean is therefore 39'8 

 inches = IS'l-S grains of oxygen from 100 of the ore. The 

 peroxide of manganese being composed of 44 metal and 16 

 oxygen, half of which it loses in becoming protoxide, it is evi- 

 dent that the Warwickshire ore is very differently constituted ; 

 for as 100: 13*48 :: 44 : 5*93, which is less than three-fourths 

 of the oxygenth at s'^^uld have been obtained from peroxide. 



In Dr. Turner's paper on tne oxides of manganese, already 

 alluded to, a peculiar oxide oi manganese is described under 

 the name of Manganite ; the principal facts relating to it are 

 stated as follows : " When manganite is heated to redness it 

 gives out 10*10 per cent of water; and the total loss from 

 exposure to a white heat is 13*15 per cent. Deducting from 

 the last number the amount of water, 3*05 remain as the loss 

 in oxygen. The result of this analysis is therefore 



Red oxide 86*85 



Oxygen 3*05 



Water 10*10 



100*00 

 According to this analysis, manganite contains an oxide of man- 

 ganese, 89*9 parts of which yield 3*05 of oxygen, on being con- 

 verted into the red oxide. An equal quantity of pure deutoxide, 

 in undergoing a similar change, should lose 2*997 of oxygen. 



" Exposed to a strong red heat and a current of hydrogen 

 gas, 100 parts of manganite lost 19*09 parts in one experi- 

 ment, and 19*07 in another. The mean is 19*08, and sub- 

 tracting 10*10 as water, 8*98 remain as oxygen. According 

 to this analysis manganite is composed of 



Protoxide 80*92 



Oxygen 8*98 



Water 10*10 



foo-oo 



•' Now as 80-92 : 8*98 : : 36 : 3*995. 



2 K 2 " From 



