212 Mr. Phillips o;» a ?iew Oxide of Manganese ; S(C. 



" From the resuh of both analyses, it is apparent that man- 

 ganite, in relation to manganese and oxygen, is a deutoxide. 



"Also as 89-90 : lO'lO : : 4.-4.94;. 



" The fourth number is so near 4*5, half an equivalent of 

 water, that we may safely regard manganite as a compound 

 of 80 parts, or two equivalents of the deutoxide of manga- 

 nese, and 9 parts or one equivalent of water." 



There are two circumstances in which the Warwickshire 

 ore agrees very nearly with manganite, viz. in the weight 

 which it loses by exposure to a strong, and a low red heat. 

 I have already observed that the first-mentioned oxide loses 

 13*26 per cent by a strong heat, which differs only O'll 

 from that lost by manganite according to Dr. Turner : by a 

 low red heat, the ore now under consideration loses 10"2 per 

 cent; while manganite loses lO'l. There is, however, one fact 

 which proves that the Warwickshire oxide is not deutoxide, 

 as manganite appears to be by Dr. Turner's analysis : it has 

 been already shown that 44? grains of the ore now under exa- 

 mination, lose 5'95 of oxygen by conversion into protoxide ; 

 but an equal quantity of a compound of two atoms deutoxide 

 = 80+1 water = 9 would give scarcely 4 by the same opera- 

 tion, for as 89 : 8 : : 44 : 4 very nearly. 



More particularly to examine the source of the loss of 10*2 

 per cent at a low red heat, I put 200 grains of the powdered 

 Warwickshire ore, which had been previously dried by steam, 

 into a small coated glass retort, and heated it to redness in 

 an open charcoal fire; an accurately weighed receiver was 

 adapted to the retort; water came over very readily, and a 

 little which remained near the mouth of the retort was ex- 

 pelled by a spirit-lamp, and condensed in the receiver. 



The oxide, weighed when cold, had lost 22"4 grains ; but the 

 weight of the water was only 10*8 grains: it then occurred to 

 me that part of the loss was owing to the extrication of oxy- 

 gen, and this I found to be the case ; for an ignited piece of 

 wood immediately burnt with a vivid flame on being introduced 

 into the receiver, although no precautions had been taken to 

 receive any gas. I repeated this experiment with the addi- 

 tion of the pneumatic apparatus ; the capacity of the retort 

 was 14 cubic inches, and there was obtained a mixture of the 

 atmospheric air of the retort and oxygen gas, amounting to 

 20 inches. I do not give the results of this experiment with 

 any claim for their accuracy ; but if we deduct from the gas 

 even the whole of the atmospheric air of the retort, a con- 

 siderable portion of oxygen remains; the oxide lost 20*4 

 grains. 



It has been already mentioned that the ore loses 13'48 per 



cent 



