Mr. Phillips on a new Oxide of Manganese ; ^c. 213 



cent of oxygen by solution in sulphuric acid ; and the water 

 amounting to 5*4 per cent, the mineral consists of 



Protoxide of Manganese 81 "12 



Oxygen 13*48 



Water 5-40 



100-00 

 which are equivalent to 



Manganese 63-0 



Oxygen 31-6 



Water 5-4 



lOO-O 

 Its atomic constitution appears to be 



Two atoms Deutoxide . . 80 or Manganese . . 63'275 

 Two atoms Peroxide . . . 88 Oxygen .... 3r637 

 One atom Water 9 Water 5*088 



177 100*000 



The agreement between the experimental results and the 

 calculated composition seems to me sufficiently near to de- 

 termine the nature of the Warwickshire ore ; and it may be 

 observed, that the atom of oxygen which the water contains 

 would convert the two atoms of deutoxide into two of per- 

 oxide. 



As Dr. Turner, in his analysis of manganite, does not ap- 

 pear to have suspected that it loses oxygen at a red heat, it 

 seems to me extremely probable that the composition of man- 

 ganite is similar to that of the Warwickshire oxide ; and con- 

 sequently, about one half ot the loss, which is attributed by 

 Dr. Turner wholly to the expulsion of water, is in fact derived 

 from the extrication of oxygen. I am confirmed in the pro- 

 bability of this view of the subject, by the analyses which 

 Dr. Turner has given of psilomelane and the ma?iganese oxide 

 noir barytifere : if we suppose the former to consist of 69*795 

 red oxide and 6*018 oxygen, instead of 7*364; and the latter 

 to be composed of 70*967 red oxide and 6*119 oxygen, instead 

 of 7*260 as stated, — the difficulty which Dr. Turner has ob- 

 served exists in reconciling these oxides with an atomic consti- 

 tution will vanish ; and from the near approach to equality of 

 the atomic weights of oxygen and water, such an error as 

 I have j)roposed to correct might very reatlily occur. One 

 circumstance may be observed with respect to the peculiar 

 oxide which I have now described, viz. that it is the only one 

 of five oxides of manganese which has not been formed 

 artificially. 



'I'hcrc 



