1821.] and on the Composition of its Oxides. 63 



which are equivalent to 2*7181 grammes of sulphuric acid, allow- 

 ing that ] 00 parts sulphate of barytes contain 34*35 parts of 

 sulphuric acid. /ol 



One hundred parts of sulphate of manganese consist, thefisb 

 fore, of 



Sulphuric acid 54*378 



Protoxide of manganese. 45*622 



100*000 !^ 



One hundred parts of protoxide of manganese combine with 

 119*192 parts of sulphuric acid, which contain 71*5155 parts of 

 oxygen, and thus we find the protoxide of manganese consist- 

 ins: of ']' ** 



Oxygen 23*8385 '^'~'J'^^' ■ 



Manganese 76*1615 |^^ 



100*0000 r/otoiq 



Or 100 parts of manganese combine with 31*29 parts of oxygen 

 to form the protoxide. 



In another experiment, where I had reason to suspect that the 

 heated sulphate of manganese had again attracted some water, 

 I obtained 7*731 grammes sulphate of barytes from five grammes 

 of sulphate of manganese. After having precipitated all the 

 excess of barytes in the solution, I threw down the manganese 

 by carbonate of potash, and having converted it into deutoxide 

 by exposing it to a red heat in an open vessel, the quantity 

 obtained was 2*480 grms. I shall be able hereafter to prove, 

 that the deutoxide consists of 92*4342 parts of protoxide and 

 7*5658 parts of oxygen : 2*480 grms. of deutoxide consist, there- 

 fore, of 



Oxygen 0*18764 



Protoxide 2*29236 



The sulphate of barytes obtained indicates 2* 6555 grms. sul- 

 phuric acid, which combine with 2*29236 parts of sulphuric 

 acid. 



One hundred parts of protoxide of manganese, according to 

 this experiment, would combine with 115*90 of sulphuric acid; 

 and they, therefore, would consist of 



Oxygen 23*18 



Manganese 76*^2 



Or 100 parts of manganese combihe with 30*18 parts of oxygen 

 to form the protoxide. 



I several times heated the deutoxide with sulphuric acid ; and by 

 the quantity of sulphate of manganese thus obtamed, I endeavoured 

 to find the quantity of sulphuric acid, but the vapours of this 

 acid always carried off some sulphate of manganese, which was 



