136 Dr. Funhhammer on the [Aug, 



tain some traces of carbonic acid if submagnesite of potash had 

 absorbed any carbonic gas, and there had been formed together 

 with the brown powder some carbonate of lead. However, the 

 volume of carbonic acid was very small, and easily removed by 

 cold water. After all the reductions necessary for the difference 

 of temperature and pressure of the air after and before the expe- 

 riment, &.C. Sec. the volume of oxygen thus obtained was 4*82 

 French duodecimal cubic inches at a temperature of 10° of 

 the centigrade scale, which, according to Biot, is equal ta 

 0* 1303057 grammes oxygen. The salt in the retort was dissolved 

 by water, and as the sulphate of lead is insoluble in water, car- 

 bonate of soda precipitated the carbonate of manganese, which, 

 by igniting in an open crucible, gave 0*282 grammes deutoxide, 

 I shall prove hereafter that 100 parts of deutoxide of manganese 

 consist of 92-4342 protoxide, and 7-5568 oxygen ; and, there- 

 fore, 0-282 deutoxide are equal to 0-261 protoxide, and this 

 quantity of protoxide was combined with 0-1303 of oxygen in 

 the manganeseous acid ; for the protoxide of lead which wa& 

 added only served to fix the oxygen, and it was removed in the 

 same state of protoxide in which it was first used ; therefore 

 100 protoxide are combined in the manganeseous acid with 

 49- 92 oxygen. But I shall prove by direct experiments that the 

 suboxide of manganese consists of 20-576 oxygen, and 100 

 metal; that the protoxide consists of 100 metal and 31-29 

 oxygen ; that the deutoxide consists of 100 metal and 42-04 

 oxygen ; and that the peroxide consists of 100 metal and 

 62-819 oxygen ; and that, therefore, the oxygen in the different 

 oxides is very near to the numbers 2, 3, 4, 6. 



The manganeseous acid consists of 100 metal and 96-847 

 oxygen, which is pretty near to the number 9, but the number 

 i) in the oxides of a metal never has been yet found, and it is not 

 very probable that this metal should make an exception. 

 Besides that, it appears almost as necessary that the effect which 

 water has in the green solution, already, in a certain degree, has 

 been exercised during the fiirst solution of the dry salt, and that 

 the green solution contains already some portion of manganesic 

 acid, that, therefore, the blue salt which now and then is obtained 

 by igniting potash and peroxide of manganese is the real manga- 

 nesite of potash, and that the green solution is a compound of 

 blue and red. There is still another reason which induces me to 

 believe that not 9 but 8 is the number for the manganeseous acid, 

 and which depends on the nature of the brown compound of 

 lead, manganese, and oxygen. We have considered it as a com- 

 pound of peroxide of lead and deutoxide of manganese, but that 

 is only possible if the manganesic acid contains double the quan- 

 tity of oxygen of the deutoxide ; for as the peroxide of lead 

 contains double the quantity of oxygen of the protoxide of lead» 

 it is only in that case possible that such a compound can exist. 

 If the manganeseous acid contains really three times as mucl> 



