1820.] Manganeseoiis and Manganesic Acids. 137 



oxygen as the protoxide, it is necessary to consider the brown 

 powder as composed of acid of lead, containing three times as 

 much oxygen as the protoxide, and protoxide of manganese, 

 which is merely hypothetical. 



In the analysis of the brown powder as well as in many other 

 analyses of deutoxide and peroxide of manganese, I always used 

 bisulphate of potash to expel all the oxygen which is combined 

 with the protoxide, and this salt is much preferable to the pure 

 sulphuric acid, as it decomposes the deutoxide, and hyperoxide very 

 easily, does not give any vapour of sulphuric acid, and melts so 

 easy that all the parts of the oxide come in contact with the salt. 



The manganesic acid I analyzed in the following way : I made 

 a solution of green manganesite of potash, quite the same as 

 before, and converted it by carbonic acid gas into manganesiate 

 of potash and deutoxide. The weight of the ignited deutoxide 

 was 0"136 gramme. The manganesiate of potash I decom- 

 posed by alcohol, and obtained 0"214 gramme of ignited 

 deutoxide. As in the experiment above quoted 0*282 gramme 

 deutoxide are combined with 0'1093 gramme oxygen in the 

 manganeseous acid, 0-350 (0*136 + 0-214) gramme deutoxide 

 will be combined with 0-1354 gramme of oxygen in the green 

 manganesite potash, and this whole quantity of oxygen = 

 0*1354 gramme is combined with 0-214 gramme of deutoxide 

 in the manganesic acid ; and as 0-214 gramme deutoxide con- 

 sist of 0*1506 metal and 0-0634 of oxygen, 0-1506 of metal are 

 combined with 0-1988 of oxygen in the manganesic acid, or 100 

 of manganese metal are combined with 132 of oxygen in the 

 manganesic acid, which approaches pretty near to the number 

 12, if we consider the difficulty of the analysis, and the small 

 quantity of matter on which the experiment was made. 



Article III. 



Researches into the Mathematical Principles of Chemical PJiilo- 

 sophj/. By J. B. Emmett. 



(To Dr. Thomson.) 



SIR, Hull, June 28, 18'20. 



Introductory Remarks. 



That the primary laws of chemical action may be investigated 

 upon mathematical principles appears probable \vhen we consider 

 that in a neutral salt the proportion of the elements to each other 

 is invariable, that when a sub and neutral, or neutral and super- 

 salt may be formed by the union of the same acid and base, the 

 ratio that subsists between them in one of the compounds, is to 

 that in the other, as 1 : 2 or 1 : 3 or 1 : 4, &c. never as 2 : 3 or 3 : 4, 



