154 Dr TURNER'S Chemical Examination 



phuric acid, an intense heat is instantly evolved ; and the same 

 phenomenon is produced, though in a less degree, by strong 

 muriatic acid. This oxide is likewise the base of the salts which 

 are formed when sulphuric or muriatic acid is heated with the 

 peroxide, deutoxide, or red oxide of manganese. As the accuracy 

 of this statement, as respects sulphuric acid, has been denied by 

 an acute chemist and good observer, I have been induced to ex- 

 amine the question with considerable care. I mentioned in my 

 Elements of Chemistry, in explaining the process for procuring 

 oxygen gas by means of sulphuric acid and the black oxide of 

 manganese, that the peroxide loses a whole proportion of oxygen, 

 and is converted into the protoxide, which unites with the acid, 

 forming a sulphate of the protoxide of manganese. The gentle- 

 man who has done me the honour to review that work in the 

 Annals of Philosophy, I apprehend Mr RICHARD PHILLIPS, has 

 made the following remark on the preceding passage. " This 

 statement is at variance with both Dr THOMSON'S and also with 

 the results of our experiments ; for we find that 44 or one atom 

 of peroxide of manganese yield 4.2 of oxygen, which is so much 

 nearer 4 than 8, that there is no question but that the deutoxide, 

 and not the protoxide is obtained by the action of sulphuric acid ; 

 that this is the case is farther proved by the deep red colour of 

 the solution of the sulphate, and by its losing that colour, as 

 stated by Dr THOMSON, when mixed with sulphurous or nitrous 

 acid." 



To decide this point between the reviewer and myself, it is 

 only necessary to heat the peroxide of manganese with concen- 

 trated sulphuric acid, so as to form a solution highly charged 

 with the oxide of manganese, and decant off the solution while 

 hot from the undecomposed peroxide. The liquid on cooling- 

 deposits a perfectly white salt, which possesses every property of 

 the protosulphate of manganese. If the acid, which retains an 

 amethyst-tint even when cold, be again heated, the red colour 



