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III. The Chemistry of Sulphuric Acid-manufacture. 

 By H. A. Smith*. 



IT is astonishing, considering the importance of the subject, 

 how little the chemistry of vitriol-manufacture has been 

 inquired into. If we look over the records of its progress for 

 the last hundred years, as embodied in the specifications of 

 patents, we will find that the fundamental atoms of the struc- 

 ture remain the same, and that it is merely some particular 

 point in the building itself which has been improved or embel- 

 lished. I propose in this and succeeding papers to make a 

 minute inquiry into the chemistry of this manufacture, and to 

 elucidate, as far as I possibly can, the various laws which deter- 

 mine the combinations and decompositions occurring in the 

 actions, and the causes which prevent these actions taking place. 



I shall not in these papers attempt to give, even on a general 

 scale, the various methods which have been used for the pro- 

 duction of sulphurous acid, but shall take as the starting- 

 point the use of sulphur for this purpose, the earliest substance 

 from which this gas was obtained, and one which still exists as 

 the purest source of all our vitriol-manufacture. 



The subjects treated of in this paper are :— 



Sect. 1. An experimental examination into the causes which 

 determine the action, inter se, of the gases in the lead chamber. 



Sect. 2. The distribution of the gases in the lead chamber ; and 

 following from this, 



An inquiry into the best form of chamber to be used in the 

 manufacture of sulphuric acid. 



I hope to treat in another paper of the distribution of heat 

 in the lead chamber, and also of one or two subjects intimately 

 connected with this manufacture. 



Section I. — An experimental examination of the circumstances 

 which determine the action, inter se, of the gases in the lead 

 chamber. 



This inquiry was entered into in the hopes of being able to 

 throw some light on the interior economy of the lead chamber, as 

 at present used in the manufacture of sulphuric acid. Although 

 the method ordinarily employed to show the theory of the 

 formation of this acid is a very good one, yet there are nu- 

 merous points which cannot be shown, and which can only 

 be pointed out through the agency of chemical analysis. 



No one has yet attempted to do this minutely; and our 

 knowledge of the phenomena of alkali-manufacture is in many 



* Communicated by the Author. 



