Sulphuric Acid-manufacture. 29 



the much vexed question regarding the best form of chamber 

 for use in the manufacture of sulphuric acid. 



Section II. On the Distribution of Gases in the Lead Chamber, 

 and also an inquiry into the best form of chamber to be used in 

 the manufacture of Sulphuric Acid. 



In the preceding page the following observation is made 

 when speaking of the laboratory method of showing the theory 

 of sulphuric acid-manufacture : — " Near to the deposit, and 

 long after the ruddiness has apparently disappeared, a very 

 small narrow band of red fumes is noticed wherever the crys- 

 tallization has taken place." This, then, when taken into con- 

 sideration along with exp. X. in the same section, tended to lead 

 me to the belief that the greatest amount of condensation takes 

 place at the bottom of the chamber, near the surface of any sul- 

 phuric acid which has been already formed, and that the upper 

 portion of the chamber is of use principally as a reservoir for the 

 gases ; so that if, instead of having a long high chamber, one 

 that was long but of low height were to be used, the same pur- 

 pose would be answered to a greater degree, and the expense of 

 chamber-building greatly reduced. It was with the intention of 

 proving or disproving the truth of this theory that the following 

 investigation was undertaken. The size of chamber used was 

 about 140 feet in length by 30 high and 25 wide. The gases 

 were introduced at the end of the chamber through an iron pipe 

 12 feet long by 3^ in diameter — the chamber-draft very mode- 

 rate — steam injected at three points in the side and along with 

 the gases at the end. In order to have a definite plan of pro- 

 ceeding, I took specimens of chamber air at every 10 feet along 

 its length, 15 feet from the bottom — and also specimens at the 

 same distances at 3 feet from the bottom,— thus having 



14 analyses, chamber air at 15 feet 

 and 



14 a ), 3 „ 



the first being in reality a bisection of the chamber along its 

 length. 



The gases of which the percentages were obtained were sul- 

 phurous, sulphuric, and nitric acids. 



Before giving my own results, I should be glad if I could 

 quote those of any other observer ; but I am unaware of any 

 work having been done on this subject ; so that the following 

 observations may be interesting from their newness. 



