Sulphuric Acid-manufacture. 



37 



The numbers "25 per cent." &c. represent the percentage of 

 acid at 15 feet from bottom of chamber. 



I also give the following Proportional Tables for Diagrams III. 



No. I. At 15 feet height. 



No. II. At 3 feet height. 

 140 J "" i 



S}-.» 



30 =2 



130 J * 

 120 =5 



80 =5-7 

 90 =67 



ioo\ _ 8 . 7 

 no/- 87 



We have now before us results which may assist us in coming 

 to some conclusion regarding the most useful form of chamber. 

 We have seen that the chamber must be divided into two parts 

 — the working portion, and the reservoir (so to speak) for the 

 gases. If, then, instead of employing this reservoir we lowered 

 the height of the chamber and extended its length, we should 

 have a greater condensing surface, as we have seen that the 

 greater amount of acid condenses near the surface of already 

 formed sulphuric acid. We should also have a form of chamber 

 better adapted for getting a good draught. It would not be at 

 all difficult for manufacturers to have a Table drawn up for the 

 manager of their chambers, showing him the amounts of steam 

 necessary to be thrown into the chamber according to the in- 

 crease or diminution of temperature ; they would thus have a 

 great saving, both in the amount of gas escaping useless to 

 the chimney, and also in the amount of acid manufactured. I 

 hope soon to show the temperature at which the greatest amount 

 of action takes place between the gases in the chamber, but 

 would merely mention that it is of the greatest consequence to 

 the manufacturer to take particular notice of the temperatures of 

 his chamber, as upon the successful management of this depends 

 in a very great degree the yield of acid, and also that trouble to 

 all manufacturers, the flowering of the sulphur in the acid. 



[To be continued.] 



