30 



Mr. H. A. Smith on the Chemistry of 



Sulphurous Acid. 



Taking, then, in the first place, sulphurous acid, I will show 

 first its distribution in the chamber, then take the two others in 

 the order given above. 



As is naturally expected, the largest amount of sulphurous 

 acid is present at the entrance to the chamber; but dispersion 

 takes place very rapidly indeed, so that each 10 feet makes a 

 decided change in the percentage of acid present. 



The amount of sulphurous acid present at a distance of 10 

 feet from end of chamber is equal to 72 per cent., continuing 

 the same till about 20 feet from end. There is then a rapid fall 

 to 46 per cent, at 30 feet, falling rapidly still, till at 40 feet from 

 end the amount only equals 31 to 33 per cent. After this the 

 variations are not so remarkable ; the amount of sulphurous acid, 

 however, becomes gradually less, and less till its lowest point is 

 reached at 120 feet from entrance, when 13 per cent, is the 

 amount present. These analyses were made at 15 feet from 

 bottom of chamber. In those made at 3 feet from bottom the 

 variations are not so sudden. At 10 feet from entrance the 

 amount present is 3 per cent. ; this rises rapidly, till at 40 feet 

 from end it attains its maximum and 29 per cent, of acid. It is 

 now at its highest point ; and from this it begins to descend very 

 gradually, till at 130 feet it falls to 8 per cent., and near its 

 exit rises to 16 per cent. 



The following diagrams will show this variation more plainly. 

 The numbers along the top indicate the length of the chamber 

 divided into distances of 10 feet each ; those down the side of 

 Diagram la the percentage of acid present. 



Diagram Ih. 

 Length of chamber in feet. 

 (Entrance.) 10 20 30 40 50 60 70 80 90 100 110 120 130 140 (Exit. 



1 5 feet in 

 height 



3 feet in 

 height 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



p. c. 



p.c. 



p.c. 



p.c. 



p.c 



p.c. 



p.c. 



p.c. 



p.c. 



72 



70to 



72 



46 



31to 

 33 



25 



26 



30 



22 



29 to 

 30 



22 



23 



13 



18 



18 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



p. c, 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



p.c. 



3 



8 



16 



29 



28 



18 



19 



20 



17 



i-7 



H 



13 



8 



16 



(Entrance.) 10 20 30 40 



50 60 70 80 90 100 110 120 130 140 



Length of chamber in feet. 



15 feel 

 heigl 



3 feet 

 heigh 



(Exit. 



The figures in the divisions of the above diagram represent 

 the percentages of sulphurous acid corresponding to diagram la. 



The numbers " 3 per cent." &c. represent the percentage of 

 acid at 3 feet from bottom of chamber. 



The numbers " 72 per cent." &c. represent the percentage of 

 acid at 15 feet from bottom of chamber. 



