ARSENIC FROM ALKALI-WORKS. 



183 



variation considerable, owing to the fact that at one time 

 more furnaces were in use than at another ; but, as the 

 analyses extended over a long period, the results may, 

 I think, be taken as a very fair average. 



Table III. — Air in Flue leading from Condensing-towers 



to Chimney. 



(Amount of air taken for each analysis = 500 cubic feet.) 

 (Amount of air passing = 31,722 cubic feet.) 



No. of analysis. 



1 

 2 

 3 



4 

 5 

 6 



7 

 8 



9 



10 

 11 

 12 



Arsenic trioxide 

 per 1000 cb. ft. 



grain. 

 0*068 



Arsenic trioxide 

 per hour, 

 grains. 

 2-157 



0*082 

 0*072 



0*102 

 0*064. 

 0*198 

 0*248 

 Ol86 

 0*232 

 0*262 

 0*382 



I*8 9 6 



Means -158 



2*601 

 2*284 



3*235 



2*030 



6280 

 7*867 

 5*900 



7359 



8*311 



12*117 



60*141 



5*012 



Arsenic trioxide 

 per day. 

 grains. 



5x768 



62*424 



54*8 1 6 



77*640 



48720 



150*720 



188808 



141*600 



176*616 



199*464 



290*808 



H4T384 



120*282 



The quantity of arsenic trioxide per 1000 cubic feet varies 

 from 0*068 to 0*382 of a grain. This gives, as an average 

 of twelve analyses, 0*158 grain As a O ? per 1000 cubic feet. 

 Taking then the amount of air passing through the flue as 

 31,722 cubic feet per hour, the average amount of arsenic 

 trioxide escaping per hour would be 5*012 grains, this be- 

 coming in twenty-four hours 120*282 grains As z O r This 

 will probably escape either as arsenious acid or as arsenic 

 trichloride. If as the latter, it may be decomposed, on 

 coming into contact with the atmospheric moisture, into 

 arsenious acid and hydrochloric acid — 



2AsCl ; + 3H z O = A Si O ? 4 6HCl. 



