174 



Table IV. 



Specimens of Air. 



Taken 10 feet from hotto'ni of Ckhnney. 



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



Arsenic Trioxide 

 per 1,000 cubic feet. 



Mean of 9 analyses = O'OSG. 



The author did not know the amount of air passing in the 

 chimney, so he only calculated the amount of Arsenic Tri- 

 oxide in grains per 1,000 cubic feet. 



The method employed for collecting the Arsenic Trioxide 

 contained in the two last two Tables was very simple. The 

 air was drawn through three bottles containing respectively 

 Water, Hydrochloric Acid, and Nitrate of Silver. The gas 

 was allowed to bubble very slowly through the solutions. 

 The bottles containing them were capable of holding 40 

 ounces and were filled about half full. 



The idea of Arsenic being present in the atmosphere sur- 

 rounding chemical works is by no means new. The fact of 

 its existence in large amounts in the ore from which the 

 o-reater proportion of our vitriol is made leads one to suppose 

 that it must find its way into the atmosphere at one place 

 or another, but the author believes that this is the first time 

 the comparative amounts have been brought forward. 



''■ On Animal Life in Water containing Free Acids," by 

 H. A. Smith, F.C.S. Communicated by Professor Roscoe, 



r.ii.s. 



At a time when so much is being written concerning 

 animal life, its origin, and the conditions under which it 

 can exist, it was thought it might be interesting to find out 

 to what extent it was influenced by the presence of free 

 acid in the water in v/hich it existed, and also to see to 

 what extent free acid prevented its origination. 



