Table IV. 
Specimens of Ain. 
Taken 10 feet from bottom of Chimney. 
Amount of air taken for each analysis = 500 cubic feet. 
Arsenic Trioxide 
per 1,000 cubic feet. 
Mean of 9 analyses = 0086. 
The author clicl 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 
greater 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, 
F.R.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 which it existed, and also to see to 
what extent free acid prevented its origination. 
