174 



Dr, Thomas Thomsons Experiments 



filled with it, while boiling hot, a small cylindrical glass 

 jar: the capacity of the jar was about 11 cubic inches. I 

 determined what bulk of the boiling water would when 

 cold constitute 10 cubic inches. This quantity was put into 

 the glass, and the rest of it being filled with mercury it 

 was placed inverted on the shelf of a mercurial trough. 

 As soon as the water was cold, a cubic inch of air was let 

 up into the glass, and the whole was left one day, then two 

 days, then three days, then four days, and at last eight days, 

 in order to see how much of it would be absorbed by the 

 water during that time. The following table exhibits the 

 residue of the air, the original cubic inch being considered 

 as divided into 10,000 parts : 



I was very much surprised at the great discordance in 

 these results, as every experiment was made exactly in the 

 same way, and the air was always collected from the outside 

 of the window of my laboratory at the commencement of 

 each trial. The mean absorption in these trials by 100 

 cubic inches of newly boiled water is 1*722 cubic inches of 

 air. The greatest absorption by 100 cubic inches of water 

 was 2*793 cubic inches, and the least 0-938 cubic inches. 



But it has been stated above that by boiling 100 cubic 

 inches of the water of the Clyde, 3-1 13 cubic inches of air 

 could be extricated. The mean absorption found amounts 

 only to about the half of this quantity. The greatest 

 absorption falls short of it by almost -i^th, while the 

 smallest absorption amounts only to about a third of it. It 

 is obvious from this that the absorption of air by water is 

 a very slow process. 



