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ter, these chemists proceeded to ascertain the changes 
which it experienced by the respiration of fishes. 
With this view, they confined young fishes in bell- 
glasses of river-water, inverted over mercury ; and 
suffered them to remain till their respiration became 
laborious. The animals were then withdrawn, and 
the water, in which they had respired, was transferred 
into the balloon, and its air expelled, by submitting it 
to ebullition, in the manner before stated. Seven 
tenches were, in this manner, confined in 4000 cu- 
bic centimeters, equal to 250.5 cubic inches of river- 
water, where they remained eight hours and a half. 
A portion of this water, equal to 2582 cubic centime- 
ters, or 161.5 cubic inches, was then transferred from 
the glass-bell into the balloon, and its air expelled by 
heat. The air, thus obtained, measured 453 parts, 
at temperature 50 Fahrenheit. These 453 parts 
were then washed in lime water, by which they were 
reduced to 300, so that 153 parts of carbonic acid 
were thus removed. The residue was afterwards 
analysed by combustion with hydrogen, and by mix- 
ture with nitrous gas; and the mean of three analy- 
ses afforded 0.035 of oxygen ; wherefore it is con- 
cluded, that the 453 parts of air, obtained from wa- 
ter which had been in contact with the respiratory 
organs of fishes, consisted of 105 oxygen, 289.5 ni- 
trogen, and 153.0 carbonic acid gas. But by former 
experiments, it was found, that an equal volume of 
pure river-water afforded 524 parts of air, consisting 
of 155.9 oxygen, 347.1 nitrogen, and 21.0 carbonic 
acid ; consequently, say these chemists, these seven 
tenches have absorbed, in eight hours, 145.4 of oxy- 
gen, and 57.6 of nitrogen gas : and they have pro- 
