222 Vindication of Dalion’s Theory of [Marca, 
This was Dr. Henry’s discovery; but I adopt it as an essential 
principle of the theory: Saussure also confirms it. 
‘2. The quantities of any mixture of gases which water absorbs 
are alsoin proportion to the pressure or densities of the several 
incumbent gases after the absorption has ceased, (but not in pro- 
portion to their pressures before the absorption, unless these two 
ratios happen to be the same); and are the same as if the gases 
were alone, allowing for the diminished density.x—Thus, water 
charged with atmospheric air of unlimited volume contains 23, of 
a full eharge of oxygen, and 22. of a full charge of azote ; but if 
0 
water be charged with a limited volume of air, as =+., then it will 
contain less oxygen and more azote than specified above. 
This was a discovery of mine; it is confirmed by the experiments 
of Henry, and by the four experiments of Saussure above explained, 
the only ones of his that apply to it. 
3. Heat and cold, or change of temperature, has no influence 
on the quantities of gas absorbed by water. 
This was an observation of mine; the idea was at first suggested 
by a consideration of other facts, and afterwards confirmed by expe- 
riment. As heat increases the force of the incumbent air in pro- 
portion as it increases that of the air in the water, the equilibrium 
is not disturbed. The reason why heat seems to expel air from 
liquids is that it generates steam, which removes the atmospheric 
air from the surface. The air-pump, or hydrogen gas, will re- 
move the pressure of the azote and oxygen uf the atmosphere, and 
are equally efficacious in expelling the air from water without heat. 
This feature of the theory, as has been observed, has not been’ 
noticed by Saussure. 
4. 'The quantities of the several gases absorbed by water are as 1, 
1, 1, zt, &c.; the volume of water being unity. 
This observation occurred to me during the investigation, and I 
attempted to show that these proportions necessarsly resulted from 
the preceding phenomena. Though many of Saussure’s results 
differ widely from the above proportions, in consequence of their 
being erroneous as shewn above, yet it must be allowed that some 
exceptions occur in regard to this law, particularly in the class 
which should be 2; absorbable: whether the approximations are 
accidental, or whether they are founded on the principle of equi- 
librium [ have suggested, may bea fair subject for future discussion 
when the facts are ascertained beyond doubt. 
The assertion that I made, that most liquids freed from visci- 
dity, such as acids, alcohol, liquid sulphurets, and saline solutions 
in water, absorb the same quantity of gases as pure water, except 
they have an affinity for the gas, such as the sulphurets for oxygen, 
&c.” appears to me to be too general and comprehensive. Saussure 
has clearly shown that oils, acids, alcohol, and saline solutions 
differ very materially from waters in the quantity of gases absorbed ; 
but for any thing that appears these liquids all agree with water in 
the other three primary laws. 
