46 MEMOIR OF DR. DALTON, AND 



part of it, equal to some one of the following fractions, 

 namely, l-8th, l-27th, l-64th, l-125th, these being the 

 cubes of the reciprocals of the natural numbers 1, 2, 3, &c.;" 

 This has not found general assent, nor can it flow from 

 any known natural law ; indeed if it were true it would not 

 shew itself by the usual mode of experimenting, as we can 

 readily imagine one part of the water having l-4th, another 

 l-5th, both being distinct parts of the whole, but so mixed 

 with each other in the water that no result is perceived. 



4. " If a quantity of water free from air be agitated with 

 a mixture of two or more gases, such as atmospheric air, 

 the water will absorb portions of each gas the same as if 

 they were presented to it separately in their proper density." 



5. " If water impregnated with any one gas (as hydrogenous) 

 be agitated with another gas equally absorbable (as azotic), 

 there will apparently be no absorption of the latter gas ; 

 just as much gas being found after agitation as was intro- 

 duced to the water ; but upon examination the residuary gas 

 will be found a mixture of the two, and the parts of each, in 

 the water, will be exactly proportional to those out of the 

 water." 



" 10. Pure distilled water, rain and spring water, contain 

 nearly their due share of atmospheric air ; if not, they quickly 

 acquire that share by agitation in it, and lose any other gas 

 they may be impregnated with. It is remarkable however 

 that water by stagnation in certain circumstances loses part 

 or all of its oxygen, notwithstanding its constant exposition 

 to the atmosphere. This I have uniformly found to be the 

 case in my large wooden pneumatic trough, containing 

 about 8 gallons. * * * * The quantity of azotic ^s is 

 not materially diminished by stagnation, if at all." He has 

 not here considered the action of the organic substances. 



Theory of the absorption of gases by water, p. 283. 



" 1. All gases that enter into water and other liquids, by 

 means of pressure, and are wholly disengaged again by the 



