On the Theory of mixed Gases. 107 



which are pert'ectiy inelastic in respect of each other, the 

 particles of A meeting with no repulsion from those of B 

 further than that repulsion, which as obstacles in the way 

 they may exert, would instantly recede from each other as 

 far as possible in their circumstances, and consequently ar- 

 range themselves just as in a void space. The preceding are 

 the words of the author of the theory ; and it is readily 

 granted that the particles of such a heterogeneous mixture 

 would recede from each other as far as circumstances will 

 permit; the present subject of inquiry, then, brings the dis- 

 pute to this issue— Can that arrangement take place amongst 

 the particles of two or more gases, which will make their 

 centres of gravity coincide in one point ? For the separate 

 equilibria of the fluids uhich enter into the constitution (if 

 the compound, will not be established until this arrangement 

 be perfectly formed. The completion of this process being 

 essential to the new theory, the effect of it has been, per- 

 haps, too hastily inferred in the fourth proposition of Mr. 

 Dalton's first essay ; for I am sorry to observe that the iii- 

 ference is not supported bv demonstration drawn from the 

 doctrine of mechanics. It is the business of the present 

 essav to supply what has been omitted, and to investigate 

 the consequences which must arise from the collision of two 

 heterogeneous gases differing in their specific gravities. • 



The existence of the fluid mixture, required by the theory, 

 has been granted already for the sake of argument ; and in 

 order to continue the inquiry it must be remarked at pre- 

 sent, that the nccessarv internal arrangement of the com- 

 pound C, is liable to be disturbed perpetually by accidents 

 resulting from the course of things; to which course the 

 author of the theory undoubtedly wishes to accommodate 

 his ideas. The preceding assertion may be exemplified in 

 a manner which is familiar, and may be applied with ease 

 to natural phcenomena : let us suppose, then, an additional 

 quantity of the gas A to he thrown into the pneumatic ap- 

 paratus containing the compound C, v^hich was in a state of 

 proper adjustment previous to this event. No one will ima- 

 gine that this fresh matter can difl'use itself through the mas8 

 of C with the same expedition that the elQctric fluid shows 



in 



