4*C^ 0)^ ihi Thbhnj of Mixed Gases. 



which implies, ^that the force of gravity upon a 

 particle of an elastic fluid is infinitely surpassed 

 by the repulsive force of that particle. The 

 truth of this remark, considered as a maxim 

 in pneumatics, is fully admitted on my part ; 

 but as no logical deductions are derived from 

 it by my friend, J am obliged in the present 

 instance to pursue thesame conduct which I have 

 observed on a former occasion in this dispute, 

 and to attack the application of his principles ; 

 because it is in vain to look for a scrutiny of 

 arguments, where no arguments exist. The 

 business then of the next paragraph is to shew, 

 that Mr. Dalton*s maxim in pneumatics does 

 not forbid a philosopher, who is going to assign 

 the phenomena of a gaseous mixture, to take 

 into consideration the centres of gravity of the 

 fluids, which are to be mixed. 



Mathematicians have proved the centre of 

 gravity to constitute an important point in evejry 

 body, being the place of its motion as well as 

 inertia: and had not my friend's zeal for. his 

 hypothesis got the better of his geometry, he 

 inust have recollected, that the theorem, which 

 determines the existence and true situation of 

 this centre, is derived from the relative po- 

 sitions and respective quantities of matter con- 

 tained in the particles, composing a body or 

 , system of bodies ; which quantities of matter 



