48 LarmoR, Physical Aspect of the Atomic Theory. 



unit volume, with similar meanings assigned for the other 

 symbols. There can be present in the interaction seven 

 substances, viz., ABC, AB, BC, CA, A, B, C, some of 

 them perhaps of such slight permanence that they are not 

 apparent. 



Of the amount ABC, suppose the quantity k^.ABC 

 changes into ^C and A per unit time, k.^.ABC into CA 

 and B, k^.ABC into AB and C : suppose the quantity 

 a . BC dissociates into B and C per unit time, and so on : 

 suppose/".^. C is the quantity which associates into BC 

 per unit time, and so on; suppose l.BC.A is the 

 quantity which associates into ABC per unit time from 

 BC and A, and so on : — the coefficients a, b, c, k,. .. being 

 proper fractions. Thus we have a scheme of formally 

 possible transformations 



(^1 + h + k^ABC 



a . BC, b .CA,c. AB 



f.B.C,g.C.A,h.A.B 



I. BC. A, m .CA.B,n.AB. C. 



Ifany of these intermediate substances (say AB) is 

 so transient as practically not to occur, the corresponding 

 association factor (//) must be very small compared with 

 the dissociation factor {c). 



When chemical equilibrium is attained, the dissocia- 

 tions and associations continually going on do not alter 

 the amount of the substance A ; therefore 



ki . ABC+ b.AC+c.AB~g.A.C-h.A.B-i.BC.A = o, 

 and there are two similar equations. 



In the same way the constancy of the amount of the 

 substance BC requires 



-kx.ABC+a.BC-f.B. C+l.BC.A = o, 



and there are two similar equations. 



