92 Mr. J. Kam on Molecular Attraction and 



converges towards 1*7, and we obtain 



k = 1'7.C.^ = l-7.C.w s .m s , . . . (38) 



i. e. for the same n only dependent on the square of the 

 mass m. 



The error we commit by assuming k to be directed 

 between and every molecule of the surface RFL influences 

 the result alike for any density, but is entirely eliminated by 

 making it act between and every three molecules of that 

 surface ; and we find, substituting eq. (38) in eq. (36), 



1-7 1-7 m 2 



p H = Y-n.O.««.m 2 = ^n.C.J, . (39) 



if v =l is the volume containing n 3 molecules. 



If we consider m of equation (39) to be the mass of a molecule 

 H 2 , Hydrogen being the lightest of all gases, and then make 

 p n = a (vide equation 28), then the molecular attraction or 

 Inward Pressure of a substance with the molecular weight M 

 would be at r =l, 0° and 760 mm., 



M2 fA(H 



e = -j- • *, (40) 



c being the constant of attraction of the substance. 

 At the volume v in respect of v —l, 



M 2 x Co /iM v 



i>i = T .- 2 =^ (41) 



and for the critical state 



*.-3r?-£ ^ 



But as we found the critical Inward Pressure p le equal to 

 the critical pressure p c , we must also find 



*-T*«? ; m 



hence * = *$& • • ( 44 > 



and ^ is the "Inward Pressure" of Hydrogen at v =l, 

 t = 0, and 760 mm., expressed as a fraction of 1 atmosphere. 



