672 Dr. R. D. Kieeman on the Equation of Continuity 



external pressure is then small in comparison with the 

 intrinsic pressure, and equation (1) becomes 



RT, 



mv 



or the intrinsic pressure would also be given by - — if the 



matter obeyed Boyle's law. For ether this equation gives 



P H — 240*3 atmos. per cm. 2 



This is a much smaller value for the intrinsic pressure than 

 that obtained from equation (2) or (5), viz. 1992 and 2L87 

 atmos. per cm. 2 respectively, and the effect in question is 

 therefore quite large in liquids. 



But b is strictly not a constant; the apparent volume of 

 two colliding molecules will be influenced by their forces of 

 attraction and those of the surrounding molecules, and con- 

 sequently depends to a certain extent on the density of the 

 matter. We must therefore write b a function of v and T. 

 Equation (1) may then be written 



'++&*)&"* ™- *-%*ior ■ (G) 



This is a general equation for any state of matter liquid or 

 gaseous, for the same conditions of equilibrium apply to the 

 gaseous as to the liquid state. 



We have obtained some evidence that yjr 2 ( ~,/3) or K 2 is 



a function of the temperature only, which must be such that 

 its value is the same for all liquids at corresponding states. 

 Let us first consider the equation taking yjr z (v, T) a constant 

 b and K 2 a function of the temperature only. Substituting 



for v the equation may be written 



\ RTV 



\ 



<-'"-h"A L T^ L )<-k-"- 



or 



<r 10 -i<r< 



W^' 



b \ bA a / bA 



3 -^=0.. • • (7) 



where 



a=p^ 



and A 3 = k 2 ( — -^~) 



