266 Free Path Phenomena [OH. xin 



rlT 



As in 312, the flow of energy is J^ -=- , so that by comparison we find 



By equations (273) and (402), we have 



ri - 1 - Ct 



V = -jT- -ZTm > 



Jm dT 

 so that equation (613) becomes 



^= -jFsrr-oQi (614). 



320. We have so far made no correction for the persistence of velocities. 

 We are, however, trying to correct equation (589), namely, 



( * = K C V , 



by determining the numerical multiplier. We are therefore trying to 

 evaluate the ratio ^/r. Now S- and K are each proportional to the mean 

 free path, and are therefore both affected in the same way by the persistence 

 of velocities. It is therefore clear that the fraction *&/K will be approximately 

 unaffected by this persistence. 



Hence, if we use the value of K which was obtained before correction, we 

 can use the value of ^ given by equation (614) without further correction, 

 and shall obtain approximately accurate results. 



The value of K obtained before correction (equations (537) and (539)) was 



(615). 



By comparison with equation (614), 



giving the multiplying factor, by which equation (589) must be corrected. 



The value of the integral / has been calculated by P. Neugebauer, and 

 from this value Meyer reduces equation (616) to the form 



*= 1-602? K C V .............................. (617). 



