160 Intelligence and Miscellaneous Articles. 



ing out the three integrations, 



k 2 u~ 

 \~^n~) 



in which 



Prom this we hud 



^M 3M T M A , 3 



K > , — — = L, — — A < -77- J 



m 4\ 2 4a- 



that is, the part of the mean vis viva expended upon oscillating 

 motions of the atom is in general less than, and for A=0 is equal 

 to the mean vis viva of an atom m. For A=oo it is equal to 0. 

 The author demonstrates also that 



t M . 



L A- 



with A increasing must always constantly diminish. 



By integrating Ydl over the three differentials therein contained, 

 the author finds the number Z of the collisions which the atom M 

 suffers in unit time, and by threefold integration of F . £2 the sum 

 S of all the lengths of path of the atom during the unit of time. 

 p=S/Z is the mean path between two collisions. Simple values 

 were obtained only for A=0. 



Since the atoms m form a resting gas, it is clear that the atom 

 M will continually lose more and more of its own proper velocity 

 through the collisions. The author calculates, fix'st, how much a 

 collision of any kind changes the X component of the velocity of M. 

 This quantity, multiplied by the number of collisions of that kind 

 in unit time, and integrated over all kinds of collisions, gives the 

 diminution d.A/dt which the proper velocity of the atom 31 under- 

 goes on the average in the unit of time, and which the author, like 

 Stefan (in his theory of gas-diffusion), designates the resistance of 

 the gas to the atom M. If A is very small, the calculation gives 



C ^:=_r/A, A=A e-« 2 *, 



dt l ° 



while 



2 _ v/ttNR 1 yi 4 m m- m 3 



— "Wiedemann's Btiblatkr. 1882, no. 6, pp. 451— loo. 



