826 S. Kinoshita. S. Nishikawa, and S. Ono on Amount 



where r and r' are the distances of P from A and A' 

 respectively. 



It will be seen that the motion is analogous to an irrota- 

 tional motion of: liquid in two dimensions, and there exists a, 

 velocity-potential 



<j>= — 2/Jik log — — W.V, 



' dnd --d;=dt' 



which satisfies the equations 



_ d<£ _ da> 



^x ~~ dt 



The stream-function -v|r, which is orthogonal to the function 

 </>, can be represented by 



^=-2 f j t .k(d , -e)-wz, 



where and 6 l denote the angles which r and r' make 

 respectively with the axis of z. 



To show the path of the particles, we have, in fig. 2, 



OA = K = I50 cm. 

 2/uk=K56 cm'.fierscc. 



w si 27 cm. ^cr see- 



graphically traced the curve ^ = const., or 

 2fik(d' — 0)-\-iuz = c, 



where c is a parameter. 



Let o?o, ^o be the coordinates of a point at which the particle 

 has no velocity, i. e., the velocity of the particle due to the 

 electric field is equal and opposite to that due to the wind. 



They are found by solving the equations 



^~=0 and ^ 

 Ox Oz 



0. 



