270 Mr KELLAND, ON THE MOTION OF 



and u = -- sin -—{ct- x) . r y\ 



Q _ 



and representing — (c^-.r) by 0, we thus get 



^ = - bcose.F y. 

 ax 



till b\ . „„ 



di) Stt •' 



—r = CO cos . r y, 

 (It •' 



-=— = « — sm . r y, 

 dx X •' 



^ = b cos 9. F'y, 

 dy "' 



j-f = - b—csmO.Fy, 



.: ^ = - ^ sin 6 cos {F'yY + ^~ sin cos . Fy F" y 

 dt 27r ' -" Stt ■' •' 



+ cb COS e. F'y 



= 1^ sin cos 6 {Fy F"y - {F'yY\ + cb cos 6 . F'y 



^ = ¥sm'9FyF'y + b' cos' 9 Fy F'y -~bsm9.Fy 

 at \ 



^b'FyF'y- ^smO. Fy; 



and hence the equation (a) is reduced to 



— ^ CO cos . /'y 



A 



