the Rotatory Motion of Bodies. 289 
* - V ’ 
the equatorial diameter of the faid fpheroid, and - very 
C 
fmall. 
APPENDIX. 
Shewing how the joint centrifugal force of the particles of 
a fpheroid or cylinder , having a rotatory motion about 
any momentary axis , is computed. 
1 . FIG. 9. Let p be a particle of matter firmly connected 
'di the plane doefqg, in which the line qcqJs fituated ; 
and pq being a perpendicular from p to the faid plane, 
let the diftance pq be denoted by u; alfo, the line ql 
being at right angles to o/cq_, let the diftance pi be de- 
noted by h. Then, the faid plane with the particle p 
being made to revolve about o/cQ^as an axis, with the 
angular velocity e meafured at the diftance a from the 
faid axis, the velocity of p will be = y , and its centri- 
fugal force from / will (by a well-known theorem) be = 
he 7 " he 7 " 
to make it or the expreflion being ~ x p. Whence, 
by refolving that force into two others, one in the 
direction qp , and the other in a direction parallel to 
lq, it appears that the force urging p from the plane 
ue 7 " 
doefqg will be= — x />, let the diftance lq be what it will. 
Vol. LX VII. P p 2. The 
