tbe Rotatory Motion of Bodies. 293 
5. Fig. 12. In the fpheroid whofe proper axis is 2 b 
and equatorial diameter 2 r, y 1 being — j l y.b z —x z f- — x z y z 
confequently, the 
... . , r r x r x 
will be = r x — - -yjr + — b 
fluent of 
+ -AT + 
x*x 
X T 
7 2 : 
jjy - - x*x+y , generated whilft a from 
, , , . Pb Pb Pb b 3 P 2 — — 
o becomes = b , being — — g- + — — -+-•=— x r b-b 3 , we 
have 
16 a/j 
y.mny.r z b—b i —- — s for the force 
which, a6ting at the diftance g from c the center of the 
fpheroid,. would be equivalent to the efficacy of the 
forces adting as above on all. the particles of the fpheroid. 
to turn it about a diameter of its equator,, s being the mafs 
or content of the fpheroid. 
Thefe equivalent forces are diftinguifhed by the name 
of motive forces; the correfpondent accelerative forces 
are computed in the following articles. 
6. Fig. 13. The body being a fpheroid whole center 
is c, and whofe proper axis pn is = 2 b and equatorial dia- 
meter ab — ir\ let f be the accelerative force of a par- 
ticle at the diftance^ - from the. axis about which the body 
is urged to turn, which axis is fuppofed to be a diameter 
of its equator. Denote by ki by y; and let the 
abfciffa ko and its correfpondent ordinate (parallel to the 
laft mentioned axis) in the circle whofe radius is ki be 
denoted 
