8 6 Mr. lan den’s new 'Theory of 
-fpheroid after receiving the impulfe of the percuffive 
force. Therefore, having reference to onr conclufions in 
the preceding articles, we, by fubftitution, readily obtain 
folution to our problem. 
By fubfhtuting properly or — x —~p. ror F ,we 
find, 
d 2 r 
dr 
— — X 
r’ + i’ 
l/SS^zcdrF+r' ‘ + 
& 
r xca + r f 
2r 
y/d % ? ^%cdrF + r z F 2 ^ 
d 2 
, in rF 2 r c 
andc + 7 = pq^i* 
Which equations, refpedt being had to the conclufions in 
art. 8. and 9. indicate that, whether b be lefs or greater 
than r, if an immoveable circle dl, whofe radius is = 
.. — ~ t , be conceived to be defcribed in a plane 
v 4 ,A + 7qrT><- 
inclined to the plane of the equator of the fpheroid (be- 
fore the impulfe) in an angle whofe fine (to the radius r) 
dr 
IS = ~ x 
v; 
r^ + b 2 
, fo that the faid circle touch 
4r + +7+7yx — 
the faid equator in the point d in the fedtion o/dqje; 
the fpheroid after the impulfe will fo revolve, that its 
equator 
