[3X4] 
Fig.) to move with equal and uniform velocities, 
from D b and R h along A H, in order to generate the 
areas H D b, R W b, A D h j C/ will at fird not only 
decreafe fader than Q^, and than F t j but the 
ratio of the rate at which Qj decreafes to the rate 
at which decreafes, will be greater than the ratio 
of the rate at which decreafes to the rate at 
which F t decreafes. It appears alfo that after fome 
time, firft C f and and then Q^and F t will 
come to decreafe equally ; after which, Qj will de- 
creafe fader than Cf, and F t fader than Qt . 
iy. The curves DFH, RQW, DC A, have 
each of them a point of contrary dexure ; and the 
value of z , or of the equal abfcifles at that point, is 
in all three — L - — . This may be found in the 
n 3 — • n 1 < 
common manner, by putting the fecond fluxions of 
the ordinates equal to nothing. In the Angle cafe, 
when either p or q is equal to unity, one of thefe 
points vanidies, or coincides with A or H. 
iB. At the points of contrary flexure ( q be- 
ing greater than p) the ratio of the fluxion of Qf_ 
to the fluxion of F t is a maximum ; and the fame 
is true of the ratio of the fluxion of C / to the 
fluxion of QY. This is found by making the 
fluxions of the logarithms of thefe ratios, or of 
A * 
n z 
— i 
