150 On Cog or Toothed Wheels. 
CB (1035,) may be resolved into two others, 
namely, AB and AC, which will represent the 
pressures on those lines respectively, (268 and 
1000.) Hence the pressure on BC, is aug- 
mented only in the ratio of 1035 to 1000, or 
about .*, part by the obliquity ; and the ten- 
dency of the wheels to move in the direction 
of their axes, when this angle is used, ) is the 
tots of the original stress, that is, rather 
more than one quarter. But since the longi- 
tudinal motion of an axis can be prevented 
by a point almost invisible applied to its cen- 
tre, it follows that the effect of this tendency 
can be annulled, without any sensible loss of 
the active power. It may be added, that in 
vertical axes, these circumstances lose all their 
importance, since whatever force tends to de- 
press the one and increase its friction, tends © 
equally to elevate the other, and relieve its 
step of its load; a case that would be made 
eminently useful, by throwing a larger’ por- 
tion of the pressure on the slow-moving axes, 
and taking it off from the more rapid ones. 
We now proceed to the second proposition. 
The truth of the assertions, contained in this 
proposition, must, I should suppose, be evi- 
dent, from the consideration of two circles 
touching each other, and at the point of con- 
tact, coinciding with their common tangent 
