. 
50 W. Ferrel on motions of Fluids and Solids, &c. 
the ag velocity about the center of curvature, the centrifu- 
gal force of the body is gm? which must be put equal to the 
Milscting force, omrasn Be Hence we have 
= 2nv cosd 
Also, since x is the lineal sealer of the moving body, 
em. 
From these two equations we get 
ee Vv 
oon cos f 
=2ne 
50.. When the range are ohana is so small that cos 6 may be 
regarded as constant, g@ and m are constant, and hence the hod 
then moves with a uniform angular velocity i in the circumference — 
~ acircle. If we put 7’ for the time of a revolution, we shall 
ve 
wpe wus = 4 day X sec 6.* 
m necosd 
Hence, — v disappears in the result, 7’is independent of the — 
aes ve 
Body i is forced to move in a straight oe F (equation — 
6) is the pod pressure of that body. If we put v=60, which 
is ™ velocity of about 40 miles per hour, the be totes gives P= — 
3Tzz 9, at the parallel of 45°. Hence if a railroad train moves 
in a straight line 40 rte es hour at the parallel of 45°, the 
lateral pressure is 51; of its weight, and this is precisely the | 
same in all directions, em not in the direciion of the meridian 
only as has been generally supposed. 
52. The deflecting force (§ 5) also causes the gyration of a vi- 
brating pendulum. If the pendulum were suspended at the : 
pole it a evidently vibrate in the same plane in space, and — 
rform a gyration in one day. Since the beers : 
of the artis revolution around any other point of the e 
surface is ncos@ (§ 28), the time of gyration there is iy : 
6 
1 day x sec. 4. 
3 
the motions of a rotating 
~rta Minie in which it is, gives the axis of rotation cade : 
to assume a ndicular position. But there are other forces 
beside these icereenbidly deflecting forces, so that all the forces — 
* This result was erroneously given in the Mathematical Monthly, 1 day X sec.f. 
same my may be used to explain some of : 
=, i Ane such a body be placed — 
with its axis of rotation in 1 with the hori- — 
