DEFINITIONS, 
é, n, €, linear displacements of the ground. 
w, rotation of the ground. 
fg period of linear displacements of the 
ground, 
Q, period of rotations of the ground. 
p=2r/P. 
T; period of the pendulum with damping. 
Th; period of the pendulum without damp- 
ing. 
y period of the pendulum without damp- 
ing when swung vertically. 
CG, center of gravity of the pendulum at 
any time, 
CG, center of gravity of the pendulum when 
at rest. 
OG,, center of gravity of the pendulum sup- 
posed rigidly connected with the 
support and moving with it. 
fq, moment of inertia of the pendulum 
about CG. 
Iy, moment of inertia of the pendulum 
about axis of rotation. 
[ZI], complete moment of inertia about axis 
of rotation, including the magnifying 
levers, 
191 
M, mass of the pendulum. 
l, distance of CG from the axis of rotation. 
L=([I]/MI, distance of center of oscillation 
from axis of rotation. 
z inclination of axis of rotation to the 
vertical. 
L'= L/i, length of simple mathematical pen- 
dulum having the same period. 
ky coefficient of viscous damping. 
relaxation time, that is, the time re- 
quired for the amplitude to diminish 
in the proportion 1: 1/e. 
g damping ratio, 
A, logarithmic decrement. 
T; frictional displacement of medial line. 
a, amplitude of the recording point. 
“.¥ range of the recording point. 
V; magnifying power for rapid linear har- 
monic displacements. 
W, magnifying power for linear harmonic 
displacements of any period. 
U, magnifying power for harmonic rota- 
tions of any period. 
