HUYGENS’S PARABOLOIDAL CONICAL
PENDULUM CLOCK MEASUREMENTS
OF SURFACE GRAVITY (1673)
1st
Distance of fall in second
= 2latus rectum/P2
Original
sketch
Latus rectum of a one-half sec
paraboloidal-conical-pendulum
clock: 4 inches 7.1 lines
1st
Distance of fall in second:
15 Paris feet 1.1 inches
Diagram in
Horologium
Oscllatorium
19
HUYGENS’S CONSTANT-HEIGHT CONICAL
PENDULUM MEASUREMENT OF THE
STRENGTH OF SURFACE GRAVITY (1659)
Distance of fall in 1st second
= 22height of pendulum/P2
Height of a three-quarter sec
constant-height conical-pendulum clock: 5 inches 1.9 lines
Distance of fall in 1st second:
15 Paris feet 1.1 inches
18