6538. PENDULUM, Experiments with.—
I had taken no notice of the precaution of
making the experiment of the pendulum on
the sea-shore, because the highest mountain in
the United States would not add 1-5000 part to
the length of the earth's radius, nor 1-128 of an
inch to the length of the pendulum. The highest
part of the Andes, indeed, might add about
1-1000 to the earth's radius, and 1-25 of an
inch to the pendulum. As it has been thought
worth mention, I will insert it also.—
To David Rittenhouse. Washington ed. iii, 149.
(N.Y.,
1790)
