, p.
319-354.) Nouet's latitudes, engraved on Egyptian monuments, offer a more
recent example of the danger presented by the grave perpetuation of false or
careless results.
Galileo, who first observed when a boy (having, probably, suffered his
thoughts to wander from the service) that the height of the vaulted roof of
a church might be measured by the time of the vibration of the chandeliers
suspended at different altitudes, could hardly have anticipated that the
pendulum would one day be carried from pole to pole, in order to determine
the form of the Earth, or, rather, that the unequal density of the strata of
the Earth affects the length of the seconds pendulum by means of intricate
forces of local attraction, which are, however, almost regular in large
tracts of land. These geognostic relations of an instrument intended for
the measurement of time -- this property of the pendulum, by which, like a
sounding line, it searches unknown depths, and reveals in volcanic islands,*
or in the declivity of elevated continental mountain chains,** dense masses
of basalt and melaphyre instead of cavities, render it difficult,
notwithstanding the admirable simplicity of the method, to arrive at any
great result regarding the figure of the Earth from observation of the
oscillations of the pendulum.
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