ome back to her starting-point.
Henceforth the theological doctrine of the flatness of the earth was
irretrievably overthrown.

Five years after the completion of the voyage of Magellan, was made the
first attempt in Christendom to ascertain the size of the earth. This
was by Fernel, a French physician, who, having observed the height of
the pole at Paris, went thence northward until he came to a place where
the height of the pole was exactly one degree more than at that city.
He measured the distance between the two stations by the number of
revolutions of one of the wheels of his carriage, to which a proper
indicator bad been attached, and came to the conclusion that the earth's
circumference is about twenty-four thousand four hundred and eighty
Italian miles.

Measures executed more and more carefully were made in many countries:
by Snell in Holland; by Norwood between London and York in England; by
Picard, under the auspices of the French Academy of Sciences, in France.
Picard's plan was to connect two points by a series of triangles,
and, thus ascertaining the length of the arc of a meridian intercepted
between them, to compare it with the difference of latitudes found from
celestial observations. The stations were Malvoisine in the vicinity
of Paris, and Sourdon near Amiens. The difference of latitudes was
determined by observing the zenith-distances, of delta Cassiopeia. There
are two points of interest connected with Picard's operation: it was the
first in which instruments furnished with telescopes were employed;
and its result, as we shall shortly see, was to Newton the first
confirmation of the theory of universal gravitation.

At this time it had become clear from mechanical considerations, more
especially such as had been deduced by Newton, that, since the earth is
a rotating body, her form cannot be that of a perfect sphere, but
must be that of a spheroid, oblate or flattened at the poles. It would
follow, from this, that the length of a degree must be greater near the
poles than at the equator.

The French Academy resolved to extend Picard's operation, by prolonging
the measures in each direction, and making the result the basis of a
more accurate map of France. Delays, however, took place, and it was not
until 1718 that the measures, from Dunkirk on the north to the southern
extremity of France, were completed. A discussion arose as to the
interpretation of these measures, some affirming that they in