Observatory of Paris, Dominic Cassini (1625-1712),
whose reputation among his contemporaries was
much greater than among succeeding generations of
astronomers. Perhaps the most deserving of these
successors was Nicolas Louis de Lacaille (1713-1762),
a theologian who had been educated at the expense
of the Duke of Bourbon, and who, soon after completing
his clerical studies, came under the patronage
of Cassini, whose attention had been called to the
young man's interest in the sciences. One of Lacaille's
first under-takings was the remeasuring of the French
are of the meridian, which had been incorrectly measured
by his patron in 1684. This was begun in 1739,
and occupied him for two years before successfully
completed. As a reward, however, he was admitted
to the academy and appointed mathematical professor
in Mazarin College.

In 1751 he went to the Cape of Good Hope for the
purpose of determining the sun's parallax by observations
of the parallaxes of Mars and Venus, and incidentally
to make observations on the other southern
hemisphere stars. The results of this undertaking
were most successful, and were given in his Coelum
australe stelligerum, etc., published in 1763. In this he
shows that in the course of a single year he had observed
some ten thousand stars, and computed the
places of one thousand nine hundred and forty-two of
them, measured a degree of the meridian, and made
many observations of the moon--productive industry