Nicolas-Louis de la Caille Astronomer and Geodesist
by I.S. Glass
Oxford University Press, Published December 2012, ISBN 978-0-19-966840-3
This is the first comprehensive biography of one of the greatest and most careful observational astronomers of all time, Nicolas-Louis de La Caille (1713-1762). Trained at the Paris Observatory under Cassini II, La Caille became Professor of Mathematics at the Mazarin College and built an observatory on its roof. Here La Caille began his lifelong programme of finding accurate postions for the bright stars, against which he could measure the paths of the Sun and planets.
During his expedition to the Cape of Good Hope in the years 1751-53 he mapped the southern sky and gave many of the constellations the names by which they are still known. In conjunction with simultaneous measurements from Europe, he determined the distances of the planets Venus and Mars.
In addition, while at the Cape, he contributed to geodesy by measuring the radius of the earth and paradoxically came to the conclusion that it is pear-shaped. The explanation of his error lay with local gravitational anomalies caused by mountains that deflected his plumb lines.
La Caille interested himself in navigation and developed a practical procedure for making use of the Moon to determine longitudes at sea, known as the method of Lunars.
He fed precise data to the leading applied mathematicians of the time, D'Alembert, Maupertuis and Clairaut. This information was critical to the development of the theory of planetary perturbations. La Caille was a firm believer in Newton's theory of universal gravitation, for which he was an able propagandist.
Apart from his astronomical and geodetic work, while at the Cape La Caille made extensive notes of conditions among the colonists and slaves. His remarks constitute perhaps the most reliable commentary on conditions at the time.
http://www.saao.ac.za/~isg/lacaille.html
http://ukcatalogue.oup.com/product/9...o#.Ua-l5ZyBaoR
