NICOLAS LOUIS DE LA, a celebrated French astronomer, born at Rumigny in the department of Aisne, March 15, 1713. His father was a gentleman in easy circumstances, who devoted the greater part of his time to the study of philosophy and natural science, and early succeeded in inspiring his son with similar tastes. On the death of this parent the young La Caille found himself entirely destitute. He was soon enabled, however, to resume his studies by the generous interposition of the Duke of Bourbon. His first intention was to enter the church, but he speedily abandoned his theological studies, and devoted himself to the physical sciences, especially astronomy. On his arrival at Paris he was cordially welcomed by Cassini, who gave him an apartment in the observatory. He here gained the friendship of Maraldi, whom he helped to take the bearings of the French coast from Nantes to Bayonne. Such was Caimac's ability he displayed on this occasion, that he was employed to assist in the verification of the French meridian. This gave him an opportunity of correcting the measurements of Picard, taken in 1669. While absent on this mission, he was appointed professor of mathematics in the Mazarin college. His calculations completed, he proved by a comparison of the different arcs which he had measured that degrees go on increasing from the equator to the pole; a proposition familiar to every one now, but at that time directly opposed to the results of previous researches. After taking possession of his professorial chair he published successively Leçons élémentaires de Mathématiques, 1741; Leçons de Mécanique, 1743; Leçons d'Astronomie, 1746, re-edited by Lalande in 1780; Éléments d'Optique, 1750. He also calculated the eclipses for 1800 years for the first edition of the work entitled L'art de vérifier les dates.

Being curious to determine and verify the stars of the southern hemisphere, he undertook a voyage to the Cape of Good Hope, where in 127 nights he calculated the positions of 10,000 stars, with a quickness and correctness, says Delambre, that would have been deemed impossible, considering the deficient means at his disposal. He likewise determined at the Cape the parallax of the moon, and of the planets Mars and Venus, and measured a degree of the southern hemisphere. While engaged in these duties, he received orders from the French government to survey the islands of Bourbon and Mauritius, and determine their positions. During these various voyages he devoted much of his time to the problem of longitudes, on which subject he had a controversy with the German Euler on his return to Paris in 1754. To escape the public curiosity, he shut himself up in his observatory, dividing his time between his calculations and his duties of professor and academician. In 1757 he published his Astronomie fondamenta, and in the following year his Tables Solaires. He soon after published the Traité de la gradation de la lumière, of which Bouguer had bequeathed him the manuscript at his death, and brought out a new edition of the Traité de la Navigation by the same author. In the midst of his multifarious labours, he was surprised by a violent attack of the gout. Feeling his illness increase, and that he had no prospect of recovery, he gave back all the instruments that he had borrowed from his friends, and died March 21, 1762, leaving his MSS. to Maraldi, who published the Codex Australis Stellaferum in the year after the author's death. It was said of La Caille by Lalande, that he made more observations and calculations than all the astronomers of his time put together.