Having completed his legal studies, he was about to return to Bourg to practise as an advocate, when Le Monnier obtained permission to send him to Berlin, to make observations on the lunar parallax in concert with those of Lacaille at the Cape of Good Hope.

His house became an astronomical seminary, and amongst his pupils were Delambre, Giuseppe Piazzi, Pierre Méchain, and his own nephew Michel Lalande.

[2] In 1766, Lalande, with Helvetius, founded the "Les Sciences" lodge in Paris, and received its recognition from Grand Orient de France in 1772.

Pierre-Antoine Véron, the young astronomer who for the first time in history determined the size of the Pacific Ocean from east to west, was Lalande's disciple.

[9] In February 1847 Sears C. Walker of the US Naval Observatory was searching historical records and surveys for possible prediscovery sightings of the planet Neptune that had been discovered the year before.