The French astronomers were accompanied by Mongkut, the King of Siam who had calculated the location and the date of the eclipse by himself two years before and prepared a comfortable watching place for the scientists.

[1] In 1873 he was appointed director of the observatory at Toulouse, where he published his Recueil d'exercices sur le calcul infinitesimal, and in 1874 became corresponding member of the Académie des Sciences.

[1] Tisserand always found time to continue his important researches in mathematical astronomy, and the pages of the Comptes rendus bear witness to his activity.

In this treatise, published in four quarto volumes, the last of which appeared only a few months before his death, he fused into one harmonious whole the researches of Laplace and those of other workers in the same field since his time.

[1] In 1892 he succeeded Mouchez as director of the Paris Observatory, and as president of the committee of the photographic chart of the heavens he contributed largely to the success of that great project.