APPENDIX. 333 



perpetual secretary of the Academy of Sciences, member 

 of the Bureau des Longitudes, and Director of the 

 Observatory. This illustrious man, who has only lately 

 closed his chequered career, was the eldest son of a 

 numerous family. Although he had been destined by 

 his father for the bar, Arago at first chose the profession 

 of arms, and prepared himself without the help of any 

 masters for his examinations at the Polytechnic School, 

 which he entered with the highest honours. His remark- 

 able aptitude for the exact sciences attracted the atten- 

 tion of Monge, who secured his services for the observa- 

 tory. When, in 1806, the French Government wished 

 to complete the measurement of an arc of the meridian, 

 which had been begun by Delambre and Mechain, and 

 interrupted by the death of the latter, they selected 

 Arago and M. Biot (who was twelve years his senior, 

 and already a member of the Institute) to conclude this 

 undertaking.* They were associated in this labour with 

 the Spanish Commissioners, Chaix and Rodriguez. 



* M. Biot, who is a member of the Institute (Academy of 

 Sciences, and Academy of Inscriptions and Belles-Lettres), has 

 survived his old fellow labourer, and is now one of the Deans of the 

 Institute. In 1853 he completed the fiftieth anniversary of his 

 election to the Institute, and this very rare circumstance gave 

 occasion to a demonstration of affection and esteem which was alike 

 honourable to M. Biot and the Institute. Notwithstanding his 

 great age, M. Biot has lost none of that scientific ardour which he 

 so frequently exhibited throughout his earlier life. We owe to this 

 physicist a very considerable number of works, treating both of 

 experimental and mathematical physics, and of pure mathematics. 

 The Traite Analytique des Courbes et des Surfaces du Second Dfyre, 

 and the Traite de Physique Experimentale et Mathematique have 

 passed through several editions. M. Biot has directed much atten- 

 tion to the astronomy of the Egyptians, Chaldeans, and Chinese. 

 He was for a long time aided in these historical researches by his 

 son Edouard Biot, who has been prematurely removed by death. 



