56 Notes on the Life of Arago. 



In 1806, when only twenty years of age, so much had he 

 distinguished himself, that he was appointed a secretary of 

 the Board of Longitude ; and almost immediately afterwards, 

 his acquirements having attracted the attention of M. Monge, 

 he was recommended as the fitting assistant to M. Biot for 

 undertaking the measurement of an arc "of the meridian in 

 Spain. This scientific labour was considerably advanced in 

 ] 807, when Biot returned to Paris, leaving Arago in charge 

 of the important work. 



In the execution of this arduous work, MM. Biot and Arago 

 were stationed on the summit of Mount Galatzo, one of the 

 highest of the Catalonian branch of the Eastern Pyrenees, 

 while MM. Chaix and Rodriguez established themselves on 

 Mount Campecey in Ivica, one of the Balearic Islands. In 

 this cold and desolate position the astronomers remained for 

 several months, keeping up a constant communication with 

 each other by means of fire signals, lighted up at particular 

 intervals. Here they were exposed to various kinds of pri- 

 vations and particularly to the fierce blasts which sweep 

 over these lofty solitudes. The huts in which they dwelt 

 were frequently blown down, and their lives endangered. 

 But these calamities were nothing compared with the dan- 

 gers to which they were exposed from the ignorance of the 

 people. Before Arago had finished his work, his colleague, 

 M. Biot, had returned to Paris, and war had broken out be- 

 tween France and Spain. The fires which blazed at the 

 signal-stations were regarded by the ignorant mountaineers 

 as telegraphic despatches informing the invading army of the 

 movements of the patriots. Arago was therefore denounced 

 as a spy, and it required all the courage and skill which he 

 possessed to escape the dangers to which he was thus ex- 

 posed. Born near the Spanish frontiers, he spoke the same 

 dialect which prevails round Mount Galatzo, and, disguised 

 in the mantle and red cap of a Catalonian mountaineer, he 

 effected his escape to Majorca, where he found shelter, along 

 with his papers and instruments, in the fortress of Belver. 

 After completing in this retirement his geodesical calcula- 

 tions, he obtained liberty, on the condition of proceeding to 

 Algiers, which lie did by the first opportunity. On his pas- 

 sage from Algiers to Marseilles, in an Algerine frigate pro- 



