148 EULOGY ON GAY-LUSSAC. 



We will refer farther on to this very remarkable portion of Gay-Lus- 

 sac's works. Gay-Lussac, assistant professor of the Fourcroy course, 

 obtained, through the friendly intervention of Bertbollet, leave for a year 

 to accompany M. de Humboldt in his travels through Italy and Ger- 

 many. The two friends, before leaving Paris, provided themselves 

 with meteorological instruments, and especially apparatus suitable for 

 determining the inclination of the magnetic needle and the intensity of 

 the variable force which directs the magnetic needle in different lati- 

 tudes. They left Paris March 12, 1805, and experimented with their 

 instruments at Lyons, Chamb6ry, St. Jean de Maurienne, St. Michel, 

 Lanslebourg, and Mont Cenis, &c. I will return elsewhere to the 

 magnetic results of this journey in a memoir of our colleague inserted 

 in the collection of the Society of Arcueil. Gay-Lussac had imbibed in 

 his youth the meoeorological theories of Deluc, some of which had almost 

 captivated him, but in his passage over the Alps his ideas were entirely 

 modified. He felt the need, for example, of having recourse to the 

 action of ascending atmospheric currents to explain a large number of 

 curious phenomena. 



Nothing enlightens and enlarges the ideas more, with regard to 

 natural phenomena, than traveling in mountainous regions, especially 

 when so fortunate as to enjoy the society of as cultivated, ingenious, and 

 experienced an observer as M. de Humboldt. 



Gay-Lussac and his illustrious fellow-traveler, after visiting Genoa, 

 went to Eome, where they arrived July 5, 1805, and alighted at the 

 palace Tommati alia Trinita di Monte, the residence of William de 

 Humboldt, charg6 d'affaires of Prussia. 



In the society of him who has so eloquently described it, the grand 

 scenery of the Alpine regions could not fail to excite genuine enthusi- 

 asm in Gay-Lussac's soul. The sight of the immortal monuments of 

 architecture, of the painting and sculpture with which Eome abounds, 

 joined to the learned conversations of the Eauches, Thorwaldsens, &c, 

 habitu6s of the Tommati Palace, awakened in the youthful traveler a 

 taste for the fine arts, which until then had been latent Finally he 

 enjoyed the advantage of admiring the fascination of talent ; for Madame 

 de Stael then held every salon of the Eternal City under the spell of her 

 eloquent and spirituel conversational powers. Gay-Lussac's sojourn in 

 Eome was not without fruit to the science of chemistry. Thanks to the 

 courtesy of Morrichini in placing a chemical laboratory at the disposal 

 of the young traveler, he was able to announce, July 7, that fluoric acid 

 existed with phosphoric acid in the bones of fishes. July 9, he finished 

 the analysis of the alum rock of the Tolfa. 



July 15, 1805, Messrs. de Humboldt and Gay-Lussac left Eome and 

 started for Naples, accompanied by M. Leopold de Buch, who, though 

 still young, had already distinguished himself by very valuable geologi- 

 cal researches. Vesuvius, in a state of rest at that period, suddenly 

 exhibited the most magnificent and terrible evolutions, (as if to celebrate 



