198 



ed with the circumstance that rendered it pecu- 

 liarly interesting to us. Mr. de Borda, whose 

 death we deplored, was it's inmate during his 

 last visit to the Canary islands. It was in a small 

 neighbouring plain, that this gentleman mea- 

 sured the base, by which he determined the 

 height of the Peak. In this geometrical opera- 

 tion, the great dracoena of Orotava served as a 

 mark. If any well-informed traveller should 

 some future day undertake a new measurement 

 of the volcano with more exactness, and by 

 means of astronomical repeating circles, he 

 ought to measure the base, not near Orotava, 

 but near Silos, at a place called Bante. Accord- 

 ing to Mr. Broussonet, there is no plain near the 

 Peak of greater extent. In herbalizing near La 

 Paz, we found a great quantity of lichen roccella 

 on the basaltic rocks bathed by the waters of the 

 sea. The archil of the Canaries is a very ancient 

 branch of commerce ; this lichen is however 

 found in less abundance in the isle of TenerifFe, 

 than in the desert islands of Salvage, La Gra- 

 ciosa, and L'Alegranza, or even in Canary and 

 Hierro. 



We left the port of Orotava on the 24th of 

 June in the morning : we dined, as we passed 

 through Laguna, with the French consul. He 

 had the kindness to take charge of the geologi- 

 cal collections* we had made, and which we 



* Mr. Hergen has described them in the Annates de Ciencias 

 naturales, which he published jointly with Abbe Cavanilles. 



