71 



which direction is then that of the wind *. In 

 the Bay of Naples M. Gay-Lussac and myself 

 observed luminous phenomena, very analogous 

 to those which fixed my attention during a long 

 abode at Mexico and Quito. These meteors are 

 perhaps modified by the nature of the soil and 

 the air, like certain effects of the looming *fr and 

 of the terrestrial refraction peculiar to the coasts 

 of Calabria and Sicily. 



During our navigation we saw neither the 

 Desert Islands nor Madeira ; I should have 

 wished to have had the means of verifying the 

 longitude of those islands, and of taking the 

 angles of altitude of the volcanic mountains, 

 which rise to the north of Funchal. M. Borda £ 

 says, that these mountains are seen at 20 leagues 

 distance, which would give a height of only 414 

 toises (806 metres) ; but we know by recent 

 measures, that the most elevated point § of Ma- 



* Such is the result of numerous observations by Mr. 

 Arago, who, at the period of the prolongation of the meridian 

 in Spain, was enabled to observe the direction of the meteors, 

 during whole nights, on the Tosal d'Encanade, a mountain in 

 the kingdom of Valencia. 



t Mirage. 



t Voy. de la Flore, vol. i, p. 65. The Salvage is visible at 

 eight leagues ; the little Desert Islands are seen at 12 leagues 

 distance. Borda, vol. i, p. 67 et 70. 



§ Smith's Tour of the Continent, vol. i, p. 200. Irish 

 Trans, vol. viii, p. 124. According to Heberden, the Peak 

 Ruivo of Madeira is 595 toises above the plane which sur- 

 rounds its basis. Cook's first Voyage, vol. i, p. 272. 



* 



