The apparent proximity of the hamlets, vineyards and coastal gardens from the summit is increased by the surprising transparency of the air. Despite the great distance we could not only pick out the houses, the tree trunks and the sails on the vessels, but also the vivid coloring of the plain's rich vegetation. The Pico de Teide is not situated in the Tropics, but the dryness of the air, which rises continuously above the neighboring African plains and is rapidly blown over by the eastern winds, gives the atmosphere of the Canary Islands a transparency which not only surpasses that of the air around Naples and Sicily, but also of the air around Quito and Peru. This transparency may be one of the main reasons for the beauty of tropical scenery; it heightens the splendors of the vegetation's coloring, and contributes to the magical effects of its harmonies and contrasts. If the light tires the eyes during part of the day, the inhabitant of these southern regions has his compensation in a moral enjoyment, for a lucid clarity of mind corresponds to the surrounding transparency of the air.

The First Secretary of State had particularly recommended BrigadierRafael Clavijo, recently appointed Inspector General of Maritime Couriers. officer advised us to board the corvette Pizarro, bound for Havana and Mexico. This light frigate was not famed for itssailing speed, although during its long journey from the River Plate it hadluckily just escaped English men-of-war. Clavijo sent instructions to thePizarro to authorize the loading of our instruments, and to allow us to carry out atmospheric testsduring the sea-voyage. The captain was ordered to stop at Tenerife andremain there as long as was needed for us to visit the port of Orotava andclimb the Pico de Teide.