G4 TEMPERATURE DURING THE VOYAGE. 
palms were conspicuous on the azure of a sky un- 
sullied by the least trace of vapour. A dazzling 
light was spread along the white hills clothed with 
cylindrical cactuses, and over the smooth sea, the 
shores of which were peopled by pelicans, egrets, 
and flamingoes. Every thing announced the mag- 
nificence of nature in the equinoctial regions. 
Before accompanying our learned friends to the 
city of Cumana, we may here take a glance of the 
physical observations made by them during the 
voyage, and which refer to the temperature of the 
air and sea, and other subjects of general interest. 
Temperature of the Air.—In the basin of the 
northern Atlantic Ocean, between the coasts of Eu- 
rope, Africa, and America, the temperature of the 
atmosphere exhibits a very slow increase. From 
Corunna to the Canary Islands, the thermometer, 
observed at noon and in the shade, gradually rose 
from 50° to 64°, and from Teneriffe to Cumana from 
64° to 77°. The maximum of heat observed during 
the voyage did not exceed 79:9°. 
The extreme slowness with which the tempera- 
ture increases during a voyage from Spain to South 
America is highly favourable to the health of Eu- 
ropeans, as it gradually prepares them for the in- 
tense heat which they have to experience. It is in’ 
a great measure attributable to the evaporation. of 
the water, augmented by the motion of the air and 
waves, together with the property possessed by trans- 
parent liquids of absorbing very little light at their 
surface. On comparing the numerous observations 
made by navigators, we are surprised to see that 
in the torrid zone, in either hemisphere, they have 
not found the thermometer to rise in the open sea 
above 93°; while in corresponding latitudes on the 
