138 SHARKS—GUAYRA. 
bloodthirsty at the island opposite the coast of Carac- 
cas, at the Roques, at Buenos Ayres, and at Curas- 
sao, they do not disturb persons swimming in the 
ports of Guayra and Santa Martha. As an analogous 
fact, Humboldt mentions that the crocodiles of one 
pool in the Llanos are cowardly, while those of ano- 
ther attack with the greatest fierceness. 
The situation of La Guayra resembles that of 
Santa Cruzin Teneriffe ; the houses, which are built 
on a flat piece of ground about 640 feet broad, 
being backed by a wall of rock, beyond which is a 
chain of mountains. The town consists of two pa- 
_ rvallel streets, and contains 6000 or 8000 inhabi- 
tants. The heat is greater than even at Cumana, 
Porto Cabello, or Coro, the seabreeze being less felt, 
and the temperature being increased by the radiant 
caloric emitted by the rocks after sunset. 
The examination of the thermometrical observa- 
tions, made at La Guayra during nine months by 
Don Joseph Herrera, enabled Humboldt to compare — 
the climate of that port with those of Cumana, Ha- 
vannah, and Vera Cruz. The result of this compa- 
rison was, that the first mentioned is one of the hottest 
places on the globe; that the quantity of heat which 
it receives in the course of a year is a little greater 
than that experienced at Cumana; but that in No- 
vember, December, and January, the atmosphere 
cools to a lower point. The mean temperature of 
the year in these several districts is as follows :—At 
La Guayra, nearly 82°6°; at Cumana, 81-2°; at 
Vera Cruz, 77:7°; at Havannah, 78:1°; while at 
Rio Janeiro it is 74:5°; at Santa Cruz in Teneriffe, 
71°4°; at Cairo, 72:3°; and at Rome, 60-4°. 
At the time of Humboldt’s visit to La Guayra,: 
