In General It Appeared To Me That, Within The Torrid Zone, Either At The Level Of The Sea, Or On

Table-lands from 1200 to 1500 toises high, there is no rain but that during storms, which falls in large

Drops very distant from each other, and is sensibly colder than the air. These drops bring with them, no doubt, the low temperature of the high regions. In the rain which I found hotter than the air, two causes may act simultaneously. Great clouds heat by the absorption of the rays of the sun which strike their surface; and the drops of water in falling cause an evaporation and produce cold in the air. The temperature of rain-water, to which I devoted much attention during my travels, has become a more important problem since M. Boisgiraud, Professor of Experimental Philosophy at Poitiers, has proved that in Europe rain is generally sufficiently cold, relatively to the air, to cause precipitation of vapour at the surface of every drop. From this fact he traces the cause of the unequal quantity of rain collected at different heights. When we recollect that one degree only of cooling precipitates more water in the hot climate of the tropics, than by a temperature of 10 to 13 degrees, we may cease to be surprised at the enormous size of the drops of rain that fall at Cumana, Carthagena and Guayaquil.)

Our passage from the island of Cuba to the coast of South America terminated at the mouth of the Rio Sinu, and it occupied sixteen days. The roadstead near the Punta del Zapote afforded very bad anchorage; and in a rough sea, and with a violent wind, we found some difficulty in reaching the coast in our canoe. Everything denoted that we had entered a wild region rarely visited by strangers. A few scattered houses form the village of Zapote: we found a great number of mariners assembled under a sort of shed, all men of colour, who had descended the Rio Sinu in their barks, to carry maize, bananas, poultry and other provisions to the port of Carthagena. These barks, which are from fifty to eighty feet long, belong for the most part to the planters (haciendados) of Lorica. The value of their largest freight amounts to about 2000 piastres. These boats are flat-bottomed, and cannot keep at sea when it is very rough. The breezes from the north-east had, during ten days, blown with violence on the coast, while, in the open sea, as far as 10 degrees latitude, we had only had slight gales, and a constantly calm sea. In the aerial, as in the pelagic currents, some layers of fluids move with extreme swiftness, while others near them remain almost motionless. The zambos of the Rio Sinu wearied us with idle questions respecting the purpose of our voyage, our books, and the use of our instruments: they regarded us with mistrust; and to escape from their importunate curiosity we went to herborize in the forest, although it rained.

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