It Rained With Violence, And I Availed Myself Of That Occasion To Measure The Temperature Of The Rain-Water:

It was 26.3 degrees, while the thermometer in the air kept up, in a place where the bulb was not wet, at 24.8 degrees.

This result differed much from that we had obtained at Cumana, where the rain-water was often a degree colder than the air.* (* As, within the tropics, it takes but little time to collect some inches of water in a vase having a wide opening, and narrowing towards the bottom, I do not think there can be any error in the observation, when the heat of the rain-water differs from that of the air. If the heat of the rain-water be less than that of the air it may be presumed that only a part of the total effect is observed. I often found at Mexico at the end of June, the rain at 19.2 or 19.4 degrees, when the air was at 17.8 and 18 degrees. 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.

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