Volume 1
Outlines of natural philosophy : being heads of lectures delivered in the University of Edinburgh / by John Playfair.
- John Playfair
- Date:
- 1814
Licence: Public Domain Mark
Credit: Outlines of natural philosophy : being heads of lectures delivered in the University of Edinburgh / by John Playfair. Source: Wellcome Collection.
Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.
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![399. The sea is preserved of a moderate tempe- rature by the statical principle which makes the heavier columns of a fluid displace the lighter. A more uniform temperature is thus given to the sea, which communicates itself to the air incumbent on it, and to that on every side. 400. Conversely, the effect of great and unbro- ken continents, is favourable to the extremes of heat or of cold. The constitution of the surface may tend to increase and sometimes to diminish this effect. High moun- tains especially, if covered with snow, may enforce the rigour of a cold climate, or temper the heats of a warm one. Forests tend to increase the cold, by preventing the sun's rays from striking on the ground. Evapora- tion produces cold; and marshes and lakes are therefore favourable to the severity of the weather. The congelation of water produces heat, and mode- rates the cold ; the melting of ice, on the other hand, increases the capacity for heat, and so pro- duces cold. 401. Height above the level of the sea, causes a diminution of heat at the constant rate of ]° for 270 feet nearly, when not far from the surface of the earth. T4- It](https://iiif.wellcomecollection.org/image/b21299730_0001_0315.jp2/full/800%2C/0/default.jpg)
