The general temperature of the earth is doubtless regulated by its situation in the universe; and more especially, by its position with respect to the sun. To this position, as formerly observed, the properties of its constituent principles have, most obviously, been all adapted with consummate wisdom; so that, under the circumstances in which they are placed, some are solid, some liquid others gaseous, according to the purposes they are intended to fulfil in nature.

But the heat and light derived from the sun, are very unequally distributed over the surface of the earth; and every one is familiar with the fact, that as we recede from the equator towards the north or south, the temperature of the earth's surface gradually diminishes, till we arrive at the polar regions.

Such is the general fact. But the circumstances which conspire to interfere with this gradual distribution of temperature, are so numerous and so influential; that the actual temperature of a place can be learnt only by observation. Among the circumstances thus more especially affecting the distribution of temperature, may be mentioned, the nature of the surface, whether water or land;—and the situation, whether at a greater, or at a less height, above the level of the ocean. To such circumstances may be added, the particular configuration and geographical relations of places: as their aspect to the north or south; their being sheltered or exposed; the composition and nature of the soil, particularly its colour and state of aggregation; on which depend its powers of absorbing and of radiating heat and light; and of retaining or of parting with humidity, &c.; also the proximity, or absence of, seas; the predominancy of certain winds; the frequency of clouds, fogs, &c.