Climate : an inquiry into the causes of its differences, and into its influence on vegetable life : comprising the substance of four lectures delivered before the Natural History Society, at the Museum, Torquay, in February, 1863 / by C. Daubeny.

  • Daubeny, Charles Giles Bridle, 1795-1867.
Date:
1863
Catalogue details

Licence: Public Domain Mark

Credit: Climate : an inquiry into the causes of its differences, and into its influence on vegetable life : comprising the substance of four lectures delivered before the Natural History Society, at the Museum, Torquay, in February, 1863 / by C. Daubeny. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    distance of ninety-five millions of miles from the earth we inhabit. Moreover, by employing the same method, it has since been inferred, that the composition of the fixed stars is not always identical with that of the sun ; Sirius, for instance, and some others that have been examined, presenting a spec- trum differing from that of our own luminary, and one which appears to indicate the existence of other elements ^. But it is time to terminate this digression, for which my best apology is the great general interest felt in the novel and beautiful investigation alluded to, as it is with the effects of the solar orb upon the condition of our own planet, rather than with its own intrinsic nature, that we as meteorologists have to deal. These effects, it is evident, will be experienced more sen- sibly in proportion to the directness or perpendicularity with which its rays impinge upon the earth's surface, so that they will be least energetic in the polar regions, and most so within the tropics. If indeed the globe presented throughout a solid surface, unchequered by any irregularities, and uniform both as to texture and colour, the temperature of each portion might be calculated by simply appealing to its latitude, since each parallel would differ from the one above or below it in a cer- tain fixed and easily ascertainable ratio. Were the earth for instance, as the ancients considered it, and as for convenience sake it is represented on Mercator's projection, a plain surface, it is evident that, granting the mean temperature of the equator to be 80*^, and that of the poles zero of Fahrenheit, there would be a decrease of 8|° of Fahr. for every addition of 10° of latitude. But as it is a sphere, the ratio is different; and it appears ^ Professor Donati, in a recent memoir read before the Astronomical Society, has classified a few of the more conspicuous of the fixed stars into four groups, according to the kind of light they emit, namely, into white, yellow, orange, and red stars, and has observed that whilst in each class the position of the dark lines corresponds one with the other, every separate group differs from the remaining ones, as well as from the solar orb, in that respect. Ch. News, March 21, 1863.