Meteorological observations and essays / By John Dalton.

  • John Dalton
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: Meteorological observations and essays / By John Dalton. Source: Wellcome Collection.

    112/280 (page 86)
    a wind between the south and west. And, vice versa, if it move southward, it becomes a NE. wind. Likewise in the southern hemisphere, it will appear the winds, upon similar suppositions, will be NW. and SE. respectively.* The trade-winds therefore may be explained thus: the two general masses of air proceeding from both hemispheres towards the equator, as they advance are constantly deflected more and more towards the east, on account of the earth’s rotation ; that from the northern hemisphere, or1- ginally a north wind, is made to veer more and more towards the east, and that from the southern hemisphere in like manner is made to veer from the south towards the east; these two masses meeting about the equator, or in the torrid zone, their velocities north and south destroy each other, and they proceed afterwards with their common velocity from east to west round the torrid zone, excepting the irregularities produced by the con- tinents. Indeed the equator is not the centre or place of concourse, but the northern parallel of 4°; because the centre of heat is about that place, the sun being longer on the north side of the equator than on the south side. Moreover, when the sun is near one of the tropics, the centre of heat upon the earth’s surface is then nearer that * M. De Luc is the only person, as far as I know, who has sug- gested the idea of the earth’s rotation altering the direction of the wind, which idea we have here pursued more at large.—Vide “ Lettres Physiques, &c.”” Tom. 5. Part. 2. Let. cxly.