of a direct Passage over the Pole. 299 



The influence of the sun, in rarefying the atmosphere to the 

 greatest degree, between the tropics, together with the earth's 

 rotation on its axis from west to east, would produce a constant 

 wind from east to west, all round the globe, if no land intervened; 

 because, the points of greatest rarefaction being successively west- 

 ward ; and those eastward of each other, parting successively, as 

 the sun sets in their horizons, with part of the heat received in 

 his' passage over them, the motion of the atmosphere nearest the 

 surface of the water, must necessarily be from east to west ; fol- 

 lowing the apparent motion of the sun. We find this proved by 

 fact, on ihoi>e portions of the globe where the general law is not 

 obstructed bv causes 'if an opposite nature, arising from terrene 

 influence; viz. in the great Pacific ocean, between America 

 and the coast of New Holland, and also in the open sea, be- 

 tween AiVica and America. The central medium line of greatest 

 rarefaction, is the eiiuator ; but, according to the sini's declina- 

 tion, north or south, it will be more to the northward or south- 

 ward. The air, thus rarefied in the lower regions of the atmo- 

 sphere surrounding the earth, and comprised within the limits of 

 the sun's path between the tropics, must be continually ascend- 

 ing into the higher, and thence, north of the equator, advancing 

 towards the north pole; and south of the line, towards the south 

 pole, till, somewhere in its passage, it acquires that degree of con- 

 densation bv cold, which compels it again to return in the lower 

 strata, to the point of greatest rarefaction, to undergo the same 

 process. This seems to be the grand general law of nature's ope- 

 ration upon the atmosphere; that by "universal motion, it may 

 be preserved in a state of purity." Let us now incpiire, whether 

 this same law is not equally applicable to that universal motion 

 of the great deep which must be equally necessary to its purity, 

 and therefore we certainly may presume, does take place on some 

 general principle. We indeed already know, that the watfers of 

 the ocean in the Pacific, and in the Atlantic between the tropics 

 wliere least obstructed by land, move at and near the surface, iti 

 a similar direction, nearly and generally, to that of the wind. 

 When obstructed by lands, they take the various turnings and 

 windings, which the forms and trendings of those lands, and 

 other local causes, impose on them. 



If it be allowed, that the influence of ^' the sun, in rarefynig 

 the atmosphere to the greatest degree between the tropics, to- 

 gether with the earth's rotation on its axis from west to east, 

 would produce (if no land intervened) a constant wind from east 

 to west," may we not suppose, if the same causes operate si- 

 milarly, but proportionably, on the waters of the ocean, that 

 they must produce a similar effect, and oblige them to take a 

 like direction ? That is from east to west, at and near the sur- 

 face 



