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Show WINDS. NoTE XXXlli. • ·11. 1 · h vould fall throucrh the inferior current upon the earth to depofit thetr molllure, w nc " o in fomc part of their paffage. . . . . f h . fl have increafcd m qua11t1ty, becaufc It appe:us by 2. The whole atmo p ere mu . , I I h 'fls one-fifteenth part more a1r over liS for many "ee \S the barometer t 1at t ere ex 1 . I · 1 ld t be thus accumulated by difference of temperature 111 rcfpcc~ to <Tether, w 11c 1 cou no . .-. b llatic laws at jJrufent known, or by any lunar mflucm:e. to heat, or y any aeroll ' v . • . • • h · 11 ea· that immenfe malfcs of a1r we1e fct at l1bctty from From w encc 1t wou c app 1 . • • · b' · 'tl r 1· l boc\ies along with a fuffic1cnt quantity of comb1ncd heat, their com matwns wt 1 ro IL , · · 1 · 1 · fomc region to the north of us; and that they thus per-w1thm the po ar crrc e, or m . . . , . . . ' \\ · f th 11 t'rty of the atmofphere · ami that thts IS agam at ccnam tunes petua y mcrea c e qua . . ' . . . . . , re- abforbcd, or enters into new combwat10ns at the lme or trop1cal regrons. :·v wlm:h wonderful contrivance the atmofpherc is perpetually rencwcd and rend red t for the fupport of animal and vegetable life. SOUTH-EAST WlNDS. The fouth-cafl winds of this country confdl: of air from the north which had paOcd by us, or over us, and before it had obtained the velocity o_f the e:uth's fmf~ce in this climate had been driven back, owing to a deficiency of a1r now commencmg at the polar regions. Hence thefe arc generally dry or fr~ezi~g winds, and if they fuccced north-eafl: winds ibould prognoflicate a change of wtnd from north-cafl. to fouth-we!l:; the barometer is rrenerally about 30. They arc fometimes attended with cloudy weather, or rain, bowing to their having acquin:d an increafed degree of warmth and moill:mc before they became retrograde; or to their being mixed with air from the fouth. 2. Sometimes thcfc fouth-cai1. winds confifl of a vertical eddy of north-call: air, without any mixwre of fouth-wefl: air; in that cafe the barometer continues above 30, and the weather is 'dry or frofly for four or five days together. It fhoulcl here be obfervecl, that air being an elai1.ic fluid mull: be more liable to eddies than water, and that thefc eddies mull: extend into cylinders or vortexes of greater diameter, and that if a vertical eddy of north-eaft air be of fmall diameter or has pa!fed but a little way to the fouth of us before its return, it will not have gained the velocity of the earth's furface to the fouth of us, and will in confcquence become a fouth-eaft wind.-Bnt if the vertical eddy be of large diameter, or has pa!fed much to the fouth of us, it will have acquired velocity from its frietion with the earth's furface to the fouth of us, and will in confequcnce on its return become a fouth-weft wind, producing great cold. · NORTH-WEST WINDS. There feem to be three fources of the north-weft winds of this hemifphere of the earth. 1. When a portion of fouthern air, which was palling over us, is driven back by accumulation of new air in the polar regions. In this cafe I fuppofe they are generally moill: or rainy winds, with the barometer under 30, and if the wind had previoufly been in the fouth-well:, it would fecm to prognofticate a change to the north-eaft. NoTE XXXIII. WINDS. 2. If a. curr.e nt of north wind is 'palling over us bu t a few 'I 1· . . cafterly dJreetJOn; and is bent down upo . . ffil es 11gn, Wtthout any I . .n. n us, It mu{l: unmedi:lt I Hi f: ( tre\;oon, becaufc it will now move f'a ller th ant he {iu r1ca ce of the e Y1 P0h e s .a we!. terly and thus becomes changed from a 1101 th fl eart 1 w ere tt arnves ; I 11 • ' -ea to a north-well: wind Th d r n,o rt 1-eaa current of at r proc!Pci ng 'a llOrtl1 We1l1l • d · e e1ccnt of a Wll1 may · fi clear or freezing weather as it moy b r. 1 . conttnue ome days with ' e ump y owmO' to a . I dd eafl: air, as will be fpoken of below It I ·r b ' verttca e y of north- . · may ot Jerw11C be forced d . b fouth-wcH Wind paOing over it ' and itJ tlJ.1 5 ca1r e . 'II own y a c~rrent of It \\1 be attended · 1 • c days by the mixture of the two •a irs o.f d'r£rrr,c rent de greesof heat. andW wll'1ll ram 10r a. few a change of wind from uorth-eafl t fouth weft 'f tl . d ' I prognofilcatc e:~lt quarter. ' - 1 lC wtn was pre..-iou!ly in the north- 3· On the eaflern coafl: of North America the north-well . d b . f I fl. • d d . . . n Win s nng roll a~ til nort 1-ean w. m s o In thts conn try ' as app ears f rom van.e ty of teflu. non Th'' fl~ e to happen I rom a vertical f piral eddy made in the atmoliph b I y. rs eems . d t· . . ere ctween t te lhore and th nf ge o m. ountams wh1ch form the fpine or back-b one o f t ha t contm. cnt. If a currenet o w1 ater l1 1.1 1I1 5 al.o ng the hypothenufc of a triangle an ed d y . ·11 b d · . WI c rna e 111 the mcluded ang e,d W llfC 1· wdl turn round like a water-wheel as the ftrea m pa (l'e s · · 111 contaCl: with one he gef to ·rt t. The fame muft . h<ippcn when a lheet of air fl owt·n g a1 o ng fjr om the nort -ea rt1es from the fhore 111 a ftraio-ht line to th r · f h A . . b e Iummtt o t e palach1an mo.u nta·um s, a part of .t he fircam of north eafl air will flow over the tn oun t at· ns, anot he r ipba t t WI rev· ert· and ctrculate fpirally between the f-nwm· mit of the co un t ryan d t he ea111L ern ore, contmumg to move toward the fouth · and thus be h d f a north-weft wind. ' c ange rom a north-eaft to This_ vertical fpiral eddy having been in contaCt with the cold furnmits of thefc moun tams, and defcending from higher parts of the atmofphere will Jofe part of it: heat, _and thus conftitutc one caufe of the greater coldnefs of the eaflern fides of North Amenca than of the European Owres oppolite to them, which is faid to be equal to twelv: degrees of north latitude, which is a wonderful fact, nor otherwife eafy to be explamed, ~nee the heat of the fprings at Philadelphia is faid to b(! 52, which is greater than the mediUm heat of the earth in this country. The exi~ence of vertical eddies, or great cylinders of air rolling on the furface of th~ e_arth, IS agreeable to the obfervations of the conlhuetors of windmills ; who on thl~ tdea place the area of the fails leaning l>ackwards, inclined to the horizon ; and b_clrcve that then they have greater power than when they are placed quite perpcndr~ u~arly. The fame kind of rolling cylinders of water obtain in rivers vwing to the fntl10n of the water againft the earth at their bottoms ; as is known by bodies having been obferved to float upon their furfaces quicker th::m when immerlcd to a certain dept_h. Thcfe vertical eddies of air probably exifl ::tll over the earth's furfacc, but particularly at the bottom or fides of mountains; and more fa probably in the courfe of the fouth-weft than of the north-eafl winds; bec.wfe the fermer fall from an cmin_ ence, ~s it were, on a part of the earth where there is a deficiency of the quantity of atr; as IS !hewn by the finking of the barometer: whereas the latter arc pulhed or |