OCR Text |
Show vVINDS. NOTE XXXIII. that as h.:at and elechicity, and perhaps magnetifm, :ue k1:0wn to di!place air, that it is not impofli b\c but that the increafed or diminifhed quantit ies of thcfc fb ids cli!fufc:d in the atmofphere may incr(a fc its "' eight as well as its b 1lk; fincc the ir fpecifi_c :.1: tra8 ions or affiniti es to matter ll l"l.: n ?ry !hong, th ey probably a\ fo poffe fs gcner::!l gr:mt:HIO ll to the e:trth ; a fubjcCl: which \\"ants fu rther invefl:igat ion. Sec note XXVI· SOt ' fiJ . WEST i\'1 t\ DS. Thev<:lo.:ity of the fmL.ce of the nrth in movi ng round i1 axh diminifhes from the equator to the poles. \ Vhencc if a region of air in this coun try fhould be fuddenly removed a few degrees towards the north it mufl: conflitutc a wefl:ern wind, becaufe from the velocity it had previouily acqnired in this climate by its fri ct ion with the earth it would for a time mo\·e qu icker th :m the fur!'acc of the country it was removed to; the ontrary muft en fue when a region of air is tranfported from this country a few ocgrecs fouthw:~rcl, bcclllfe the velocity it had acquired in this climate would be lcfs than that of the ea rth's ll rface where it was removed to, "hence it would appear to conltitute a wind from the eaft, while in reality the eminent p:t rts of the earth would be carried <Jgainll the too flow air. But if this tranfporuti on of air from fouth to norih be performed gr~du <J ll y , the motion of the wind will blow in the diagonal between fouth and ·wefL Artd on the contrary if a region of air be gradually removed from north to Iouth it would alfo blow diagonal\y between the north and call, from whence we m:1y fafely conclude that all our winds in this country which blow from the north or e:tfl:, or any point betw cc.n them, confi(t of regions of air brought from the north; and that all our winds blowing from the fouth or well:, or from any point between them, arc . regions of air brought from the foutb. It frequently happens during the vernal months that after a north-eafl: wind bas paned over us for feveral weeks, during which time the barometer has fl:ood at above 3of inches, it bc:comes fudder.ly fuccecdcd by a !outh-wefl: wind, which al!o continues feveral weeks, and the barometer finks to nearly 28-~ inches. Now as two inches of the mercury in the barometer balance one-fifteenth part of the whole atmofphere, an important quefl:ion here prefents itfelf, UJhat is become of all this air? r. This great quantity of air cannot be carried in a fuperior current towards the line, while the inferior current flows towards the poles, bccaufe then it would equally :~ffeet the barometer, which fhould not therefore fubfide from 30-i- inches to 28 ~ for fix weeks together. 2. It cannot be owing to the air having lofl: all the moifl:ure which was previonfly diWolved in it, becaufe thefe warm fouth-wefl: winds arc replete with moifl:ure, and the cold north-eafl: winds, which weigh up the mercury in the barometer to 3 r inches, c.onfifl: of dry air. 3· It cannot be carried over the polar regions and be accumulated on the meridian oppoll~e to us in its paffage towards the line, as fuch an accumulation would equal one-fitteenth of the whole atmofphere, and can not be fuppofed to remain in that fttu<Jtion for fix weeks together. NoTE XXXIII. WINDS. 4-· It cannot depend on the . fl: 8 3 f1 d CXI ence of tides i th corre pon to lunar periods N n e atmofphere fince 't 1l: th . . or to accumulation f . f: ' l mu then e upper regions of the atmofiphere fin . s o air rom the fpecific Ievit f its tenu't d ' ce Jts degree of fl ·d· Y 0 I y, an confequemly fuch great . Ul lty mufl: correflpond w· h for fo k mountams of a·. lt many ':ee S together as the fouth-wefl: winds {i II _can not ~e fuppofed to exr{f: 5. It remams therefore that th<: It b . orne tunes contmue. f . . re IIllln e at thls . o. air m ~he polar circle by fame unknown o er tl.me a great and fudden abforption wmd runs m to fupply the deficiency. Now asp . atiOn of ~ature, and that the fouth from a part of the earth's furface wl. I this fouth WJnd confills of air bro h 1t I uc 1 moves fait h . ug t mun laVe . h d a. t the fame time ad "Ir e cl:'J On f rom the w, efel:r bt an J.t .d oes in this cJ"J tnate I. t It d a prevJOufly acquired. Th CrJ e r l . y rctalnmg part of the I . lOlli 1-Wefl: W d . Ve OCJty an becoming colder by their contact \\ ith h 111 s commg from a warmer country expanflon, (fu great a part of the f' . t e earth of this climate, and by th . ' c· 't h . upenncumbcnt :.1tmo~ 1 I . e!r 'P' ate t Clr moiflme. and I . . p lcre 1avmg vanifhed ) I . ' as t 1ey conunue fo [, 1 , prc-po ar Circle would fl.!em to rcce· r evera weeks to be abforbecl . h . 1\'C a perpetual fu 1 f . Jn t e over the lme, a~. will hereafter be fpok cn of. pp y rom the tropical regions, efpecially It mt~y fume tunes happen that a no th n . . be n t d own an d d riven back befo·· . h r -ca., l wmd hav lng pa ffic c I over us may b l fi 1e Jt as ::JCqlllred any h f. e t ms or a few hours or a d h fi eat rom the climate and f . ay a\'e a OUth-well dir Cl. ' may rom a higher region of the atmofphe ffi e Jon, and from its defcendino- . fi . re may po efs a gre t d o m enor north-call: current of air. c a tr egree of cold than an The extreme cold of Jan 13 P . d ,. . . · ' 1 7oq, at ans came on .-.h an was OlmmJOled when the wind cf;an I h ~~" :t gentle fouth wind Mr. H amberg from a reflux of a· 'h.glcch tdo t e north, which is accounted for by' h , lr w IC 1 a been flo . fi fi nort . Chemica\ Effilys by R W [, V wmg or orne time from the It ma } at 011 ' ol. V. P· 182. ~ 1appcn that ~ north-eafl: current rna for produce mccfbnt rnin by mixing ' "tf l . c Y_ a day or two pals over us and I VI .l t !C ,n,enor {; h fl: we I as the former is of fhort duration as ·, f ·c:r .out -we current; but this as ::~long with it, and dry or fron:y we th' ~_lsi rll wn wdl foon carry the inferior current a er WJ t len fuccecd. NORTH-EAST vVJ:\'DS. Th~ r:orth eafl:. winds of this country confiH of re io . travelli ng fomctimcs at the t f b . g ns of :llr from the north • ra c: o a OI~ t a mile 1 t · . ' months for fcvcn l weds to th f h n wu mmutcs dunng the vernal ' ' ge t:r rom t e polar reg i on~ t d h r cmy in the b:u ometcr fia d. b • . • owar t c wuth, the mer-b n ln g a ovc 30. I helc v. irr!s co fill f . y the cv:.lporation of the ice and f . I. h . . . n l o aJr greatly cooled b I . . now over \\ lie It p lffes and as tl b y t l e ~r contaa with the earth f tl . r , . ' ley ccome warmer as the f.. o us c lmatc are C:!p<Jblc: of diffolving more moifiur h y ~a_, along, anJ are thence at tcncb! with frofis in winter ~ nd ' tl d 1 e wcat rr 111 fummcr. u WJ J ry Jot I. This great quantity of · b 11 · contrary direction fro r alr ca~not e upp!Ied by fuperior currents paffing in a h m lOUth to nOJth, becaufc fuch currents mull as tlley '{i . t e atmofph '] . an c Into ere a mJ e or two high become rxpofed to [o great cold as to occafion them L2 |