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hut upon lelling lhe air ioto the rcceiver again . tO prefa upon
the applc:, It \Vdl ir.flantly returo la ics [urme, dc:caycd ¡ilOd
fitriveJl<J lIate.
~ 3. T,.ke a rrdh c~~• • nd Cut off • lit. le o r lhe fhelJ aod
.film from in fm J!ldlcuJ; lhen pUl (he egg unocr a I(cciver.
and pump out (he í1i r; upon which, aH ,he ConteSlS in the
~r.J: will lJe (orced OUt imo lhe receiver, l>y~thc: c:xpanfion uf
a fmall bublllc: of Olir cootaioed iD tbe greal eoil, bClw~cn the
/heU and film.
~4' Put fbme bc:c:r in a gl.lf5; and hilving rel it on
~hc: pumr, cover it with a cloCe rcceirc:r, and (hen exhaull
the airo V/hilll this is doinn. and lhcreby thc prelTure more
and m:Jre takcn off from the bccr in lhe: glars, ,he ¡ir (here"
in will expand ¡trelr, and rife up in innumerable bubbles tO
ahe furface of fhe becr; ílnd fram thence it \ViII be: taken ¡–
way Wilh the ol:ler air in rhe receiveJ:. Wheo the rchiver
is near exhaull:ed, ,he air in [he beer, which cO:.lld nor dif·
e.ntangle itCdr<Pliek enough ca get off with the refl, will now
expand itr<ir ro, .. to e¿ure ,he bce, tO have all the ap
pear.nce or boiling; and the gr.atell part of it will go o·
ver the ~Iars.
25 . PUl fome warm water in a glars, and pUl a bit of
dry walnrcot or other wood into the water, Tben, cover
the' glars with a cloCe receiver.· and exhauCl the air; upoa
",hich, the air in the wood having Jiberty tO expanq ¡t–
felr, will come out plentifully, aod make ,,11 the water lO
hubble about the lVood, efpeei.lly about tbe ends, be9,ure
the poces lie lengthwife. A eubic ineh or dry w,inrcot has
fo mueh air in it, that it \ViII eOlltioue bubbling roe Dear half
An bour together.
O. WINDS,
AS the .ir i. "Ruid, fubj.-é\ed to the rame I.w. or gravi–
tatioo as orher Auids, it necclT¡Jily ~as a conl1ant tendency
to preCerve an equilibrium in cvery pan; fo rhat, if by any
means whatcver it is rendered Jighter in any ooe place than,
abother, the ~eightier air will lufh in from evc::r)' fide too
wards this place, tilJ as much be there accumul.ued as makcs
it or an equal \Yeight with the rell or the atmorphere: lt i.
,heCe CurrentS of "ir which are called 'WindJ.
Many are (he cauCes which may TaPJ the weigh( of the
atmorphere, an.d occa}ioD pttrticular topieal winds.
Although other cauCes may oecalion winds in certain cir·
cumflances, yet their principal and morl univerCal caufe is
~he fun, which warmeth the ..air to a mueh greater dt:gree
In Come places of the atmoCphere than in otheu; and as the
air is CuCcepublc of a Rrcat degree of cxpanfion by heat in
thoCe pb. ..:es where it is heatcd (o any confiderable degree,
it is expADdod fo mueh as te become lighter than (he .ir in
'~oCe plae~s where it is colder; fo that the weigluier cold
atr from all the circumjacenl p¡ns rul'hes towards this poinr
to rellore the equilibrium whieh had been dellroyed So
,hat if tllere be any particular pan upoo the earth's filrface
where t..he Cun alh conflantly Wilh grea1er fo,"ce lhan 00 any
other part, a Curren( of ..ir VIiI! coofhntly flow rrom thefe
'owarcls the warmer regiün: bu( the fun alh with greatc:r
force upon thoCe parts nf the earth which are nearel1 the
Equ::ltlJr. Ihan thoCe whieh approach (owards either Po/e'
fo rhu we migh[ naturally expea tha( a wind would con:
Ih~d y .blo·v from rhe poJar r~gioDs towards lhe Equittor i
whlch IS re:llly found tO be the caCe in the To,.rid ZDIJ~,
4IIhere ,he IOftuence of the fun overcomes ::Ilmon all the o·
taer IdTtr e~utes w"'kh produce rhe variable winds io our
VOL . Il!. N°. 89. ,
A T e s, '1 95
more nOflherly regions. H owever, even lO lhe T orrid Zoo(",
th~C~ oonh and (o\uh winds are v.'..ried in ¿ifFerent ways.
,Altbough lhe h~at of ,he equatorial region ¡s greilter
than aoy o:h.a; yct as lhe !un ~as In his
diurnal courre upon one poi nt of the elluator onl)' at one
time, and immcdiately p.¡(fc,:s over it; and as tbe air retaio.
the heat communlcítted to it by the Cun bUI for 3. Iban tiole,
cooJir'6 gradually as he 'retires, ",nei continuing l1ill 10 dc:·
creaCe tiJl his ¡nfluence agaio returns lhe d.¡ y; the
degree of heat upon this great ci rcle mua be vc:' y di!fc:rer.t
in differeot p.lrts, and perpetuaJly varying in tvery poior;
wilich n\un in Come meaCure lend tO dinul'b thoCe wlnds co ..
ming from lhe polar regioos, which \Ve h~vc already meno
tion.d , To eompr<henJ c1e.rly what will be ,he elfetls of
this 'rotation, Jet us confiJer what tfFl.:l1: it \\'ould naturally
produce upon lhe equator with regard to wind, Cuppoling
no orher cauCe fllOUld inrenupt it. And here we muO obfervc.
th.H as lhe poiot upoo which the fun aas Wilb the greatdt
power is coo(1..otly moving from eaO to wefl. (he air 'o lhe
eaelof lha! poiot over whieh the ruo bas more 1"e1y palToJ
\LIilt be .more rareG!d tban that tO the werl, and wdl natU ..
nlJy Bow towards that point froOl eaO lO wefi with greater
veÍJcity (han (rom well to eall, as lhe cool air [O lhe wefl
of tIJat point \ViII be ioterrupted in its motion '{owards! t by
t he motian oC (he Cun O1~cting ¡e. H ence thcrc:rore;t rollows,
that (rom che diurnal motiao of che eanh [rom wcll tO taO:
a coollant can Wifld would always be produced, were it not
obflruéted by other cauCes. But as there i~ a conllant {frcam
of air Bowine [rom the polar towards th~equatorial regionS:i
a comporition of thefe (1,1,'0 curreots of air aéting at .the
{ame time wiIJ produce a nonh-eall: wind in all parts of th:
northern hemirphere, aod a [outh.eaH wind in alJ parts of
the routhern one. The[e winds are known by me n.OIe of
Ihe generaltrade.windJ .
Ir there were no inequalities on che furrace of our glob~.
and ir il wer. eompofed of a rubltanee:pcrretlly hOOlogcneou.,
this .....ind would invariably tak~ place at aJl times on every
pan of the earth's furface: but as this is not t..he il is
liable to Ceveral very confidc:rable variations . In all thoCe re_
gions towards the potes, as the ¡nfluence of the fan is tlll:re
but wedk, ethcr le{f~r cauCes oceafion parrieulcll wu:ds . and
diflurb that rcgularity which at G¡[t ..iew we ruight expcét.
Ca the gr:ner.11 traJe 'Wind does not invariJ.bJy plJce
b'yond lhe 28'h or '30'h degree or latitude ; and the regiQn.
between that and the pales have nOlhiog but v. riable windl.
Even in the Torrid Zone, there are O1;ny cauCes which in
panicular pliKes alter this direélion of the WiDd, Ca thac
the genlline trad~_'l.JJind, do oot tak: pl..¡,ce except in the
Atlantic and P.. cific ocean, 00 each lide the .t:qua(or tO rhe
difl ..nce of 28 or 30 degrees, and io tht" greatell pan of the
I ndian ocean tothe fouth of the Equator as appC:::Irs. more di –
Hintl ly "pon lhe M AP ; rce Plate CXLVI. where lhe courre
of Ihe winds :lre markcd bythe direétioo of thefirr.lCJ, the
dartl poinnng in the {ame direétion as the wind blows.
H avins thus explained (he nature and C.lUres ofthe 6ene.
ral trade wiod, we now procecd to take notice of the prin_
cipal deviations which take place in the Torr-id Z one. The
general tr::lde.wind. whcA thus altered a( rarticular feafons.
is known by the name of 1nonftonl. Thcre a~c: orher varia ..
tions, which, although aS general, are yet of fnulJer :ind more
limited influence. Thefe arc known by the name of " 1".0<"
%(1; and as th:y blow periodieally ' rrom tho rea. t h,y
are Jenominated (ea or /afUi ~ru=(/; and takt place: m Of l.!
6 1 t Or