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Show ( So NOTE XXXIII.--WINDS. IVbi!e (outhern Gales o'er 'Wrjlcrn ocea1ls roll, And Eurus Jleals his ice-'Zvindl·from the Pole. CANTO IV. I. 15. THE theory of the winds is yet very imperfeCt, in part perhaps o\-ving to the wa~1t of obtr ervatw· ns {iu ffi ci·e ntly numerous of the exaC1 times ami places where thbe y behg. nI t and ceafe to blow, but chiefly to our yet imperfect knowledge of the means y w IC I reat re ions of air are either fudJenly produced or fuddenly dcflr~yed. . . . g The <gJ. ir ·IS perpetua 11 y f ub J'e Cl: to increa' fe or diminution from It.S combmat10n With 1 • other bodies or its evolution from them. The vitnl part of the atr, cal.lec oxygen~, IS contm· ually p' ro du ce d m· t1 u · sc 1·t ma. t e f,r om the perfpiration of vc.g et~bles m . the furdhme, 1 . ·mel probably f rom t I1 e ac.nu·o n o f J'Ioo ht on clouds or on water 111 the troptcaf lc ltm.a tes, 'w here the fun has greater power, an d ma y exert fome yet unknown laws. o umtnous combination. Another part of the atmofphere, which is ca~led azote, IS p~rpet u~lly fet at liberty from nnimal and vegetable bodies by putrefacbon or combl~ll:Ion, ft ~>m many fprings of water, from volatile alcali, and probably from fixed alcalt, of wht ch I . x11auaJ.ers fource in the water of the ocean. Both thefe compot:cnt parts t 1ere IS an e" n 1' · h' ] of the air are perpetually again dimini!hed by their conta~ w.i th. tl~c fod~ w IC 1 covers the furfaccof the earth, producing nitre. The oxygene IS dumndl1ed 111 the prod~ction of all acids, of which the carbonic and muriatic exifl: .in ~reat a?uncbnce. 1 he azote is diminifhed in the growth of animal bodies, of wh1ch 1t COI~(l:ttutcs an impor-tant part, and in its combinations with many other n:~tur~I. produC11~~s. . . . They are both probably dimini!hed in immenfe quantities by uniting With the Inflammable air, which arifes from the mud of rivers and lakes at fome feafons, when the atmofphere is light: the oxygene of the air producing water, .and the azote producing volatile alcali by their combinations with t.his infl a.mt~ab l e :m. At 0thcr feafot~s of the year thefe principles may again change thetr comb111at10ns, and the atmofphenc air be reproduced. Mr. Lavoifier found that one pouml of charcoal in burning confumed two pounds nine ounces of vit:~l air, or oxygene. The confumption of vital air in the procefs of making red lead may readily be reduced to calculation; a fmall barrel contains about twelve hundred weight of this commodity, 1200 pounds of lead by calcination abfor.b ~!bout 14'~ pounds of \'ita! air; now as a cubic foot of water w<.ighs 1000 avcrclupots ounces, and as vital air is above 8oo times lighter than water, it follows that e1·ery barrel of red lead contains ne01rly 2ooo cubic feet of ,·ita! air. If this can be performed in miniature in a fmall oven, what may not be done in the immenfe elaboratories of nature! Thefe great elaboratories of nature iP.clude almofl: all her foffil as well as hc.r animal :md ve£et<lble productions. Dr. P1 icftlcy obt:\incd air of greater or Iefs punty, both NOTE XXXIII. 8z vital and azotic, from almo!l.: all the £off1il fi bfi h . u ances e fub,ecred t · ounce-weight of lava from Iceland he t d. J o expenment. Four meafures of air. • a e m an earthen rete r t yt·e ld ed twenty ounce- 4 ounce-weight of 7 ---------- 2 ---------- Jf ---------- 1 -------- 7 4 4 4 5 3 3f 4 2 2 2 4 3 X 2 ! ---------- ---------- lava bafaltes toadftone granite elva in gyp fum gave blue Date __ _ clay __ _ limefl:one-fpar __ _ limeftone chalk __ _ white iron-ore __ _ dark iron-ore molybdena fl:ream tin fl:eatites barytes black wad fand fione coal 2o ounce-meafures of air. I 04 - - - . _ • • • _ _ _ _ _ 40 - - - - - - - - - - - - - 20 - - - - - - - - - - - - - 30 - - - - - - - - - - - - - 230 -- -- --------- 210 - - - - - - - - - - - ·- - - 20 - - - - - - - - - - - - - 8jo - • - _______ _ : _ 11 6o - - . _ _ _ _ _ _ _ _ _ _ 630 - - - - - - - - - - - - - s6o - - - - - - - - - - - - - 4I 0 - - - ________ • _ 25 - - - - - - - - - - - - - 20 - - - - - - - - - - - - - 40------------- 26 - - - - - - - - - - - - - 8o - - • - • _____ • __ 75 - - - ---------- 700 - - - - - - - - - - - - - In this account the fixed air was previoufly cxtran d c h 1· fi b · cte JCOm t e 1me ones y actds and.the heat applied was mu~h lefs than was neceffary to extraC1 all the air from th; bodt.es employed. Add to thts the known quantities of air which are combined with the c::llCJform orcs, as the ochres of iron, t~anganefe, calamy, grey ore of lead, and fome idea may be formed of the great proc!uchon of air in volcanic eruptions, as mentioned in note on C~unda, Vol. II. and of the perpetual abforptions and evolutions of whole oceans of atr from every part of the earth. But there \~ould fcem to be an officina aeris, a nwp where air is both manufaC1ured and defiroye~ m the greatefi abundance within the polar circles, as will hereafter be fpoken of.. Ca~ ti11S b~ effc.:led by fot~e yet unknown law of the congelation of aqueous or falme .fluJds, wht~h may fet at hberty their combined heat, and convert a part both of the a~~~ and alcal1 of fea-water into their component airs? Or on the contrary can the eleC1nctty of the northern ligh ts convert inflammable air and oxygene into water, whilf!: the great degree of cold at the poles unites the azote with fome other bafe? Another ~fficina aeris,. or manufacture of air, would feem to exifi within the tropics or at the line, though In a much lefs quantity than at the poles, owing perhaps to the acrion of the fun's light on the moifl:ure fufp ended in the air, as will alfo be fpoken of hereafter; but in all other parts of the earth thefe abforptions and evolutions of air in a greater or lefs degree arc perpetual I y going on in inconceivable abundance; increafed probably, and diminilhed at different feafons of the year hy the approach or retroceffion of the fun's light; future difcoveries mufi elucidate this part of the fubjecl'. To this fhould be added L |
