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Show r' wqu‘mmgw [504] Suppo/z'tz'om and Conjeflun'r towards formmg an vaothefis, for flat) explanation of tbe Aurora Borealis 9*. 1- A IR heated by any means, becomes rar1- tied and fpecifically [lg/afar than other air in the fame fituation not heated. 2 Air being made thus lighter 1‘1fes, and the "(:1 g l1 boll l Ill g CO 0 [e r he aVleI a" tflk€a ltS plACC a 3 If in the middle of a room you heat the air ' or coals neafr thedflgve; b a Prove, or pot ofburnmg . plrgawalq ceding, the to tlile heated air will rife it: i; co the to comes it till air the cooler there being condenfed and made lieay1er,‘v}]iCh tend; to fupply the place of that coo' an dér to had moved towards the fiovedor fire}, ill}: (1:151 af_ t 1-e_ l the lace 0ti the heate 1111' w 1 lu ‘ cehfigd fronl: the {pace around the {toye orcufilation ‘ there Will ' be a contmu 21 c1 "11 _ c 1 "(e ' h may b e r endercd1 V111) in an ' the room ,- w l11C i Thus 4. b; making a little fmoke, for that fmoke vs 111 and circulate with the am It ‘ put 111 ‘ the text '11: or other mark 15 h a1931:., Eingrigegghgpoiidcgith it will be found at the end of t e ' | d the fill)Plece y murdered 3.5 the 3.] thle 1n the [ex t 15 numbered, d The notes lnal be le‘ld ill 1661 Of If there brieflyxecapitulated. leifure. E.] 5. A [M. R] Coly'eflzz/‘e r (250242" theAuroraBor ealis. 505 5. A fimilar operat ion is performed by on the air of this nature globe. Our atmo fphere is of , t a medium [ ve that height it is fo rare as to be almoft a vacuum. The air heated be tween the tropics is continua lly rifing; its plac e is fup~ phed by northerly and foutherly winds, which come from the cool er regions. 6. The light heated air flo ating above the cooler and denfer, mutt {p read northward and fouthward ,and defcend near th e two poles, to fupp ly the place of the cool air , which had move d towards the equator. 7. Thus a circulatio n of air it is kept up in our atmofphere, as in th e room above mentione d. 8. That heavier and li ghter air may move in Eerent and ev appears fometimes by th en oppofite direction, e cl be in thofe currents, as pl ouds that happen to ainly as by the [moire in the experime nt above opening a door between twmentioned-Alto in o chambers, one of which has been warmed, by holding a candle near the top, ne ar the bottom, and near the middle, you will find a {t rong current of warm air pafling out of the wa rmed room above, and another of cool air enteri ng below ; while in the middle th ere is little or no motion. 9. The great quantity of vapour rifi ng between the tropics forms clouds, whi ch contain much eleétricity. "Some of them fall in rain, befo re they come to_the polar regions. T 10. If t t ‘llllllllllllllill-"Wm - |