out. Then turning the cock fo as to re-admit the air gently into
the globe during its motion, the light was broken and interrupt-'
ed, diminifhing gradually,'till at laid it appeared only on the but-
fide of the glafs, where it was accompanied' - with 1 attraction.
Does- it not appear that the 'external air, by its1 electricity, at firft
drives back the eleCtric effluvia of the glafs, which go; then-to
the infide of the globe, -where there is the leaib refiftance? For
we obferve that as the air comes in, it repels the eleCtric effluvia,
that go inwards no longer when all the air is come in. If the
faCt be fo, as the. experiment fhews, is not myconjeCtóre» proved,
viz. that the air is. eleCtrical?
In the reverend and learned Dr. Hales’s Vegetable;?Statics,
feveral of his experiments fhew, that air is abforbed, and lofes. its
elafticity by the mixture of fulphurcous • vapours, fo that. four
quarts of air in a glafs-vefl'el will, by the. mixture of thofe effluvia,
be reduced to three. Will -npt £this; phenomenon fÉjjj ex7,
plained by the different elêCtncity of fulphur and air?1.! he cffli£j
via of fixlphur, being eleCtric, repel one another: and thepadtieles?
of air, ^being alfo eleCtric,. do likewife repel e#ch'other .^yRut the
air being an' HeCtrieof a vitreous electricity, -and-fulphuföóf a’ refif
nous- ele.Cfficity, the< particles o£.air;attraCt thMfe:hf'fu^liürjê.knd
the Molecuke compounded of them,- becoming non-cleCtric, lofe
their repulfivê force.” -.
The judicious reader may, of himfelf, apply this paffage to the
north-light; and perhaps, by a mature difcuffion of it, ftrike out
clearer ideas of that phenomenon,-tkan-r can develop, who only
undertake to fet down a few things, which have occurred to me.
The terreflrial globe, together with its atmofphere,, may be
confideted. as the glafs-globe of the eleCtrical j machine. ,^Upon
the air being exhaufted, and the globe whirled about with'velb-
city, there appears within it a purple flame, andJ this is the-Co-i
lour of the north-light ; now this flame muff be .the aether igneils.
Upon the re-admiffion of thé circumambient air, efpecially if thick
and damp,; the acid or aethereal flre within , is expelled, and^ho-
vers for fome time on the upper furface of the glafs, till, mingling
with the air, it is diffipated, and extinguished. Now this feems
to .intimate to us,?: that the north-light obferved towards the pole
or-axis of, our earth, does not only owe its origin to the aether,
but is the very, aether itfelf; which, being aggregated, gives way to
the
|he lrppreflion of the hurpid ms, .and mounts and flbkts above
the cloudy ^hq^?mpt^pnjtkewife renders *it-variable.'’ Whilff the
; ^ | 5ldry, whiter M # foil's of winter, ‘'or the: heats' ‘of 'fum-
;mer, uor noctJgli|htkis ■ t£$ef feen. Rm Hpon-^weather’i-tegin^
fe?'arthaw after a fliafp froffl;5 o % rains after
heat^and whentlyffe aro.^écedpd, by damp; exfidlatioris,* 1 1
grth-hght>maks forth, as a fiertéSn.prdgnöftic bf' théThange.
forv thefe ^exhajations, ktve^hen, nearly i i M | tffé
^s, the^afqremenriohed1 infrufibri bMhe ait !ihto the
«^ fg^ h fh T fóPellfflg upwards .ithèihghter.ffithereal air, wfieftó
ajtim|^appear^like the purplh, coloured fluid iffuing fflom^thé
A Is ,di%atdd, or mixed again With the* ambient
| | | S ,tilat ffie air near thè^doW^jÈr
M M d W p M B i i i M rebelled
with refi yicdence, ,than;that in § § f i f l l | g g l o b e / *
ForceCe* trifUg PHT 9P ^ tes^ ith a m°te'direct1 dnd immediaté
^flhóüld-this hypbthefis, as indeed I knbW'of ndhettef,;^ apd
o g . nKabl H g { ^ |
known among yhqfe people/o|the northpiwhb hatÊffie heft op-
p°rtpmti|s of pbfcrvmg ,thefe> hghts in the air, that the
:tregxonpf them 1S mot due north, hukrathbr in H H S W
r % Ê k m imagine fth e ,W i | H
Mm to e a f t r . t ó & i n ; ne §llllffIf!IB S * i^ lw 1^11^11^ mil mm a
fftlr So^ig‘Teft, Mand go tothrae l i paft W Ê & the AurorajboreaRs! is |g of ■ knotylege g| WÊÊÊÈ
m ° ers
I mufl afc the reader’s pardon far dyèllidg/fdilong W'this
pacbcular,
JÉquatorè ^ ^ § 4 r‘ S T ‘ 1 k. t° llit’ cum in earn fufa
. clebebit appatere :ni:mnu:f p r o S S j " 'P°nduS atmofPhel’® &pra
fervablones; baroscopic®' quoque evincunt P P ^ maximum; quemabmodumob-.',
m S m S M r r d 1 Vmcunt- Petr- van Mufchenbroek, Elements
Pa^t I. Ê
to