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492 r N E lT M
Dra'" Mp rhe ~ .I"r ~ , :\n I (Cl th ~ fpring u:,o'1 the
r íos as before i t:lcn covc:r Ihe machir.c w¡ d , , he rcct.:ivlT M
(ñg. 8 .) ur on the: pump phut", anJ il.lIl1l1g cxh luilcJ lb!!
n:ceiva of dir, p~)fh dUWIl Ihe wire PP (dllo\1gh tlH~ collar
of leathers in the neck q) Ilpon Ihe Oíd::. ; \' .. hj~·h will ,Iir.
cn¡;~ge ir fr(!ln (he pio!!, ..nJ d.llow the mili s 10 turn rauno
t-y Ihe.: impu lfe of che fpri,lg j ar.d as thtre is no 2.i r in lhe
r~ cei ver to m:lke aany íl!nlil.>k rcf'ifbn cl! :1.gaird1: tht m. thc:::y
wiJJ both nhH"':: a confider.ú le .im~ looger than they did in
Ih!. open ai r; anJ Ihl:! moment Ih:H one (laps, lhe o: h cr
wdl do ro w O. - Thi s OH:WS th:ll air rdiHs bc:A:iil..'s in mo ·
tion, and thal t qUA! b,ldi<:s mee! \Vilh cid'f.erent rlegrecs of
rr:f1 ildocc, acco rJi ng as lh,y prefl!nt gn:<ltcr or furfac.:es
10 Ihe ;¡;r, in lhe pllnes or t!H·ir mo:i\Jns.
2 . 01:' lhe rcceiver lit (r.g. 11 .) .nd lhe mi lis; ' Dd
havi ng pUl ¡he &uint'<l ti and hn h IlpOO lhe hr;¡() flap e,
turo up the flitr. ;md fllU l il inlO the: nOlch d. T heo, pat·
t ing a ·w ...[ le-tth: r o" er th e top of the tall r~ct'iver AH (i t
being opeo bo:.h al (OP and hflIlO~) Ct:..vü iI wi dl lhe f 1.ste
G, froOl which lhe J.!uine:l and 1caIher tongs ~J wiil thetl hang
'yirhin Ihe re.cei ...er. '1'hts d(me, the air OUt of lh!
Jecciver; and lhen dr:\w up lhe: \Vi re/a JinJe, whi~h by a
fq u:\re piece on ilS Jower cnú wi!J apeo lhe tongs ~d; aod
the flap f:dl ing do Vil , as :H (:, lhe gui nea anJ f~at ller will
d-::fcend Wilh equaJ v ~ hciti::s in lhe rr.c.,jver; aod bOlh wiJl
•:dl upoo lhe pump_phu: a l rh,~ [ame ¡nf1ant. N.B . In ,his
experiment, lhe obfen 'er ; o'Jtbl not ft\ lo~.,k at (he top, but
~t the bottom of the rece¡v.!r ~ in order to fte Ihe g'.Ji nea
and fe~\ther fa ll l1 ?on the othcrwire, 00 account of
9uicknef, of lheir mo'ion, lhcy will the (ght of
¡he b: hoJ¿en.
' l!. r ojh,," ID' wúghl of lh. airo
l . H ,wing fitt ed a bfafs c;¡? with a valve tied over il, [O
t:le m0Ulh of a thin bonl: or Florence fL.r¡(, whort: ccn–
tenes a:-e exaé1ly ka own, fcrew [he neck of t11is ~ p in:o I!)"!
hale i of [he pump .platl! ¡ th.!o, Inving ex.haufied the air
out" of the fhJk, and takcn it off from the punlp, let il 'be
fufp.!nded at one cnd of a b.dance. ..n:l niccly cou nterpoifed
b"y weigh's in rhe fc ale al the othcr end ; this done, n ¡re
up Ihe val v~ wit~ a pin, : the air wilJ rulh into the f) ;.O,
w:th an alluible r.oif~ ¡ during whieh time, the flJO< will
dcrecnd, and Full cluwn end of the be;;."., Vtoen rbe
noif:: is over, pUl as r:Jany grains ioto the f:ale at the otlla
éno :!.s wi ll reHo:-e the equiJi~ rium; 2nd l~ey \....ilJ :lL~',\' ex·
atUy the wei~h t of t:-ae qll;tntiry of lir ",hic:, has go~ iOlo
lhc A,I!c, .nd fitl.d iL If lhe Dalle hoLI, .0 '''.:él 'lu"t,
it will be f..:>uorl, tI:Jt 17 grt\ins wi!l r eHor~ ti.:: cqlii!~o:re of
(he b,d .a[;cc, wht n [he '1U1 kfi l\'er fiands at l e¡} 1OC'r,CS in
t he b<t rom("It:T; which (h ~ws, tbat when rhe 3i r IS il..t a ;Hl
r~te o( J ..:n!ity, a C¡WlrI of j, weiglrs J 7 grai,ls ~ i\ wcighs
H1NC W:l~O e::! quiddil\'er Ha:tGS hi:;hcr, anJ Ic:fs wh..::n i[
nAnaS IO'Ner.
2. PI . ce lhe fll'JII recei." o ("l:. 8 .) ol·er lhe hole i
in lhe pllrnp Il:~rc.; and uron t!xhallff ing t~C airo ,he recej ·
" t:r \"Ji l! !IC Ji )Ceo cown 10 the pl,Ht: l:-r the pre(fure of lbe
air ón il!: OUI E./e, which is Icft, tO aét al.:>ne, witho\1t any
air in Ihe rc.:c~¡ver 10 atl tI¿;,i:l lt ii: ~nd lhis prdr.: re will be
C(Jll ti ~o ~s í1lany til':1C:s 1 ) /.mlt1rl~ . as th ere are fq\lare inch·
es io th1t par! <.f lhe pl,He \~hic:1 ch~ rc.:celvcr covers¡ whi('h
wilJ hn!.t Jliwn Ihe recei"cr (o f.• n, th.u ic C<lnnot be gn
ofr. u ! the ai r be! h: i:~~u it ~y u:rnir.g lLc co.:;,- k ; and
t!\l'¡) it b,:,,:oOles !oc f('.
A T e s.
3· S{!t tI.e Ji·d e g!Jfi A O (~~ . 12 r (whk!l ·i.i O?c~ at
bctb cnd.•) over the h:,!c i uroo the rllmp·pltt te LL, and
pl:t yvur h 10" dof~ U?,)¡') lhe tO? of ir :ir R : th en upon
exhaiJfbng th: 2.i r om oi" lhe gl;¡,f3, you \ViII fiod your IHiOd
prdl::d OOWiI wirh <t. gledr weight upon it j fo 111M Yf}U can
J¡¡¡ rd ly rek,d~ il, ,hcair b~ re!\dmitled imo th.-: glafs by
(U rniog Ihe cock .f ¡. which air, by atl-ing as lirongly up.ward
ag:tioa the I~;¡ nd as lhe external ..ir 3ét<:d io prenillg itduwo–
wilI reltaf.~ the IIt\od frol1l in confinemenr.
4. H .iI·ing tieu • piece of wet bl. dder b (fig. 13.) over
lhe open lO? of lhe gbfs /J (which is .Ifo open at bOllom)
fet il to d ry• • nd then the . r witl be ligllt like a drum.
Then lhe open end /J upon lhe pump pl.,e, over lhe.
hoJe i l anu begin tO exhiluf1 tlJe air out uf the glafs . As
tl:!e air is <:xhauHing, its fpring io the glaCs \ViII be \Vc:tktoed,
apo give w:ty' to the prelr:J re ofthe outward air on 'the bJat!·
dcr, whic!l. as it js pre(f~d down, will put on a fpherieal
conctlve ~gure, which will grow dceper and de!:per, umil
the (! ,·cngth o'f lhe l' l.dder be overcome by lhe weighl of
the 2i r ; aod lhen it will break \Vilh a repon as loud as that
o( • &u n - Ir. fl" piece of glafs be " pon lhe open lOp
o~· this rec...iv~r, and joined lU it by t\ 'fllt ring of \Vet Icather
betwctn th~m ; upon pumping lhe air OUl of lhe receiver,
lhe prclfure of lhe outwud air tlpon the H" will break
it all to pieces.
5. Tmolerfe lhe neck cd (fig . '4.) of lhe hollolV glafs b.U
tb In waCt:r, cootaioed in the phial QQ; rhen fel it upon (he
pUOlp. plare. and coror ir and the hoJe i wich the clole recei·
v~ , Ji; and then bcgin tO pump out the ¡¡ir. As cbe.air
gOfS CUl of liJe recelVer by in fpring, il wdl . !fo by lb7
fam:: means go out of lhe hollow b?·U ~b. through the neck
de, and rife IIpin bl111bl!!s to the furface of tbe water in the
phi al j from whcnce it wiJl make in w:th th'c reCl of
t ~e ai r in the r~ccir'erJ throup,!l the air.pipe ce ano valres
o and b, iOlo the opeo ...ir. ' Vhen ir has done bubblingin
the pllial, the ball is fufficie::ltLy eli:haufied i and theo, UpOR
turning the co!:k k" rh e air wll l get ioto the' recei ver, and
pr<fs fo up-on the (ur(<lce of the water in lhe phlal. as co
force che water up intO the ball in a j et, rhrough (he neck
cd, .od IV:!I fill lhe ball . 100ol! f"tI of water. The re, fon
why t!le ball is n Ol quite filJ ed, is bee..1ufe 0111 lhe air could
nOl be token OC" of ir: and lhe .f.lI.n 'lu.nlily lb" w., tefe
in , , nd had ex pJorld ilfelf fo " la fi ll the whol. ball, i·s
oow cúojenft d ioto th e (ame nat! as the out warJ airo aOli
rem.:i ns in 2 (maJl hu,ble . , lhe lOp of lhe b.1I ; and fo kecps
the wa!cr frolll fi:ling ·t ha~ pan of the ball.
6 . P ou r focle q uickr.I" er into the jar D (fig. 15.) and
(~f il on t~)e p'J \lP pIate near the holl' i; lhen fee on lhe
td!! o?~n recei,e r AB, (o t\s to h~ nver the jar anJ hole ;
anJ covc!r the récciver with rhe brafs pl:tte C. Serew th.:
opcn glals tllh:/g {which has <l :i ~op on it at h) ioto
the fyri nge H¡ and puttiog lhe tube throug'l 3. hole 10 tlle
middleof the plale, Co as to immerfe the lo\V~r eod oroth!:
tube e in the qui:ktil\'e. at D , fcr~\Y rhe end h of (he (}'r
ioto the plal~. T h;s dllne , dl"aw U? the pillon io the frr~ngo
by the ri:1g r, whicil will Illílke a v..cuum in the ryTlng~
bdow tht: pil~o:l; a!1d as the up?,'r end of the tube opl n.,
ioto the fyrinr.e, lhe air \ViJl be dil:.ned in the tubc, bcc~u'e
r t\rt of it . by ilS fpring o gc:s up inro lhe fyringe; and lhe
filrin~ of the uoJil.1tcd ¡¿Ir in the r~ee¡vcr :4~ior. uroo the
furf.t...:e of tht.' qlli.:k(jh·cr in the: jaro will forc~ p trt lo! Ir ep
ioto Ihe lube : for 1he quickli/vcr will follnw lhe pt1ion In the
fyringe, in lhe r.~mc \Yay, anu fOl" the reafoo, th.a wa·
la