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'V, ,';i,li 





roo TMC INC or coLLcaes and schools. 

Tiii.'iHiXnn isn tmtn rttAH - - ' 


E. ATKINSON, Pn.l>., F.GA 

mimam -or ttmajani.t. •cibkk. BWjtL kiutihi cauwa. luiiiiiiairr. 

C^iil) Cbilion, obUti) anlt tnliqi^ 

tuvanuTKo ht a coiovkko nurs jaa t<a 






Ikl SUmtMU de Phytipu of Profanor Gakot, of wbicb the praMM 
^Bapk m m trwuhbom, luu aeqtiired a high reputatioa aa aa Intio* 
^^BuioB to PlijneBl Scwnee. In Pmec it baa paased lliroiigli Ntsa 
^^^be Kditintu in little more ihna >• numy yean, and it luu bMn 
^PCffiilatad into Gtrmnn anil Sponiid). 

Tki* rvpntalion it doabtleatowc* to the clearacas and conctaenoK 
with which tlie priDct|x(t ptiymcal lav* and pbenoaaena an ax* 
phtavd, to it* methodical anangvnicnt, and to ifae exoeUenca of ita 
iSiiatiatioDit. In nudortaltitig a tnnalatMin, I was ieilueDced by the 
firtootabla opinioo which a prcrioua uw of it id Usching had 
■iibled nw to form. 

I (bond ifaat tto principal de&ci oooaiatcd in its loo doM adapta- 
tiaa to ibo Prwieh Njntvmn of inMruction, and aocoidingly , tnj cbitf 
labour, bCTond that of men emulation, haa bean eap«atd«d in maldiig 
■ndi all«tatioiui and additioaii ok might render it more useful to the 
Eagliili fltudenl. 

I bare r«tainpd throof^ot tli« nse of ibe ocntigndo iht na oiogtar, 
■4 in Kme caata liave exprawed thv luuaJtvr liDunr mouarcii on tha 
Britrical afMeiB. Tbaae wjtbeau am uuw ererywliiero gaining ground, 
•ad an apology t* ncarcclj needed fbr an innoration which aaj b«lp 
Id famiUarise the EngltWi Ntadunt with their nae in tba panual of 
rg«r and mom complele works on Phyncal Sdenet to which 
orit may serve aa nn introduction. 

loTU. MnJTaav Collvi^ Sumavasr- 





Tn itfio ULi or a large impfw'oo of the SmodcI Editioo of tli« 
tmhticiii of Gaxot's ParflCi ia Dutinl/ due to iu increMed adoption 
I m text-book in acboola and eoOcges. 

The oltanttiaiui in (be preaent edtlMo oompnae 57 page* of 
wUiiioaal nwttcr, aad 49 now iUiHtiatijoaa. Ia maJcing tlieu 
^whiJatbc waata of tbo gcottn] nador havo bMnallMldad 
, the nain objeci of the Editor ha* hc«n to naia the book more 
laaaiezt-book fortiMtctadcot ofphynealBcienoe. Aooordimgljr, 
ngarda oew matter, th« main additioos hare bees in thoM 
•nbjccta which are calcolaled to take a penuazieni pbce in elemcntaiy 
iaMractioti. Some parts, too, wluch the esperience of tcacbcn had 
iaJK iri^*^ as b«isg treated with loo great brevity have been nxpandcd. 
TUi ia more eq>ceiaUj the coae with th« Book on Mechanics, tat • 
eoniplece reviaion of which the Editor ia indcbtod to hia ooUcRg^ne, 
fa Mwt. 3. F. Tvishek, of the Staff CoUe^ 




fair. rtaa 

L ti^FPn" Kotnuo 1 

Q. Okbkai. PsorBMTiBS OP BODm X 

Qt, Oh KviiO, Eqviumnuii, «n> Hdtkhi t 

BOOK n. 


L 0«*TiTt. CiumiB iw OtuntT, tbb Bauho . . . . « 
C hir» ur PAUJsin Doniia, bmmiTT of Tsbkbothui. OsATirt, 

rU« PKKI>tIl«M 40 

nt UoucruB StntOK U 

BOOK m. 


L HYW»o»TiTi« 6a 

■nox . . 9S 


I. PmoVKtnva or Qum. AfVimmaKK Bakavrsm 

n. MkucBKiaurT or tax Ri.ahtic Porcs of Quam 

DL pBXaiTBE OH ItotnBI in A IB. lUujrana . 

IT. Apfuutt* Fockdkh ox Tta Taoewtma or Atn 




Phodoctumi, PnopiinTiaK, *!ni BHrtncriOK or SftcXD 

MEiaciiuiiBd or ru> Nubbbb or Vibsatiohs . 

TuK Phisicu. Tbeoiit or Munc 

ViBiunuiis or VruKTCifKii Sthikor, ^no or CoLuusk or Aim 

Tnnunotis «p Ron*. Putiw, ikd Mbudrisu . 

rii>:i.iin!CiiaT Idui. TmnMmtmutii 211 

ExrmBioH or SouDi IH 

KxrAintioii or Liuvidh 236 

Rxpi»«io)f um DKni-[TT OP 0*89M S<l> 

CnAtron di* Coxdition. Yapouu SfB 

llTanoMrtBT SH 


RxillATtO!) <iv Hut SIO 

Caiabivktrt .,..'..,.. 8t8 

Steah l^nrxKS . 868 

SoDucts or IIuT Aim Cdui 878 

MaciuinuL Kutiiv*LciT or Biut 3M 

TUMMKIMIOK, V'ttLoarT. UCD Ikti^sitt or LtCIIlT . 
KKFiJurnoH i>r LiiiuT. Mibbowi 


QismnsioN AND AciinoHaTira 


TuK Er« CoKKiuKOED A« *w OtTtcu. bcn-BiTinurr 





BOOK vin. 


att. nam 

L pMiwrnH or VUexm MT 

U Tbiui>)*t»u- MAosfsniiH. Cowamw M3 

OL Li«» 'tr Marnktic Attmctiok* AMD Binxaio)'* . fiT'l 
IT. Psoc^EiM or ALunneriuTiaM >TT 

nicnoxu. KLBCTaioin. 

I. FovTiAMRnAt. Fsnicnw 

U. Hiu-ii^MnnofT or Elbttucu. Fokm 

n. AcTtoN ovEi.ncmiuaiBciciiKiaeiBoiiiKiniTmKkTruLSMT 





I. VovtAic Pus. In 9foninc4Tioir» tii 

n. ItamcnoM un SlLUL-vunDrr or Vm-taic Cvuuorn . <71 

m. Rrr«cn we trk Cc-Hurr 6S3 

[T. Ei.>cTKoi>T!cunis. Attbactkiks AVD RMn^Lciom OP CiDiKKfm 


T. llAOKvniurigs n CcHuSKn. EucntMuamm. EuktsicTklb- 

auniB 730 

TI. Ixan^nov 7J8 

VH. OrrtcAi. KtTRcw o» Povnim. Minxn^ DitutaicicTiui 7JB 

Vm. TnMMuKiM^taic Cvnaan* 781 

iX. I)*TuiH[iiiikTuiK or Euwrmciu. Ccwi wic T i yiTt .... 790 
X. AmuAi- Kt.>cTB*ciTT. AiTUUTtaii or EuxnucTTT to Tsnu- 

nrenvs 803 

BEsmrur Omimn or Hitkwouwt unt Cumatomot .All 

Inn W* 


jUaoamKi po««n . . . 320 

AtMorpttonof gnM* . . 106 

— hoc by tpuim ■ S40 

liqnidn . 333. 834 

mpoim . . 330, 3*1 

BsxtKim weight uf BuUtaneed . Bt 
BoilinB point . . M7, 3S8 

CoamrsTioH, lituit ot . SH 

CondudiDii poirm (orhtat SOS 

Conductors of eliHiricil; . . fiSS 

Dmnrnm <>f giuM . . SIS 

— ofiBpnun .... 393 
IHathoniuuioua p«»w . . 331 
Dlffuionof •alntioii . . 102 

EMDomoTic^ cquinlMit* 101 

Klrarriuil •rriuii . . SDO 

ElM-lfomolirp furc™ . 657 

— forco of ciiflnr^t tlcnxraitii 7s3 
E^wiuioD, oodBcienU nf noli J* '230. '23 1 
liquiiU . , . .238 

— gBSCE .... 24 j 

Eyn. dimpoiiotit of . . 493 

— raftaclivs indict* of modln at IDS 

naoHKO RlixtUTas . , 2Ji4 

£WlHt point* of bodio* . '2i0 

QiMituui't taetaa . . .801 
Qniity, forco of at dlfibMot ItvtU S4 

BuiiHma, tcale of . 

IiiTnrr bent, of uTitpoiaUon 


IAmsrio dtetination 

— Inlcnwt;' , 

* I 


RAuuTtna powew . 
Rodiatiiiii of jxiwdcn 
B'-fnuilion of unjils of double 
RofmctivB indifM . 434, 

of nii'dia uf Bjw , 

lUftivtlng poweni 

Sfkcitic gravily ofealldR . 

— — litjiiidB . . , 

— h«t of Bolids and liqnidi 

— indutflir* wpm'itiw . 

TjutPKiuTimu. vnrioiai ranualubU 

— of difT/iiTiit InlitudM 

— tlmruin] fj^nnux . 
Tension of uquoousvapom. 233, 

— differBQi liquids . 

UnDui.k'nofi*. Ivngtli of . 

ViLocm of sound in rocks 

~- J5ii"t« . , , 


wood« . 






oKifKiUL sonosa. 

L Oftjaet Of Pbrala.— Th« object of J^ytkt la ike study oT ibu 
jihfnnmirin {irearnlnl to tu> b} bodios. It ibould, bovevRr, b« add^d. 
Ibri dung«« in ib« nUim of the body itmlf, *ueJi m the d«C'>iiipo«ition 
rf <nia body into olhen. are phMumcoft whoae Mudj fonus th« mocii 
iomMllAiu (<bJH:l at t^tmiiby. 

1. MkiMr. — ThM whioh pocaMSM (lie ptopertles whose exutcnoe in 
WTMled to lu b<r our *rb*cii, we otU mtf/s* or wtitowe; 

AQ MbMancM nt pnwst known lo uh niaj be eauJdet«d «■ cbcnical 
(HiilinBliinMufuxiy-fiTanlaMnlMjornii^rHubslAiicciL TIM iiinnb«T, 
b»wef ar, Bw; henslW b« diatuuhed ov JDcrcased hy » iook powoful 
fbwnfad nulvti*. 

3. At*na< M*1*«b1**.— Fnib vuioua pvperties ef bodW wa caa- 
<W* that lli« matter uf wbidi tbejr m« fomwd ii not potfMtly 
•Ortuaoiu, hot conauta ot u afgivgata of an uuhmom Bumb«r of 
oeeMBqg'ljr suuU portidBa or «/«»« of matter. Th«M atoms caonot bo 
4hiM fbfneaUr, tbcy ate retftiaed tide bjr aide, without touchin^r eacb 
HWr, by ineans of etnain aUnctiou and repulidoiu, to whieli the luune 

mtKular /r/rtei U pveO. * 

A gniBp of atom* (iimu a molmilr, »o tbst a body may bv conmderod 
mm tggnttnto at rery Muall iaale«ul««, aiid tfaeee tgiia as iggregBtM 

JL, - 

i m VATTKK, roucr, xnxt MonoK. [4 

4. Kol«c«Iu atate ot bodl**.— With r^nr.t to tb« BDoImwIm i 
bodir-s thn'4> diir<-rtiit ulittiu »f a;.'i,Ti?^'ution pci-MUt thviiinelvM. 

I^rfl, tUr tiJid tiatr, an oliMirvnl in wnodn, *t<>ni>]i. nirlnln, &c., M tbs 
ofdiDur}' tcuipcmtunv Tbc^ distlui'live cliantctvr •>( ihh ittst^ i», that 
tli« relsliT^ pomtinnH af Ibn moloculcii of the bodiot ewmot bn rhangnd 
without the FipcndittiK of more or lew forve. Aa & coiMequentv, solid 
bodiea U-iiA to rotain whatever (uiu may bavn boen girun to them bjr 
asturv «t by nrt 

Scmndly, Ihe tii/trid tiale. u obBervfd Ln w»t«I', bIcoUoI, oU, St III 
th* rdftUve [WNlion of Ihn moicniln* i« nn longer jwrmftnunl, tilt 
umImuIm glide put ««c)i otli-^r niih tlit> (tk^Ic^I t^uh', aud the body 
luwumoi with RndinoMi Ihe farm of nn; veaael in which it tua; V 

Tkirdlii, tJx j/ateoui glait. hh in nir. In piuaH thi> ninliility of thi? mole* 
Qules is atill grriaU'r thnn in liquid*; but tiic ili«linntivn chiirarWof a 
gu ia ita ini-ewraut struggle to occupy a gnatwr voluiDt>, or thu tendency 
of ita tnotcculci to recede from each other. 

Th« (teDoral X>'rm JUtid ia applioii to bolh liquids aiid gftse*. 

Wo ahall nee iu the itc(]uel that tli« bUIo of a body dci]K!ndt npnn th« 
nlatidoa which Miiit IwtwecD iU nmlcculnr aitrnrtioDs and K'ptilHioai, 
and that for on>' and th^ HLUie bodv thc«e rvlutiunii vary with the 
l*impflrntiire_ On this atfount most eimplf bmiifis, and many rnmpoiuid 
onec, may bti miiA« to paa ^ucopsrivnly tbroiii;b all the tbt«e aleUt. 
Waler pivKenbi thr' most familiar cxanipti- uf this. 

l>. Pbyaloat pbeDooMM, lawa, kba t&«orloa.-^1''rery change 
wbith can liAjiiniii to a body, mi:'r>i alU'rniidu of ill tkcmir^al toiutitution 
boing •■xri'ptcd, may bo n-jrnrdpd iw n phi/Mfai pkim-inmioH. Tlin fall ol 
a ataov, tfai^ vibratioD of a «trin^', and Ibo nouud wbicb ni'i-i'mpaaits it, the 
n'pplinR- of thn lurfnceof alako, and the freeting of water, ar« nxampUa 
of auoh phenomena. 

A phyrieai lam ia the constant relation which exiata betweon any pho> 
nomenon and ita cause. As an ej:nniplr. wo havd tb* phenomanon 4 
tha diminution of the votiime of a ga« by the application of pnMOn 
th(i corn'iiponding law has bwn detemiintd, and ia Rxprensed by Mying 
that the vnlnmo of a f^na is inversely propottional to thf prnwiiTe. 

The wbulo (if the laws rcferrinft to the •ame claa« of phrnomenft, takM) 
together, coniil.ilnlo a phi/tifnl thfnn/. Thiix we have Ih? theoiy of fifftl^ 
the tbeoiy of uleclricily, and, iu uiure rtMricted furms, the theory of dt!Wi 
imd th« theory of Ihe mirnfip. 
* D. Vbyaloal Kccota. — ^In our atl«inpU to atic«Dd from a phmcntmoB 
to ita cause, we assume thr eJiirtenco of pkt/ncal agrnlt, or natvnJ forrv*, 
Uting epon matter ; h» examples of audi we have i/ruvitiilwn, hrt/l, tii/ht, 
nni yi i nti ym, nod f&rtncittf. 




SiiM* tfceir |ibjiikalBgciiburdiK]i)»edbins(iiilTbjrUi«ir«flNU,UiMr 
ialiiiuU< nsliUT M> campiidiU-ly unlinowu. In Ibu pttKUt liMe ot ichum, 
we cannot mv whi-tber th«}r are pmpcrtica uilinTRoi in niittt«r, or 
«M1mt tih«7 T««ult from aiovcini-aU iiuiimiHHl ua the nius iif-nubtilo 
lod lMfiaiid«nble fonaa of mattrr dilTuinl through Uiq uuivsna. ^le 
iMvlijpotiifin* i* kowi-vrr KfTK'rsIl}' admitW. TbM bring BO It nwj 
b* furibar aHkvid an tliere wventi distuici fomu uf iupaadi-nblc niAtwr, 
•iiu*tJwvinnalitTbutoni)Hidtliai«oi«<? Uw<iiild»MtntliutUie latter 
^ntw IvikIa to pr«vAil M tJiit plijiiickl adencM extend their limit*. In 
Menriaufp with tbin hrpoiliaiw tbue anbtila forma of maUor urn i>poken 
titt tmjKmAr/iUfjImdii, linec thi'tr weight is inappreciable bj tii« aid 
rf lbs tuuBt tlu]>c«lt< b«]uii'ui. lIuDCi; Btita* the dirtinction aoiiietimr* 
nada bctWM-n jKuutrrablt utatttr, or mattor propoily m called, and un- 
ycdaiiJ^L matter, or plijtical ipiula. 

Thr tena inaitr/ibir U nlw i^ipli«d to Uuim impnnddnblfi fluidj, (a 
Ofnai llie impoaMbilitjr of confoing tbem in, or exdading tiutm fn>iu, 
«f duaed teiul, a* we do sir and otbeT pwMi. 



' ■ Blflnrmit kind* of propefO"- — ^y t^" '■^"u prvpfrtin lu apjilioA 
IP hodiea, WB mxli-'niUiiil ibu diir«r«Dt wny» in vhicb bodioo prowat 
ihii—iilriiB to oar Mmsia. WcdiitJoffU(ihymeraJ[n<iu ^wV^c projwrtiM. 
Tha tanofK an aliared bv all bodieS) uid amonpit than the lutMt impor- 
int ai» I'lwpi nttrvbilHf, tjttmitm, d m tii iUlg , porvmtg, l^•lnf>r«*Mb^'(y, 
•fariin/y, mtthMy, and Mf/fM. 

Specilir propertlrri aiu mob m aie obtervod in (vrtain bodiu only, or 
il astain atatn of tboM bocUo* ; aucb are tolulify, JtiiidUg, UtuKity, Ak- 
HHf, maftwWiify, h^rjumt, iroMpivmiey, eoUmr, he. 

Wtlh nspcci to tbu titan genenl propurtiw, it maj be remuliMl 
tbd trnpsHtriAiUty and cjtmaoH might bo marc aptly tenncd oMoatial 
Uirih^tM or matter,. HDCG tbej miffioo to deftno il; and ihftt diviaibilitjr, 
pnofiij, MBfTMnbility, and elAttidtjr, do not apply to atonw, but only 
1* bodiea or aggngataa of atois* {&). 

6. ^m9ma0t**XMi\y.~ImpmtlmhilUji U the pmpcrtty iu virtue of 
i/iuA two portjoma uf maltor unaat, U ihn aame tiinu, occupy thn lain* 
tar&M atapM*. 

\ SttiMy RpMktng, tU> profiaty oppliai only to thn ntotna of a body. 

( h many pbaoaRMiM bodiea appear U> pcnnlmtti vneii othofj thus, the 



ib cnnfltitusDts ; Tof itutancd, the Toliune of n nnxtiiN of yrnUr nod »d1- 
phuric Bcid, or of irntor nnd alcubol, is Iom Uibji ilii! «um of the Tolmnea 
bcfurn niiitiira la nil thr-M- cmimu, however, the peoetmUon is iiii>r«l^ 
uppareut, tiiid ai'iiwi frum the fuot tUftt in ererj bodjr lliere ar» iuUntiew 
Of »p(iccH tmotcupird bj mnltor. 

0. siicHiaa.— Kifnutun or matpulude u tlip propertT in Tiitue of 
whifli Dverv liodjr uccupivs it liiuitod portion of tpACi^. 

Mniij iiiutrunx^nts hnri^ bcra invnited for ineMiirin(f linear I'XtiTiiiion 
or Icu^tliH «'il1i gtvM prccirioQ. Two of th«iW, the vpriiii?r fttid micro- 
ni«lsr leeew, «d account of tbeli great utUi^, d««erve tu bo bant 

10. Vomler. — The vernier foruw h nvceu&Tj part nf nil instnuncnta 
vh«re leDgtbe or angles have to be estimated with precision ; it derivM 
its name from it4 ioientor, a French mathejnaticifui, who died in 1637, 
and eouaists ts^ntially of a short graduated scaJe, oA, which U made la 

Fip. 1, 

*)id« along D fixtid ncnln, Alt, im that thn ^p^diifttiona of both mayboMOO- 
piiTpd with ench other. The flxed xcale. AB, beinic divided Into equftl 
partA, the whole lea^'th of the vemiur, oft, may be tnkvn equal to nine 
of thooo poft*, and itonlf dividvid into ("n equal parl>. Kecli of tlie 
parts of the vomler, ab, will then ho leas than a purl of the scale by one 
tenth of the latter. 

This gmnted, in order to nieafnire the leo^'th of any object, nui, let us 
mppoiw Uint the latter, when placed iia in the fi^furp, hn» a Ic-JHtth fn«atcr 
than four but )e«e than flvs pnrt» of ihe fixed scale. In order to deter- 
inlno by what fraction of a part nm i^iceeds four, one of the ends, «, of 
the Ternidr, at, i« placed in pontaot with one pxtremity of the object, mn, 
and the divi«iou on the veruier is sought which coincides wilh a diii^aa 
on tho ficnb. Alt. In the liirurc this coincidence ncciin nt tho eighth 
division of tlie vernier, ronniin^ ttova the eitreuiily, h, and indicates 
that tho fmclicn to be lueasureil is equal to j'^ of a part of the (calc, 
AB. In fact, each of the pnrls of tho vernier bring lew thnn a part of 
iif jea}o by ,\, uf tho latler. it is clear that on proceeding luwArds 
f/ie At/? /rvm tho jmat of coinndcnce, the div'uiioiA ot thi tMnJnr ara 



i^ijn-Urelj oiw, two, tb»«, tti^, ImUi* WkbdUirdit-unoni of tlic •(»]•; 
HI iliii ibf- citremity, h, <it the object (ilut u In My, tLo eighth dJTulan 
1)1 til' iniiitit IK ,'j Urhiiid tiic dtrudoa mukod 4 od the sod* ; in rthn 
«n«d% the Itmgth of om it »qul to 4^^ oSOit p«rto inUi n-bicb Ilia k*1» 
AB ii liinilpd. Conaeqwiilijr, if the acale AB won dii i<j»>l ioiu indin, 
th« l*s|nli of nn would b« 4j^=4J inch«a. Tlie dtdtioiM on the acalo 
rmmtntiy tlip ■nma, it wmiM be iwcwii^' to ucfcaw tha iMigth of the 
renier ia oMi>r In niMmni th« hagtli am mnvn sccumtely. For inclMiM, 
if iho ienirlh oT the reraiM wen equal lo nincieeo at the port* on the 
nala, mmI tliU Ica^b wi-re diriiltid into twenty r^oal poru, tlie kogth 
Ml coatd b« ilH^nniD^d to th« twentiMh of t> p«n on k m>Ic and m 
ttL la tMtmiiMnt*. Ulie (h» llieudolita, iBtendMl fiw noMming angln, 
the ■nk- and V«ntt*t haro a dirulnr Tonii, and the lattar uauallj cwriw 
a t^tntHn, in onler to d<M«nuiii« with ^TtMitvr precUion tb« ooinddcait 
dlriaUna of vgminr and Male. 

11. MlBtoMBtT aottw. — Another lueful little iiMtrunciM for mt*- 
Btriag amall hmRUu with prvoiaion ia the mieromtltr Kmo. It ia umd 
odef T«riutM fom*, hut the principla ia the camq in all, and Diay be 
ilUunatod by a nimpte example. SuppoM the distance lietw«ea the 
ttiiiadt of an accunti^ly cut acrow to ha equal to j'^ of an inch, and the 
liMd of the acrew to bv a tolerably larg« circle divided into oue hundred 
f^ml parta. If th« mtcw i> tixej in nidn a uaonar that it can cniy 
tnra on lia axis, hut neither tpdvanc? dm teoed*, and if it worli In a duI 
haU IwtwBan giudoa which prcvuni it from tumiof-, then evcrr turn of 
IheaDTMrwiUcaUfelhoButioailTanco through th.> unili p«K of mi inch. 
If a fixed pointer be plaotid before th« dirided cin:li^ at ihi.' Iinul of the 
iinew, and tha lattot turned through to Nnall an angle that only one 
dindoA of the circle paaaee under the pointer, the liuodrtdth put of u 
tain will bavo bocn giveo to th« acrew, and Ih« nut thonl^ oauaed 
ta ad Tsace or r«ofdr through the fanndmlth partof ths ifiatanoe between 
two ihn^JJ — that u to mt, thtonirh thn j^ part of an inch. Applica- 
bona of ihi« principle to the UMamircmant cf amdl lengths will at i>nce 
•nggnrt thrmtelToi, and be readily understood when eeen. 

13, VtHalblUV — ia the projicTly in virtue uf which a body mny Im 
: ' hI into dartinoi parte. 

N iiiii«n>ua example* nay bi? cit<d ot Ui« extrnme diTioihiUty of miitt<>r. 
Ih* tmth part of a grain of niu»li will e»ntiiiiiti fnr yean lo fill e room 
with ita odoriferoiu parlicUa, and at the eud of that lime will scarcely 
W diminiahed Id wtight. 

Blood i* eofupowd of tod, HattMied globdM flMibg in • «olourl«M 
l|ind called mthbi. In man the diun^kc of one of theie globule* ia 
bit than th* 3,Ji00lh part of an inch, and tlie drop of blood which might 
be tfaafuaStA (nta the pdol ot a octdle would coDbun about a miiliou 

$ IKt HATTXR, FORCE, AM1> WmOS. [13 

A^am> the nucnKope hu disctoipd to ii» th« «xi«hairo of iaSKte 
MMtler eTfoi iImd ihnn portidiM of Mond ; Ihe alragj^le Tor utaUnM 
receliM evi-n tu tbim- lilil« cTc«turN, fur they dvTour alill Miwllor oou 
If Uocid runii in the rtrina of thctn Atjoatti od«s, how Infiuitoaliml 
nuMt be tbu itjn)iniiliicle of it« componeal globule* f 

T(iv> thnn the diviaibililT of innttor no limits jVllhoitgli cxiiFTimenl 
biln l« d»t«tiaino «iich limit, manj facta in oheiuiilTj, such h the i»- 
Tkriabiiitr in tli« ivluit^ V«i^ts of Ihe rlrin«nlii which romhinn with 
BBch olher, would li«d u* In bnliciT« that a limit doe* «u«t. It is on 
this Hcrouat thai liodiva ur conreived to he mm|MMd of •xtrfantt; 
■niimto and iniliviaible pans oalled otenut (•t). 

U. »«r«att)r.~/*»ron^ i« tb« ijiulitj in virtue nf which intcnticw 
«r port* exirt bntweon thi^ molecitlra of ■ bod j. 

^^^ Two kmd* of pores may b* diatin- 

^^■^ ^^Hr giiiahrd : ph/firal prrrn, whniti th« 

9^V ^^P inI«ral]CM srv lo suinll that ibv aur- 

1 f '^B rnundinit mnlorule* ti'mnia within tbn 

I I 3 sflidre uf each other's attracting or 

I I 9 rqwUinft forcei ; and tmsihle port*, or 

•ctusl caritiM acroA* whicli thaw iiao- 

J«ukr foru-e» cannot act. The con- 

tntctiou aad dilatation* rr«nlting from 

vatlatbiu of t«iii]ierature are due to tbe 

existencp nf phyrieaJ porei^ whitat in ibc 

orgnnic world theseiuible porea an the 

w«l of tfa« pbenomeuB of exhalation mi 


In wood. a[>nng<i. and a great number 
of sUincH, r-jT. pumicn stnnc, tJin umidbl* 
porei ar* apparent i p)i}'«icnl pom iiii*er 
are. Yel, ainco tlio i-olumo of ot*tj' 
bndv inny be diniiniubml, wii coDoIiule 
tbnt all po«w« physical jMres. 

'I'hn e.tistcnce of unnirihle p(>r<M fflSJ 
be kIiowii by the fnll».>wiiijf experi- 
nwTit: — A Innji Riaja tnhe, A (Rk. 2), is 
provide-1 with a copper tube, m, at llif 
top, and a coppnr f'wl inadi- to scniw on 
to the pinto of a inachinn for nihnu*ting 
ajr. The bottom of the cup cunsista uf 
a thick pidrn nf Iimthnr. Aftrf pouting 
■IflWSiy tato Ihn Clip »i as entirely to (^ovet tbe liialhiT, the wr-pump ia 
/>atM aeitoa. and a fiarltaJ rafuum produced within the tubs. IJy ao 

4tln% m ahower of aeKury a *t necn ptodOMd witbia tbe tube, for tbe 
MiWMf bene pretHBie on the men-un' fomr* Uist liqdd Uirough tho pom 
df itw balilpr. In thu nudi' aiuio<;r irtlm iir mnrcury may bn forced 
Iknogh Ilia potM of wood, bjr rvpladng iIm- IrulhvT iu the aboic ex- 
ftrinmrl b^ k disc of wnod cut porpcndimJoi to tbn fibrp^ 

VkcD a p«c« of chnUi b tlifuwn into «aUr air-bublilM M odus hm 
to llu iBrfiuc, in ootiaeqaraDe or the nit in tbu potca of the duUi bdng 
rxpdM tiT lbs miM. Tlia nh&Ih wiU bv fouod to be hMtier after 
[■■iiii»iiiii than it waa b«fi>r«, ud from tbo incniaae of iU wdgkt tha 
mImb* of ilji pnnw majr he cwjlj di>timnine(l. 

Ila ]>ac«ut]r uf gold waa demoniitraied bv thi> wlubralsd Florentinv 
EKfaruoMtt made in 1661. Somo aciul(;inidnn> at Flornncc, wiiUiin^ to 
trj wbetbw watvr vr«N civrnprnwiblci, filled a ifain globeof gold wilh that 
&i(tud, and, after ctTcfutlj cliHiDg the ortGco bmnctieallT, thej' oxpcuird 
IIm ^oka to praaNire wtlb a Ttnir of allrTinir it* form, vnll itnnwins th»t 
nj-alUoatUni in fonn muat be aoMUpanied bt* a dimiuutiun in voluuiu. 
T)n> coD«oqii«iM« nws Ibat th« vtatei forced Ita yi*y tbmu^h thi- porm 
nf tbo KoM. and atood on the ouUide of tbo globe like dew. Thi* 
Riprttmcot ha* RDee been repeaded with globtw of otbur mct»U, ami lika 
naalta oblaini^d. 

14. Avpareat wi« roKt volnnea. — In coHMMjueuoe of the poroaitj 
of haUaa^ tt bccfaaea nwiMUr; lo dittin)(ui*h botwtwn thoir tnal rdiJ 
■^arat Tolmnai^ The rtal •olmnt of a b-jd^ is tlia portion of a]iatr> 
nrfnallj' occopM hy tbo matter of which the body ia eompoaad ; ita 
^fwmit Toimnt Is the sum of it* real to1uixi«i and the total toImom of 
iu pore*- Thn r««l Toliuna of a bud; in invariable, but ita apparOBt 
rotiiine rati b» alterad in variow waj«. 

15. Aypuestleae. — The property of poroaity ia uliliwd in filtera of 
pipar, fait, alone, chanoal, i>t& The porea of them mihitoacet am 
(uBcieiitly lai^ to allow liquids to pass, but small enough to arreat the 
pHai^ of any aabrtanoca which tbue liqiiida may hold in ■oiponnan. 
Again, Latgn blodlaof •tobnsrsorifin dntaehnd in (iunrri(«hyintrodiidn^ 
Wa^lgw of dry wood into gtOOTOa cut in tlif ruck. Tljese weil^'va bein^ 
matrtllind, water paMtrata* thoir pom, njiil eniucs them tn (well with 
egBBdoiwble futoe. Urycord». when iuoi»t«ii«(l, incroasn in diAniolorand 
Aninlah in tvngiih, a property of whach sdvuilngu ia aumutimiB lak>^u in 
■nUt to niw iiiinii-nw wttghts. 

lA Cw^prvaslblUV. — Comprttt^Hify in the property in Tirtuo of 
'hieJi the lolumenfa body nirky be diinioi^hM by pnauure. This pn>- 
'^f«ty ia Kt once ■ oonMifiwiict' and a proof of ponwily. 

BodiM differ fpaatly with nspect to conpreoubilily. Tbe must oom- 
piiaiiblii bodirct are gaaae: by MifH^imt prownini they may be mode to 
nufj ten, iwm^, or evra « hundred iimtv low space than thv; <lo 



uDd«T onliBarj cirouoistaucM. In moM ea«M, hAwevtr, tbmv i« n limit 
bcjond wbicfa, irlion the pieuaK i« toereucd, thvf beoOBe liquids. 

Tb« comprewbilit^ of solid* is miicb I«m thmi iitni of gMca, and !• 
fowid in «]] degTPBa. StuiS^ psp^r, cork, wood), an amon^t tbs mott 
coifJiMiiblB. Hital" Biv ■>> aim in a gniat tixt«nt, on in proved b^ the 
fnetm of coiniu^. in vtliicb the moial recvirM tbe imprnfMon from tbr 
dw. Tberc u^ io nton cwm, a limit bnt-ond wbich, vrliun tli« ptcMure Ib 
incnamd, bodiM are fnccurnl or reduced to powder. 

'fbe cotnprMKbilitv of liqaidv is m amall M to bare rvmajned for ■ 
long time imdel<>cl«d : it tnny. ln)w»T«r,bopro»*dliyciporJmuct,a« will 
seeu III tliL- cbnplcr uu IltdroBIAtics. 

7. BlaadoHr. — Eianlkilif it the proportj in virtue of nbioh bodiea 
M tlwir original form or ToltinM, wlwin th« fcmxi vhicb alt«T«d 
tbot fonu or rolunic ceiuiw to wt Elasltcily may bo denloped ui 
faodiei by [>re«sut«, traction, flnxion, or torriom. In tTBattng: of Ibp 
g«neta] |iro]iertiM of bodies, tbv< rlaslicity deTi>]o]>rd by proMBro aloD* 
reqninM contideratioc ; the utbcr Itinds uf vltuticity being peculiar Io 
aolid bodice, will be conRiderad mnongKt thdr lipccific propvrtlM (aria, 

GokiRa and Ii<(uid3 are pirf^rtly eUstic ; in other words, they regain 
exactly l1ie «nmp vnlnin'^ wiiea the pi««sure become* thi- iwmc. Solid 
bodiM preteut diifeivnt dp'^'Cs of ulo^city, thouj^li Doni» present the 
property in the name perfuc^tion as liqui<ts and ga^ea, nnd tn all it vari#s 
aecotdiu^ to the time during nhioh th« budy faa« been eaposMi to 
prMxiic. Oaoutcbouc, ivouy, glass "^ marble poweas coutidnaUa 
elasticity ; lead, clay, and fata, scarcely any. 

There h a limit to the elaeticlcy of solids, beyond wUcfa they either 
break or nro incapnble of rcRnining thoir originnl inmi and toIuum'. 
In aprains, for instance-, the elKPtivity of tlio teadoim hax been «<xceeded. 
In ftiujBs and UqitidH, on the contmry, no sudi limit can be rtitched : they 
filwnyn mtrnin their nriginnl Toluiiie. 

If fl ball of ivory, glasi, or ntnrhle. be- allowed to fall upon a sfalj of 
pi)liabpd niarbln, which han \>t^•\\ prBYioiwly "liglitly mnenn^d with oil, 
it will r«'boimd and rise to a bei);ht nenrly equal to tbnt tr<'m which it 
feU. On aflerwimU oianuninir the boll n circiilnr blot of oil will b« 
found upon it, more or less extensive nccordinjf l-> th« height from which 
it folL From Ibis we conclude Ihnt nt the moment of the shocli the hall 

Lwaa flattened, and tbnt its rebound was caused by its effort to regain its 
oiigina) form. 
IS. MoblUtj. iBotlaii, r*st> — Molality is tbe property in rirtuo of 
which the poiitiiil of a b.jdy iu "puce may be eLHu^■'^!. 
Motion and rrtt may be either reUlive or obiLilute. Ily the rttaliv* 
WM t w » or r*tl of a body we mean its cbaii|re or permanence of po«itioQ 

Korames or mdik. 

wUlt ral^Mt to ftarroiiniluig bodiw ; hj it« tAmMt Mttitn or rorf vo 
MtM tke ehug« or penaait«tuoe of ita pontiim witii mip«ct to iital 
hcdiniDU iii*p«c«. 

Tfaoa ft pMMenjKr in a nulwav rurUfin? nuj be in a «tel«< or R<lativ« 
tMt wilJi leipect to tile (rain in wbicb li« trarel*, but ho i* in « nUto 
(tf t«ktt*« ■notion with rmprct fi th« ottjoct* (Adds, bouses, e«c.) peat 
«bieli lb« miii tuibee. ThoM- kouees i^sln enjo; meretj • (lata of 
tdklire rest, tar Hui nartb itaclf which bciirii tkom i* in a ct«I« ot 
tnriBint rvUtiv* nHtkm with nepwl m tlic celv«lial bodiM of onr 
uter ajatmn. In diart, efaaolute motioa and nst uro unknown to 
Ml in nature, mUtiro motion ud tmt an alnno praMntod to oor 

10. iMcrtlM. — Iturlin ij n putely nt^fatita pnip««ly oT mnttrr; itia 
tb» incapabititj- of maltrr to fhnnxe its own state ot dioUod or ivsi. 

A h*ily when nntupporlwi in aaid-tat does nut tkii ia Ihi' carlb in 
rirto* of any iiihcTiint prnprrl;, but bnciiuw it i* nctJ^d upon I'j tho foico 
of pirilT. A billiaid baU gicatl; pushi-d dwa not move mutt anil mon 
•Inwlr, and fiaali,* Mop, bnesiun it Km tmj prcrcntncn far a state of Kst, 
hot iMcaiww its motion I* inip^^d by lli« frii-ti<iai on thn doth on which 
it rolU. and far the naietwice of th« aii. If uU Impeding cauMe wem 
«ii)i<inwn, B body oner in motion would eomtinuc to morn foir crrr. 

30. Appli«ktt«B> — lanumtraUi) pli^aoiiii^nit msj be expbdaed \ty 
tbs inrrtin o{ luatter. I'or tnstanco, bcfoni leaping a diub we nin 
IffB'Mnls IL, lu onler that tlic luolion of our bodios at tbo tinMi of iMpin^ 
m^ add itacif tu ibi- muoirulnr tffurl tbuu made. 

Ob dM<^radticg eafdealy ftnm n cnrrio^n in motion, the uppnr part of , 
tbc bod* retains its motion, whiLdt tho fe«t arv prevuDted from doing so 
hj frifiino afrainst the ground; the constqueaee is wa fall towaids tbe 
■0ring c*msg«^ 

The trrrible ftMidenb on our niJwars are chieflj duo to tn«rtia. 
Wbi>n th« motkm of tho engine is *uddt«l; nTrrvteil the cnrrin^s jitriT« 
bi fo ntinn^ tlM motion the; had acquirod, and in doiug no aiu sliutMnd 
ifiiDat Mwb other. 


on poxcK, mntiDKicii, ixd itonoit. 

SL ■«»Bitr« of TUi*. — To obtMn a proper measure offoree it is 
MBHParj. •■ B |>ivlimit)*rT, to d«dneoettaiD conceptions which are pra- 
Mppowd b ilisi nHiBKii*: and, in the Brat plu.'e, it is ni>ce<esi7 io drfine 
^ unit uf time. Vib«Bf\eT a jreouif U tpokea of iriihout qualiKcAtioit 


10 OR NA-mt, rqKK, kxtt mmox. [IS- 

it b mulCTitoed to be a ttraai of awoi aafv tuw. Tbn eutet Itnifrtb »( 
lUa anil ia fiioj bj the foDowins cMMthntioii. Tie utrtui wliM tbt 
«■!■'• ccntni in no u obtorvra-'a nMridbn —in otbcr iroidk. the inabmt <f 
tba tnnft e/ th* imit't centte— adniiu of exatl deteraniiMtinii, anil ihra 
tbe iotemJ «Uehck|MC* bctwoen two aweeanTe trukriu ebo tulmiuef 
wuuTi HpwtniDMiiM, aad u ciIM an l yy a w rf dar. IV Itoftb of ibb 
hMcvral diflen digbtl; fims ivy to ilaj, and theii^an does not »ene u 
~« taanwut nwCKum of itaH>. lu ntrtgr lenytb U fr«! from Uiii 
InooevenieiKP, and tbnvfure aarm %* the tcqidnd nwaaore^ and if 
<a]M a nMs mtor day. Ttie >!uiit band of a combuii dock muU f« 
exadlf twice rmmI tbe bor is a mean aolar di^ ir it want pttfeH^. 
The mean aolar daj ccanttM ot 2* equal paits enllMl kwa. tbeee of flO 
•qoal |ian« rallnd unitvlrt, and tbeae of 00 eqnal part* called uratiA. 
CooHquMittr tbe second ii tbe B6,400tb put of a Dwan aoUr dajr, aod ii 
tlia piierall_T rr«ei«vd unit of tiaie. 

3S. Mauw wf •vMe.-^^pam nuy b» tjtiiar len|lb or dirtanecy 
wUcb ia apafv attme dimeniLoa : area, wbicb ia apMe of two dimen^OH; 
at volnnrt, wfaM^i U )pac« af t1iif« dinneiMafUL la Biglanil tb« atandard 
of Imglh t) thr Dritish Impcrul Yard, wbicb it tbe distance bet««n 
1«0 pointt on a ccrtnia metal md, kepi in the Towrr of Londooi, when 
th»tmiipi'nauT«nrtbowholen>diii60^F. = lS°<>C. ltif,bow«vpr, umial 
l« iBtnfioj at a unit, a/a»f, wbicb ia tb« tbird pail of a rard. In Fmbc« 
the uandatd of Ienf!tb ia tbe metn : ibfe, too, ia practicall; Sxvd hy tbe 
Dcc b<-twei'n (wo nu-lu on a ocruin ataa^td rod. Tbe rdatlM 
reen ihtM- BUndardu u aa folloira ; 

1 nrd = O-DUti^ notice 

I Biilir- = I-0(".'M33_Y»id». 

^Tba unit of leogtb havioj; bcc«i fixed, tbn uniti of aiM nod vulinne M« 
naeUd wiib it tbua : — ifae unh of area U tbe ama of a eqnare, <aie 
liride of wkiofa ie the unit oT tenKth. Tbe unit of rolunie is t^ TolnSW 
t a cube, one rdice of which i> tbe niiit of lenjftb. Tbm imita in tba 
Caae of l-lngliah meaeuiee are tlie Kju&re rani (or foot) and the cubic 
vaid (oi foot) recpeottrelj ; in tbe caae of French moaAurc^ tba oquare 
BMrtn^ and cubic mnln' nwpectiTnlj'. 

SS. flCeaawa or BKaao.— Two bodiee arv^ Mid to bare eipul 
I wlien. if placed in a jierfeel bntaoee in vacuo. tboT counlfrrpiuae 
other. Snppoae wc tnlie lumpa of any «ub*Mnc(^, li^ad, buttar, 
wood, alonn, etc., mi suppose that any one of them when placed in 
^ODo pan of a Imlancn will oxactlr countarpoiao any otbor of tbam 
placed on thi! npponte pan — the balance being perfect and Ae 
Og performed in vtu-un ; lbi> beinic tho caae, Umm lanpa an 
to have equal mttuca. That thoM lumii* difTef in DMOjr rwpMti 

-14] nex«Tr. 11 

fma <mA tnhmt la pUin mougli: (a what N«p«cu tliny likve Uio 
■MM pnfcftuv in virtMi of tliv ojuality of thnt immm ia to b« teet- 
li'rwrf bf DulKi^qiwnl «Kiuir7. 

Ub KntUl) unit of idbm it iho BbuuUrd pound (Araardapoi*), «birii 
t* * eaun ptm« eJ plntinum Irapt in Ui» Ex^eqiur Offios n LandM. 
"Dot mi iHTing Uvu fixml, ihe nmm of ■ girtn mImIbiim U «»|i ro w nl 
M ■ ontldptc or ■obmultjple of thi- unit. 

ll nwd tcareely be lunntinnt^ ihnl maoj <liRteiic«a m kwertMWid and 
ftf«iwi'»l in TnnU vbich ii would Ih phjiriciCI]r inpoMriblD U maMan 
dineUf by a yaTil moasuiti.. In likn maiuior Uw mawci of bodlw an 
Aa^MBtly aM-prUliwd and MpKoMd nunivnciilly which rauld not be 
fJaead in a t»Luifi» and lubjcctnl la difwt wnighiafr. 

H. nanal^ »ad K«l«tl*a Osaalty.^If wv ciNuidcr any bod; nr 
|Kinkm of nalUr, and if we couceire it to be diTtdcd into auy numbar of 
pans kiTing itinal toIiuiuM, ibon, if tlin mamni of tbase pans an vqiial. 
la wlnlimr way the dtviMon be ooneeind an taking place, tbat body ii 
lOW of aMJAnw doutfjr. Tlir JauSfr of anich a body i* iha Omh of lli« 
■Mf o/ toAmr. CoBBMjnMitiv If H denolo the maM, V thr roltiBie, and 
U tbn douBty of Um body, wa barfi 

SI = VD. 

If now wa Lav» an aqoal toIukm T of any aecond aubotmee wboao 
BMB ia M' and danoQ^ tf, w« ahall bare 

noMaqutnlly I> : ir :: V : M' ; thnt ia Um diaritiw <ifaubalanraa are 
b tbn aanta ralio a> lh« luasMt uf vqual volunMa of lliaaa eubKanoaa. If 
anw wa taka tbo dnakty of dkliUed water at 4° C. lo be unity, ibe 
Mbtiru iJetiilly of anj Other mibtUnra ie the nlio which the raaaa of 
any (piRD tolnne ofthatanbatanoe at that ttoiipFnluie bnar* to the maM 
of aa rqual valume of water. Thiu it )« (bund that ihu nusa of any 
ntamr of platinum i> dS'OOO timn that of an equal rolume of water, 
tNaaquMiiJy the n>Iativa deiudty of pUtinara ui 33-0fl9. 

na relative ileniily of a milatanoe la geDenlly railed ita fintjfc 
frvniTy. Mntboda of delcrmininf; it am Ritcn in liooh III. 

In Kreuch inrSMraa theei>i*r cJmwwirrofUrTof diolillcd wateral4^C. 
eoottiM lb" tmit ol itam, the kilagramnM | and thenAxw the ntaa* in 
Uh)(pnniinee of V eMe dedmelma of a aubeUiic* wheae apecaSc 
patily ia D, wiU be given by tbe cquatiuo 

M = VI). 
lb *BM equatim will pjo the mass in ffi-ammM of ibe body, if V i* 
ftam in nuUioieuva. 

U hM b«aa McerUlned that K-TJ'i cable JnchM of didiUed wHnr 

M =« 

12 ON MATTEfi, roRCC, AXD ximox. [a5- 

»t the t«mp«ntun ItPVI C. or BO^ F. contain ■ pound of matter. Cmm*> 
ifUpnUv.if S'lB tlie mlrimf Ma boily lu cubic lucliM, hit* f»(jfi<- grmtt^ 
iv nuM* M in 11m. itTniTilupoU will be (^vrn by the equation 


In thj* equation D ii, properly «p^ini;, the r«^IaUve deninty of the mb' J 
»laiio« HI yW F- Mchen tho d^n^ity of n-nti^r nt 130° F. u tslioa m tb« mlt 

ia. Vfllvelty and Its meaaiire.^AVIii^D a material poiul mutM, \L\ 
dcacribe* n continuous tine- wliicli may be citiier strm^Iit or ciirrrd, aad 
ia <?a1]iyl ic> p»lh and (omotiines it« trn.incIorA'. Motiou wLifli talu* 
pUt-i? nlnofc n straigbt line ta caUnd n-ciiliijcar luotiuc ; that whicli tain* i 
place along a curved line is called curvilinonr tnotinn. Tbo rat« of ifa* 
motion of a point ia callnl iW ivJwifiy- Velocity may be bULit unifcynn at 
variabV ; it i> unifnrta wbvn the point di^.-icribai nejunl ji}wcc8 or portiau 
of it* pntb in aJI equal tim^ii i It it rarinb1« irhen tilt- point duscribo* I 
nqunl portioos of it* patli in any equal tiuiti. 

Unifi>rra velocity 1* ^l<'lulu^>d by the nunilierof unitiiof RpncedMCrtM ' 
in n )rircn unit of linw. TLe units coiiiuionly emplojr'il asv f<>rt ul 
Mconds. If, for example, a velocity & is Fpoken of unthnul qualificHlion, 
Ibin mcanii a velocity of 5 feet pi<r xecond. ConneiiUdUtly, if a body inona | 
for ( iwconda with a uniform vtlocity i', it vill duBcribc itn ft^et. 

Variable velocity i« mcMurcd nt any inftanl by ibo number of unit* of 
■pnco it would deecribe if it conriuued to movit uniforuily from thMj 
inatant for a unit of time. Thus, riippnu; a body to run down an ineliud) 
plane, it is a matter of ordinary observation that it movu* more and more 
quickly during its deicent ; suppii$i> tbnt nt any point it hmt a velodtj 
Vi. this uieauB that at ilint p.>Jnt it i« moving- at tbe mtc of 1& ft. pvJ 
second, or, in other word«i. if from tbnt point idl increase of velodlf I 
ceased, it would deaeriT* 15 ft. iu ihr, next (lecnnd. 

i^t. V«T««. — When a material point in at I>mfI, it liiu no innnt* powerof '■ 
clianging: itj Etiitt> of rest ; when it ii in motion it hn« no iuiiatu pow«r 
of clianjtiiJ}; it« state of uniforok motion iu a slrait^bt line. Tlii« prcqwirty 
of matter i* termed its incrfi'o. Any cause which «et.i a point in motion, 
or which chajigec the mo^niitude of direction of it? veli>i'i(y if in motion, 
v. afia'rr. Gravity, friction, elattk-ily of springs or poses, electrical or 
magnetic attrni-tiun or rrjiulnoH, etc. ar^/oreea. AU tliaufres obeerTwi in 
the motio[i of bodies can be referred to tlie aetiou of one or more (bicea. 

'27. Aoealaratlvfl effect or fores. — If wc suppose a force to con- 
tinue uiichaii;/i'ii in ninCTilmie, nnd to act along the line of motion of a 
point, it will eouimunic8t« in each aucceesive second n constant increase 
of velocity. This const nnt increase is the aiYrirrn/iiy rfffvt of Hie fent. _ 
Tbu* if at any ^ven insUDl ibu body lias a t-otucity 10, and if at tho end 
ofrAe £ivt, ivcaad, thini, etc., second from that instant It* velocity U i 

utASDtE or rdKCt. 

, 16, IB, tie., tbft ieeeUr*tiT« cAbct of lh« foiM te 3 ; ■ fact vhicb 1* 
hj Mjing Utat ifa* bodj W beeu actod an bjr an aeeaUat^Bg 


U tin tatet vary front iiutmt to iiwUnt, its Bcc«l«ntir« elbwt will 
I nry*. wbcn thin U thn caw thu accelenlive uffbei at uit instant U 
'. hj thv valociiT it irould eomiBunicatn in a M«aad if the force 
I Cioti«taiit ffviu tknt inslMit. 
Bt nwau uf at) I'xpvrimeiii to he ilMcribed bdow (70) it can be idimra 
tha al Uj giv*n plaro tbn arfnltimiiTv «llvct of gravjl; ^r b eramUat ; 
IM U b fiMmd to hare diir«Kiit valuM M diffistvnt pUon, adopting the 
I of iMt and aoooDd* it foond lliat T*rT approxiiuntcly 

ff =/(l-0 00iKCCo»3#) 

1 irtBti'in wliOM) latittidR b f^ wliei*/ dpnnttu thi>'tiumb«T 33'IT24. 
'». W-MirnT^m or qiianlily of motion b a uittgnilude vaiTing a* 
nuu* at a bodT nnd it* rolodtT joinlljr, uid tliiTKfoK U exprtmed 
Riartindlr \iy tlie product of the oumtwr of uniU uf maM nliich it con- 
and tbr number of unila of relocity tn ilii motion- TliuB a body 
Dg ft llw. of matter, and moring u tbe ratn of 13 ft. |ior aenond, 
' 9D. Maaawra •rnree. — Fotcp, wbenoonstant,ienieNsundbytb«inD- 
lai^iiai il Hi(uniuni<-al>.-» to a body in a Qiiit uf limtv If xlw fnrrn f anais 
il i* tb^n iimaiircid at aoy ttutsnt by tbp momentum it vuiild communi- 
tUt if it cmtliiiied oouunt for a unit of tim^ IVom tb» iniiant imdoT 
tmmAtn^tiit. Tbc umt of furce is ^at fciii<o wbicli acting on a pound 
af natter would piodoov in one SKond a Telocity of one foot pi>r wcond- 
<'DBrwi)aaatly if a body coDtaim tn tba. of matter, and isadifd on by • 
fvoe wboiM acc^lCTatiT* aflect le/, that force cootairi' n niimVr »f iiniiH 
^forcv (T), )[ivi-n by tbo cqaatim 

F = m/. 

I Hie weight of a body, ic&m Ihat ttrm dmolft a forrr. i* the forcr 
I on it by grailty ; onucqueDtly, if ni i» llif- tiiHM uf llic bidy. and 

||ha accelerating foscM of gravity, the number of uiiitB of force W 
I oa ll by gniily ia given by tbc equation 

\S = ms 
i(iit2T) W = m/(l-0HXI2C«Co»2«V 

I this it ia p1«n that the weifrbi of the mkio body will be different at 
BlparlBof the earth'* mirfacp; ■ fuel which could W v»^fi*d by 
Jag a picre of ptatinom (or other mntnl) to a delicate Rpriog, and 
_' the ffnriati'm'i 1" tbo length of tbe apring during a royape fram a 
riMiiin to th> NorlUpm Hendepbere to another in the Sootbora Hcnii- 
«ph«rB,for liialaaoe, fium I>>ndon (o tbe Cnpn of Good Hope. 
miM^ ihM*£:r^ M pound ig uteil »a a auit of force it niiut beuudct*! 



OK nATTKx, roMz, AXD Memos. 


rtood to nuHui tkn fora« W rinrted by RTHTitj an a pounit of nutter in 
liondon. Now, in Loudon. tli« uum«ric;a] valve otff u X!'t0I9. aa tlut 

{■ Otbar iTonU, whnD a pound ia taknn u tho unit cif force it contauu 
32'19IS unitB afforoi! nccordiiit' to tlir uvEUiuv girvu above. It wil] b« 
obMTCdd that a pound uf ninlter U « complcli^iy dotrrniuialn quniitity of 
inattur, iirotpecttTe at lurality, hut gTsvily «xi>rl« on a pound of itiatier 
a pound (or32-ini3 unit^l of forcL- at Loudon and othur plac«B ui aboal 
tlw siinii.' lalitudu M fyvidon only ; tliif ambi^ity in tbn Uirm ftmmd 
Khnuld bn cnn-ruLly uolicetl by \itv etuilt-ul ; tbe coiit«Xl in auy tnatiM 
wilt always Hbnw in wliicb sense the term is used. 

■SO. SepreaeBtkUoii or roreea. — Drair ftoy litiugiht line AB, and 
tix OQ auy jji.'ini I) in il. Wp may nuppoim a forco to *rt on Uif polal 
0,BtoD|itLt' liuu A B. eitberlowarda AurB: tfacs 
'9~~S 5 5 A. i> cnlli-d thp point of upplinntion of the forcfy 
Fig. 3. A B itti line of action : if it atU townnls A, iti 

dirertion a O A, if toward* B, ilJ din-ction in B. 
ft U niroty neccauiiy to ntahe tbe dininctinu between Ibe tiu«< of nctidO 
luid dirw-'tioiiof a forcti ; il being *ury convfnicnl to make the convnntkn 
that thestntctnent — a fonw itcli) on • point O alongr the lino O A— lueaai 
that it acl« fniiti to A. L«t o» iuppuw the force wbicb acta on tl alonft 
(> A to eoataJM i* unit* of foirp; fponi () lownrd* .\ mcn*ntc O X con- 
Idining; P unil* of lentrth, tho line ON 'i» (laid to repramt the fort*. It 
wiU b« rL-mnrkod that tiie unology between the lino and tho fiiret i* very 
complfitni the linn (> N ii drawn from O in a giTea direction O A, Uld 
centre B pveii iiiduIht of imita P. jittrl as tbe force aclH on () in dia 
direction A, and contains n given niimbt^r nf units P. It ia acarcely 
ner«8mry to add that if au equal fctce were !o net on O in tho oppovte 
direi^tion, it would be said to act in thii din^nlion Q B, and would be ro- 
pmRentod by M, equal in roagcitiide to (» X. 

When we are oonsideriiiK sen-ral forces nrtini; don^ the Mme line wo 
may indicate their dirrctioiiA by ihn positive and ne^^tire tdpii. Tbui 
the forL'ps meulioLed uhiivf would Lb denoted by Ibo symboU +P and 
— P respeotivply. 

SI. roroea aoHoc aloae ttie aAino Uii«.-~lf forraa act on the point 
O in the direclioii I.) A contaiaitiK P and tj uuita respectively, they are 
pquivalont to n einglo force K containing u many unil« as P and (j 
together, that ia, 

R = P + Q 
Iftliaaipi -f- in the above equBtiuiK^of^iut^riraiWadditinnjthewustioQ 
will continue I run whetlicr ono or both of thn forces act akui)^ O AorO B. 
It i» piwa that ibe wme nil* ean be extended to any numbiT of foroog. 


flil If wmil fett«a lutre th* sum IIm oT Mtion Uicy u« cqiurakal to 

«* bra canUBtnit tbn Main duibUt of anita ■■ thoir o^iAntiVa/ nun. 
Hidi if fuRM of 3 and 4 unitii oirt on O in lli« duvctioD O A. tud • faroo 
nf 1^ in tb" dbvetioo O B, ihnj «n «^irivalciit to k nn^ fbrco ooaiHniiitc 
£1 nniU fiTtn by Uie oquuhm 
H R= S+4— 8= - 1; 

^Bri (^ R in » fam onnluniny ana nut Mting tloag O B. This fonw R 
^BaiUed Umut rsauluut. If Uie Aw:«a an ia «quUibrium K U equnl to 
Mm. In this raw tliB foK«« lum eqwd tendeaeies to more tbe pniat 
faopp(i(it« dirvcliima. 

as. m«aBliant Mid «oai»»a«iit*,— In tli<» loit article wn mw tb*t • 
ilagie force R <xiuld Ui fiiuud nquiTsUnt to Mircnt uUieiW : Uli* i» hy 
BO mtmua poculior tc tli* case in wkicli all ilia fovOM 
baT* the SMn* Una ot action; in fact, whea a ma- 
tnial point, A (fig:. 4), maaiaa fai *x)uilibnuin and«r 
thu artion o^ M«rnd fbrtw, S, P, U, it doaa ao be 
caniF aay one of tL« fotcMi, as S, b fapable of 
Matraliainfc the eambived eflecta vf nil tli« athnni. 
If Ilia ton* S, tbanfnc*, had it* diroction ntienHid, 
B M to act aluD^ Ah. Uiv fcolODfalian of A8, it 
waiild luudaco tlxi aams iiSaet aa the MV«tcm of 
f-o™ P, it. 

7in«, M foTM wboM «<hct Ls eqidraleat to the 
Monbiaed afloct* of nercial other fbreca U faBvA 
thaif rtm rih mt, aad with mtpect to this raauluul, 
iW Mhor fbmaa an tanwd vomjioiiaif, 

Whtm the fotOM. P, Q. act on a pnint ihey can only have eiw reanlt- 
«a; bat anyuftle ftwoena be molTed intocuiuponciiu in an iniielinite 
■naber of my*. 

If a fotnt tnoT« trim letrt under tite action of any oumbrr of forty* it 
•rfll htipn lo 0ia*« in tb« ditoclion of their nsultaat 

XS. Faj^tlBlafraM «f tarvoa. — When iwu foiciw act aa a point thoif 
militant is found by thn ftiljowing theorem, knomi a* Iha principle of 
iW pantLlalu^raBi offomM: — 1/lieo/orvt* aft <m a point, and i/latrt fc 
4rmmi fnmt lA^ point re p r tt mliay lie /orem m magmtmdt and dirtedatt, 
titdanlk—rlm't m mdm a iMroMagrtm ht amdnuitd, Ihftr rt»tiU»a wX 
Jr rtfranited ■'■* t^ja Mfw A amd dirretiom by lAat diagaial uiAkA jiiihk 
IItm^ Mr poiiU. Tfaiw, M P and Q (Sg. 5), ba two fbr«M acting on the 
point .\ along A Pond A(J rMfiettimly, aad let AB and AC be taken cnn- 
lamiBgiimt mate lumbitafiiaibi of Ivoglh Ihat 1> and Q contain unila of 
taat; lai tha pManntogiain Alt IH.' be ci>inpl«t«d, and the dlagnual AI> 
dnwBi ihea tbe thaoreiB aUlaa Uiat the teaullani, }(, of P and Q ia n\n- 

Pis- 4- 



nitla4 by AD j UiAt i« to mv, P nnd Q tofretbtr tn equal to n ti^l; 
foFci^ It acting Along Ui» line AP, and containing w Riim; uoiu of 
w AU coDtnina nnita of length. 

VroaU of thi« thenrem are given in tMaii>ni on Merhanie* ; wn vriS 
bom give lui account of ft direct eiperi mental verification of ill 
truth 1 but tx^nrv doing to «n must promiH! an tccount of n rert nmph 

T^t A (Rir. 6), be a nn&tl pull<7, and let it turn on a nnoutb, luinl, and 
tbiD axle witli little or no friction; let Wbn a veight tied to tbe «nd ofi 

Fig. 8, 

line tliTeed wliicli paMM 0T«r tbe piillev : let a epriag CD bt attachod bjr 

on? mid l» the end of tbe thread nnd W the end D to nnolhor peco of 
lliread, tbe otlier enit of whicli is fiuieiied to a tjxed point B; a »mI« 
CK cjin be fiutenod by ouu end t" the point f! and pi»i» intide the spring 
»o tLnt tljv vIpMiKfttioH of the upriiig cbh he meamtred. Now it will b» 
found on irinl llinl with a inicu weiglit W tbe elongation of the iipring 
will be tho namci whntfvpr the nngie contnined bntween thn pnrt^ of th* 
•tring WA and ItA. AIm il would be found that if thu whole were 
«iiKp«ndod frvna a fixed point, inatciul of pn«King <iv«r tho piitloj, tlw 
welglit would in ihia cam utmtob thi> eprinfi to th« aame extent a* 
before. Thi» experiment «howB that wlieu tan' id laken to diminish t* 
tba iltmnit the friction of the itxie nf the piilloy, nn>l tlie imperfect fUdd- 
tnlity of the threiul, the weight of W is trnoHniitteil without *cn«ible 
diaunutiou to B, ojul rxerta on that point a pull or forcn along tho Ud« 
BA rirtimlly iitunl lo W. 

Thit being premised, tho experimental proof, or illuntrntion of th» 
panilUlogmui of furi^ea. is as folloir« : — 

Suppoi^ll and K (lig, 7), lobe twu pulley* with axlnmade M nnootb 
and line iia possihlo ; b't P and If bo two weights iuapmdnd tVom fine and 
flexible thrnad* which, after pacing over H and K, lae faatenvd nt A to 
* tbiid thread AL from which bangs a weight It ; let the thre? weigbti 
come to ni«t in the pogitioiu ^hown in llie flgure. Now the point A i« 
Mtod on by three forw» in eiiulihrium, \is., V from A to H, tj from A 

U K, uul It frntn A to I^ coDMqtwntl;, May one or them oitttt b« eqna] 
•■d opptMile to tlifl TOMiItanI ol llie odier two. Novr if we ■uppoae the 
■ffHOMtB* ta be MTonpH) imnwdUuly in front nf h lu;^ tdste, w« cui 
4tB« IiM* upon it cnindding with AfT, AK, mA AL. If dow wv me*- 
tuic off •long AJI the pari Afi conlunmg «* manj incbca m P conlMiia 
jDoa^ ml alcmg AK the jiart AC' cnntMning a* many inchM m Q cmi- 
tiiu prands, and compluie th« pualklograiu ABCD, it will be found 
iha th* dngotul AD w in tbn Muno lino m AIi. rniid trmtditia u many 
tadM H R wcjftia poasdj. ConseqiuiDtlv, tbe i«Aiili&ni <•{ V Had Q in 
iifM*Hit*<d b^AD. OfcoiUMrUTotherunitaorienfrtbuidfurwiui^lit 
loiTe bvcii *Bipli>yr<l Now it will b« bnnd ihiit whon P, <J. Mid K 
vt ehaatttA in aaj way wbaierer comistent with cqiiilibriuiu ibe Mnw 
ecmnTw^^in can bn made, — th« point A will bare ditToruit ponitioiu in 
tW dlfTemil ca»M ; bill when eqaiUbriiim ia eatoblitht^, and the pnral- 
Idagram ADCD ia coa*tnict«d. it will be found that Al) in yerlica], And 
. (oMaim M m»aj unit* of length n* R eoDtajns nniu of force, and con»' 
' q«EU];ilrDprea«mUarorv««qualand opprult« to R, tbatis, it Kprc»enbi 
Ika nnilUnt of P and Q. 

Fig. 7. 

Fig. 8. 

XvanlWM B' kBT nnnibAr »l ftr««« acUnK •» •■• plana •» 

■ ^lai.--l>^t it"- forcpi, I', t^, li, S(flg.S|, net on ihi- piiiiTl A, ntid Ivl 

bMaHjte npr«ait«d \ty tbe lines AB, AC-, All. A£, aa thawa in the 

^^^Kfl^rttfeotafMf. tbe parallnlnirraiti AB FC uid joia AK: thialin<< 

vfnmaia tbe rasultaiil of P and (J, Sfoniilii, conipl^ie the ptirAllelu- 

p^ AFOD and join AH ; tlii« line reprm'nta tha rvsiiltnul tif P. Q, K. 

Tkwdlif, complete Ibe purnllflograni AOIIK and join All ; tbi> line n- 

pMMiU (h» rMmllanl of P, Cj, IE. S. It is imiuife«t that the cod- 

> 4iwlioa can ht^ extendod lo any nombeT of fon^m. A Httlo cunnidern- 

IM will thow that tbe lin« AH miffht be deleruiined by the following 

NMtracUua : — tbroufrh B draw IIF pamllnl to, equal lu, uud luwnrds 

iWtaiaepart ai ACi tluougb FdrawFU paraLlel, to equal to, nod townrdt 

jhf mate part no AD ; tbnugh O dntw Oil panllvl to, eijuiil tc, and W 


wuik tlia nine part m AK; join All, then All rcjvtBmU the nqnutj.! 

In place of (ku Bbove cODitniction. the roaulbuit can Iw 
hj ntlcnUtion in th« following manner ; — Through A dinir amj 
lectnoKuUr aiw Ax ami At (6g. V), auil let ; ff. y \te the 
made villi tkc axi* Ax br IhR linits rcprmcating the priMvuni*, IbwJ 
I'. Q. It can be rMolveil into P cwc, U en* 3- IE i^im>, acting' aloOjri 
Ax, and !' lin a, Q ms B, II coa y acting; iiloiijt Ay. Now the fonna j 
', ef forces vaa b« r^iiopd W a fiin|i1« fimw .\ bj nddition, fttteatiMj 
■ pkid to tho tiga nf each compuwDt i and in like luauucr the 1 
IbrcM can ba raduevd tn • itogl* force Y, that ia, 

S=PcoBa + *)««B+Rco«y+.., 
Y = I'lin a -t- trains -!-Hinny+ ... 

I thn addition di-nnCes tlin aiijfbrairal sum nf the quantitiiis no t&rl 
bt haud aide of tlie eqiiatiuuM, both 4ijpi aod nui^nitadc of X and V i 
known. SuppiK I' to denote the rvquiitxt rvaullaiil, and * thu an^ j 
nudo by the line refiri^sKinlitt^ it with the axis As.; 

thmo U cos ^ = X, and U aiu * = Y 

TheM eqnatinna give TP ^ X* + Y^, which dotermbcfi th« ma^* 
tiids of the rMiiltanl, and then, since both ain fl 
and cua ^ arc knuwn, ^ in d<^U<riuiaed witboiUl 

Thus let P, Q. and R be forcMoflOO, 160,i 
120 unita,rpspfulively,ai[dsup|)ose x.\l'. xAQ,and I 
xAlltoboangl«s(if 4.5°, 120*. andSla" respectively., 
Then their cuiupoucDU along Ax are 70'7, — 7 
— 103'9, and their comiMini-ni* along' Ay am 707,1 
ISD-O,— 00. The «iinie of these two *ets being I*- 
^'^- *• spwUi-dy— lOdS and 140-0, we have U «»♦ = | 

- 108-3 and U dn^ = I40'B. 

thorofore U» = 008-2)* + (l40-fl)» 

or U = 177-4 

lliercfon. 17" 1 coa t = — 108-J, aad 177-4 »in ♦ = 13e'7. 

If wo mndo ubo of the former of those eqnationi only, we abod 
obtain ^ equal In ^3'J° 2S', or 1^7° 'Ab', m\A tha result would be amb 
ou* : in like manner if ws determined f from the arcond ni|Uati(io onlyJ 
w« should have 9 equal to 63° S5', or IS7' 35 ' i but as we have both i 
tioas, we koitw that $ equal* 127° 36', and conBequently the force U I 
completely di>termined a» indirniod hy the dotted line At'. 

:!■). CoBdlllOBa or eqailllirlaiii of Bnjr foreca aotluv In one pla 
mi « potat. — Jf ihc rcsultiint of thf forcra ia lero, they haTe no joinrf 
ii^ademy tc aufve tiie [loint, wid coo»e<j\ieiil\y m« m ei\ii\\\\mMm. Thii 

oUfiMDnMft or ■wii.iBiui-'x or rniiCKg. 


(ibTMUB |riM9|d» Mtablvfl lu to iMum tli« fbUowing cniunrartion* anil 
c^twll«w,irliich*Bf-ireUi>sc»rUiB wliMbHr gireu foreea will kdpp a point 

8 ttp pct» tbat bi the cam rapnwBUKl iu fig. 9, T U tbv force whidi 
wiU IbImji P,lj, II, S. It is plain t)intTinu*t act on A ailing IIAptodacvd, 
anJ in *^nitud«< nnuit b« praportuaal to IIA; for lh«D th<> nwiiltantof tfa« 
Gtb fana will rqual wro,unce th« brohi-b UneABFOUAmtaniiitnthe 
poiM A. Titix rnnatmctioabpUinly uiiuiTiilniit totlM<rollnwing; I^t P, 
*^B<ef. 10), bo forcta acting on tli« point 0,Babidlnleid,lliT'ir[nn^'nitudH 
nddhiic&iiMlmnggivMi. k b known that tbajnicfaaUncfNi lij it fourth 
bi<B,8, andit i*rH]uirvd to dotermine tli« m>;^Iud«< anddifediotiaf S. 
^•hc any point D, and draw an; tine paralld In and lomanln tfan Hmo p«rt 
^■DP, dnw -AB panllel to and Inward* th« aune put M OQ, and take AB 
Sh iliat r : tj :: DA : AB. Thnxvli B dmw ItC paraHel to and 
towanld i]i« MOM part anOR.Uki^nCiiidi thatQ : R:: AB : DC; 
](tn CD i through it dmw OS pantlUl tn and tuwaidti tlie hum part m 
CO, lh«n th« rfiquirod G>n» S aeU along OS, uid it in tnagnitnde pro- 
prtional to CIX 



Vig. 10. 

Fit II. 

B U tn tw nbMmd that thi* nostraclinn can bo eihMid<.>it to aay 
annhar of farrto. and will apply to tha ciuh in wliicli ihe*e dirrrtion* 
WtnMla one piano, cnlj in tbiaeaan thf: brokpn linn AIICI) would uut 
11* wluUf in on* piano- Tbit above const rut-tiuu h frvijupully callnl th<^ 
I V ffim t/ Form. 

Tb> caae of Ilirc9 foma artinfr on a pmnt is, of conrufi, IncludiNl in the 
•bmrn ; bat ita iroportanci* ia neb that wu may fiire a toporate RtatMSMit 
tf iL Lrt V, H, R t^n- II }. b» thnw fon^o* in ciquiUbriiini uu lh<< p)^t O. 
hoa an; poinl B draw BC pamllul u> and tuwards tlio sani« part UP, 
haCdrawCAparalUI toand ti>«ard*lhaiiiimn))nrt iM(Kj,aad trdic CA 
■id) thni I* : tj :: itn :OAitlien,aaj«inm^AB,ih(> lliird forroKmiut 
Kt alaof OR pamllcl to onit lowatd* tho hiiu« part na AB, and niiut bu 
pMfortioBal b moifDifudo Ui AD. ThU eiiwtruciuin in frufjuently (tailed 
tU Tyia^tA ^-fi-rrm. Ii U ^ritfeat that wbiic the »ulea of tb« triana\e 



ox lurrtB, Fmtx, akd MoriiKi. 


■re icTcnllj pr>^rtiiiDd to V, Q, K, the uiglM A, B, C «ra •upplomfn-J 
twy to (it>B, RnP. KMJ r>'*pwaivply, cfliMcqiiPDt]^ eTery i 
csl T«Utiaa Misting l»t«-i-eii the lidpn iwd aingleit (rf ABO will i 
exist b«tw(ira tlia («K«» 1', Q, It, and thn •iip)>1em«et» of ibe 
b»tir««n their ilireciions. Tbua in tbc triaugte ABC it i* known tliit I 
ndn «Mi ]irr>poni<H)al to tho rdm of tbn oppoiito nnKln ; now rmm I 
•biM of ibe uiglM kK equal to tho udm of ibeLt su{>ptf<DHint«, w» at ' 
oeoictiido that kAoi ikmfortrt are im rqmlihnwn. eark it frtynuiiaiuil I 
tikttiiutif At m^ bitKtm At ^ in etioiit of lif «tifr tKv. 

We can cmUj- oIh^ from Uie equstiMU wliich dFlnraiinc tbe r««ulh 
of ta^ nnmbcr of torev i^)- '•'pt^tioon wliich oxpmB thn conditioni < 
«qttiliMuiit of anj! iiiuuber of fotcM acting in one plane aa a point: I 
bet, if tt = we mnat hum X = and Y = ; that w U> m;, 
required CondilioiM of eqnilibriom are the**: — 

= Pows+QcosB+Rcoe-y-f ... 
and = pMBa+Q fin 0+11 ^07+ ... 

Th« flm of tb<«o eqnaiions shovs that no purl of tb» motion nt the potat] 
otM UtlcL- plkce along Ax, the wcond that no part can talce place akasl 
Ay. In nthct woiJs, the point cannot more at a)L 

S6. C«ntp«altfon >na rg a otntlMi of parollol fcreea- — The oaM 1 

th» equilibrium of tliree pnmllel forws is mctvlr n purtiniilaT <«•«• of I 
equilibriniii of ilin^ fircm ncting on a point. In fact lei P and Q 1 
two forte* wheat dircctioua paa* througli the poinis A and B, and 
BMt in O ; Int them be balanced by n third fore K nhoee dlr 

produced iutereecle the liui- AD in C. Non- suppovl 
tho point U to more along- AO, jirndunlly racedinc] 
from A, the magnitude Mid directiim of R will oob>| 
tinu&lly cbang«, nnd also tho point (' will continiutUyl 
change it* powtion, but will always lie between 
and U. In the limit P and Q becouiv parnllet 
acting towards the f^itif purl bnlnncinl bv a ] 
force R acting lowaois the cnnttary part throit^ i 
point X betw<-eu A aud B. The qiicslion ia : — fint, 
on this limiting cafc what it lii>; value of R : 
whnt ii ihe pivitlon ut \. Now with regard totha 
first point it is plnui, thai, if a Iriaiiglc abc 
drawn ae in art. 35, th'> tuiffles a and 6 in tha linu^ 
will iBtiiah, and c will become II^, consequently a i ultimately equ 
o c + c 6 or 

R = P + Q. 

With iv^ard to (he wcond pcant it ia plain that 

OC sin rOIt = OC sin AOC = AC sin CAO, 




C A 


ni OC «n B(iQ = OC «ii) BOC = CB «in CB() 

hutkM AC ain CAO : CUmk CBfl :: nn rOR : tin ItOP 

:: Q:P(a6) 
ytM> 19 tJw limit when OA 4nd OB Womv pwallul, 0.\B t»d OUA 

bTiiiiiiiHil ilnrr. tLiU is their nncii become equal, alao AC and CB 

nffKdivelr AS and XB : c«BM<qu«Bi]y 
AX ; XB :: Q : P. 
t|nponi(Mi wbkh (UtenuiiM* tLa poMtion of X. Thi* theorvn «t once 
tit to iIm nilm for tba compontkiii of auv two jiitnLllirl fares*, rii. 

I. Wltan two p«nUel farom V •nd Q act lowiirl* tbo Mine put, ht 

9fi4Xj conncctod poiata A »nd B, tfa«it a r j 

Willi 111 b • pftraBei f<wr« kctiiiK tovardi f ^ 7^ 

paul, c^uftl to (heir sum, mid iu 
findioa diTidM ill* liiKi Alt vaio twu puts 
AC nd CB invciwlf pA'purlioaal to tbo 

II. Wlwn two [«ndl«) forow P uid Q k 
iMtvwajd* eoDtniy P«rt», at rigidly coo- Fig. 13. 
«dad pdau A aod B of wbkh 1' U lli« 
BMtn, UirirraMiJtuit i< ■ puall^l /otm 
Ktiii^ urranla tlio Mine put m P, equftl 
te tlm Piooto of I' oT(Y (J, and tti dtrvc- 
lioB dirid«a BA product*] in a point C 
Mch ifcai CA and ('B M« toTcFKly pru* ^,-' 
|«tk»«l to r uid q. 

In flaeli uf tl)« aboTv cmc* if w wvre 
to anily R Bt Ilia paint C, in opyxviiA 
JtwctJ-'B to tbow) ibown in tlw figutv, it p 
WMld fJMSlj' {by tLe ibove tlteamo) ^V l^- 

UaBCv P uid Q. and itMrmCore wlwn it acts a* ahown in fi|». 13 and 14 
it U liin roaultsot of P uid Q in thow «Mca mqiectiTolT. It will of 
follow iliai tlie fiircf K acliiif at C can be i«)ulved into P aud Q 
at A and B re<p«rlirtJj, 

If ill* wcoBd d ibo above tbcofcmii bo i-xarained, it will bo found tliat 
■a farce It esiita aquii-ahal to P and Q wlirn tbtuo foruns an v^uaL 
Twa aocb (mcm «iiittltut« a cwifdc, which may bij d^flDnd lo bi> two 
Bfual panllel force* acting towards coiitrar)' ^orts ; tin-}' jjuMOi^ lhi» 
Wimbalil* property ibat ibey on incapable of htaag balanced by any 
rfm^ totot wbatMwrpr. 

Is ibp euK at iDure Uuu two piu&Uel fuiriu tlic rMultant of any two 
on be hund, llwn oS that and a third, iknd *o on to any cumber ; It 
an b* ibown tbat huwcT«r gnnit the tiuuibt-r of totett lli«y wlU eithui 
JUb tqviUMuiB armtact lo a tittgla rcBoJuat or Ut a couple. 



ox Mtmtt, IXWCE, UtD HOTtOV. 


ST. Ccatr* ol 9U«U«1 foree».'~OD iv&nins to fifi^ 13 and 14, it wU 
he rrnurknl llut U we ouKPitB tbe potata A Mui B Ui b« fixed la 
dirr<^'>o> Al' ud BQ of lli* forot* P and Q, ud If ire sappiMe tfcoM 
dnMtieiw 1« be unwd tenad A and B, cu ■■ to ecotuiM punllol md to 
miliB 1117 giTMi aagieu witli thdr onpaal diiwIioH, tlica ibe dinHTtian 
ot their rMulunt will cratiaiH to pMi througli Cj llwt point b tbomlini 
callod Oe ttirfra gf the puallel tonxa P uid (j. 

Il apiMon fKin iiiT«9itigmtioo, ih«t wbraever a ■]r«l«Mi of |iant]il 
Imow rcduciu to a nogle revnltant, Ibow Ibroea will have « rmiiv; thai' 
b to Mj, if wa roondT* aach cf the foraaa to act at n flx>.-d {Xiint, tbtif 
will he ■ pcaol thrungh whi^ the din«llan etf their teanltant will pMi 
wb«n llio diroctJMM af the fbrroM an tomod thnsiugh any equal aogW 
■wutd their pointi ot application io tach ■ tBanaer aa to ictua the 
panlleliani ot their din<cljoDit^ 

Th* mntt ramiliar cumjilr of a contK of parallel forcw ie the eaan ia 
which the furoa are th«< wi>iglit« of the paria of a bodr ; ia thia raao th< 
breo* nil actin); towards the nuqc pan will have a rmultairt, tis. thak 
ram : and their trntn* it caihA thn nentre of fravil; of the liodf . 

%. MoBonta «r roTcaa, — Let P denote aor force acting from B to 
f, take A any point, let fall AN a porpnndictilar frtim A on III*. The 
durt of the uutiilwr of iinita of force iu AP. aiid the nutabnr of ooiu 
' of length IB AN i* called the roomi^iit of 1' with roapoct to A. ^noe the 
foiM P can bi~ i>ppr«winted hy a ali^glit lin«^ the 
moment ot P can be ropnwented hj an luvx to tad 
if liC i* the line rppnunnbng I', the momcnl i* 
properly rcpn^aenttrd liy Iwicir theare« of thn tritiogle 
AH('. The perpend iriilar AN u eomelimu nalliid 
the anu of lh« preMuro. Now if a watch wnn placid 
witJi iu fncc upwajfd on th<! paper, the farc« P wonld 
caiiaetheariu AfilolurnrouudAindiecvntrMiydbfr- 
liaai tn the banda of tho watch. l.'Ddir theae circiimaUnceei It ia iniial 
to oouaidor th^ moment of P with it<*p(«t to the point A to be positive. If 
Pactcd from C toB, it wtmld turn NA in the tamr diroction •» the hand* 
of the waU'li. find now il* rumii^nt in reckuniid itrytttirr. 

Tho following: n-niKrkiiblf rplaliun e.xiila bi-lwiTn any forcM actiag 
In oui> plane on a body nnd thoir rcfiiiltAnt. Tnlie the momunta of the 
fnnve und of their re^iullAOt with respwl In any one point Ju the 
plane. Then the mometit of the rcaullnnt equnli thi- mim of t.lie miMneot* 
of the MTeral force*, regaid being bad in the t^tu of the momontii. 

If tho point about which the (uomectn arc inciunired be taken in tho 
diraclion of tho nwDltant, it* moment with re«pocl to that point will h« 
mo ; and conanjueutlf the aum of the momenta with irapect to audi 
point will be lero. 



tkBdSca«tUn.~W<>wn] pnMMd toaXMnplifv 
ftw liiid dnwD bv imtetii^aliii]; tbe omdittcnu of 
iflTbodiA* in a fevr simpl<- atea; but boToMdcii^Ra we miwt 
r wkich lio1<U good whraoTrj A mutual aelioD ia calM into 
■ two l)0(li««. JSnHiMM u aifmfi t^mat and tmtrary to 
I it U> My, Utt tmUmal «(4mw of lim Mitt am taeh atkrr *n 
M nfual ■> mmowd tmJ op pat H e ia dtreetion. TliU Uw u pv- 
•I, and ia oqiuUv tntn wbca tlie bodie* mm in motion m woH 
Bjr an M nvt. A vary iaMractiTe example of thii Uw kaa 
M KiTm (S3), ID nhicli tke nctian <iii tlie rpHng CD (8g. 4) 
ibl W (iKii«miUDd bt ib« otring^ to 0, Mid balutecd bj tbe 
tha grouMl tianaailied frmi B to D. VnAvt tbeae drema- 
I i]wwir i« nid to bt Rtntcbcd bj a foKfi \V. If tbe tpriag 
>wl,aidlli«lhr«<adwMecoBtinuonaboiu A toD, tt UdaMttfaat 
it i> Ktrotcbcd by two equal fonxa, tU. an action andreactkui, 
to W, and thf tbiead u nid to fDHtaiu a tewion W. WhMi a 
(•d agvMt a mMoth mrface, llic mutual aeliou can only 
iloRg th« oonuHoa perpvwlieular at tbo pMot of cootaot. If, 
be bodies ar« ron^b, thia mtiicCioB ia partially romorod, and 
ntnal action can take place in any dinMition not making; an 
*r ifcaa wmh deterounabi an^ln with tha onmmon petpen* 
Ilia dcleniunat« angle baa di^runt valuM for dlff«mt «ub> 
I la aonatitnea called the limiting angle of rMiMance, tonMtitnea 

Tiaiar iaan«it*giTent« anv bar unightorcurrod, Alt, itat- 
lad pniint or edg« e called the 
Tho fin^a acting on ihr' tnvRr 
'^ vt If ia<anr» Q. ihepowtr 
B reaction of the fulcrum. 
t arc in cinilibriain, tLe re- 
P and (J inuit act through C, 
be tJu'V r>~>nld not bo balunCMl 
ctkm. Draw (Aaiii^liiiiiigte* 
. M to I'A produced ; then ob-l 
ltPXM,and({x Mara III* mo- 
' and U with leapeotlo f, and 
ban amtraijr tigBt,w« bave 

^ X M = Q X r«: 

a ecNnrnoDly e]ipreM<>d by tli« 
b tb« litvar the powvr ia to the 
di« inreiM IMM of tbpir amu: 

m diTtdod into thnw kindi^ aetord'nig to the pocitioo of ^ 
jttpert lo Uk poiata of f^eatioa ot the power mod \h« 







vcigbt. Id ft imr »/ tittjtrrt kmd tha fulcrum u bttwcea tW poim 
and ni*i«taiic«. u b li|r. 10. In n letvr of lh« uvand laml the ratdyltmce b 
betir««Q the ponor imd tho fulcrum, m in k wbevlbnrrDW or a {iiiir of 
nuicmckera ; b ■ Jrtw of the tliird kiii(llhepoir(irU1>at«««n thefulctvn 
kud tlio rrnntnnci!, ni in o pair of Umg* ur tlie treadle of a luthi.'- 

41.Tta« 81nctePaIl«)r.— In tboraurofthc aingkiixpd pulUf, aliiwi 

in fig. 1j, it IbUoKs at onci- from (■'W) ihal wli^ti ttii* forces P and Q sic 

in (H]iii)ibritim they will hv oquul, tliu axis nf tb>- puUfj 

Witi^ siip))08t'd pdrfocllif dmnoth nnd tbe thread pi^ifwdj 

flnxilile. The eamc conclusion foUown dirLMrlly fn-ni tha 

priuoiple iif moments ; for the rwultaot tif P mul Q 

muirt pnia Uirougli C, or ulhi'nviMi thay would cauid lb* 

Fig 1 7. pulley to turn ; now tbolr momi^ta arv tv*peelively Px 

CU Mid Q X CS, anil aince tli««e liave oppiMita aigaa we h^ve (38) 

H PxCM=QxCX. _ 

But CM ttud CN Iwing equal, tblH equation shows that V and Q ■« 
cquiJ. In the case a( tho ninfilo moTunble pullty, 'hnnrn in |1^, Irt, wt 

hav« one end of tho rope t.j a point A iu a bcun. 

Tho pulley IB conssquently supporlod by two fofwn, ni. P 
and th« r«BCtion of the Hied point whioh im e<(UBlloPi 
these two force* support Q and ihe weight of the puUt; 
w. In tlie case n^presuntird in thefigwro^ th« partaof tht 
ropo are parallel, consequently (3R) 

2P = Q+w. 

When wvcml pulley* are united into un« nuuduno, thtj 
constitute H ^itrm of'pullnyi; auch are — the Block aod 
F-K- >8. TncWr, the Banon. White'* Pulley, Ac. 
43. TtM tnotlacH »luia. — \ very inntructivo and useful Rpplii-alion of 
thn rr.nuluiiuu nf I'htl'us ia to be foiiod iu the ca^W of a biKly Mipportiid oa 
an ioclinod plane. Let AB (fitr. IVI), be ibe piano, A(' it* hn"', nud BC it* 
bei^bt ; l''t a body M oouMdervd as a point, 
wbo8t>niiuH is M and weight M^ or Q, be ra|i- 
portcd on it by a force P acting alon^r ^^ 
The plane is suppowd amontb, and therefon 
rencia on Al .with a force B at right angtat to 
AB. Braw CB ut right angles to AB, tliaa 
the point M ia lield at reel by force* P, Q, &, 
vboM direclicina are aevornlly parallel to the «ideB of the triangle UBO 
which ii mmilnr to CBA. Ilunce 

P ; K : Q;:BU : DC : CB::BC : CA : .\B 
or ^Dce BO = AB sin A and C.V = AB coa A 

w» hare P = Q na A and It = (J ooa A. 

Pig. IB. 




fk tbe Mmebet ainy bo nutrd in iki* fom, wb«n « nuu )I ii> placvJ on 
IB iftdkivd pkno, iw prtMuif on Dm plativ U M/omA uid it* ff>rcr 
4«ifii Uw pUnw ia MjpiinA. Is tb« abure cue thcac (oro*iu«bHtuun<d 
br P nd R twpectivolT. 

That luppoM DC iwd CA to be ft. vtA IS ft., TwpectiivljF, timn 
Ar«aiM|aU 1& ft Coo<«qiu>ntlf, ir ih* weight of q i« 3(K>ltt9. it 
fnimta on the pluw n iM-rp«<id]cu]u ptuMim^ of 3^ Iba., and requira 
&« itt nippOTt > force of L'Itt Iba. aetic^' np Ibc plooc. 

4& Tbe irads*. — Thi* iiutnimcni it n:>tiiing imt a Diove«bl« iodined 
|llat. It U ummI ta M^Fral forniii. oif whii-li ihv Bnncxcil is, pcrrhiip*, Hm 
iMGwtlMwinif tb«tctiD«i of the forec* called iaioplnv. AB isaSx«d 
tUk. ACDE if> a pleee whom laieral motioo U pivn-uiLil by a Rxcd 
!■!• F. A nc ID ■ irnl>rr «hoi» iui);lu i* Hich that oan of iu fanr« it jn 
wttactwiih » face of ACIiE an sliovii in the figure. ADC bcinj.* furcci) 
brwanl bv T, •iy«a«oiOM the THUtaiitv Q Ot'iintC an ACDK. Tho Tarinu* 
bmra tallnl inu play am r»pi«wnl«d in tli« 
dufnwt, n*Ri«ly. I', Q, tbe nactioo of the 
uUeS, Ike tuuUial action bitwocn tli« picctn 
R, R, uui tbareactiuDToftheguideP. We 
will lappoap the aaglo* B^ 1>, E, and E.\B to 
U ri|;lil aagUw, «nil tbat P and Q act at ritcht 
aufrlet iu DRaod BC rcapectivdy. iicntAvt, 
mcr tb« Mirfacca In contact ara (maoili, S act* 
in a dlraction at ngU% unjcW to AB, R and 
R, to AC, ai>J T t« AE. Tbro.igh C^ drew CO at right angles to AC ; 
tWn iIm* bodv ABC being kept in fijuilibritim by tbrce furc«ii, P, R, S, 
wbow dirKticaw u* nvpcctiTcly pamlLel to tbe aide* of tha triangle 
DOC, we hata 

P:B ::II0:GC 

Tte bodj- ACDE being hepi in oqiulibri&n by tbne forcM, T, K^, Q, 
vbive dirertioM »n re«poctively parallel to ibe tide of the triangle 
Dfir, we hare 

B, : Q :: «C ; Cl> 

Saw I( and It, are eqnal, bttog the mutual aelions of the two bodiea 
ABC, ACItK; tbciwfiwe, compounding the rniio*, wb have 

P:Q::liO :DC 
w, \^ dHiiUr triAnglca, 

P:Q;: CB : BA 

tfaifOitiiMi cqairalent to ibe oquati<jn 

P = g tail A 
44. The aervw.— It wlU be reni»rkwl tbat vrben the wedge ia mnil 





M in ibv l»M uticl*, (j CBDsnt Ih' manr tiniM gnater thHn P. Mid tbo | 
tb«t the s[)ikce Ihruuttb which P (-an tlfl Q in The scnw it i 
mervljr a m'idilicaiioa of ihn nptini! by which thr^ limiti of ila a^ipU^uiM i 
in bolh (hrw n'kji^cU »iv <<t1<<ii'j(>il. To i-X|)laiu tliis it amy he iihiniiiJ ', 
ihaX if tliu thn-ad of a scn^w were mtuced to a Iiii«, it would bccoiM a | 
euTve called the Mui, rimning in whnrlaiouDd die cylinder; lh«< dlMaan] 
bfitw^D any twu cunsvculivi' liirns mcwiimd prmllel to the ui* of I 
cyliltdnr Ixiing conitaut. and taIW the j/iVcA at the 'Ciyiw, Now if ABC 
(fig. 20) wi-rc- wrappvil round a vyUodvr, whoK ilimcnstcina wen twk \ 
tbat Ih* hasp AB cMnc-idnl with thii circiiniffiivDc* of the haw of tbi 
cylindor, nnd the height BC with Ihu pitch, ihe hypothtviuu CA oouU i 
ba brought into coinei(ti>Dc!e with onn wbnTl nf tlx' hvUx. llnd«<r thaw 
ciicuniatanceti, ihv an^ile BAC i A | is cailed th<i iucliuntinii uf tho tbmd, 
and if r dcnotd the rndius uf lh<^ biiMi of the cylinder, A the pili:h of the . 
soren, we thnll have, niiico ABiAn.X «qntila BC (Bg, S0)| 

2.r tea A = A 

l&MOTer, if ACDE wore wrapped n>und the iniidc of ii hollow nylisdcr . 

or n»'(fi);. 31juf <'<]tial radium it wooU 
take tlio tonD of n hnlii, or companion 
acrew cut uu ihv iuvidc of the nut: aad i 
if tbu KTcw were placed wilbia thi j 
nut the two hclice* would be in eMbl 
contact If now we Buppaw tlw 1 
pnwcr to Oct at th? ciid of an ami, wa 
nhnll Lnv« tntuHfuriiifd th# wed^ of 
tig.iiO ioti) a 6iTeiv, one end nf whic^ 
wijrk« on a fined tnbk with a tnoi«- 
nhl« nut. The anurncd figure show* 
the nrroDii'eiiient, hnlf the nill hdltg , 
reniuvcd in ordt^r to ahuw how tba 
thread of the scjew works within tbp 
groovu uf the couipauiou. When the 
onTi is tiimt^d in the direction indicated 
by 1* Ihe point B will paaa tu B', bul, 
m thn nut in lurpt by the iiuidpf G, II 
from turning with the «crew, it miut ' 
iit>w oc(:ii{>y tha ftnat C of the com- 
paniiMi. and consvqiiently the nut niuM 

be lifted no that t' Conic* to B'. If tba , 
nut wpre fixed the screw would b* ' 
dcpressud by th>< mrih amount, whi-u I' actii lu indicnied. 
If the iKtrvi WMT turned by a force P' acting tangeutially to the biue 

Fig. li. 

FmcTios. 27 

of ih* rrUndcr, it ia pbua tbat wben «U (rictian* nrr noitl^cl*!!) tile T«lft- 
tJM letwmi P" and Q inu«l be ibn mdic m ibM lwtw<wa P nd H in lb* 
iMtutiel*, th»t ia, 

fPsQ laa A 
3w r = QA 

>W F •ajpy (miyindiculttjly U ibr vad of ao anna will ban (b^eqoalilj 
•4mtumUt Uit- Mia« Uadmc/ u P to tiim tb« icrev, |>n>v)il«d 

l"r = l*a 

RlbetvCur*) the rvbtioD l><nwe«n T* Anil Q U given hj the equntinn 
[ :}» P = QA 

w power ka> to Ui« r«ai«Uiic» ili« mme »tio wbkli the pitch of ihr 
Knw tuM to tlic cimuitf«Nac« of the orclv diMcnbcd by tho rnd of th» 
Dm -. fur naniplr, if A r^nai 1 inch, a R<iiial 2fc, n pow^r of 100 lb*. 
•dbIiI oTrrcome a reuuauoe not exM«diii^ lu.OOO Ibi. 

■tA. ^rlMl««i — To ioTcaliKiiti! ibo effrci nf tho friction of the ports of 
iMrhlwin on the nUtlon coDnecting: ihr powut and renBtanci- woM uko 
H Ibr bsTood nor pifMcnt limitii, bat Ute following points mny be tnvn- 
rtHBil ir there wen ma ftiction there would (cvm-rullj' be ouu rntiu 
■■JM*^ bwtworn ibo powrr and tbo renistanw, tbat pquiltbrium mny be 
pDaible ; thus in tii«i •ingle filed pulley the ratio i« one of eqttality, to 
Ikat if r w nol i<qual Us Q (fig. 17) motion will ensue. IT, bowoTer, tba 
lai* ot iho pullry i* taoffh co M to tum wiilt fricti<m on it« b«anuff, 
iWe will hf two limiling ralioi, such tbat if Iho ratio of P : (J hare 
|Bjr iaiitnuisliate yalv« the mncbise will bo at rvnt. Thun, hiippoee (J 
lobe aOlb*., the fnclMin on the axln may bv such ibat Sf P ezcectl 
n Rw. it win UR Q, and will alluw Q la dro]) if it be !«u tbui 19 lht>. 
UPhATe any raluK ialmMdiatn to 19 and 21 it will balance tj. lu the 
MM taumer ud an Inclined pUue if Ibe plane b« einuiilb and if P act a* 
^[Hiii i1 in 1,43 1 imlo* P worn exactly equal to Q sin A, thii bodv 
hoaU more either tip or down ibe plane, ttut if ibe pl&De tie rou^h 
lU* ia BO longBT title ; iIkt« will in tbiri caae be two rorceo. nami'ly, }" 
|iwlii and P" leM titan QsinA, such that thi^ fnrniRr will just not 
dnw 111* body op tbn plwM, and the lttt«r will just not allow ibe bniv 
lo diilr down t&e pUike, jmd then anjr force P intertncdiale to I" and P" 
«t!l »u]i[>nrt Q. Mowoter, If the b<Mlj be left without t>apport ou the 
fllM' it will alid<> down however nnnll the iticliniition, if the plane bo 
nonth, but if tlie plane be roufth it will not slide down, though unsiip- 
ftfttd, nnleaa llie inctinstion exceed b ccrtnin anfrte, whose uiaKnitude, 
lkiU||h diilernil for difl«i«t]t subattiDces, in tiiliinlly tho ■ame for tbo 
•i^ MbManon. and is In fact the onKle of repose mentioQed in (39). 
ihtf ia t4 the iiliaoft imjionaiuH- w tbi> pncticnl application of tbe 

28 mt hattek, roiecK, xvz< motiox. [4S- 

wt<d|K(i>4>. F«rif iIm Mflt of iodinktian Aof l)iewv<lgi> (Sg.W) be 
lew tlion the angle of npwn, Q will not fotcc tbe wodim out, fVMi wken P 
cenvH lu ad. Now in practice llie w«dg« is (diuiikui]^ driven fuimiid 
hy a blow ; but, n* wd ihiiU «e« in smjuvI. n blow >■ it In^ fo(«f> »x(<it»d 
for a ihort timn, ronwi^iinntlv ■ blow will cai)Si< h NaiBlaiMe Q. mn 
when T«r7 prnil, lu vieM tliruuf^li a miiall npiiCF, tkiu each blow Ktntdl 
on tlie back of IK' (fis(. SO) will caiun thn wr^ip? to advance a liltlt, 
aod, fU Q chuiilX fnrw it bark. Il \iill«ta_v iu thH poaitiou to which it hw 
htrvn AdvnQcvid. and iroiKcqiictitl; by n iiiccntiinn ofsiich blowt It can bt 
CBuwd lo adianco rhnxi^b anj requisite- tpacv. 

Vi. VDlfornUr *«*>l«r>t«^ raoUUacar invtlMi. — Let u* uippoMa 
body cimtaininff /» utiila of luosi to move frtiiii n»t under tbe acticii "f ■ 
loree ooDtainiD^ F >iiiit«. th« Iiodr will more in the liue of actioB of tb 
foi«e, aad will HCiiuirc' in vacb iH?coad an additional vdgnty/givMlbf 
the ^nation 

T = mf 
eonKquentiy. if n U it4 v«Iocity at tbe end of I noeonda, we faar« 

■■ - /' (1) 

Tn del«nninif the (pare it will dnirnbti in ( Meoudn, wn niRT teaaa w 
follow*. The velocity ai the tiino I being Ji that at a lime « + * 
will b* /t* + t). If tbo body moved UDiformlf during tbr time » witk 
the former velocity it would deecnbe a apaea t equal to ftr, if wilk 
tbo Utter relodly a apao? (, equal loJ(t -f i)r. Consequently, 

. : *, :: 1 + T : 1 

thereftinr. wlim i i" itidefiiiitely stnnll, tbe liinilinf: vfllues of i and t, m 
equal. Xtiw jiiicc tliu body's vdoclty is coutinnnliy iiicrmmy durinff 
the timo T, the «paoe aftimlly deneribcd U 
grenter ifaao i aiu] Icsa than 9, But i>ia(a 
ibe limitinff riiluM of « and », are equal, 
the limiting value of the Rpace Anaenbtd i* 
ibt' nameaa tlint of *nr«,. In other wutdt, 
if wo »uppoBp the wbole tinifi of the body'* 
motion lo be ilirided inln anv number of 
equal pMi^ir we iletenuine the i-elocitrof 
the body at the be^innin); of each of iImm 
parts, and if we RAeenatii the epace* de- 

Fig. 32. 

JaUJiF,... flfld drtw I'D, QE, RF, .. 

equal poxta 
BCat ri^hl auglea to AC, thta 



iPD* AP x/,QE = .\Kx/,RF = AFx/,BC = ACx/, 
Nt. PD will repivKBt tbf^ tvloriU of tbe body at tbo cod of dm tinio 
WfMMwJ b^ AD, BBii Rmilwlv UK, RF, ... BC, will repmwut tbo 
nladt; al tbv tmil of tht tlin«8 A£, AF, ... AC. Compleu tlu tret- 
—^ IV, ^, Vff ... Tbes ncUofl-ln r<i]itiwvat ibe space dMcribed br 
the hoif duritifr (he wooBd, third, fourth, ... povtlcnu of the tune cm tbo 
tin* npi^oaitina. CaiiBH|Uimtlj the i^muo octiMlly dMcrihvil during 
ikt \im» AC i» lh«> limit of tha aun of the recEaBglM: tb':' liuil Mn^ 
BMinmtly appnincbHl u th« nunilivrof pariainio wbich .\(' i> diiiilod i> 
MittnBallv ini;r^M<nl. Itiit thin limit in tit" wes of tbe Iriuiglr Alt*' lluil 
a (.\C X CIt lit t AC X AC X / Tbcrrforr. if AC rffprewtta tbo limp 
I danng wbii-b Um- bndy doKribn s jipace «, w« bnve 

* = i/P 


SinM tbia cquatioD can be wrill«o 

ira find, oa tmnparing thi* «itb niiuiiinn (I), tbfii 

r" = 2/. (3> 

Ta illiMOate tb««> nquatimu let ua nippoM llin nrclomtivc elSect of tlie 
inm to be (^ Ijiat b to mj, ihst io rirliw of ilie acij'.in of tli« force, lli« 
haij aajiafM in «*ch MiooMnvc scMmd an addiliniial vnlocily of ft. jk-t 
(Moad, knd l«t It be aalnd wbat, on the mippcnitioi) of tbe ^Miy moving 
bant nat, will b« the Tvlodly acquired aud lhi> apai-p divcri))^ al tlit^ 
^ of 13 aermdi ; tqaaliniM (I) and (2) raiibln im to aniiwrc that at that 
iaatant it will be moTing at the rate of 72 ft. pvr lecoiid and will bave 
d«inib«i *:t3h. 

Tbp fi>Uo«i]i^ ImpimaBt rwult follow* trom equation (S). At the *«il 
atHrn Strt, aeoond, tfaitd, fourth, vte. ■aocaid of tfaa motion th« body will 
ha«a (tMnibcd If, 4/ x 4, */ x 8, J/ x 10. etp. ft,, and coiuwqunntly 
imiaf the Bnt, (coand, third, fuurtb, el^. iwi^ood of tlii^ uiotiou will have 
JiaailxJ i/i )/ X S, t/ X A, }/ x 7, Mc. (t„ namely, aiuii!** in arith* 
iMticKl progRaMoa. 

The nvulta of tlw abar* artielo can bo Mated in the form of law* 
lAkJi ^pty to tbvatate of a body Btorin^f^ui a ttaWof rmt: — 

L Ttf iWooiti'M are frvparHomii to lA« timt^ Jurmg KhiiA Ihr vvaion 

IL 7^' ifMoM JurrAfd arr prujiurlional lo tJie iqua/r* of M« limtt 
imfla^ in llttir ibtarijittaii. 

in, JA* fpdPM JetcriM «n proportumai lo liir fjua/vi of Ihr wforifiXi 
^ftirtJ during iMr tttneri/iatm. 

tV. Tir qMoM tlMcnM in fqaal mretttiif ptnodt oftiim increoM bj( a 


Tiiiml if nfi ill it ill 1 1 Ijiitglii' T-Tft T - ^-'- -' — ■ — 
nu* nppB» to u> hmm tm iattaJ nloeinr V, ia tW^inetMi of lli« t<mx 
In diii CMS MpHtuM (1) <X) aad (3) cin W «id<r ilMwn to take ihr 
Inlbnriaf bm* iMpMimh : 

.= V +^ 

^ = v» + y. 

If tka bodr Bon bi • iBnctiaa ujifajla w Jkat of tlm few*, / muM l» 

47. MvtMo M» Ba to»Ma« »laa^— R'f'TTiafr la i4Sl, nippcMC lir 
fom r Doi ID acl; Uwn ttie cuin M b <ict«il on bv u unbatMrail 
f<w» M; aiA A. in the dinetioci MA, ca«M«iiM<idT ttie McelMUlag fan 

Ldoara tbo plaM U f «n A, uJ ik ■WUoa bcconiM a [wrdcaUr cam «( 
Uiat illniiiw«il in III* laat Bnici*. If it begia to nore trom nM, it 
will at tlie oal i/l wmoib acqaiiv a Tcfed^ r gitw br tbe equatida 
T ^^nn A 
■nd will ilcaoibp a Imgth > (ft.) of the plaac fiTea br tb« tquitiM 
. = i^rinA 
AIm. if r h Um TtlodtT acqaired while daaeriUag « feet uf ibe jiUiv 
' t* = 2)rtMBA 

Uenca llg. 10) if a bodv alidM down iJ u? plai w &«■ B to A ilie Tdoei^ 
wbidi it aeqabw at A eqoak ^^lABria Aor v^^BCTthat u Vtmg, 
iba Tvlodtj wbicb ib« boily kw at A doM aol dapcod on tba tmfir Ai 
bat uoIt on tb» pt^pcndienlar h«igkt DC. Th* mudf wovld be UM If 
for EL\ we RubM)tut«d aaj Mimth curve, and hcnat wn maj- Ntata 
IftBually, ibai wbrn a bodjr vhitm ulcmfc uj aiuootli lint- under tba 
■ction of f[iavily, tbe cban;p> of i^lm-itT it •i[htrpiicp> in moving from 
mt point ta anollwr ia tliat dae to tbe nrftcxi/ height of the fomwr poial 
above tW lattOT. 

48. CoMpoklUaB or relodtlea.— Tbe nile for tb* com^MNntins of 
Tclocitim i' lliL- naiRF u llial fur tlic coinposi6uD of fomw ; ibw loUom 
evidently fmin thn (act that Ii>rc«« ara m^wumd bv IIm momciMBm tbajr 
eommunical<'. aud are ihcwfun; to one anotber io the Mue ratio U tlu> 
velodtiei tb<7 mmmotiicMc to tbe mhm body. Thiu (Utr. ». art. -IS) if 
tlw point htM at xny iu«tfiat a relocitjr AB, in the dinxtion AT, and 
tbere i» couuutuiictttcd to it a veloeitjr AC in tbe directum AQ it will 
aiOTu in the ilirrclion AR vitb a Telocitr reprnvnud b_T AD. Aad 
ocnverwl)' th* veloritr of a body rvpinaeiitcct by Al> oui be raiolnd iato 
two compnacnt veloritiri' AT) And .\0. This miggmti the ni«tbod of 
detennuriag Ibe niolion of a budy wlieu nclrd ou by a force in a diteettM 
Onaarena to ttiP direclion nf itn vnlocilT. namely, luppoie tbo tiino to ba 

diHdfid iato a gnrat titinibi^r of intot^-nU, and ru^bh Ite ")o\o«l's wKuAi) 

ba Dksv iW' 
BB i^Md *• Aft>H CH. «i 
to AH ^ CL ■ ri^ aq 
^ i> M to fainai AB ■ 
BOk • idoci^ ^ ^U « Ife 
» • to. B/^iM «. 

viU «a*» AHVf tkr »sl A«t twc t, 
viU Ite mldd^ MM|y ■ill Id V Md^ 
w- ■» BB iqnk Vt, if/ bN 

BC, tB the «DMi faMmL b «a b «*- 
■■<«d ihM » BC Md AB ■• ^^ »4 

«ia^BC»tk« ^MMib^Afi^lWiK 

iW CnetiM, ar« the MRMBi itf lb niaeitT. 
Wba lb faoAj ■ at lb pnat C n 

ft» Mib ^ rflb ihM Mhwrilbb^win bMD. Ob tb 
>(bb4;^«ill A^oOa A* ptir^H ABCD_ m& 
Td«j»V. Xm &«■ li^hr ttbqtio JIGB. BCL «c b** 
HB ; DC :: BC : BL 
Sr : Vf :: T< : iO*> "' ' 

Hwutmate an nba^r (, nd ibnAw dM vba t k M Ji faH i lj 
wA. ?Co»l.y ij^liii lilnttwuwtehbaiMatba^WrfMMPirf 
tW plTffM, a«im «bM (» Urfsiulr mbH, tb J 

Mihi til <^ iHw ■ iiiil»i iifciMi iill^i li S(L with at i^fbrM wfad^ 
•fSlLpvanad. 1^ fw* Mti^ «• i> laAV to ^ flntniritt 







body tundK nt (vich jxiint to ninvn tilnaa thn tiin)[<«t itt Ihnt pouit, eooM- 
quHutt; a foni! must cuutuiualiv act oa it toKtmit tlie moUv I« doBetf 
it (Kmi th<i untp^nt, aiuI kiwp it movinj^ in the ciielo : is Ibe abom 0M» 
tho forp'' (vxilnin" Ji^O iinil*, wliieh in nunrly 1ft lb«. of fo«*. 

TiO, KotloB IB a T«rU««d ett«l«. — Lvt ACDBlwar^iirlvwbowpliac 
in v^ilii-jil and niiliii]) dcnotM by r, S<i|ip<Mt4 
puiut plucvit at A, and hUuitmI to alide 
tho curve, what vplociti- will it have angiii 
i*ttctiiiifr any ^v(in p.ViutP?' Draw tbi 
diamelcr CD. join ("A, CI', «nd draw dw 
iiiTital linos AMB and PNl''. Nnw amuhiUuI'' 
cun? tu bt- BID uo til lh(> velucilr accjuiriid a 
fallic)! from A tti i* In thnt dui to M X tlx* VHilieil 
hi^ight of A a)>i)v« r (47), if, thpreforw, r dcoirie 
the Tclodty of the point at I' wc ohall have 

Kow by rimilar trinnglw DCl', PCS' w ham 


i!on*«^uMitly, if we denote by t the cbofd CP, 


in like mannqr if d denote tlii^ rhord CA, 

2r . MC = n' 

Sc . MN = o*-»' 

and »« = ^ (fl._^) 

It iritl be remarked that v will have equal values (vhen i baa the Mine valne 
whfitliT po.iitivR or nngnlivi^. nnd far any one value of < there are two 
equal TAliieii nf c, i-im- [in>ttiie and one iii'irntive. Thai ia tu any, rinoe 
CI" in i-quiil Ui CI', tliQ liody will have the snine velocity at P' that It 
ha« at I', anil al any poiiil the body will haie the aauie Telocity whe- 
thur it is ;^>iuJI up ihu ouri'i; or down tlio curve. Uf oourx; it ia ia> 
eluded in ihia alntoniotit that if the body begins tn move from A 11 will 
Juat iweend lo a point It on th-? oih-T sidu of C, duch that A aud B are in 
(lie Munn horii'mtal tini'. It will also he remarked that at (' thn valnt 
of t ja zero, (?oii«oqii"utly, if V i» the velocitj' acquired by the body in 
fallinj; frciiu A to C we have 

■od, OQ the other baud, if the liody begins lo move from C with a t*1o> 
city V it will reach a point A »iich that the chord AC or a ia given hf 




Ik Mmr fqutioo. In other wonb, lb« vekwdty Nt thr toWMi pttiM i* 
HfottionBl I» thn cliord 'ifihr nrc ipxri}trd. 

AL KvUaa of m atinpia pCBdnisiii.— Br • Nmpln pMidnlum Ja 
kMHt ■ be«vy pajtide aii>p«ixlMl br a &ae ihmad fri>fa a lixcd point, 
iboM «Uch it oacillnU* irithout frinikin. So 
kr w ht ctuuigca of Teluciiy art- coacenied 
kfj will bv Umi wuiie ai ihoao of tint, point 
n tba pNvious aniciv, tot the tanokai of tb» 
hwd actinic at each pcuitiOD in a iltmtiuQ 
S tiglit wiglw tn Ibnt of til* motion of ihi> 
mini will no mon ntFf^t it« moliiHi thiui ikp 
Metimi nf t)H> miofitli currc offodd Ihnt of 
im point in tba la«t article. Tbe tiiiiH of 
n oariUation, tiiat La Ui« tinx! in wbicli lbi> 
nint noTM fram A to Il> <»n Im «««ilT v- 
mtainni irbMi tit* ate of ribtatioa is sinal), that it, whon tliit ehoti and 
Iw are do uo( RmmblT diflWr. 

Tbua, let .MI(Hit. 2&)«qu*l tfa^areorob'-nl ACB (Gf . 34) witb Mo- 
rn* C aw] radioa A(! or a ileaaihr- a drcic, aa<l inppow a point to de- 
<ribe Umi cii<cuini«f«nee of thai drcb wiib a (uiiTorm THloritv V or 

'^^- • At any inatant Ut tiic point bs at Q. join C(}, draw tfae iaDj;ent 

jT, alM draw QP at rigbt fuig)<« and (jN parallel to AB, tli«o tbc an^ln 
KQT and CQl' an Mjoa), Now th« vetuoitjr of Q tntolrtd pafallc! to 

iB ii T ena TSQ «« ^/^co* CQI*, tbat U. if CP «^i>al« f ib* reWity 

if q panlld to AB U! 

r<5. S4. 


y*.pQ ory?,rf_».) 

Ilf wp nippoM a point to rooic aloai; AB in mich a innaiier that ita 
ritlndty ia ««dl position u the nnio aa tlmt uf lb« CAcillitliiiff bodr, it* 

njodty at P would alw> ofinal^* («■ - f) and, thorefoiv, tbii pcini 

■««M d«<M«ib« AB in tiM aanse timir that Q d«acrlbe» Xhv tHrmi-circiini- 
bMOBACli. If ^\^ta t bo the roqiiirod time of an oacillttion vtv bavu 

1^ . ' - --Vf = VJ 

rbb rMsIt ia indepeadenl of tli« leofttli of th« arc of ribratiou, provided 
ll apyfthirfr. tint i* AB, bi> maalL It is nvidrul fn-ui tb« formula that llie 
)■■ of a vibraticm is dirwlly proporlional to lb' tqiiaji.' wu of il« 
H^tk, and inMisely propoftioaal to the aquat« root of tbo accplmting 

OK mna, nwa, and kotiox. 


A* M ciuaple of tite iiw of tbn fonniiU nc lunj- takii th* follniriiiit: 
— It luu beoB faiuil by rni'i^ru) (yiporiini^iii tiint .'Htl;BtH.'l iiioliM 'u li« 
leuglli of a Nmple pondiilum, nhtiw tinie of nKiUatJiiii at (imtnwieb it 
am (wcond, ibv formulu Bt unoe lends tu an *ceiirU« di^leritiiiiattoo of tbt 
Hce<'l'~niting foivi' of ^imvity : for uiinj; fwt and spttrnda w our writ 
h«»e/= I, r = 3-2(HtSft. miii »«iind» fnr ihp known nuiHb«>T3-14 
■borofnra the foraiuln girea lu 

ff = f;i 14IM)' X 3-3IJ1IS5 = .121012 

'I'hin w thp mlui: cmployeil in (20). 

53. Oniplilo r«prB>ealattaa or tb« CBaacaa of valaelty sf u 

••eUlatiDB baOT.—Thf cIiiuli.i'k, wljii-b lli'^ vt<l<icily ■>{ a vibrnliii^loili 
luidorgooi may bo iini|iliicidiy reprcienlcd lu followe : — llinw « liar "I 
iadefiiiib> leogtli iiud mnrk oO'^Vll lo rv'prpwnt tbo time of one ribn 

mi' to nprcitciil itie lime of the secoml ribrnTiou. and aa OIL Dtihnf 
the llmt rihrnlioD tliu trlocity inErewM from lero to a maxiiiutin at tlic 
half vibntion, miA thnn drrri'iuni during thti Micond ba1f vibiralion BrMa 
the niflxinium to jtero. Coiiwtiui.-iiLly, if & curved line or ok AQU ii 
drnwn, tlie ordinate Qi[ at any point (J will n>prrJHnt th» Tolority oflfc* 
body nt the timo rfijirexjnted by AM. If a eimilar curved tine or art 
lil'ir bo drnwu, the ordinnte I'N of any point I' will mprawDttli«r«Ia* 
jcitT at ft liiue denotw! by .VN. Ilnl (■iiicw tb* ilirecUon uf ibe T«looitrl& 
f'th* WM^ind omnllalion is foiitriiry to tliat of the rnlocitr in the flrel oaal' 
lati'n), tie ordinate NI' must be drnwn in ibt- roiilniry dtKetioa to Hat 
«f MQ. If, Iheii. Ibe curiH be coiiliiiued by h nuroeuion of r<iiial a 

atolf en Dpjiowle lilies of AD. tlm variation* of the velocity of thi 
vibrating iHtdy wiU be completely roprwented by ihc 
vnrytij); iiiH^uitud«ii of the ordinato* at aiiocMMT* 
points of tiin ciicvn. 

53. CoBtval p«ii4nlaiB. — When a ptont P i* 
•uspended from a pant A nx a Mmple peuduluui U 
bo CRUMd to df#cribe a licriionlal circle witli a uri- 
''') form Telocity ^', A point moling in tncli a nmnwT 
constitulM wbiit i« called a coiiicul pendDluiti, and 
admit* of numy useful and intrreating applintioUL 
Wo will, in thin place, aitcerlftin the tvlatioa wkioti 
psiftta betwi'i.'u ibe Irngtii r of the tb[vad, Al*. the nugle of llie oon* 
PAN or S, and the velocity V. Since ibe point I'moiv-iiii a circle, wlioaa 



nmMVK miticKti 


. U PX wjtli ft •elodty V, ■ fore* K naott net eo it in tbn dirw:- 
I'.V glTcn by the oqiudMi (4B) 



5iiw tb* oolr foma actbg are tlia t«iulea of tbe thrrad T tlniifi P.V, 
ml the wcigbt of (h0 hxlj My nrtioalljr, oeaaaqnoaLl; lii«dr tMuItant 
aaa bo k tan*' U acting alon^ I'N. And Un't^rora tliMe tone* will b« 
pnlltl U> tiir dd«« of tlw. iriuiglo ANP. So that (3S] 









I'N = r tin « Kid AN' = VS . tan « 

V" = ^ rin e Ian t 
Oa* nauliuinn fram ibi* atnj be noticed. With cvntra A and nuJiu* 
4r, dtiKnbp thi' arc W. Now wImui the aoglo PAC it anitll, tba 
■Hi-, I'M, doo* not M-ouiblf differ Irum tbo chord, nor the ooaino, AK, 
fnwi lh« tadioa, tborcfcn in thu can vro have 

V-y/'M-PC)! ^ V = (chd. PM) ^ /* 

On e<mp«riDg tltU rMult with (fiO) w« sm that wh«ii thi- an^i" PAH 
11 MBall the vnlnriti^ or I' nKiTingc in n coniral praduluni is the saiue m P 
WoaU ban at tbn Uiwmi poiat C if it ON^illslod m * timple pendulum; 
M— ^nimllr. if wr mmmto dw poiat P (o be miilcin^- •mnll oacilla- 
liowdbotit the pnint A, and denota th» valoritr at th» Ii>wm[ point b>- 
V, and If when at tlia C'lirMne point tj tlt« ate of Ttlintion, thora i« com- 

»I-<I tnit»*dotitr VinadimetkmBtRKht an^W to tho piano of 

in, it* motion will bv chaoged inUi that of a cooicat pBnduluni. 
•* Xoipvtatv* Ihr wa . — Wlicn a forci- BcUcinnbn>ly f<>raii in«piirevi- 
«Mt *h<irtlin»e,nnil i^tM««dblydi«aputit* velwiiv, iiinltmnrd ani»»lat>- 
IMMOU or (mpuUvo focce. 8iicb a (om U called into plajr wh«n one 
lulj *tnkr9> Mfpdaal another. A form of lhi» «'liar«ot«r la nothing but a 
lillc thnnt^h verv infffr fotcc, acting for a time *o nhort thut its duration 
b mail] _ or quite, inxiiMibU^ In fai't, if M ii thn maw <it' the bndj, uid 
tha toKB coaUin* a/ uiiiti, it wilt, in a lima t, oonununii.-att< a Trlocitj 
fti now, boweref Muall ( nay be, M/ and therefon/maj b« "o lant" 

S6 ox mattkr, roKCR, axp tmnox. [M- 

tlut^ tmj be or tenaJMe or ptfui enn»i(l<^»ble nw^ltude. Thu* if 31 
eontain n pciund artiuitnt, nnd if the force cunUtu ten tlMUMiid laaiu, 
though I w«w M itlinrt w In W (inly tbn |^f,;;lh nf a Moond, the reloctqi 
cmninuuicatpd hj the fcim irould be one of 10 ft. per ■econd. It ia ■bo 
to bp n^mnrkn) tlial tlu< hniy will noi *pn*ibly ninTo whilr tliis velodlf 
is belujt coiiiuiuiiiriiti'd ; tliiu, iii llie case Ktippowd, tliv body wonM onh 
more Ihmu^b ^ff ur ihn yS^th of n fnoi wbilo liii' fitvo iii"t« upon it. 

Wbi'Q Liiir biiJy iiiipiujr-* ou an<>ib<-T it foUww* fr&iu Ibe law of At 
vqualitT nf action nnd roartion (30) that whatcrrr foreo th« firrt bodj 
pxert« upon tlw i^cond, lli^ second will exirt an «qii«l fopcp upon lliefiM 
{□theuppo!qiedin!Ctian:liowfun?tMan'pr.>poniounl lo thnmonientAgNia- 
atndin thniami- time; conMuiiipntlytb<<>nforc«frRnorBto during tlirwheil^ 
nrauy piirt of Iliftiruv uf impact in tb«bod)««n<»p6Ct4rely equal niOfMnll 
witb contrnry "iinw ; wd coniwc|uently tha nuiu of the momenta of tie 
two bmii-'t will wmBidfonatBiil during and at tlmend nf the impact. ili< 
of courir unili^ml'jod llmt if ilie two Vidiea move in cdiitniry dtrwrtion* 
thfiirmoniontn hnv<' iipjiojjtr ei^i* and the sum is an algrhraicnl sum. In 
onlur ill (»1 tbi' plii^icnl validity uf lhi« coudu^ioii, Newton made* 
•nriiTt of cjpcriniputa wliieh mnr be hrieUy denrribod thus : — two ball* A 
and 11 are linng from points C, D, in tli« «anie bcrizonial tin^ by lht«id* 
2 O D V a '" *"'^'' * niiinner tbat their OPUtrM A 

and ') am in tbn inmn liorixoutnl Una 
With centre C and radius CA de*frihf> 
n BPniicifrlc KAF, and with <»ntTo D 
nnd radiua DB d^Ftcribe a »eiiiiciicle 
OBI! on the wall in front of which the 
ball* bang. Lot A bp movnd back M 
It, nod be allowed to dean^ud to A : !t 
theri> impin^s on It, l>oth A and B 
irill now move nlonR the arcs AF slid BH roBjwctivelv, let A and B 
roma to ibcir bi(.'best poiut< at r and k respectively. Now if V duoots 
tbe velofily witb which .V rcncbcs the lownet piiiiit, i' and u the vel«citie« 
with which A and B Icare ihe loweel puiuti aflt-r iuipiu:). and r the 
radiiw AC, i[ iippetire from yK) that 

V =ehd.AK^^ -= chd, St ^9, and u = did . BA V? 

ihgraforc if .V and B aw tlie uinsip." of the two ball*, tbn mnmwiiiim at 
the instant befure iitipnct ira^ A ;< cbd . AH and Ihe uiomeulum afl«T 
impact wa» A x rhd . Ar + B x ubd , BA-. Now when tie pmritionn of 
the poJDta R, r, and k had been properly corrnctnd for the rwli-taiice "f 
tbn ail, it was found that llisso two niprnsiiono w^re v*\\i\\ to within 
<l<iantiUes »o BUial] that they could b« properly refcndd to etrora of 

mk ■*»" 

rOLLUioat or two nontEs. 


n/nt. The exprriinniil MWrwd«d e^iMlly under ererr ratiatMa, 
wWher A ipBpinsinl 04i B at reM or in niotioa, and wluiteTcr tka 
BUUariab of A anil D mitibt be. 

&&. MMCt ealUatea sr tv* 1»«dt«a.— Let A anil B be two heMm 
iBnTti^; wtUi TclaatiH V Mid L' RspQcurely, along Ui* flame line, ajid 1*1 
iMr nuiiuU acu-n tak* placs in thai lin* ; if iIm ow ovenalw ibr Mhtr 
wW will bn their napocIiTe rdodtiM at tfae iiwtut after impact ? W>* 
will anawfir ibia qvoation ia tw« «xti«ma <»mu. 

i Let us nippoae tba bedie* W be fwiU mmIo^. In ihia cMe, when 
A tmcbn* B, it will eoatiitiw to prva ^raiiMt U antil tbrir vclocitw* an 
•fualiaed* wtian tW nunal actkn oeaM*. For whatvicr dafotniMiaa ifca 
boiBaa iwtjr liare nndergimc, Umt have no tendcocv to noonr thair 
•lu|v^ If, tWrpforv. T ia tbMr Mnimcm Tekwitr afttr impact, we ekall 
barn Ajt -i- Bx Ibeir joint monMiitvn at the end of impact, but tbetr 
BnoaBUn httan ini|act wn* AV + Bl'. WbeiK« 
(A + B) * = AV + BO 

IB aqnatian which detCisilMO -r. 

IL Let w Mippoen the bodm prrfnUy 4ailk. Tn ihi* caM they 
iMovn their HhapeB, villi a loKx vxadl; «qiia] to that with which they 
mf* eomprpaiKL Caoicquentlv, the whole mniopnium Imt br tlw* <iim^ 
Md galtieil br lli« oUkt, man b« exactly doubl« of ibal lost while mib- 
pwriati took places tluttU up to the inataiit at which Iheij TelocitiM wtt* 
■qnUted. Bill IhMo an> Kap^tivelT AV - Ajt and Bx — BU lhet«f<MV 
If ■ and M are ihc requiriHt tittal vvlooltiet 



Ap = AV — S(AV — Ajt) oa- e = _V + a« 
Ba = BU + 2(Br - BU)or« = ar-D 

(A + B) p = SBU + (A - B)V 

(A + B)»= 2AV - (A - B)C 

Tha raltowin^ roocliuioa &om tb»c cquntions may be noticed: aniipaae a 
Wn A moTin^ with a voIocIct \', (o urikn lilrcclly nn itqaal hall B at 
M. In thi* eaae A = B, aod U = 0, «oii8e<iuei>tl.v o = U and u = V, 
ihil is the biraer hall A b brouftht tn rent, iiu<l tliu latter B diotm cm 
■ilk a Tvlocity V. If now B strike on a lliirj ^uiU ball C at mt, B 
«ill b titrii be bmngbt tfl rent, andC will acquirt^ the ^«l(M-ity V. And lh<> 
^B* \» inia if then in a fourth, or fiftli, or iiid'wd imy number of ball*. 
^Ah nwolt may bn ubiiwB with iroiy ball*, and if carefully perfomiod 
^|pa very remvknble axperimeat 

^^ fifl. ir«rk »n4 esarKr-— If tbo point of appUcaiJoR «S b f.ircr nioTes 
I titMia^htluu'.aiMlif tli<? part of the fbrc«mol*ed along this line act* in 



tbe dirccdnn of Uw motion, tba prndurt of iIiai Kimponeni u»<l the k«fik 
of the Um In the wurk don<t b}r tbn forM. If th« coinponmt kIk in tk 
opfNMito diMclioD lo Uie mnlion, thn ccimjinemt nuiy be ooBtidernl w* 
ndaUnce *ad tlie prodiKt i* work d<inv n^aiu«t tbo mwtuc". Thtu,ii 
(43) if ir« aiippow M lo move up tbo plniic from A to B, ibe work taf 
bTPbP X AB;Ui«w<nkdoi»«gabtit ib'.'rc*ii>un(^(Ji>*^sut A x Alt' 
*ltwin beobHmvd (but if tbcfomv nr« in cquilibTium during tli'MOtiM, 
to thnl the r«<]i-icilT n[ H (4 uniform, P iiqiiai" Cj >in A, uid cuuM^iKOtl; 
tlw work d<ine bv tkv power cqunli that ituiio Hgfunrt llio wwi l w w. 
Abo liiiM Allnin A oqufllii Vl(' ilio work dnop Biwiut tlte ret toW W 
nqiiaU Q x ItC. In otb«r wurda. to ruiM Q from A to B rnquuea At 
Mtnie ■mnunt of n-ork m to rnu» it from C to U. 

For nirii-tly ixieulific purpo*M ft unit of work U Ukru to bo tbi- weak 
doni- b; a unit of force when it* point of appliMllon mOTm thimif h Mw 
foot in tl» dirvction of it« arlion. If, m in friMjutntlv dunp, tndtflC 
work u AviitiKi III bv ft form of one pound «x*rl«d thmngb onr fool. 
tUti.-Dlion must bo pwd lo the nimiurk in I Lf) rr^uding Ihu meaning «l iIk 
lorni ^''i/itiJ wb^n coDudered M a tirat n( /arc*. Thin unit may b» ood- 
Tt'uit'iilly diitiii);uisb»l m ■ ' fout-iKiuiid.' To raise a poond of maltri 
ibimiirb oiii- foot rtiqiiirpi mon- or Ii'« tlinii n ' foot-pound ' of worli, 
Acooiding »t ibe forc« uf f^ravitr -ju tliai pound of nialMr rxcp«dt or falb 
•hort ofSaiOia uaitit. 

By tho tnrni emtrgj/ or i<m vim i» meant ft qunnti^ propordooftl to ibe 
product of the uism of & body m and tbe oquare of ita vdoi^ty i^ it tf 
looiit convcnicutl; turamirrd by ^rrir*. If • forw contwning P uate 
acts on a body wboH mftM ia m causing lo move from rcift over A feat, 4> 
foK* wiU do I'h units of work, or if I' rqunli wi/il will do m/lt nulu of 
work. Now if I' U ilje vuloiity of tbe body ut tbe end of tba A f**t, wo 
know that p* oqualu i/i (-Wt). Thotcforo 

I'A or niffl := (nil'' 

Tbal ia 111 say, tlif iruri ilrnt by Ihr forfr tyiinb tJif murfij u/(A# hoif. 
la tbu uiui' manner, if thv. body bnvn nn initial mlority ^', ao Hal, 
whi-n tho fori?" bi.'gin" to acl, il Itaie ulrtiady nu <'nergy i"'V', tbo w<irk 
doue bv the toKK will cjqunl tbe cbiuiKP in tb« courpv of tbe body 1* 

It daterrM particular notint that if tho point of uppliculion of lb« Com 

OTovffl in 11 dirrction at right nnplra to ihnt of ilio fnrei", llip force doc* no 
wfirk, and ihnri'foti' will uol (.■omniuaii-alK vatrgy Id the body, nor r»ni>c 
it> Velocity tt> underipj cliniifte. .\ n:in>picuniia nxnniplo of thin fuel \r 
fumitliod by ih" co*" of circular m>>li<>n diKUSscd iu (4fl). llfm tbe 
only fatwi Ib M V'+r which actoan tho body nlong thr mdius, ftnd, th«^- 
foK, at ri^ht angliu to the direction of the Rioiii'>n At each iuMftnt, in 
cunaequence It dora no work, nud the velocity of the body u i^nifotm. 

CO!ISRSVAII<>.\ ni- ntXKT.V. 


&7. TIm oaaBvrvattoB »l tnmrtj. — If w«i ooliMiT* a niacfain^ to 
fOfB uniformlT vithout CrictMn it mar be proved that tli« irori( Aoae tnr 
k> pmrcr axacUj ujDaU tJikt dnsia af^ntt the mi«tasp«. W«i haTi> 
MB ia (66) ibM Uiu if tU* cms witb one atmplo machbe— tbo inclined 
InN. It ia obrioualy *o too in tbo cue of tlia *cra« ; for, on *xiunin- 
Bg (44) it tt pUia that if tJi« ami uakta <hm complete turn the reoBlMicv 
■ raiaej throagh a beif^t equal to tlie pilck of the acawr. Now as P 
eta taagentiaUy to tbe drele doxeribed I7 tba ead of the arm it iloe* 
\am V mits of work, and tlip wurb duuv HpiinBt Q vquali QA, and tki«c 
lata been diown to bo equal io thn orticln |44) irfirrci 1», It can b1«0 
H abowa to be true in all otlii^r cawia. This xn llit- [irinciplc which it 
ba yim tly atatcd thiw :— ihut vhat ia i/aineJ ia poKa- it Imi in niorily. 
la bet, the whole efficacy nod valiin of ntachiues ooutiot in this ifaat, by 
Hiimri-*'i"C the rotacitv of ihr point of appIicatioB of tho pmuIbboc, we 
inajr ovKtooue tlie raMtfance, boweTer taige, bjr a girea iotcf. 

Uwe aappaaa the macfatne to novo lubjiK^t to friction and with a 
tariaUa relodlT, the tJton piodple under^oet the fi>lloiriDK ^'iteoMon. 
If tba worii dune agwait tlie minbutcc, that doneapunat the frictioiu) «f 
dw paMa of tb* machine, lliat which nxisui in die clMaged mer^ of ihr 
parte of tba machine be added together, their suiu will equal the work 
team bjr tbe power. If wo andetMand ibe U^rm MurAnr to mnan an; 
qMnn of bodia* inoiinii:, under tbv action of iriieu futces this principle 
■awbat ha« been gciwndl}' called the coaaerTation of n'l m«. 

Tbie prinripU luu of late underi^OQo a remarkable exteosion, which 
m^ bo explained aa followa. Keferring to (oS) we bare aerai that to 
nina U tnm AtaU tfiain* Mj x BC nnit< nf work. Now if it fell 
ben B tu C it would aequite My x DC units irf etMiKT, eoaatqnta&jH 
[hriTl at B ma; Ini heM to ecntnin M; x ItC unita <f p o lmU al eneqy 
«nre than wlMn it i« placed el O or anv other poitil in the hxriiouUl line 
lie. .\)raiti, it ha* been atcortmned that for emy ucit of work ilone 
*iruw>t fricti'm tbei* i« aa exact eqaiTalent of Ktat, and that aninimt of 
baf na tie nuulo to jUd the auue number ot unite of work. In Ukf 
OMBner, wlion tha fonn oJ a bodv i* changed hj tlie action of f<>rce.i 
rlrtwrr tlui work done a^ainH tlie intenial fomie will lemsJn etav^d up m 
lalalial ennriz; a* in n CflOipreMcd ipring, or will hare btrn rvplaced by 
the inAfpamal of aa eqaivalent of beat. Nnw thb bMns )iii>nii*rd wc 
we that tlur awTRT coamaunicated to any body oe ^t«ui of bodiei), u 
irilUnwa bom eonin fund of energy previoualy exUliu?: thus, tbe 
iBMUjj coaDniinicat«l to the piitcm of a tuma eogfine i» withdrawn from 
ibeAMi of thesle«Bi: woalnoHv that of the ener^ thun communkHted 
r b ^Mtrayed. but ie uurely di«{rili<ited, and nxiit* drhnr a* p^t^ntial 
j.or i« tnottMi of the bodicaactcd on, or bat been teplaced by aa equi- 
nldUofbeaL Thia fact lecaUadtAemaMnafteN^^wv^ or man property 
th* MHMrntfien of auryy. ^ 




BOOK 11. 




IK. VnlTersal mttraoHon, IM lam. — rWorrnl' atlrartiiM \» n ferrr 
in rirtut- ot triiitli thf iiiniiTiiil jinrtlclm of nil bodi« teml iiicpmantly «■ 
•pproArh <^ni-li fiihtir; il jan mutual Hctimi. hnw*ier, vbich rU bodirf, iI 
nM ov to tuuiiorj, exvrt iijkiu (>uf aiioilier, no oikitt-r liow great or ho* 
■mill the B|wcp bvinifn th«n mny bn, or whntbnr thU ■pnce be oceufM 
or unoccupied br other inntt^r. 

A vs^e bfpMh««i8 of the bodencr of the nmttcr of the ewtb vA 
Mm to A «oiuni(ni Mmtrc wni ndopted ovpn bv nnmncritua nnd Epiimnk 
Baplw ■wuini'd ihii PTiiti-iiro nf a miitunl atiraetioii between the nv> 
(he euth, nnd Ih* otbrr planL>[s. Hncon. (inlib^o, nail Ilwilii-. ii1w> iVMg- 
lli«od tbc exutpBoo of univiruil Rtlrnntinn. But Xfvlon nA8 ibe finl 
who Mtabli*h«tl tha Iaw )tnd ibe uiitvi^niHlily of ) 

Ssce Newlon'ii timi' tlu- nilmction of mnttcr l)y raoitcr wiw rxpni* 
nwntAllv »«t«bli»hed by ('svnndMh. This eminent Etigili^ pliynielft 
mic«eeded by m-.-ans uf n dclii'Ht« t;>rBioii bajano.' \>*0) in rendoiiii^ rinble 
tbe BtUnrtion bntwecn « Inrgo leaden nnd a ■niall rnpper Imll. 

The attnrtioii between hnr Ino bodira is the rmultHiit of the AtttW- 
tiom of each molecule of the one upon every inoieoule of the othn 
•crordinR' to the tnw nf Newtiin, wbich may lie lliii" espr^Med ; At Hi- 
traetiof hrtlcrm titv tmitrriat parttch-t i» itirrtlltj prupurtiannl tv Ihr proilitd 
o/lheir mtuttt, and tnnrw/j/ propirrliininl ta Ihr t^iiar* of Ihrir diittmn* 
atunAfr. To lUiutrate IbiH. we ujay tuktf the en>>e i-f two tipliemi irhich, 
owinjt to th^ir "Vinmrtry, BttrncI i-utb oilier just ri» if their maHnt won 
coDcenirnte'l in thtiir c.-iitre*. If without oth(frnlierBtiiin1b.Mii(iiii« of one 
■phero weru doubted, In^bled. vie, tlie HltrnL-liou Iwltveen thtmi wouU 
he doiiblpd. trebled, etc. If, liuwever, tin; luniic of nun ipbtrv being 
doubted, that of the itther were inctetined thnw tiuieg, the diktAnw 
b^twMin their centres remaining iho smnc, the ntttnetion would be 10' 
cTvtaed tax timnt. Lnslly, if, without nlldring thuir inii8«o*>, the dlaluee 
WtwofiQ their cwitrw wwn* ntcrtuvml (Vom 1 to a. 3, 4, . . . . unit*, the 



troold be «(umMuuW to tho 4tli, 9lb, lOUi, .... pnn of iu 
an iaUoMt^. Id slion, if ir» drfao th« unit of aiintclioD aa tliu 
||k voald exut botwrvn tira nsibi uf niow irbnw diitaaoe aiund 
B» wul of ]m0Ii, thntraractjancf twotoolMulMiliAvingtbenia 

B ■m', «t the diMancc r, irould bo tixjiraMod bv ^ - . 

K Tail Mil la 1 tT*vltatl«D.— The tondcncy of my bodv to fall 
ratd* Um aartb U duo to ilin iduiimI anractinn of tbal bwlr nnil lh«i 
lb : or. tn tenotrUl i^vitatinn, and ia, in bet, merely a pmtictilar 
t at aR)>«real graTiuttoo. 

Uaoypcnotof tlweartli'asurl'iu;^ tli« diNctioa cJ^ gniTitv, tbat is tlitf 
>birh • fallinfr body lUocribni, ia called the icrfioi/ lino. The vcr- 
I drawn at difierent pobu nf ibe oarUi'a «urfac« eoarnrge rerj 
' to Um oarlb'a etoirr. t'<ir pouita aituat«d on thn same mt^idiiuk 
eoalaitiMl b«tiren) tlk« variical linro cqunla tbn ditferenca ] 
I the latitodca of iboae pobta. 
yhm dit«ctk<M of lb(> <«nh'i> nttraction upon naighbouring tK>diM, or 
BB iUcrent molMiltM of on« and tbo muii(> tiudy, uiubI, Uicrefnre, ba j 
Mdand a* panlUl, for Ihr tvo vertical tinea form the adn n{ a tri-l 
I «ha*e rcrtez l» near tbr t^rth'x crntrv, about -1,000 uiili-'' ilLetaai, 
I baaa h tba amall diatonor betwucn the moleciilei uiidi-r con- 

I or tine ia ti^d to b« SerisMtlai when it ia perpendicular to tliD 

rorlleal Hue at aoj pobt of the ^lobe b i^nenitlf determined 
tfbamMmt (lig. 1'9), which cotwita of a WDiR-bt 
Um ond of a Mria^. Ii U ^vidnnt that 
tcvnot bo in n|uilibirium unlcs tho dim'-tinn 
flM mnb'a ailractioa npuu it paM>w tl>rr>ti)f]i the 
■t ot aiipporl, and iberefor* coinddca with thnt <•<[ 

B horiiontal plane ia alw deteraiined with grvnt 
^kiiMW it CDJDCtdei, a* will bo afUrwarda ahown, 
Pka irtW aurfaca of nt*r;^ liquid wbeo in a atAte of 

I ibe iD««n S^urv of tlio ctrtb baa been npproii- 
i4>t*fix^ed, it becooii-a puwibU to coroparn tbn 

rtb«|JuiBb line at any place vritb tb&l of the Fig. 29. 

tatma fi)nu« at that plncn. When any 

' 111 tbei*e directiona can be detected, it euu->liiiitM t drviaiion at 

ab-llno, and iadue to tlui attraction of toiiie ^rfnt ninaa nf niatttr 

llialfrbbourliood, tu«h aa a mouulaic, Thii» in tiie ca«e uf tho 

of Scb«baHie4i. in Perthahire, it wa» found by Dr. Mnakelyne 


aunTAtmt xxa nounxA* xmucnon. 


that Ht* aagb hilpuui the dnortMO* «f nra pbnnMum, oac at *| 
•uUm to lb* Donli, nd U>» «ik«r M ^ aomfc df tbo mnmnlam, «■» I 
fTMrtcrbi U''etluii Uw w^ebrt«wallMM>Bul«aribeBMBpnflM»| 
df tk «wtb «t thnw pdat*; to odMT wwd*, cMch plnmb-line nl 
4«Am(«1 bT akout (T Unmtb iIm BOaMUB. Bt (xIcnUtinK tb<> ralooN I 
od BaM nir tiw moDiiUin, jt ww isfenrd fnm Uiis obsemtion, Uiat ibf ' 
AMa dendtj if Um OMmutkiB wm t« Uial of tlio Mrtb ia thr nli»af^ 
9 : B, and that di* mea* ittmtx of Qtv earth u al>o«it flT« timaa i 
WBt«r,~« TM«h •pwiog pntty c)o«>It witli tkat dMiucnl front i 
4uli'« cxprrinwtilii rcfcTml lo in llie UM allMe. 

00: tfaav* af K****tr> ■■• «xr***aaaaHl dalermlamtla«.' 
-ohaUTcr posilioa a bod^ bst be luriMd wjib rMpnct to thr cu-th. tk*n ' 
ia a cartMO point, inrariablj- ritualcd with inspect lo tbe bodr, (kniu^ i 
wUA Die mmIimiI of th« attmnisz Kikm b«tw«Mi the earth and itt 


Fi|. 31. 

anvcral molotrulnii rIwuvc pastes. Tbis point i«eaUe)IdtH(>ni(rro/')im^: 
It iiujrbviritbiD or wiUionlthd bodr, nf cording tA (he form of thp IntWt; 
iti esirti-nec, hoirBver, i* eanlf e*l«lili»hed by ihe followin^f cijuxidec*- 
lion* : 1^1 m, m', m", m'". . . (if. 90) be molpciOci of nny hady. IV 
«artli'( attraction apoo these hioIm^uIps will cr>ni>litiit«A>v)rteiii nf pivallll 
forOM, hnriu^ a commoQ iy<rtivul din^irtiuii, vhi>!iF resultant, ni^iioidiiif to 
(SB), will be found by »wirinp first the rcsultflnt nf the fmrn* whieh 
Mt on mj two moleculni, m, and m'. then thnt of thin reaultBiit. and * 
third fiirce nrling on ni", and lu on until we arrivf at tin- finnl tvmltiat 
W, ropmcntbg ihc w(ii((ht of thp bodr, and RppUed at a cert^n polM 
G. If the body be now turned into tlip position nhown in Sfi. SI, the 
ino)«Culea m, m', m", . . will cnntiuuc to he acted on hy the «aiiie forrt* 
M b«(orc, the Ti-aiiltant of the forces on »i and m' will slill pii*= threiurb 
lb* aam* publ " in the line mm', ihf foUowintr msiilliuit will ft;i;Bin \t» 
throui^h tho iwmo point >/ in om", and «■* on up to (he linal rwitLltiint P, 
which will Mill paiv< tljruu^b llir Mniir point O. which is the rentN if 

To Hnd the rentrc of graTity of a body in a purely geomeliical 

•aj litAviTT, tnenK or OKAvm, tmi: imlancx. ' 4S 

)»B l ilew i in niaiij oms howsm, it nan Iw delcnniiwd JniiitediHtplr. 
For inrtlwws ihr reotiv of ^n^i ity of ■ rifiht liuo of unirorm dciuil^ ij> 
iba peJBt wbteh bMorta itt longtli ; to tho ebnl* uid uphMv it CMiici<l<H 
iiith ilwr geoniMnctl ttatn ; ia cjliDdrWl ban It b the nlddle piHiU 
of thm asia. Tb« centrr of graTity or ■ finae triBngte i* in th« line 
jirina aiiv i'«rt#i wilJi Uui iBid^ of the opparit«i tUt, utd at a 
bmn tJie Tertei eqiul to tviv-tUnb of tbb line ; in a conn or 
fjntaii it ia in tit- linn wtikh jnina tbo rcrtox with tho ceotn of 
IfMrilT (if tho baae, aad ai a disl«iio« bom tb« tpKi^x equal to thrce- 
Sairtb of thia litw. Thno ruli^ it malt be tanienibvrvd. pmnuppoaf that 
th> wtanl hotliea ar# of uiilfntiii dpiiaJty. 

to dctemiiaB MperiniMltally tho cninn- of jrrarity of a l>odr. 
'■wapapdad fey a «lnD^ in tvo liiRpKrni piWttiiris ti> tbown in tiHi>. :i3 
■oil 3.1 : tlnr point ahem the diroclions ATI nnd t'l> of the Hiring i>i th<> 
l«o BiptrtHiontii intnnwct taich other ia th<> cnttra of gravity ivqiiind. 
For tliB reMaltanl of Ihv 4tMth'* altrBL-tiua being a Trrtical force opplic^d 
•1 the MBtre of trraritr, the bodr can only bo in (•quilihriiiia wli^n Ihif- 
IDial lieaTwTti'«lly>iDdortbn point of aiiapMiMOii, thai lain tliepnilanf^&tiun 
if the niapmde*! itring. Itut tfau ci-olri! of frmviiy bring iu AB w v-fl\ 
■• in (71) niMrt ooincidn with tbn pnici of inti»nHirtion of iliive two lines. 

(IL ■^■lllfcilMao ot keavr kaAloa.— Siuce Ihi! nvt'i-n of gravity 
ipoo a body tiidiK*it itnoif m • «nf(lr n-rlicnl frm* ■j.iplii-d at f\>f rnntrc 
t4 gtnitj Kii dinfiiri li>«Brd? the ^rtlis teiitrv, . nuilibrium will be 
i«ahBAril imly wiini thi> iciullant i* bnlnn^nl by iIil- n-«iilUnl of other 
htm and remaUmset acting on Ili« body at tlw fixnd point through 
*biph it pai w . 

Whm unly om point uf the body ia Axod. it will be in equilibrium if 
ih« teTiiml liui> Uin>il|i;b ita ceotrp of irmvily piw»(» thtoutfh ihi- lixed_ 
|aiM. IftlKin' tbnn •m« point i* aupportni. llie liudy will be io v<iuiU4 



briaai if a r«tt»ckl liu* tlirough llie oeoM of gnTit; 

praat irithin \he polygon fimnad by joJBiBjt iIm point* of mi^ccrL 

Tbe iMoing tower of Pitt ooaliitiws W Hand b(««>ui> ikv mtkal 
dMirn tluough it* cmtn ot ^mrity p«Wf» nitbin ita tmc. 

ft M »»<i«r to MjuiiI oa our f<.>et Uiiin 'Hi jwilui, b«<Mue in tli« 
GMB tbi! smallrxt iiioti«u ii ■uSicittiit ta («iui> tbn Tcrttcal liiio 
ihi ctmlro of gravity of our bodlm to finu ouuoda tlte supfi^tltn^ 
wbidi U h<^iv ivdDMd to* ni«4v line Joiuiiig ihef««(of tbcitilto. .' 
it i* tmpdMiiblc to vtand oa one l^g if wc knip omi siilo of ilio 
bead clow W « T«nical vai], becau>« tJi? I*lt«r prarpnt* u* from tbia< 
be bmly'ii cputre uf gravity T«nicaUr above the aupporting baM. 
OS. SUforwBt atat** of •quUlbrlan.— Allhoaph a body cniL;* 
by a lixwl poiiil in in wiuilibrium wliL-uuret its cvnlra of grarity ii in _ _ 
V«rticiil line tbroiigh ihnt pf'int, tliv< fu-t that th« CMitiv of gn\ ' '• 

fawcNantly to occupy tliu lon'i.-9l pimibl? potation Icsdii u> to di . . ■ ■ , ) 
bfrtwrinQ thrrji ■tatci of cquUibriiini- — ufaldr, tiHtUililf, tuHtral. 

A body ia »tuil to be io ff'iUir ryaitS,ri'im if it ivcd^ (i> nTC4im to it* 
poution after tbo equilibrium baa btfji slifl^btlj diiturhnl. Krctj 
i* in thi* (into when it* poHiiion i« *uch that the 'ligbii'Si alt«iatioi 
tli^i ««ine elovalet ita centre of i^rity : for the teiiln nf gianty 
de«vnd AiRua when permitted, and after a fen* owilUtiolw llie bod; 
miiTii Io it* oriifinal pMltion. 

Tbo pmdiiluiu uf a clock onntinually cucillatm about ita pontio 

stable eqiiilibriiui), and tui tgf on a li*vel tiUtl 
in tbifi state wben ita long a.xi* !■ horiioiitii' 
\Vc bavo anotbor illuntnitinn in tb* toy v>}^' 
scnted in tbc adjoioitig fig. Si. A omall ti^uf 
cut ID ivory i* mnd-i lii «tand on on* foot *i tlK 
lup ni a pedestal bybeiug Ioadt.>d witb two Itadc 
ballii, a, h, placiid auifidenitly low In ibrov tbi' 
centrv of gravity, jit, of tbe whole cumpouiid body 
boliiw thn fo3t of tho fijrure. After bniiifc di*- 
tiicbi^d tbe little figure o»ciUnivs like a pfiiduluni. 
Iinviog ita puttit of suspension at tbe toe, and iD 
centre of ^nvity at a lower piiini, ;/. 

A body is snid to be in ntutnble r^iiiliinH«', 
wh^n aftor the sligbtest diiturhnnc* it t<^nd* to 
depart alill more from its original poaitioa. A 
body ii in tbii itatf< when it* cvntm of ^tityi* 
Fig. 84. vertically above tbv point of support, or hi^har 

than it would bL< in any luljni'cnt poHtion of tbe 
An egg standing on ile end or a stick batancpd upright on tbr 
'Rnger is in thi* atnto. 



llv, if in my KJjaOTat pMition a bodr joiII nniain* in Kjullibriuin. 
\tteor MialUldiim i» Miid tn t* urabW. In tkU cmo mi KltcTmti<ai 

rig. 33. 

rpnmtioaof tkebudj nriiherndannor kiwera its oentra ofgnvlQr. 
trfed ifibere rwtiag oa * liorijcait&I plane ii in thii »int«^ 
i Sfi K^nMtU tbra* coom A, B, C, plwcd roffecUvel; in atkbl*. 


■UttpUtd neotnil Mjirilibntim qpno BhoriiMiUl pluifi. TbA Uttw; 
uk abmra tli« pooilloo of the cenlTD of gnvltr. 

1 ^h* tialaniw. Thw baliuic* i« mi innUumcnt Tor drU'iminia^ tli* 
tiifl w-iiuliu or HMHM of bodies. There »t« ruhit vnririicn. 

MnlMduce(fig. 30)ecnuiiUof ftle«<T<jrUi« flrel 


Uie inun, with iu fukruiu in Uie middle; *t tW exlnmitiei ol Ibv ka 

Kaipeaiei two Mala pMi>: one intMided to mnir* the o^ect to 
'wMghfd, And tbo otkar tli* cowit«rpoiii(i. Th« fulcnim conouU oT a 
pnmi, d, comsiotilj called « ifaH/« n^, tcbtch pwae* ihrnagh tbe 
Hid r««t> with il« xlut|> vdgv, or ajia •>/ m y nMila w , upon (wo M[ 
tbeac uv fcinncit of ^^t«, or poliiliMl tUxl, in ordar to iHminMt' 
Mcliaa. A necdln or poinim i' fixrd tn th* b(titiii, and oscilUtM 
in fmnt cS a gnduited uv, ii ; wbvn Ih« benm in pi-rrccUy borinintttl 
MMdls pcJat* to tho iDfD of tlin KrnduaW arr. 

ffloM by (40) two equal forcaa in a lever uf the lini kind cbddoI 
■•qiiilibfium nnlcM tluir 1eT«va^ are aqiMl, the leoj^h nf iho 
HDd nit ought to remain equal diiring the proc«« of wrif^hin^. To 
ihi* iho (ca]** arv auapendcd &01U hculu, whoK curred pait* ban 
L-dgv«,aDd rMt on vimitar ^Afvn at thonndnof thabnam- In (hia 
dio icalea are nipporti'd on m«n< points, which remain uiuuovod 
Ibe oscillations nf the boftnt. Thin mode of iiu>pnnri»n is rp]ii 
the nbovp fijfiii*. 

<<4. o»o«lti«aa to b* aatlaBsd br k balaave.— A gnod 
'lUBhi !■• •MiliF'fv tbn Mk.wiii^r n«»r 

i. The liEo armi of the heam uiiyht fa hr prfcittU/ r^ual. otbi-rVM 
sccirrtiiig lo ihn prindpli- of ibn 1<>v»t, iinK|unl irrigbt* will bv Tv<i<utf4 
to priiducu Mjiiilibrluiii. To l<-st wbvthi-r tlit> nmin of Ibn beau Mt 
«i)unl, Wrights arc plocvd in (lii! two rcbIck until thr brnm beoomm htri- 
xonta] : the enDt<niiii of tho acal<.-# being th«n inl^'TchaDgnl, tlio buam will 
r^nnnin hotiiuutnl if ita arms aiv vquol, but if not, it will doKWHl on tin 
i«de of the Inngrr arm. 

a. The balatitv oiiyhl lo he in eiiatlibrium n-hen thr mviAem ant rmflf, 
for otlieTwiiii> ii]ii:<]iuil wd^lit* inu*t be plMod in the ncalee bi onkr U 
prnduci! i^qiiUibrium. It luunt bu boriii? iu luiuil, howeviT, thai llii> am* 
■ri! not n>'Ci.'iwirily ntiiial, pvmi if thr boam rcnuiini borixonlal whvn Uw 
*caltJ< iirt! nnipty : for thiii rvsult tntght also bu pn>duo«d bj giving to |ha 
longer arm thr ligiitiir spnlcr. 

lii. The Win iriiij/ finriamta!, ill mttrr uf grai'tty lai^. to be in tk 
tainr milii^l line leilh the edge of Ihe/ulcrum. arid a little beloic Ukt tatim, 
for utluTwlAe the beam would not bp in "labln rqiiilibrium ((S), 

Tbn rffi'Ct of chaiiiring tbt- pOBilion of tht ci-utrv of |nttvit)r naa^ ^ 
ahown by inrnnn nf n boitni (fig. Xi) wboar fulcrum, bning the nut of i 
Bcrcw, a oui bt- raisuJ or lowi-red by turning the M.-rew-hpad, b. 

Whnn thr fulcrum it at thr top of thr groove r, in which it dides, Ihi 
GWitK of gravity of tlin l>rani is bnlow its ndgn, nod the latlor MCtUatM 
frMly abuut a poialiua uf !ilabtr Kjuilibriuin. Ity grndunlly lowering 
the fulcrum it« "Nig" may be madn to pass thruugh tlie cenlrt of gravity 
of the buam when the latter in \a neutral equilibrium : that ia to iwy, it 


nuvtrv, cu(iK£ (f CKAvrtY, the dalance. 


I twf- cMdbtM, but KB«bB in eqiulibriiini in all positiouB. Whm 
L bknuB ■ lowKKd Btilt mora, ifce ceolre of gnvity piusM abtn-c iu 

I Fig. 37. 

ba. ifcv beam l# in o swte of uiui^k cquUilwiiim, and » overturn^ by 

k Tcry imaU diffrtetwe btt«<«n the wciglito JB iho •cal*. «iw« « 

HRwptUiUdeflrctiuti of Uie pointer. 

itoiyoM, MiJ C Ui« «i» of KUfpwiuaon of the beam. A, B, wrf C 

Fig. 89. 

: 10 b« in tltH Mine «tnight line, aocotdltig Iu the UBiml nf ' 
SnppoM w^hta r uiil Q to bQ in tbo pDiu iii»ipcn<l«4 fnim 
ta^ B iMportivclf, and l«t G be the centra of ^ravil^ ut llie bvam, 
'Ita tb« bouu will camo to teat in tbo pontion sbown in the tigaK 
tW» ihe tine l>CN U T«ni«al, and T.Cd U th« dimction of th<^ [lointer. 
Atncdi^ to ibe abovi- ataivnMiit tbe grt^ter tbe tn^h BCD fur n gi\vn faotwtfcn P aod Q th« ^atcr i* the tcnritivoncM of tho balance. 
Ota* ON at right aivliM to 00. 

La W W tbft wnigbt of tli« beani, tbco &oiu tbc propvitiea of the 
'vTtrit ftiUirwa that HKMuriag moments niih r«<[H)ct to (', ihn innmunt 
<i P eqittli ilic ■">■> *'^ ^be moments of (J and \V, a conditiou which nt 
I to tba mtalton 

lP-(i) . AO!=W. ON 


Now it ia plain Uial tat n (riven value of CG tlie angle GCN (thu it 
ECI>. Willi*!! m<«;(umii th«HtniiibilitT)u frmttmaiiGN i* fn<«ii>r:aiidfNa 
ibe formula \l U plain ihat for a iriv«a ralue of P— Q vri- iikaU haie (IS 
gfKCtoM AC b Kicatcr^anil an Win loai. Agiiiii, for a girtm TalneofQ!) 
Utc ang:l« (iCN M irTfabT h CG U Icm. Ileiiee tlw poeuw uf rendeiiif J 
Ik halnncv senriilh-v are; — fi-) ^<* (ualfi! the Mnw of Uut iMlaiiea loig, 
(ij.) To make th« weight of tho bean v Hnall an ii canaivlent wilh ill 
ripHitv. I iii.) To brinf tli« mlik of gnvilj- of ih« Iimuu a \ety Ciik 
bfltuir thn point at *uppoR. Moteorer, tdnce (riction iriil alvare oppcM 
tbo acliuu iif the foKe tliat l/enAi vo prf'poD derate, (h« balaoc? niQ b* 


Fig. 40. 

reudunii more Ai'iisitivn by dimininhiog fHrtion; t>) wTiitv this adnn- 
Ingvi tha I'dp^i from wliicli thu bviuii and smlvs an: aus^ieuded are mnde 
OK aharp an [loa^ibl?, and thn mipporta od whli^h thev rest are vvrr hud. 
And fiinhcr, thi' pcinter i« made long since its flonjniliDu tcuden a gireo 
defiecUt'-D more perc»ptiblo b; incruasbg the MC whicli its extmuit)' 

00. rtoyaloBl and cbetolOKl bnlasoea. — Fig. 40 reprut-iils od« of 
ihd Bcciiralv Imliiiic''" const nic ted bv Ili'leuil of Farin. and uned toi 
cheniicnl nnnlT«i.i. Its (wnsitivcueBu is euch that when i:liiiri.i.'ii with 
a Idluj^iumo Oi'^' gi^*-) >■■ f»cii s<.'b1«, ui i^c«8e of a milligninune 



|« gmt.} ia »itkev«nilH prodiwM r vctty p«raept)U« dcflwtkni of 

Ptt to ph>t«ct Uio hdnii^ rraiB aur-cunwnU, dual, and mojatare, 
'aisripii whRu w-'i|.'|]iii^'. luiTOiuiiled bva ti;laat mar, wboMtront 
■ad domi, U> mmUb tbo oprralor to iotroduco the nljnrtJi to be 

' tn pnMKTVi' llie nigc of ihu fulcnuo at mucli u poMibtt^ Ibn 

KB, wiiU it* fiilcnuii K, con be nuoxl Cmni tlio anpport on 

he Utter rrnla by nnilitir luminf; Ui« buUun O uulaiile the 

n«unUlU>- uf tbe bma is detcmiiKd by meuw of a luni^ index, 
itkiwnwBrda la a ipwdiMted nrc ucar tlic foot of tho nijipon- 

f, the bolton C bftvb* Ui >ll«r thr wiuitirmiw of the bnkiKS; 
B^ it, tlio rKntrr of (^'■I'ily of ihn bi-«in can he ninil<' Ui approach 
' fni-a tl»^ fialL-rutn {tU i, 

Bad ot OMBkla walthlnx-— Notwittistiuidin^ tho inaccuntey 

. tbr Irat' wdghi of* biHly may nln-ayobe detetmiued b; it- 

^'A« fandy (u be w»i);h«l u ijluNrd in uue ncale, and ahot oraand 

lUieotliOT iinlil «)iulihr]iiiu i> produced; tbo body is then 

bf hnowB mi^tB uutil «quillbriuiii ia ni-eatabliilivd. Tbr 

I weigbla will DDccAMrily bn pqiinl to ihr weight of the body, 

under firvfimh lhi> wnit^ cimiiii)>Iftncee, both baip prwiticed 

ibv now Rllrrl. 

rjiujHa MPiu. ixntKliiT or TicKKitKTKr.ii uratitt. nut 

•r taUlas botfla*.— iiinci; a In dy falU to the y:ivund in 
of ilie carih'a attmction on miaA m iw uioUculca, it follow* 
lylliliili: *!«■ lifin? the wuu.',all bodies t. -pal and •iiiAll.lighland 
lU^rkt lu fnll will) Aquftl rapidity, and u iiimp of Hiiid without 
abiMild, during its (kll, rdoiu ll» original fonn oa prrfirlly u if 
CoBpact «toii«i- Th«< (net Uiat a utotiu CUla mon.- rapidly Ihnn a 
b A»« aoUly to Ibe luetiiul r««iatMiCM <f poand by the air In the 
af tfacOT bo^ita ; m a rotwim M hvdin ftJt xnith e-ptut rapidity. 
nnalntv ihia by i-xpcntuaDI * gtaH tube alioul Iwu yard* lony 
luy be taken, IwiiiaK ;iiv ii ita eitwnii^ coiaplftiJ^ 
a ' ' 


iMAntATwm axd vouctlak AmAcma;. 


«d a Inw cnek in4 to th« athar. After hrnihg teUodKBd 
£flbn«t wc%lit> Mil 4aMtM (|iM>M e< iMd, |Mptir, bMhrr,te.)\ 
th* tab*, ib« dr ia iritMnim from U 
«r pmtp. and tlw oock cLoBcd. If th> tkhi j 
MW (MldMiT rvf«nF< all tbm bodMs wlS I 
«^bbDv quicklr. (to faktrodufiag « UOlr 
■nd araia inrntta^ Ui* iDbn,tbii ligfawr Uilr* 
teeMMtUghllr w t w Ari. and tUa n-t 
taoaaaaa vitb Aa ^■antiiT of air intraduoML, 

Th» ?«lMaaee a p poa t j by tht air to < 
hodia* i* ttfeaaOj NowikBUn in tlia > 
UqiMa. Ik 8«miUm1i iii S«ii 
^ food lUnrttatMS: aa iiii nwiw e imam of' 

7 it turn bUinir over a higli prvdpw*^ Iwt 

rMwfaiag the bolUim U i* dianetal I17 1 
into dw BttMt nUL Id a rwnium, bo 
1k|Nid* fall like Nilidc witli>>ut wf 
lh«tr BioWulca. Tb« leiitn- iomiMir ill 
tluB 1 lb« iBrtnniMiit coMrta nf a ihidc 
luW aboirt a fimt km;, balf tilled vriib • 
Uie air having bMO «X|iflleiI bv 
prarioua Ui cloalng' one estrrmity 
Uow-pipc^ Wito aucb a tuba i* Md 
inverted Uie water falk In one uiidiviiM 
agWBft tb« otbet rxtnTtuitT at \b* luW, 
|i«udiic«B a ibarp dry •miDil, iMCMblinir ' 
wlik^ acoompaidu* tbc abuck uf twi> 

Fram Newton'* law (&8) it followi^ 
when a Ixvly fall* to the cartb, lb* futca 
■Itrnction whicU CAUSri il lo do eo 
ne ili-^ liodv nppmachcs tbo eartli. I'nleM 
hi-iiilit tfjoi wliidi ifan bodv fAlln, howev 
b« vvn- gmnl, thin incrpwe will tw alloRttbcrl 
ioAppreoiiiblp, and thp fnrpc in quoxtioii n^Tj 
b« ^onnd(^r«t u moatuit and cmitiiiHinu. 
the reliance of the air w(w mnumd, tlMM-l 
Ftg. 41- fore, the motion of all bodies Tailing to thai 

■nth would bo uniformly iwcelor^tmJ, and would obey the law« alrMd;! 

nplained (4in. 

00, Attwosd'a ta^ehtm».—^vral inatruntenta hni« hfisa inr 
(or illtistrniing lujd cvjj_>Tini«itnll:r verifying tb» law» of faltinit 
GalUM; w^o fltaeiv<i*d: 4c*j lawjfip t)>« iwrly wart of tbc itrontcaiith ( 



QIulni«l thvm hy mcMt* of _ bodi«B rolling rfowii incLinnl 

TIm fITM* <4ljrct of 
uutruatFaU w la ji- 
bo rapidity at the fall 

wUlioat altannir iki- 

of diMr MOtkiii, fur 

DHMi* thMr motiiM 

only l» bell** ob- 
bul it will be lev 

by UiE remMnoe of 

■DAl DODTcalMit in- 
^ of Uii* kind i* thnt 

br AUwumI at ibe 
tb* k« liMitiuT, ud 
ted b lif. -IS. It 

of » ftAut pjlbr of 
out St y&nb liigh, » 
rf irbicb b A bnua 
rbote aik rF>>t« uid 
DM but athrt whrvb, 
VirfMM >dW<A inu- 

tiwr aerrn lo diuu- 
aiob. Two pqnAl 

11 Mill H', SRf at- 
I tbe eztTMnitua of * 
tbnmd wUeb pwici 
b«9 pullej; • tini»- 

ftud to the pilUr, 
■Ui4 by > iwcnodii 
n, P, in tbl^ uitiial 
ab totaT,llH>rMni1> 
if tbe pendnliuii are 
cW4n1 to • nirbct, 
wo tanlb, *» urea in 
M^ fli into tbmc nf 
wbwL Tbe ule 
3ihI fJTM raolioH tn 
If bud of tbp dial, 

to M> flxoKiitiic ly- 

dtal, ■• abuwii at i- 
Igurr. Tliif 

fiaj* Bgalnat tbe 

Kig. «. 





nxIrrtDtty of it Icvir. I>. whwh it pinhii until the lM1«r wi 
kiippiirl* ill" tmnll pUii-. >, niiii ihiin tkn votglil M. wl)i«li al tint 
on (hi* |)Ule, in «u(|il"(ily i-it|HiH<<(l ti> the frw' atrlioo of ffimnUr. 
fXcenlrir in m <vin*iriii'U'il ihnl ihii littln ptaio ■ full* itrraKlj i 
til* kiud of lh« <)iBl [Jiiintii tri "•r» 

The wsiyhu H itn(t M' bpini.* i^iiuU bob) twJi otiMr in nqnilibria 
tho n-igtbc M. htnevpr, i* inBile to (liwi-nd •Uiwly bv puttiDi; • 
Wr or o[onKi|{hl m upon it ; ami to niMUure tbc (ftauca wfak 
iIiaciibM. tliH Md fir >cnW, i), U ilividml into AhiI uii) ]ni-hn>. > 
nMoirinir from th** plnii.- i To foaipl-<t>! Iba uiHiranni^Bt thnti i 
number of pl«i>it, A, A', f", V, mul « niimbir of Rnurs 11. U', ' 
may hr tii>>-l by kt«v.h nt tny pxrt of )li<> m»I«. Thr ptatn 
ihfl Hnwiiniliin: w.'iflht U, llie rin)r> onh nmvt the h«f i» ove 
m, wlikli wan l>ii> nttiHK of nioiiiin, mi Tlmt allvr piutiBf; through ' 
thn wripbt -M. in (■(iii*i>mirDre nf iln inerlia. will mnvn on iinifil 
with llir vi-.loi-ily it liwl Bitiiiin-d nr n>nrhin)[ llie rinjr. The 
piirta oi Ilir appKrnluii b<-iaj; doH-ribcHi, a f«w worda will hi(Km 
pliiin tlif Ki^ilidd of i-tiiitriincntinfr' 

l.i-i ilip haiiil of lb>' din) bi^ piftpoij behhiit ill* urn point, lh*4 
II niljiiiilrtl to tupport ibc plnti? i*. on u-liirh ihn wMgbt M 
Ov«rvr(i)glit It THtit, nn<l lli» [wndiiliirii put in motiuD. A> *(MNi i 
band of th« din! pniulx to iriv th? plntit i vill (all, tbi> wmkIiI« K i 
tu will d'-miid. and by a lillln ntli'nlion and n f<-w IriaU it wiU W 
eiin- 10 plifp a plnT'' A w tbnl M mar rvarb it riartiv a* the di<l 
indicnt<-( ihr rxiiifation of oiiP •ri'oiid. To niiiki> a wi^ind ^Xpwiwi^ 
li-t tll■^ w.-ighlf H am! iii, ibo pUl« i' aixl iIip Iptit U, bo pWoIaari, 
iirnt : rpiiKiTo ibi- pluli' A, aud in itn plnci- put a riair. B, no ■« lu i 
thn ovi'TWi-iiibt Ml juat wiico tbp wciaht M would Imve nMuJipd Ai i 
pulling thn iw-ndulmn in niotioi) airniii it will bv caiiv. aft«r 
triaU, to ptil u plalp. (', m ibal lb'- wnlehi M mitr fall up«n ''■ 
precinely whrni tli<- liimd of th<.> liial ]Hiiiiti" lo two >i>cnnd». SId 
thp "viTwi'i^lit HI in tbi" expvriiiieiil wm nrrttte*\ bv IJiu rina B allk 
etpirnlion of oik- wmind. Ibe •pncn HC wm* litmcribnl br M is 
iw<!Ond piiroly in \>niw nf il" nwti ili^rlin. iind Ciini«)li«ii1ly, Iit (I 
IM' will iudicHtr tbc' vcloi'ily of tbc fnlliittr niHw at tbp e\pinitim ■ 
on* "I'fonil. 

[•rowediiig in Tbi. NHinp niiinmr nn borLini, Wl a third rxpuKmcM 
madn in otdrr to ii»f«tBiii iho point If nt nbich tlic wnighl M utJ 
arrive aflir iho iapm" of two wcoiidB, and, pultinK a ring al K', n* 
by a fourth eipi-riim-nl tb« pmnt C nt which M iirrivtii nlonii, ibr 
rrcoodr aftnr tli« dcun-nt cntnnieni-cd : H'C will lhi>n v*ptv» 
r.'lodty atquiwd afti-r a dfaei-Dt of two wrond*. In a xiitulnr 
1)T a 6tb and »ixlh cxpcrimrtii, we may detvrmiiia tho npaet OE 


K itr rit^ in UiTM «Maiid*. awl llie t-elocitj K"C" M^iiiirtd d«riii^ UiMo 
ftam' mmatiila, >iwl •!> un ; «v olikll htid thai IT'C i» twiiw, u»d 1)''C" 
Uwoa tisiw M f.nmt •• DC — in iMJi«r wutds, that the vclodlin* DC, 
Ifl'', ifC', lacfMM in the Binu» pnipomua •• ihn liniM (I, 'J, 3, . . , 
Lhxmm1«) nmplnjrnd in ibitir aDiuiifiiw^l. Uy lliv dulinitiuu (-ht>. there- 
pm;. tho notiun i» uiilfiiruilv ik-i-i-lvnitn]. Tim mUip cipi'nniiiiils will 
I- til Trrity aoil illiutmn tbn four Uw* of uiiil'iiniilv HOCrlvnled 
. >i- niiinoiHt^l in i4«|. Fix- pxampte, the ipaivs OU, OJC, OH", 
L , . . , doKTibnl bctn B siatn nf nut in 1, 9, 3, ... . McnndK, will be 
UtMrf lu be [in>p<iniiuiiil id Ihw nwiiiben 1, 4, H, . . , ibat ia Ui 
Bvr, bi till) iquarai of thuw niiailwn a( MNxrodi^ v ■Utml in tho 
'(Unl Uw. 

LmMly. if lh« overwelyhl m W chcDfTod, tin? aocvlflniticia or vnlodt): 

HL' ■ciiiitrt] p'T •Fi-nii() trill old) bi! olutnynL, anl ir« mny naiily T^lty 

Air ■AH-tlioa IB < :3> ). lliAt f'irve i* prLipurtioiukl I" llii^ pruiiucl uf tliF tuaoa 

wmtnl iu1» till- atjculi-tnlion jiroducod in ■ Rivnn time. Var inalnnce. 

«Kim)nz tliB imlley lii b^ ir> tiirlit that it* inirlift cau Iw ii«ghwial, if m 

' hdlf an ouofp, and M Nad .M' c-ocjj ISj ounoM, Uio acetlaimtian 

U'i Lv (mukI U>bo MS tnebek; rliiUt it m w«igh«d 1 oud»i*ii<1 

X and M' nu^ iCtj ouiii-e*, tliv mwe'lemLiou IH* wuulil bo finmd la be 

lfc)w inriiea. 

Nnw in thir^e cMealberomapiftliielntt mouuu, lliatiatiM overweight p, 
•n> in ikv ralta nf 1 : ^ : while tLc pradacta of til* maaaea n&d ihf arci.-- 
\rm»rm» an in (be nlio of 4}'f IS] + 1-H>>«I} ^ (l-f<Mt+<tH^|x:t. 
ikal ta, tli«7 an alss b the rattci of t : J. Now tliu sollie ruault U ob- 
•aint«] in wbatctcr way the Biagnitntl^a of rn, M, anil M' urn vnrivd, and 
x'tilir in all caH-s tli>^ ratio of ibe forces iiroduciii^' luotioii equab 
' ■■■ u( ibv liU'ini'iiln tffnvratj^. 
vU. Laactli Of the eompoaiiil pcadulaak—Tlii; funiitila for Ibtt 
linr nl iibruljoii of n umjUi- jB'niiuliiiit. and tlit- cociRlutitmi diHlucnd 
it tAl) m alwi ap^Ioibl* tu lliv o>ni|>i>iiiul peiidiiluiu, thniigli in 
Ikl* rarr' [t W'iU br neCM^^ to define acninlely what ia mi^anl by tliii 
uf nii-h a pfilduluai. A ci>inj)oi9n<l jiriidiiliim bning formnd of a 
J md t rnniniited by ■ i^twater -it l-nw uikm. il fullowa that th(> M<VFrat 
pniiilB iif till* witnlf fij>lBni will xtrivn to p«rfomi ihpir ivcil- 
ia ■lifl'-n-nt liinct.tbvir distniu'ea from th<^ aiiaof miafiHdxiuiil'ning 
■ml tfai- tiinm dixluit {uiiiita r>^uinnir a lcnt(«r time lo e>)nip1i!tfl 
m •x-lllaiinn. Fiuin ltii\ and from the fnot llini Voini:; pnint* of tbo 
MBwbody ihi-v iiiiuii iinrtllAto topritlii'r, it follow* thul tlip ui-rti<in of liio 
polM* ikMr iho axia of ta*pmiii)n will U> n-lnrd>>i), whJNt tlini ot ihtt 

Euil puLnl* will b" acMb-ralcd, and betwufu tbu two Mirpmilitf* 
I lHawwarily be a wrlnt of poiDt" wimiw niotiom will be nMthor 
,1 not ratudiid, but whWi will .wilklc pwcimly »• if 
rrtli ftw* anil imcimin-ctni! witli ibe ulhor poinl* of Ae tjt 



VKMvnJcnoK A)E» ATnumttK. 

Tb» ptfaMi, btW (qimlbtatti fn» tiie ub <tf anapNMbn, md 
pamlM axukBOwn ■■ tlu ani ^«nMi(iaa: and it U to llie dia 
liniM ibcM two u« ifcat ili« t«nii in^ y faU lawpMoW 
•f^&id; wa mnt tn, ibMcfom, timt tkt kmplA a/ a t em p oimd j 
d^ ^(V ji'mH* /' i " *' '"^ !! MiIkA mMM Jmrnk lit* (Mrt'tfaf>«iM ■■ tit I 

Hhj^Im*. Ike mWbmW Patch phynciM, diieoi*n>d Itint tht u«« 
MMfiMim md ncUUlioa uv mutOAllT eociTcrtlble— tlinl i* to m*. t 
lina <f dtdUtttan vill nmuun unaltitrcd wIms tim pcnduloi* u > 
pcnled from tta uis cJ u«cillii(i<«. Tbu imm^U* fact mmUm 
de(«Rnii>> «xp«riiBMitaIlr tbe Uofrtb of a cowpo u ad poadulan. 
•o tli« peadnluiu b LiiTCVt«al nni «iMp(nd«d from > KCimd and i 
ui*, wUrh, ^W Mowi trial*, i* pteeed m tku ihs InrenioB 
•ffivi xh« bvibW of <MciUuiaM ■!«)• in a ptVD tun*; tha 
qiripcd U UkM tlie diitanoe botirecn Uie two uts, and on givlif lo j 
Wna tkiM d«C«raiilMd, th* faramU of fAl) for the nniple 
l>»n>in*s applicaMc to tlw MupMaid pcwlulNB, wboM 

Tbo length of llw vniMb poadulnsi— ihU M to My, nf tbn ] 
wkkli nakLv oeu osciUalioa pvr aeoond — miiM, of cniirw. wjili ' 
tMuit; of K^Tity I at tbc kvol of ikn ae* it m, tecariing lo SaIwif, 

3M3074 mrh-M al the Rqjunim- fSt. TIoiimm i, 
80-13063 „ ai IjjiicIun.aDd 
SO^Mai „ at Hpiubcr^m. 

Aocoiding to tW firninlaof (SI), ilier«foTC>. th* an^lnmtive 
gfBTJtr at ihir hI>i>v« ptanq la (iblatnnj by tdmply nalliplyin^ tbi^ aba**! 
numWni rrdunnl lo fi'ct by tho aqiinni of 3-14IS9L l.'invqiiAntly ^f tr 1 
the Kpticv (t'Tibed iu l)it> fir«i wcoiid of ita molion by a body Tailing i 
I from a state of n-sl ( W ) i« 

Irt-wor r*«t at the EquaUw, 

Itl-awKJ „ at London, and 

16'1SB4 „ at Kpitzbtftgnn. 

nm •)>iinrFBt)oiui of ihi* kini], ikfUr applying tbe naoaiaarT forreMio 
and lahiii;: Lii to account thi; effect of rotntion <78), thefotm uf tha 
can be ilciluri'd. 

71. VnUoatlaa «f U>« lawa orib« pvBdiiliim.^lii ordM Iti KtUyt 
tile luws of the aiuiplu petiduliim (ftl ) Wo are coni])pIipd to (-tiiploj- a com- 
pouiid '"in, wbou- i«n»t ruction differx as lill!# as ponsible from that oT] 
th» foniier. For tliis puT|)UM a ■uiall ipliorc of a reiy deniu^ aubntaaM^ , 
■neb M lead or platiuimi, is nuitp'ndnd (mm a lixod point by nifasi of 1 
a very line llin<iid. A penduJum Ibtu funned oMiiUatM nlmoBt like 
nmpl* pnndulum, wIiluu lengtli i« oqual to the dtxtanoe of the C«atre of { 
tbe Dphetv fr»u tbe point of 8iiapen«Ioii. 

in to ratify ill* iMdnontiaa ot muU oMiknoiu. it u amnAj 
7 to munt tho numbar of oiril- 
nwd* in equal liuioi, ai Uie A 

d«a of Umm occitlBtJOMi dimiaiah 
legtMB tosfncliuiiioriiil((;Tiw; 
abtr y fao&d to b« ci'iuiUuit. 
the time of vibrBitoB it propor- 
> tile aqtun root of the iMgtb 
mI bj aunay pendtiluiiu, vrbooo 
■re a* iIm munben 1, 4, Oy , . . . 
kta «B)ilUM«HMtT. Tfaa oon«- 
f wniiben of oaaUatiaiw in * 
gw en tlwa f<Muid to br [irofNr- 
I tlw (nciioiu 1, i, i, vu. . . ■ , 
bowi Uiat tbo tiinoii nf owrUla- 
aa ibo nuinben 1, ^,11, 


knf Mvnral {NndiilsciR of ox- 
ml kavth B, C, D. (tig. 4»J but 
^vMT, it b fcMind that, Mcgtisctiiig 
Haaem at Iko lur, tba** pandB- 
cfUate in etiukl tiae*, llicrebr 
OuU ibm Bccnkiratitii rffbct of 
■■ all liediea b Uie aamu at tlie 

Fig. « 

MDw of an amninDient rea^nhliiig thv aboTe, Nenrton veriltcd 
tliat titc mimta of botlie* are dnUrminod bj the balance ; whic3), 
B KfnarlMil, Um at tbo foundatiuii of the nMuuni of fortw (30), 
ill be waiD oa conpariug (50) and <St) with (47) that thn law 

mot* «nall iMcillatkin It ob4«ined ou thit tuppontiuu that th« 
Ifmrily on all bodiea i« leiirotrntnl br M;, io which M b deter- 
If ibfl baUtio'. In otdor to i'«rify thli, li>- had ntaik two round 
[HidtfD boiea; be dlWooe witli wumL. aud as iiparl)' lu poiniblo in 
m nf oadllalkin of the ntiii'T hi* pliu^iid an nqiiol ircight of ([old. 
MwpauM tltf WxM by (hmadu hIdtco fr«i luntc, no that tbcf 
•ndiUiuna exactly equal ■■> far tm wM^t, fiRii'*', and rt'Kutniim 
r wem onaoenwid. TkuiT oMtllalittot w«ra prfanued iu cxactl* 

tin*. Tbe aame naulla wuk ubuuued when othnr «iibatance» 
d, euch aa ttttor, laid, K^**"' und, mUi, wood, wiiti<r, i^om. Now 

bodiaa had «4imI WKif:bl», mid If Iha iufcrvncf? that ilinrefniv 
I r%iiml maaip* had bwn cTTani^ua by wi mufh m thn 
Itb part of ibfl whole, lh« eiprnni<-nt would liav'i (l«lMt«d . 




I'J. Appllc*Uoa ar tbfl paadBtomto eloek*. — Tb^ivyulniinni/lbJ 
■nolirin 'if I'lii'k* ix f'tlWi'.-'l I'V im-nGs of pmiliiliimii, thai of watcbM 
bii!nri^-i'-anriiifn>. IVjiiiiiliioi* Werw fir"! 

^d^4ft^S^ '" ''"" I'^n"*"' '*>' Hi>>'|.tii«m» ill HIM. auil 
Hr ^Bi^Jki^* ""I"-' y" llo'hi.- uppti^l ■ ifiral upriag 
^^ I^FII^Mr iiftUni'tf of » watch. The mnniifir of enpli 
ibp ptrDiluluni ia bLiiwii in li|;. 44. Tb) 
diiliim rod pnminjr bnt.wiwn tlw prmiini tit tf' 
'I iMinmiiui>:nt>.'(i it4 luutiuu to ■ rod 1. vUch 
<iKd1iiitt9i tin n lioriiontnl nx't* o. To tki* 
lixed a pLW« ini* vn\hi\ mi (tM^^munf or 
IrtMiiiimti"! by iwo pn>j«?tio[ut or jMtttf^ 
work iiltxmiiti'lr with tho tiwlh rtf Um 
icArcJ I{. TliiB iy1i«v1 b«t!i^ Hfted on 
wiiijiht tftid* tn movn ftnntiniiniinly, Id U(| 
ta ibi- direction iiirlioHt-.-ii bv tlir arrow*! 
Now if tlm ponduluin i> nt n-it, tbi> wbi 
held Hi r>!wt by thn pallet m, Rtid wiUi 
wholu of tho clockwork raid the voiftlil. 
hi>wi>vnr, the |u>ndii1iim niovn* And Itikfl 
[HMiliou niton-ii by the dolti-d Ii[|(^, m b 
the ivliinl rti^pfi (mm Ihn r.nnfine.mi>nt in 
it wait belli liy l)ie ptdU-t. the wvi^ht di 
•nd cniim* th« wliei^l to turn imlil it* million in nnvsti^d by tbit othnr 
n; which in omfMiuenci.' of thi" iimtioii up the peudiilitm will he hmu^ 
into contact with atiothiT uxitb of ihc! cnciiiii-tnfnt whci'L In thin nuni- 
tmt thn dmni'ot of tbp woij^iit ie BiternBliily pfvmiitli^ and nrTv*ti«l— «f, 
JQ a word, Kgiihiliiil — 'hy the jieDdutum, By luvanH n( a propei trait 
■f whcvlworh tho inution of the ■'•eHpnmi'iit in <iomniuiii«)tt(>d to tl* 
rhMidaof theclnnk ; and u«nwr|iieiitly tlirir ni^tlon, ton. ia rejpilnied l|f 
llhc pvodtitum. 

T-t, Oauaaa wbloh moiUfT tha Inlrailtr or tMT«alrlBl ctstI* 
tftUan. — Tbe irili'ii-'iiy nl" lb.- fLirn- of ^/riivilr nt llir i-iirih'n .niifncp t* 
nKidil)(<d by two chuhui: vix. by the form, and 1^ th* mtntinii of Ihi 

i. If tbi.' i-nrtli wi're n uphen- of uniform drniiity the militant of 
tliH ntlnirtiiini> which iin pnrU f-K-rl on an r^KtcriwI |>oint wixild bf 
lh« Mime ax if the whole of its tnnxi u-cn! cotleL'tml at ilt cmiItv, md' 
lliPI^forr the attrnction nt nil point* of i|* Nirfaco would be tli« italMt. 
!■ eoiuequeace t>f the llNtU>nin|i of the aarth at it« polw, this i* no lonffcr 
«»i:lly, but only Tory m'ftrly true; and ih.- attnirtion fin an •rxlAniiit 
point i* only rmaMtj iiiviir^'Iy »» the "i|ii8re of iti di-limce from (he vorthV 
Mnlm. Aa a fnrthur i^onivquciK-i' of thr Hattenlnii nt th* polif, iht 

Fig. i\. 



Ima thi> tvntnnfa poiaton UieiuTCKvd^cKUM m ireptooMd 
I cf lutnr to i^illicr pole : but m the ilioUnci' itcncuoi tlio itttrac- 
I iMnMMi umI POMuqumUj- ibe force of f(nviiy inrn>itt^ m Uio 
J B CH i M i, bntnif ImUt U the c(|ii>t«r, and frnolwt nl tbn poloi. 
whd would bo trao if, other iJiiugt noMinini; tbe mm», Hi» 
mat (Kit. 

«KiivqiimrR nf the earth'* mtalion, thi- forrt- uf ^rnrrlv tiDd(ir> 
inker niudilUntlon. If wf iiiui;.'inp ■ IkhIv rclatirclF at fmi 
i|Mtar, it tmlly ihatva the oarth'a rotation, and dMcribeti In 
18 of lum day, a riivte whow «»ntM auti ndius an the centre 
a« of the cnrtti. Now aince a body in nuilion tonib by reaMii 
Brti* to taovf in a straight linv, It follow* iliai to iiiah«i it uiinr« 
a, « (utcv ntiBt Iw uiiipli>]^i<d at iHwh inalant t(i deilwt it frtnn 
Mil (41t>. Oo«ii«)ii*iitly a crrlain pikrlion of the «artlr« altrac- 
Ft ht rmpUiTnl in kwpin^' Ibe bIki>« b>)ily op tbv surfaon of tbe 
id mly th' n-maiiiJnr i* «nn«blr n* trrigi/ or aereimTtiiig /nrft. 
fn ttntu nl<-iilaiiD«) lliat on ilir m|cui<<>r iLu ji^th part ''•f tlio 
^tttacliun un any tindy is ibu* miplDyctl, nu that ihr nia^ilude 
lit> )n)iui!or >• bw hv tliiT jj^tb pnrt of what it wngld bo wvrt 
B at t««L If llii< tMdy, Instead uf bving' on ()ih «<]uat4ir. is in 
n iatilude, it will dMcribe in one day a ciroto cninddin^ with 
VU t^ talilmif on wbicb It ii> MiitaiMl. Now Rhmi biidiHi 
I ia the mmuf line druln of diffcntit radu, it ton bo deduud 
mt) llial the fomn n<qiiin>d to keep ihem in thow circlM are 
|hu1 tu ibrir nHlii, lli^orf tbi^ forct? reqttim) in tliv cak' uf a Wly 

Pv lalitudw i* !>■>■ thno that mquirad if thr body wiTa on tlin 
ad Im* aa lli« Ullln-ie ■> intrat'^r, cv«H-qupiitly wi-rv gravity 
by tlia wliolo aaioutit of tbii force thn diminution would bs 
bnarrr tlie body in !■> oitli*T polu. But bince . Ibe foiV4- in 'pro- 
ily by an inditpci action ofmnTity, it appnan that the diniinu- 
Ihmtiy mndnvd Mill Inu a« tli« Uritude w gmttor. On the 
banffiMv, the furcv i-r (.ivTity mcnnaea •* we pan ^m the 
Id eilber pole, tu cDtunqnencn of tliti rotation of the earth. 
b* renarliMl that bulb cbiumu, tW. lli« flaluniiifr of tht^ nitUi 
ha, and it« lutnlioa, roacin- in producing an inrn'Htiii in tha 
broM uf gTwvity Mlb« oWrrvr Icavua th««4UBtoi and npprja^hiM 





■ocHrTLtK POiiaM. 


bodiM pniuil ibow iKu iHw ooIkiiI** uc unilct th* intL: 
ttaawn tonm, «ac of wfakk tank to brag lh«v (opetbtf r, and Um 
tuwpwato tbm bm Mck ottrar. Ttw fiiM fixcp, wbkh 
mahttiwr afhMitim, mm !a one tad lb» «ain« bo^lv witb Ui« iliMuu 
■Ij, Th* wMnd liuea. wUch i» d«M to tlM •etioii of bunt, mrici wilk 
ibe iatvBMiv v^ tkis •^nt. anil with [be ilwUnce. ll M ibe mBUat 
rdktwn betwvou tbnv (orcm, tb> {mpniuScnuioe of tbi- noe or ibc dlhA 
wkich dfiMtoiiiM tb* ittokcttUr rtsu of t> body {4),~wli<'th«Tit brfoU, 
Uxjuld, or gannu. 

UoIbcuIu BttiutioA U <miy n«n*i »X infiniMlj ■unll dUtancot. !• 
vtttei b ui*pitmriBbtF irlvrii ibr tlulanw betiron tbe aMheulM ie *p|a>- 
aablCk Tb« Uni wbicb mtnilnt'' tbl* fofca uw sot known. 

Aecnrdiiig to tb* nuiBCr iii which it is ptpuAtA, ii»ol«vulu kllr«rtM 
i* <l«aifBat«l bv tbe l«nw raAnwrn, aglm^, at oMmvu. 

7Al Oab«al«a. — CoiiMiaN U ibe foice wblcb naltM two mdecute it 
(ba Miu« iMture ; for uxAmpto, two inolMtile* of wnter. or two oMilMibt 
of iraa. ColicMoci i* (tronitiT ns«rt«d )B aolidtt l«M vtronxlT in li^uidi 
•nd scajwij Bt all is gMc*. Ita blvwtl; j^ aw t w u lli« t(^iii|irratDi>' 
wwBMw, beniiae tb*n the Rjiulnivc fo«* du* to baat tnawwHi. I)«dc« 
il ii that whan folid bodlM aiv bvaliHl ibpy tliM li^iiicrfj, and Wt 
ullimnielv conreiUd iotu tbe 'gawmu >^tc, piuirid«(l that beat praducc* 
in them no rhrmiral (-bang*. 

Cob»"ion varli^ nnt oiilj* witb ibe natim of bodice, but atdo with At 
amui/pnicnt of their molLTiilci : for piamplr. thfi iliir<>rcno» hntwrcu 
Kmp'TPd and iinti-mpcri'il utiwl in du» ti> a diflVrtuce ill the luoleciiUr 
amnif^ni'-ul pri'doctdby teniprriog. It U l»i iho niodificationji whidi 
thi> forcL- iinck-r^pa llmt maoy o( tbe ]»op«rtiM of bod)«* aro due, mc^ 
M tpnooitv, hnr\ln«u, sail diiclUitr. 

In lurge miuwi of liciuid*, lbs tarn of irratity •iTi'K^inM that vl 
rahr'niiin. Ilom-i^ liqnidi aiMed upon by the formi-r fiircc haTe no 
spMtal ahapr ; tliey lake that ot the TPi^fl in irhii-h tbny arv eniilnjacd. 
Ihit in nmnller mnuci oiheaion g«ta thv ti|ipi.T bund, niid liquids proaBDl 
kXhvn thw »|<h>'n>idal form. Thie is seen in tlin dmpi of drw on tbe 
InavM of planta : it in also hvmi whirn n liquid is pluc^d on a «olid wbicb 
It doe» nc't uiniitirn : a*, for rinnip])-, niercury upon wood. Tbn ei- 
{wrinuiDt may ftUi> be madu with water, by fprinklin^ npmi tbv mtftevol 

Ught pamitr, Micb m Ij-tupodiiini or lanphlaek, Hid 
atf aoan wfttcf oa ii. Tbn fiillflwinir p^icy «ip«riBiPDt U 
lion of ibo foK* nt onbeaMid CAiuuig a li^jaU la Mwaw 
■dal fMiD. A nturaUd ■olutiMi of mlpluito at n»c k 
A BttrfowHMclwd bottle, uid a few dia)M of iMMlpikid* of 
auMd witb iodine, made to float en the aiu&oe. If pwra 
iw carvfull; addad, to m to rr't oo th« nifMa of Um nlphMte 
itUiB, the biMitpfcido mllecta ia tbc torn at ■ flatt«D«d iphraaid. 
Mia til* aifiwMiiaK cf Uoks eolonred kUm, and in larfpir than 
' the bottl«, pruviil<id II sulllcteiilqiiaiitiljr Iim 1>e«in takm. 
dty. — CAflniiai/ o/Snify ia tbe force nbii^b is nx^ftrrl betwMfl 
iiM of Um mna kind. Tbu». in wat^i, wliicb ia tMnpoanl of 
1 bj^rogat, it ia aAntlr wbii-li luilea tbew elanMBta, but it i* 
Aich Unda tofBiber Im nolaculaa of wktor. In compound 
^MkNi HmI affintj opanU riMwltnaenualy, nthile ia Hinpio 
anon haa aloaa (o ba ccMidand. 

lljr an doa all tba pbrnxuana of combuttkm. and nf Rbnmical 
■n and dcconipofitian. 

1MB wliich i«iid to wvaketi oobeaion hk nnaal fanxiraMn to 
w iuMaaco, ibe adioa of al&iitr botwmti ■ubManoa ia farUl- 
lldr dlTiuod, and KiU miin* by mludog ilinn lo a liquid or 
■te. It ia mosl puwerfully vxcrted b_T a body in ita m<uemt 
» ia, tbo Ktala in which lh« hoAy «il*l« at llie niomnnt it ia 
I 6iim a coinpuund ; the InnIt ia tbpn fnw. asd ready to obej 
dJbd^. Aa inercaaaortcmpnniturr nndiflea afiiDily- difbr- 
n dlAfeat ciicnmataMaa. In luiav num. by diminlahlatr 
■nd incraunqg tbc diataneo battrrvn Ihi- molrc-ula. bi^at 
eonbuiation. Sulphur and oxygva, w)iii.'}i ai tbv unliiiaiy 
ra Ant wflbnut action on each oibnr. eombice ta torm wilpbur- 
trhM Uh> l*iia|wtatiu*> ia r«iat<d ; in other ra»M h«al tend* lo 
> eoBipound« by iuipailiNgr to their elcmenU atx unequal 
(ty. It i« for ifaia itaaoa tbat raaay metallic oxidm. iw for 
boa* of filrm and Bercur^, arv dn:i>iiipoMid, by the action of 
faa and nrtal. 

Malao.— Tb« uolacular attraeiioD oxCTtod between bodioi in 
Mllrd imUmiW. 

Mco takaa plaoa batwoen aoiida. If twnlnadan bullcta are cut 
akldft aa aa to form two «qaal and bri)clilly poliidini tatfuctm, 
tit fKaa apa preMgd and lurnad aipunit tafb other until tl>vy 
ilimO contact, thuj adhere m atmoirly a« to trquire a form 
lan 100 Krammnt lu aaparato tbem. The aam^ experimeiti 
lada with two tqitsl piece* of ([lus which am poliahed and 
fcdf plane. When tber are prnaed un<s a^^iat the olk| 

-^* tie wHihL, 
■^ » tie fc„,' 




nal wlurk oa W Klfo^eJ in m >*nnl pruiti^ W nnaa tf 
MM a«d tka ftvaA lioa. A •■nil wIl li|ii^ nan I] U rifkl 

F «bKHV««»P 

«4 ■> 

W « W « I I Ib>— 

to O* 
to Ur 

F 1^ fiMw iibH^ Id rrafao* iiMuij >i Md t: 

uyri wBrti OB (br eUiCidtTii/ sctria SMd* br S*- 
ItewwH 17 mad SttT k« fa«d ibr 





' of J mtmw . trao and boim apedweftt of sU«L, hii-". 

M. SiBMteHj aC awMiM, — TW bw« of tli« UinMii of «iM 
(Wienni'oHi b* Conlomb, bj meuia of 
m pwUiH nlled tbii farMM ifltoK* {6f. 

.^^^U It FciBiJBti of a natallie v'at, cUsp*^ i 

** ^Ln "tf «xtranitT in m lupport. A, Had 

^^ M Ute ttthet exlrvaiitj ii niAUlUc t| 

■ to wkirit it Rffiind ui indDX. C Iini 

9 brlirw tht* ibrre Is & ftwlujiUil dtcl*, 

If th» MMdU b tumod from its ]>o«ti< 
eqniUbrium tlLKiufti ■ cMtsin an^le whicb 
tlia an^ a/ (ar»a, tke furiru noMwai; 
produm tbUef!«ct U calW ikn/ortvo/ 
WIhoi after tliu dodt^tion, ibe spbeK 
la iwH^ tlw maeiinM of tondao 
ttteot, Uw win untwuu itaolf. aad di* 
ntaWa round its rertkaJ axii with i 
rafiidin' iiniil it it>»cli«a it4> pwlinn nl 
boitim. It ilniM not, ha««T«r, rert then 
lirtue of iu iiwlis it jaiaiii tbU pcHtlMn, 
the win imdrrfTtwa a Mrwon in lb« 
diNctioa. TW w|iiiK)iriuin brioft agaia 
i<uoj«d the wira tfaui Uada to untwist iladf, tbe nunn alivntii 
^[gaiMprodaciod,aiid tbp ■Mdkdoranot mn at cmo of the arale until 
I ««rtun nnnber of ocdUationa abaul ibi> p-MnI kaia been ronplei 
fir niMuia of tbb ^tfianlM CDnlnmb fonnd thai nbt-u ihi! ancpl 
of tbn ofcillationa i* wfiUn cattaia limita, ibr oAcillAtioiu nm miI^ 
tb* fi>Uuwii])( lawi : 

I. Til* oteillatiim* «r» wry ntarig umAronauL 

II. For tif tiimt tdrr, the mtfU ^ larmtm i* pn^KviioHot to l^ mon^ 
f^ rtr /wre oftermtm. 

III. With lltr naniii/iiFtt ■>/* rniWett, nai' iriM unrri of tli* tamt tHaimiw, 
tit im^Im o/tornom arr prt>pvr1i«mtd lo f Ar Intfflhi of lit inr*t. 

IV. TAe mniw /mvt of tortioH briny apjtlieit to trirrt of the tame ImfA, 
lit tngkt of (4UVKUI art iitvmrfy yn/portkaud to thtfourtk /unptrt ^&» 

Wnrtfutim hai rxaminnl th« niartidty of tnnQon in th« caan nf rtoot 
»>da by iu(«Q» of a dill'<<n>ut apparatus "■"A flnds that it la aho mbjeci 
to tliivc laws. IIp hiu furthtrr found tbnl, all diincnrion* bring tbe 
same, difletvnt taib«taucea iindnrgo diircri'nt dpgr«eD of lomim, fg^ 

■>ach kiibatatict' hi* it« own cocfliciMit nf Ionian, which ia doQOtfd I 

tV. *a. 


riinrrirrtCB rKcvLiAK to SOlim. 


Tin kw» (rf torwon m«r be MunriM«d in tli« ronnnU w^- - in 

1 r* 

I V k tiif> uiglc of lonioB, F Um* moraeni o( ibc fore* nf lordoo. ' 

f\. aiaattoHx sf SMavva — A mUJ, wlwD cut bto ■ this jAhtt, Mid 
[nl ■! unr 'if Its exU«niitie«,aA«T bkriog U«ti inrawor )m» beol, atrlvov 
muiti to it* ofi^insl poatkui wb«n laft to itmll. Thia pmp«T^ » v«ry 
Itiact in (tnl, caoutcbovc wood, anil paper. 

IIm •larticity of llnxuro i* applied in n va*( rariotT of tnclaacM, tat 
■■pie in buwr, watch upriiijre. niriage apriugs ; iu Hpfing Iwlaiinia it i» 
it tn ietoinuDP wigfats. in dvnamninctoni to ilnprmine tho foKw of 
HMa on ptime noTun ; and, u rxlMJag in w<w), hair, and fvatben, it 
l^ili**! to doiniiilic ii»e« ID ciwhiotu and mattivaarii. 
Wb4i«VM W lli« kind of uUaticily, ikcre h, m liaa beoo sli^iiwly mid. 
Iniit to tt-tknt u, xhetr U ■ luolccuJar diiplacemcnt, bcvoad wliick 
Dm atv lrnk«a, or al naj rata do noC Ttipiiii tlMiir primiUviF form. Thia 
lit *• aSorlnl br larioua oauiMi. Tli« Flatflicilr of miinv tii»u]« u \a- 
md b; Aartl/tuHff, irhvtbcr hf CoJd, br niraiui of the draw-ptnli.-, Iij 
Gajr, or hy bammning. Suiav •ulMMure^, viicli m M^'A, com iron, and 
p^ hacnoM- hntli butlvT and mote plutic by tempering iSa), 
Elaibcilj, ''«i the i>lb«r luind, is dimiiii«hnd br aimniiUng. which <ian- 
bt in nuiintr tbt- body lo b tcmpi'mtuiv lower tliaii tbnt nww-aiy for 
Kptriiiit, and allowin); it to cool ■lowly. It i* br Ihi* mrans that ths 
iittdiT of •prinipi niay Im r^guUted ai pli-tMure. OIsm whvn ii it 
Had, uwlns!''*' ■ ""^ '"'"P^'V B** beinK npidly cooled, auil Iicuito, in 
bf Iu prarent too grt^i • fra^litily of |;la«» object*, tbnr azr ri'hcaltid 
■ hmao, Hid an cantfully nlluwvd to cool alowly, no tlut the partitlea 
n tllM to aiwiinM) ibnir n>o«l nabln poddtiaai. 

^i. TaMUily. — Tmaeity Is the imiBUiiio- w)iii<li bodi'A oppn«e Iii 
miict. It i* dct«m)iiiHl in diflbrcat bodies by forming tbi-m into 
Ibalrie*! or priamMic wire*, and sMerliuaing the wMgbl n^wmary to 

Mb ibMR. 

J\mmil!i u dtrrrtfy fuyporiiimal U, ik* hrtaiang itnffAt, and mifrmljf 
Ipiafi'iMiiir to tAa nwa of n f nnHnrnv tt<1i<m of thr in'rv. 
FanMcity diminiidMa with llic duration of ilm tnurljon. A uma]! forrv 
tKMaaAj Bpplin) f"r a long tiine will ofl«n break a wit«, which 
■U DDl «l L>n<w bi- brnlien by a bu'^er winghl- 

Vm obIt doea tenacily Tary with dtlToninl fnibatailOM, hot it aim tatim 
Ik Iha tana of thi- body. 'nitu. witb lh« aamti aMtioiial anik, a 
Itdcr hao |ri*>'*!f tAliacity tlun a [tri>iu. I'hf quantity of tnntttrr being 
ga, a hollow cylindw ha« gnialer tunacity than a tolid nnc : and 




tW tiwaritT nl U»* ItuQnv ntiMdet i* |rT*«l««l wfaim Uie FXIt-nal i 
■■lit Uh- intersal noe iu ihr iBlio of 1 1 t» ^ 

The ihaiw Im* aLn tb* ■■»» iaSamcp oa ihr resiNUiicF lo i 
U hm Ml tbr mialance lo tnctlon. A tii»Il<nr cf lindrr witb I 
UUM, aari Uio MiDa vtriykt, at^tn ■ cw«l<v rMiitanrci- ihim » 
ij*r. Il H for Iki* KvMiB UuU Uw> bonn or minisU. ibr rnUbcMoft 

WW *llid, lb* VMW riBMMIHf ibp Mflie- 

TmacttT, Ul» rlaoiriiT. b difamil ia diffiTROl din-ctioiui in 1 
•Kxtod, tir pumplp, both llw IfaarlW aad tU? vUttkitir we gr 
Hmclion nf ibp fthrrw tbiw id ■ tnuurrnB iltrvtion. Anil tbiii* 
iibtatiM ■> fVBFiiil in all bntin, llw imui* i>l' wblcb i« mt UmI 
•11 4in«t»ei(u. 

Tb* IbUoTUiir ubb- si"« the bn«kiD|r wi«|^ ia poundii (irl 
bkvini; • h<ci|1>«i>1 anvi at n mjuiv otilUmvlpr: 

ADiinMoy, nM . 

. h; 

CoppHt, unMled 


[&aiutb. „ . 


„ drawn . 


UmA, „ . 


Ino, ■BnwJnl . 

'. \IV» 

n drawn 


^ drawd 

. i»a 

Tto. ., 


C«»I ■tpffl, drawn 


„ e»M 


7.»e, annealod . 

. .-tl«4 

IF'ptirf M Mf lAunnfmH 


n drawn 

. ai*8 

(inlil, lUinpalMi . 

. S*-30 

Mdbogwnv . 

. . Il« 

,. draws 

. R1«0 

()i.k . ■ . 

. »* 

J<iUcr. uinnaM 

, snott 

llMch . 

. I»< 

.. dravm 

. 63«0 

Mr . 

. tw 

I'Utinuni. uinpitlnl 

. S6«5 

A#fa . . . 

. m 

_ Jrawn 

. rrw 

Box . . 

. w 

Tn tbi4 lablc til'- b^idiri Btt) la^puacd to 1w Ml tlir ordiiiHtv tMt^ 
ralurr. Al k liiglw'r ii>iii|ier*Iun." l)i>' Wnncity M^iIIt divrrjutf, M. 
SagiitD, HD., whn hit" iTftntlv inncii! tome ripi'iiiUPiitA oii tlii* point intli 
iion md «>pi>er. hon cibuiiiMl tlic follviwiiiii laluu far lli« I«>ii&cl(V(ii 
pnnnilti, <-f ■niltimtil^T wire iit dlllifrciil Iciupeniluivs : 

Iron . . at n)°, i3iOi ntaro', U8-fi; Maoo»,"r«: 

C<.pp.>r . .. 4tiUi p 10«i „ Ol 

HS. SuoUllty. — Ihtfiilifg it the piiipcrlv i:i virtue of whicb ■ 

uuiiiWr (if bddica I'hmifjV tlinir tVirmn liy ihii action ul' tradioa 


Wltli curtain budin*, uutsh lu cUv, wiuc, olc, iho application of 

little furcc ii stillitii^nt to produca a chiiDgi> ; with ollur*, aiich at tht' 

fiMtan nod glM>, the aid of k«at in needed, while with tlic uivtaU, man ' 

ti] TKoravnts rmxhtKR w munx 6A 

■mf«l iiirmta latul bu umsJ, vuidi lu pFtvinwi-m, tlir <tniw-plai«, ar tbtr 

KalbaUli^ in iliat modiSmiion of ductitity whirh >• exhibJtMl bj 
|ii— ring- Thf mokt nuMtMv tmM m gold, irliioh !»» twi?n bntiPii 
b l«nB Btiuiit lliir iiJ^ or&n iiKli ibk'k. 

tla tDort dorlila tuetnl i* platinum. WoiUmlon obUined a win of it 
MnoO iif an iarh Jn iliftBieKr. Tbit he vdwiMi brcoveriui^with mIvtpI 
il..,^.,.,, laritT- O'Ol of an iacfa in dUiDcU-r, hi m t» ohitaiti a c\liiid#r 1 
■llaniobT anlr, tbo 4Xi> of whirlt ««« of plniintim. Thia was j 
•n untan out tn Ibi* tnna uf vrire aa liue as jiuHiibli? i (bv l<*o in''t*U 

tr «q«allj Fitnidcil. 1i\')ii!ii thin win- wnx nftcrward* ti'anivd wilh 
trnrthcaciclihir vilrorwa«i}i»><l>il, aiid lb<» platinum wintlpit liilact. 
# wife tm* BO litip that i.(MO janU cmlj- wci}{hcii 0-75 of a gniin. 
U MfJaaaa.— ^ ItarJmru t* lii« NSWIaiws wlui-h bodka offer tn Win).' 
Mhfanl nr wora liy otlium. II in calf ■ relative property, for n body 
Bi It hard in rorTtniN) io on» bnd; may Vh> wifl in rvffivniw to nth<tr>. 
■Mativn hantnena of two bodies li UHcertuiiied bv tryiug which «l' 
^ mil amiiRh the other. IKamond U the baidc«l of aU bodJM, for it 
I all, ant) in not amIdiMl b; any- Tb« lutntneM of a bcidy b< 
1 by tvfcrriDg i( lo a tmh tf hardnnt : that nmally ailoptud u— 
I. Tair 4. tiuoripar 6. Top*i 

9. Rwrh mU S. Apnlif 0. Coniuduiu 

3. Cnlopar 0. FelBpar 10. Diamond 

7. Qnartx 

HtUiv baHnnw xT a b»)y wbich would wratch fcltpor, but wnuld bii 
hrd by qiiartj:, wniild be expr«8M>d by tLe niiuilwr BJi. 
pint iDiTtab are M>ftfr lluui their alloyii. Ilfju:c it i* that for 
' Had ixui>aK« froU atid ■ilT«T are allny^l wiili capper t" incraaw 

' hatviiiiiH oX a body luia nn rflnlion lo il* n»ii>t»nr^r to ['oiiiprcsaion. 
H and diamiaid an) naarli banltr than woud. iiiit (bu \%V.i.t vllvn fur 
Uar PMtMaiM^ to tbn blow nf a hnrnnvr. llnnl bodii'j aiv <t{\K\x ui«l 
paUafaiiiFT |H>wdrr*i for rxamplt', •^iien.piiiiiii-", and Iripnli. IMamond, 
9 lb* baidi-ft uf nil bnlit^, ciui oiilv Iw tfruuud bv iu«biib vf ila uwn 

r> TmnFcr.^Bf aodden cnolinif after tliey bav>^ been niird lo a hi)th 
J«■ml'^^-, mnny bt-di«t Hcrjiiiri' gi^'ol bnrdnun. Tbi« operiilion i* 
t^lruipenng. Allcutiin;! iiuitriiiiiuuij" are niadn of tt-nipi^rod ftt«e>l. 
Harr, bowviFT, •Mime Tew lHidt« apuu wlik'b (eni;i('ring; prodiuwa 
K nrnirATV I'llw^l. Aa alloy i>f one part kA tin auU four parla (if 
KoiUpd lamlot%, Hufal, is ductll*' and DialleHblv whrn tapidly coolml, 
PEd anil britll: a* r1»« wllcn coi>Ird iluwly. 

BOOK ni. 

OS UQEtDtl. 

ciurrEB L 


8S. nijiii I f »j <■ iMi l i w T ill iriiiif iiT li jifli nf i ir i i m r 
wkiUMc witkin di^ ovB iimm or n« ihe «Um of the vtmeh Ifti 

Thf acwM* which trrals «f tk* Wolida «f Hfirid* i* 
and llw apitUcatiaii «t tW |«iiii iftm oT tU« ntnw to coailuctiof I 
ntuiiig waiM in ftpM k known b^ ih« wwm of AyAwi&f. 

t^. ••■•Ml rtiamii mt lifMa. It haa b««ii already '••"' i'^ ' 
thui liquiila an hoJ&m vboa* ««j»ca1«o uv <Uif Uml bjr tb« - 

Tktrir flaiilitT, hoireTn'. u not perfect, xherv \* idw«ye a smiui 
ncr betinwn tbnir molcciUen to prmduTP « (cn^tFT ur hat < 

Om» »l«n pa<b««i fluidilv, bnl m a hlgh«r i*fn* than Itquidti. 
ilwtuictkiD bc4nr«TQ the two form* of nMtter i« tb«t liquiils are i 
[nranpiwmblti ami am ooaip*miT<-lT inripamiblp, whiU pMta I 
i-niiiM>tly compTMdhk, aad eipaud rpnoUiwousU. 

Th«i floklity if li<]uidi> u •rrn m the readifio* «iih which tbtj) 
all mrt> of ^hiptti. Th*<ir (miijifMNbility U M(ahli.>he<t by the toM 

>^. Oampr^aalMUty •r llqaiaa. — Frnm th« 'xpfrimenl of lh« Plo-' 
reiitiofAi-ad<fni>oiaBS(t-1}, liquid* wtK for aloD)r lime ivpiniBd as bdnf 
ftoinplnti-ly inefimpTeaaible. SintT l\n.-ii. rMearvhes haro bam mad* on 
ihi" Mibj*ct by Tarioiw pbyiiristx, whirh liavn hIi'Iwti that liqtiMii Ut 
h-ally eompreMible. 

The appiualuii tiicd for meaiuriD); the compmHiibility of liqulilf b« 
named the [linMiiftrr (wiifai, I rominv**, ^par, measure). Thul 

lOwn in ^f. 47 in llie furui inveuled by Opnrtwl aa impniTMl 



PesptcU and Saigfv; it nniuUu of k ntfORf ^Uw cyliBdM 
^- (birk Mdm> utd an inlrniKl ilis- 

E'«k™i 3i inch**. The b»e o< ibv 
w flnnlT ccmeninl inlu ■ wooden 
em tU upp^r pan u &Itad ■ »•• 
ntinA^r einmtd bv > rap wlikk can 
CvwmL In ihU c*p then) h ■ fiin- 
Oor intruludnti ««t«r iaU Uie cj- 
UihI ■ onull b«ml hcnwAiMllv 
kjr • pintoa. ivhidi u nov«d bf * 

bukl« of lb* oppantui Uicpd i* « 
vl, A, conUluing ike Uquid M be 
imL Tb« Dpfwr fait of tliu t«m(>I 
in k capUlwj tuli«, whi«b dipn 
imuTT, O. This lube bM bnn 
ilfdiiM^d Into puuof 0qu*l npa- 
I rt luo bxn d«liiniuiMid huw nmny 
parta th« vMwl A oanUia*. Tbn 
HccrtuBud hx fiodiutf tbe weiitbi, 
BK W nry which ihn rmi nroif , A, 
•ail the Wright, p. of thv mercurj 
ta K cniaia munbcr uf divuioiui, 
CBpUlKry lubo. If N be tli« nuia- 
4Mioi» of tlia ■nail lube roa- 
tk« wbol« rettmir, «» )mi« 

1 - IT 

whii-fa tliv xalne of N is obtaim^d. Tbm h further a nui- 

lliu ia a gUpi (iib«. B. fwnUinintr HJr, cln^i-il ai nnc ond. and 

BXtlamity af which dip* under mcrtnry. Wbi'ii iberc i« ni- 

DO the wM«r in the c^ lindrr, the Inbn 11 ia n>mplct<rlT ftiU of 

wban tb* water within tbo cylinder it ctnu^remtd bv meaiu of 

P, Uw pnMur* ia transmitted to the mrrcurT, wbii^b liaM la 

MMUprpaain;; the air wbtcli it «cmt^s. A gradiiaml *c»it fix«d 

of th« tiib» uluiwii the n>di>ctiaa of Tolunii^, and tliijt wdudion 

M inilicatM the pfvtMire Uwted an tbo liquid in tbo cylinder, iu> 

in appiiliinft of th« nianoniMvr (164 ). 
lldnir thi- eip?rimoat, thi' teMel A ia filUd with the liquid to he 
(^ and thn md dippnd iindi-r th« Dwrciirr. Itv mruiii of tli<> 
, fh« Cflindi'r in L-nlircl_v fiUed with wntei. Tli» wrnw t' bring 
M*l tlto pialun moToa downwarda. and Ih* piuaurr rxert^d upon 
r ia iraiiMnitlnl lo the mercurr and tlic air : in conarqueucn of 
motcun ti«a in ibn lube. R. and nlau in tbe capdllMy tuba. 


OK Ltm'ira. 

Thp DiKwai of m^nwy in llii> capilUrr lulw •koi>-« llmt llie EqiiUkl 
vrtuti A bu dJDimislicd in tolumi-, and pvM tin uitoiuu el tu i 
prmrioa, for the mpurilv of iltp who)<> T<vi><«>l A in ttmu of tht g 
ditUMOia oa llie eapillaiT (ubn hw brrn pnvtiMinlv delarminrd. 

In h» tint «>i[N'riiBeQU, Oentod urtuiuivl th«t the MjjM-iiy 4i 
vnvl A rvHuunMl ibe mmn. ita >i<la« triii^- i-uoipivHeil Win uii 
md i-\terMllv ti; Um liquid. Hut mMbrnuittnl HnalTiia prvni I 
tliii «t{«dtT diifiiiu«liMi ia iyiiis»qu('iin> -rf ihr vxti^mal and 

fpTHaiirM. OnII»{i>n nod ISiitnu have mnde muc rxpnriniMt* alb 
(or thi* clutip? lit capaciiv, and havi' l<iund Ilinl for a preeaar* i 
tbax of llMt aiaia>|^crr, mnri-urii- ftxprrimcBi a cainpnMdon of I 
jmtU of tto origiual viilunif ; wator a rimpriwrion nf (HNXIOA, «mI( 

!« compTMsioa uf 0-0001.1.^ part* of ila original bulk. 

/W it^*r oaH uifrrwy ic m» alfo fnund that wiCliin eertma linivf 
dMTMDv of TiUuinr is propoftMonl (u tlii; [AfMurv. 

^^'hIltPtlT^ bn tli« pn-uuM tu nrhtrli a liquid Uai be**) *ntj« 
«xp"riitiont «hun-« thai u aoou ax lli» prHuniH in rcnioved ih« I 
ragBinn itn oriipQal lotuuic, fiom wtikli it ia cuiicluded that Hffii* 
furftttfy tiiutir. 

^K*. B4|n«tltr or *r«Har«a, raae*!** law.— lti contddrrln!; l>qi^ 
n* iM'rfoctlv lluiil, and uiuiniiig thum to be iiiiiiiflt)i!nci.-d by Uta i 
of gravity. lli« fnltnvBig law boa been <-*t»l>U>ii«d. It la cAmI 

' ftanal'a lair, for it wa* fint nnuncutlnd W that diatinmiobed ; 


PlYttmrr rirrlril mjru'Arrr ir^Hin a niotg ofli^ul it IrtuumUM 
niihfJ IN all ilirtrtiani, and ait* iiiVA the nniir forrx on aU aytwif 4 
murf in rt diffffiim at righl anyln to llumf ntrfHcu. 

To ^t a rlcoroT idt'ii of the irnih of thii principle, let ii* oono 
v«>««el of anj ^tmi furai in ili<' i-iJcx <if wlilch are pliu->Ml raiioiMI 
driral api-riiin-s, all of Ihv mim nt 
closed by niovenble piatotiR. liVI u*. I 
imaeinp thii tptaeX to be tilled witli ll^a 
withdrnlvn from 1I11' nclion of (nvilv; tbl 
pieliilia will, aliviuiikly, hnin Uo Ii-iidencr If 
rii"vi'. If now upon tliu piitun A (li;|. -Wl 
n'liirlt liaH A Kiirfiio" a. n ndnrht of P poilMl 
be plni-nl. it nill bi; pivMed iiivanl*, and A 
p^T■ullrI^ will bi' trunMnill^l lo ibi> intMni 
I'ai^i** of HHcli of the pi*loiii>, It, C, D. and E 
Ahicli will enc^h Ik.- I'nn.'-.-d 11 u (ward* faj 
pnuKurc 1'. Ihrir ■mrfiu'iv b«iiig equal to tbi 
Since rorli of tin- pistune niideifEKeH n pmwnnE 

■Rg. *8, 

t>f dM fitst pidlon. 

oqiifll tn (hat on A, let us Huppow twi> of ibi' pi^loiiK imilnd »i> ■« 1 

miirBss&iBiLiTr or lkil-im. 


Ki«. w. 

■urf*ri> i». it witt Iwvp to Buppoirt a pmxun; HP, Similulj', 
Wen wrni n^ujil lo So, il woulil ■^ii^tirncir * jireMute of SP; 
to ■»■■ w«n> 100 or lOlW (iumi (liat of d, it n-anld mwHmd a 
of IDO at iUUO tinWB I*. In ntlii-r wonli, ihn prvawre on ao^v 
W IntenMkl wall* nf Uii* Tec«*l woaM W proportiunal In thi^ 

jadpl* of ill* •qiiality of }x*miir<' U auiim^ w, a caoMiluaita) 
OHtitHtiOii of flulile. Bt ihv fulluvrili^ ciprriiiK^iit it <MI 1m 

Mt pmanm in tMiisiiiitl»il in all <tirr«iioefl, ultfanngli it <w)iuii 

It II id usually imiMiitlnl. A cdiud^ proTiilvd villi • 
iDln * bnllow tphcn! | li^. W), in vrbSob onall cj'lindricBl 
Mcni |>IT^p^■ll^icuU^ I.) «lio aidrji. The uphnn- and lli» cylinder 

II Ull>») Willi Vkirr. wbi-u llie piston i* diiivihI the liquid opoulfl 
D bU ttif »rilic<>, uk] nnt tnQKly Irotn tlial wliicli it apptmU> In 

wun why ■ Mliifitclonr qiwatitative «xp«rini«ntal demoontmlioii 
inriplv o( ihe «i|iiality if prruurc ■■annnt hv. pvtm U, Uiat tlir 

III Uie weight of Ihu luiuid anil of ttie frieti^n uf tin? pinloiin 
) eliminated. 

rRmrBB rsoDccKD Dc uamm bt ounrr. 

■m«Bl dowitward prwMar*, Ita lawa.— Any )[iv<tii liquid 
a utati? uf rnt in ■ ti'iwvl, if "o nuppnw it lo be dividiid intfl 
i] ]arin> of tlm mubo deiiAty, it is vriduut tbnt nu-h Inytrr 
tbf! wttuhl of Ibow above it. <)wvitT, thurnfow. pr«iui*» 
pnaraina in (bit miua of a liquid wliicb vary at diirt-imt points. 
iiwinri arr Ribmilln] in ibc folluwliig p^iwral kit-* : — 
\pttmU" ul fviA Arytr t* pr^/p/uli/mal lo llii' dtjilh. 
iM £fer*nt Uiftadt and iMr tame <lfplh, lA« prvatmv it prtporiioHtU 
miff «f Uf Ufiml. 
Tu prttmft H <^ tamt at aUpoitiU of the tame hvrtaanial layir. 




Tb« two Sit Un u* Mtr^-ridcnt; ili« tkird oeMMb^ly Id1W> b«_ 
flw and (VoM rMtal** priBctpk. 

L T— ^ f i ■*««*« i wiM M i.— TIk prcawm wlwk tbt i 
«f s%«Um«ii m ihg toww kyw mm m ibcm to nxm m 

id fttmmv in 'all dJRCtioni. Thii upwwt pnnNMl 
Ifa* latyvMy <</ Uqitida: it i« tn7 sMUDbW when iht \aA I 
win B Uf aU. ■»«« MpactallT taw of gnU dennqr, latt i> 
IV fanowiag upcriHnt l6g. AO) <««*«■ to exhibit Dm- : 
pcoMtR of liqnidit. A largo open fU.- 
A. ea« Md of which i« (rroitDd, i* Eitr^ <-<^ 
ft ftrooiMl gtlM 41m\ O, or idill Wn^r -li^ < 
thin Mnl or piw« of mka. ihtf nciffUi ut< 
msv be n*gl«c(^. To thn iUk u fill> 
ttring, C, hx wkich it ras be held ajiMo^' 
WHon of the tube Tie vbote ia thtfl i 
MMa«d in waivr, and now th* diae doM I 
lUl, altfaougk no loagw beM b^ tb« Mii^; 
ia cowai^wMUly Infit in H* poritkn if ' 
upward praawe td the irml4-r If wiMrl 
nnw •tmrijr pnuicd inio the tubi', the ditC ' 
onlj aiah wbnn lh4> brijihl nf tbn ^e%Ux iatili 
thn lube is «{ua) to Ibv height oiriaidft A 
Mktva thraiv that th« upwanl piiwm (* 
the dbe b eqii&l tA the pnauitc of a oolunui cf water, the baei^ cf vUA 
if tlM> intomal urction of the tub* A, and tho heif[ht the diitaiMn bra 
the iite to the ouler ratftwe of th« liquid. Htorc Of ifuvnipnam 
i4 AfwaJ!) at amy pomt h yatwnia/ ly Me mrh hrt at iMe dtHmnri 

OS. Prcsaar* la Indapandaat of tba fonn of tbo TaaaeL— Thtt 
proMiii« AxeHad bj a liquid, in i irlu*' of its wight, mi any poiliaa <^ 
the liquid, ov on the aidea of ibc vnurl ia nhif b it i* rOBAined. dtr|>endi 
on thn ilfplh uud dnnfity nf iKi- liquid, but m iWr/HiHlntf of Mr/orat ^ j 
•mm/ ami of lAr fiioirft^ «/' /Ac A^Hnf. 

Thia principle, which f»Ilowr> fmm ihf law of th« equalttir of pr«Mttt, 
tahf be oxperim«in tally demoiL«lnt«l bv man; foniM of apparaioft. Tba i 
following ia tli« udl- ninit frequently uaod, and U due lo llaldat. Kl 
fonniitoof abnnt luW, AltC ifig. fill, al one and of which, A, is 8tte< 
a atop-cuclf . in which uiui Im K-rcwcd two veaaeb, H and I*, of the Mine . 
hwgbt, but diftcr«nt in shape and caparity, the flnl hniog cooiical, . 
Ihe other nvarlv ryliodrical. Slen-urr ie [wuivtl i\tUi the tube, 
until it» Inrd iieiiily rcncbca A. The v.-wol M i« thim ncdrwmi o 
filled with water. The pn««ui* of th« water actiug on the mtacutj ' 

PcuMTU fwuorcui ox uqi'iiiH bt cKjivrrT. 

lit Id riw tt iIm tkbe C, and its Ivifrlit emj h* matbed b* nMB 
ik e<)lki,m, wUcdi ilidM up and lioirn tbe tube. Tlu<* IbirI of 
W itt M w abo niarkHl by mean* of ili« noTfiabJ* rod o. nim 
|d<M H i» Uhw Muptiod bj neaiw of the (tOiji-MtdE. «iwn«ired 
I bf f. Wben watnr is now poarad in tJit^ the ai«fc«f , 
1 lu arifrinal lord ia (b« tab* A RC, ainb riiM n V, 
I tb> watar in 1' hu Uip aotp bri^rbl aa it bad in M, whi«b U 
1 17 tha lud IS tbo mtKary will liava riitni to Um biagbt il bad 
[■Utb b nacbad bj ib« collar a Hbmw the pw— 11 on tbn 
• iatfaBMiM. Thi« 111 la wia ii t b ar i A ti i a ie f /e n iuM 

■^ ot tb» «MMb^ asil, cDMBqucAtlT, alao of the qnantilf 0'' 
nr baM of tbo T<«el i* «briaiialy Ib« «ani« in V^h laaea ; )l b 
w oT Um marany in Ibc int*rior of li>p labv A. 
t CDaMdendinn of Iben princtplet jl will bo rtadilj wen ihai 
bmD quantity nf water can prodiiw Miuidenblp preanoML 
iMgw aajp TBMal. a CMb. fur rianfle, Itllpd with otater and 
1^ mnvw labn ti^tlj- fiUal into tlw aU*. tf walw » poorad 
nbe, then win be a prmfiD* on tbe botKnn of ibe taak aqnal 
sifilt at a oaluntn uf water whoM baao ia tbc Urttoin )la«UV 
M hdfbt b •quni to that nf tbo w«l«rln tbe Iiib«. Tbo pna- 
lia tVMta aa grMt iw> we pleats ; bj M Biia of a narrow tbivad 
fbrtj fMt knp, Taical (uoc«ed«d ta biuating ■ verj MUdlf 


t)X Liqi'lM. 

TIm toV IcMivo w t^ kgJitMi'ilir brttoifw defeat on tli« i 
nfj*. And wn ftmll p wrMt ly *•• • wnat JmporUinl applicatkm tfl 

FrMD thn pniKJfiU ji»c UiA down, Ihr pniMurM produoMl 
botiom a( ibf wn may W nlrulMxl. It will W piuvnilv dt 
tW Um pnoMuv .if the •tmn^bm u C(|ii>l to ihal iif * mIu 
.awamw abMi tkirtr-thnw f<wi kigk. Al •>« ibc land hw &«qi 

^ i l we c d i J ia m drpUi of tliirtn-n tbMiwiid uot : at the botliMD i^ I 
jr«, il» n>riiiv. thiriv in««; I"' a pn«Min> of fyiir liiuidivd ata 

1*^. Vraunr* oa tk* ■!«•• af **aaals. — ^inoi tiip prtitKiiia i 
hv irraititv in Ui* DMM of « liqatd i* tmiMnitUxi in ^vvry 
■cniniinp <>■ >he iraenl U« oj the tniBNaiauau of Uiuil 
fiilluvn that M averr point of tbe nie of any tmwcI h prcmiii« 
vrud, at right aufiW in ih' Mile, wklch w« will snppiiM to b* | 
The PMultant nf aU lh«« prTsMma ia the total pmsurc on dift i 
But Mncti thi>M> pnmurMi ini-rpaMt in propratton <■» lh«' ilFptb, mil 

Mm prou»rli<7n to Uw horiiMiIal r^xUAt of th« sidv. their rKnltut] 
•mlr be ahtnined by ralroUtion, irliicb nhowa that the tol*l pr 
an* fi\t* pordoti o{ ili« Mr h r^iitUlotJie trrifM of a eolaiuM of I 

■ mUot W Uu portitm »f At tiJt far iU ha*e. tmd lehom Mgh 
trrlittil Jitimer fmH tilt tmtrr ^jvnrily </(Af pwlnrn lo thf i 
lA# AgmriL If ibi- «>de of a vnaepl i« a cund warfacv the Mino ni]D ( 
Ibo prowutw on thi- turfaiv. but the total prDMnK U Do losgw tlni 
tniltMit ot llie 9aiA pmuurv*. 

Tbf pfliot in the Mdr mippaird plane at vrhicb tfao mmiltant of aSi 
prMHiira id applM i« rall«ii lh« rmlr* ^ pramrtt, sni! is alnya I 
the ou>tn! of irrarily of ibi- side. For if tlip [iiT»uri'* Pirrt4^ al dil 
part« of \\ifi pinnp Riilf wvn equal, the point of spplicalioii of tfadt '■ 
miltnnt, tb? n-nlre of pnMurc, would ohviounly oiinddc with lb* i 
of gravity nf th^ nids. But nnc* tlio pivwiiitM incrvaM' witli ih«< dv 
tbe crntiv of pn-wuiv t<> n<^->'maril_< Iwluw the i«uIt« of gravity, 
point i* di'U-rminett by cnli^utntion, which Icada to (be IbllowiiiK VMollll 
— i, Wltb a n^clananlsr AA.« wbow upp-r mIjw is It'vel with the W« 
the MdtK of prv«urf is Kt tn'o-tliinls of tbo Una wbiub joiiw thn mtdd 
of lli«i hariiontal mdea incaaiimd from Ih* top. ii. Wilh a triaoK 
Mile wbow biMe i« horiumtHl, find cotiii^iduul wilh tlio loi el of thi' 
die crntm of pivmiiv in at thv mlddlu of tha iiiii; which jnitia tliv' ivt 

.of the trifli)gli> with tb^ niiildln of tbn baw. iii, Willi a ttiangular i 

'wboM verti'X IN lewil with ihe walor, the centre of priuBure u in tbelio 
joining Ihrt rertei and the- miiidle of Ihn base, and at tbroo-fourtli* I 
ihf ili*tnii<?i> of thi.- lattvr Iruiii tht^ vi>rtei. 

111. MjrdroiitaUc parsdoa. — Wi! Iiuvc already wen that Ihv ' 
on the bottom of a veswl depends oelllter on the foriu of thx 

COXDITI0X3 or TME EttUILIBlllUlI Of tt<mim. 


Ml Hm qiuwlity of Uie liqitid, bnl Minpl}: an tbe bDigbt of thq 
•Ikiv« tlie bottoni. Itut ibo prcMnn tbm osetted muit nol be 
ltd with iIm' pnwurc which the Ttmel itaeit exerts on th« bod; 
•■pparU IL Tlui Uttec is atir»T* i<(|ual to tlic combiiiod WMgkt 
liquid and Uh vmmJ in wliicli it iti coQinined, while the funner 
hm (Jtlier tnall«T or gnttt«T than tliii WEighi, according to the fomi 
THwL Tbi* (net )* iwuallj t«ained lh« f^tbvtMiii pamdux, b««uM 
Htlhl it kppian pandoxiwd. 

{1i^. A3) i> ■ TMwl oompiHH'Xi of two rTlindricul pnrU uf uooqnftl 
ina, an>l fillnl villi vUrr to it. rriiiii 
fcu boaiD wiii bcfon?, ih« boitom of tbo 
CD •upporln llift MHte pnwniM m if 
diani*t«t were evn^irlictv th« tainf- :u_tbat 
lower {Hirt ; and it would nt tiM liglit 
thai iIk H-al« UN uf tli« baliuiM, iu 
lW vo«*el CD U placed, ouglit to dhow 
■iw vd^t a» if therv lud heoo placed 
\t • ejlindtiol Tcwd baling tbo aatu« height 
vat«r, Hiii barlnt^ the dinneter of the part 
Bat lh« ptOBitro «ier1«l on thu Ixittoia of 
I III it La not all miuiiBilt«<] to the xcnlo MN ; 
tba uftcm^ prHHin iipua lli>? aurfiu'u no of 
rniael is prvrinrty ■'qiinl In tin- wi^i^rbl i^ ''I- ''*■ 

I ttrtm i|UMilily nf n-Hlcr which a cj'titidrical vi-uul nuul'l eualuiu, and 
I an f^uul portion of Ihc doawrvrJ ptCMur'? on ui. Coau!<iiic]itljt, 
lk> pRMBR uo lh« plat* MN is riinpl^r vqnal t^ the ir«ighl of th« 
tMHl CO and of tbo water which it contAin*. 

cuKiimoxs or thr mtiuDKirx or uqcids. 

SB, BqnUllirfm ml » UqiUa in > aUtEl* ve«*al.— in urdor that 
a UqiiM may rvmain at rcct in a idskI of any uivcn i.tim, it mint mtiid'y 
th* twn tMiim\a^ oasditMiM: — 

L /(■ tKffarf amd it, rttryirJurr, perpt^icalar to l/ie rtrtiUiml of tkt 

IL Ertry nofaWa tf /A* miu*.<^ iJm tiqmd tmat be ail^jfct in ivrry 
iirrrtitm Ui tyna/ Awf eomlmry prttmmt. 

Th« •acond coaitIt><« in M<lf-«vid«IM ; for if, in twn i>ppo«iI<r dircctioiia, 
Uw |iii^iirrn aiertol on uojr ((ircu noltvnle ayrenntoqual and contrar;, 

flit BwilacnLa would be moT^d in thi* din-ction of iha gtttMt pmnuru, 
pi ib«n wQuld be DO tquilibrfiim. Tiiu* ilii< Mi-ond coaditioD followa 
&«n thw prindpl« of lh« atiualitj of prntturiw, aud Iruui Uti tvaclioii 
wbidi all jwiMiiri cmum on \u<c nan of liquids 
. ^ 


<m uquiM- 


( — 


r<it. A3. 

To |iru*« tiM firu wmdlliiM, iM iis itditpiMr tbat mp U tlii^ TtMillui 
■It tbn totem »ctia% apon ny molecule m on tbn surface ((iR.iSMc^ 
tlial tb>* aur&Dc M inclined in nfoKHm lo tba force mp. T%i IWr ' 
iwii MmwqiMntly bn 4«:aiuipOHed inU I 
rnrcp*. nif and f^i ibf oni' 
(be aurfucu of die liqaii] anil tlie otiMr 1 
ditvctiun np. Now Uic fint (lnK*,nf.i 
bt- tl>«tro_v«d \iy tb« kmMuum of ikel 

whilr tbn •roaod would mote the : 
in th« din>ction mf, which •h<nr« UHt< 
librium in impuvjble. 
If ^'mvilT Iw ih" foTcn actintr on tbp liquid, the dimction Htpix^m 
liuncn, if \\if liquid is mntniiK^ lu h baalii or vmmI of amall exten 
nirfBM uufrht tn bn plan'- and horitonUl (fiU), broaiiae tkrn tbc din 
of itravitr i» ilii? natiiv iu every point. Dut the caw io ditTirnin i 
liquid BurfACcaof (rmMiT axti<nl. like the oomh. Tbc nurfaca ' 
piir]i>cDdiculMr Ii> tlip rlirwtJoTt i>f ^ravily ; hut hh thin r-hangtM < 
point k> uiothpr, nod nln-nvn lead* towuda ■ point Dear tbc omtnl 
I NTth, it foilnwi that tlio JireiHian of tb» lurfiue of tlio tmaa will i 
■1m, and U!dii[ii<.- a nmilr ipheiical fonu. 

"<'. BquUlbrlnm of lb* aiuiiv llqold li> aavartJ «oa>BiaBl< 
Teaaela. — When «iv>-ral »i*»»i!1b of «uy (fiven I'rinn cumiiiiiuiraW I 
each oihnr, there will be equilibriurn when tlii- liquid in i-nch 

m^mSm iha two pn-vedingi 
ditjon* (J)0). and furtlxtf, i 
Mr tutfaef.1 of Iht HifttitU 
thr I'mrlt art in (he t«me i 
iontal platu, 

Iu iht^ vtMaela ABCB (Kg.l 
wbich communicntc with utfe | 
other, l*t u« conmiliT Any tnwj 
veno BTctiou of tb«^ liibc nwi ibij 
liquid can only icmaiB in > 
libriuni m lon^ na ili« pi< 
which ihia Mction auppona titam\ 
m in tliv dirrwtina of n, and frenl 
niu iho direction of m, arwqnilj 
«nd appusile. Now it hnf- Wn j 
■Iroftdy prorod tbat tli«M- 
ncrca nio mipectivcly equal to the wsijthl of » column of wutcr, wli 
baM )• the oiippowd Miction, and whow hniubt in tlic diitancQ i 
eeatre of jrruvity of thiR at>ction to (be luHkoe of the bquid. If i 
ntre llicn, a boriiontAl plaOQ, um, dtnnn tbrougb tbu centre of grarltyl 

Fig, M- 

KMTiwn iir mc e<tt''ana:iiix of lkk-'im. 


ill be t*vo IhAt lJi«To will onljr bn oqnilihriuni no long 
le liquid ibovp this pUnii it ihn MUno Lu «acb TWMlf 
oalKtM th« prinri|il(? ■■nuiicinKd. 

Avtaaa «raa^ni»a«a« u^uidi. — loiwderthM tii^reriioaU 
.M wbcn H-v-nl li<'l>.-r^->.<it<(>iis Uquidt iu« mipeipiaed is tiio 
Hpfa of thrtn lutul mtiify Ui« conditioti* ncoouaiy hr 9 
^PP) ; ud fiirUier, (Anv wiff &r ilablr mjmliiriam imlg n'Acn 
V^ipraifW wt (A* ordM' 0/ tiru- tinrmaing daaitin/rtrm tAe 

umdJliMH ia t-ipmuienMllv deiuoiietnilvd by ui^iuih c-t the 
■ <J«neab. It oamriMn at n luofr norraw bottU MDIaiatng 
lef Mtiir«l*<l iffiili cnrbotiAti- nf potiMS alroliol «oloiiHd red, 

IWbttn Uiu pliial iii Bludivii tin- liquids laiii, but when it is 
F thej wp«n>IR : Ibo nictcury ■ink* Iji Ihti bottmn, th«n 
W, then ihe itlcobol, Hud t)ivii lL« iiHi>UtliB, This is tbt! 
dwmuiliK ibinidlin* of tbr bodies. 'I'Iki nnier i> Katiirnlpd 
t« of }H<4aM 10 pivvunt its iiiiiLog with lli« alcobul. 
•tifwi or tlir liqaidi U due Ut the Mine oniwa u that which 
bodim tu Boat on tlie #nrfflre of a liquid of preal^r d*Mi*ity 
wn. U if kloa 61MU tbu prini-ipte thai tri-sb wMcr. nt tbn 
ren, fliMtA for n liiog tiniti nn tlir dimwr mit vmXn n{ ib^ 
tfor tbr tmmv nHuou that crvntu, which is li^'hliT thaniuilk, 


Iftftajn 0t twc Uffcrmil U^nMs In avn^uDltwHnc 

Iwii two liqiiidmif dillrmit 
kli do not 111' 

commuBici 1 . 

In eqililibrii.i :n 

til* pocoolicv j'r.ii<..|il' '. 
«Ct lo tl>^ foll»wiii){ : liud 
Mw (Ar iioHsontai turftn* «/ 

1 MArunx of li^d m r^i- 
tHttri* ratio 0/ thrir 

MMm iiittn* 

'a a lii!iit )iUiu lulw, ann, 
in iiprifrbt wnoaVm mippurt 
tbcn watirr is pouml Into 
IKHf All 'i'bo onliimn (if 
1 iDen-un; at 
bI ia ihv IifT All, «ih1 
ber tiy a quuility, Cl>i 
tiquiUbriiuu i« attabliilied w« inu^ine h horiKOnUl 


(jane, UC, to pws tLA-uxh B, ibi- «>liiiiiu uf n-Htur to AB will hM 
ttta column uf mcrcur; CI). If ibc Itci^bu uf llu-ac tno <wliiaH*j 
ihtoi iiManiiTvd, by nii^Aii* of ihn k-jOm, it will W fonnd ihai iht M 
of ilw coluTDD of vntvt in abo'it l$t UiuM ihnt uT tbp bdiitil«<i| 
colaiun of Dit^irary. Wi' ihnll pi'twDtly mo thnl tii« (lHu>liviif Mtf4 
ia nbuul 13( liuii-i thHt of nater, from whlcli it follovm tluU Uiu bri^ 
tkTD invi^nu'ly nx tli« duniitim. 

Il mav b« luliieil UiAt Ul•^ i^ijiiilibriiim Mtiiiot eklat unkua tli«i« ll 
miHirionl qiinnlitj nf llie hoiiviirr lii^nid f^rpnn of ii to ivbiuo la Mil 
nf tbe tiiUi- I 

Vhv {iivi-istiug priiiFipli! miiv b« <ll^<tu(.■Ml bv a very iiinipltt tulnklil 
IavIiJ nod </' bo ibo deofiiip* of wnter nnd mitmivy, ami A and A'Ul 
TtaiM^i-tive lipigiiu. Hud leij; bt* thf for™ of gnvitj. The prnwimn 
will be pniponiiiitnl In lh« drnnity of thn lii{uid, Id iu bright, and Hl| 
ToKV of gntvitv : uii ilit- wliolv, tlien>fi>rft, to the {irwluri ri^. lAodU 
tbc prvwuri' nl (' will in- priipiirlitniul to ifk'f/. Hot in unlrr u> facAl 
<y|iiilibriiiin, rfAy mii"I \<v I'qiiiJ ta J'h'g, or •I4=rf'A'. Th'w b anlte 
inure tliuii im uIifFbriu<.-nl rxpn-iisiim uf lliv ubovv piiuciplci for «aMtl 
two producU miitl nlwayn bo etiunl, if inuKt ba m many ttOaMgnil 
tbHii ^. a* i' i^ Itw ibnu A. ' 

In thin iiiiuiiii:r thr dc-niitr uf a liquid ta»,y be cRlriiUt^d. S^fo 
ooe of the brHii>.-!ii>8 oi'iilHJned wnlvr and tti« olIivT oil, and tli«ir Ufk 
WRti: n-'cpii-ilvvly 15 iiiclics fur the ail, audi J incb^for th*«sl«r. II 
deaiiily if wau<r bein^ inknn a» unity, and iJinl nf nil beia^ i 
■hail havif 

ICx 4=14x1: wben«j-= '4 = 0^'-t3». 

Ai-fLH-*iHiSi5 «*■ inE PRECEiiisa hiobo»tatic i-iiisiipi 

UH. SjdraoUo preaa. — Tbtf kw of the Mjuality of proMora I 

Tvi'^itt^ii & iiiO'-t impnrirtnt np|>1iciitirin iii \\i<- /ii/JraiJic /ufff, a marhl 
by which onorinoaK jjieBiiirL-* may hv (iiinlin.'ed. Iln piiucipla ia dw 
l^wsl, but ic woa lint construe (<'d by Brntnnh in ITW. 

It coiuiBta of » l■yliIldt^^, B, "illi viTy strong thirk sidM (fig. S6), 
which ihew il a castiMa ram, I', working water tight iu (bt.- collar o( I 
cyltndvr. On th^ rftin I' there U a ciidt iron pliitc nn which ibr aiibtWI 
t(v hv prtmed is piftci-d. Kour alr«iig culuuiiis ^ern^ to mipport and t\ 
ncnnd plitUi y. 

By lutMULH uf A Ivadi'ii pipp, K, the cylindtr B, which b fillvd w 
watfir, commiimniicd willi n ■tnnll foii^c pump, A, which worhabrniai 
of a l0vvr. M . Wlien ih« piston of ibla pump p aacend^ a varavm 
jiroduced luid thi; wnlvr riixw in the lulw a, at the end v( which th«ca 

OK LHtl-'ll>^ 


duiiiig thi« <l(Mc»nt, ia A|)oii«d liv lli« pr««siii« at th« wiiI«t, irk 
puam bj the pipe K, Tte valve i it a ni/tty iWr#, heM by a ' 
whinli Bct* on it hv mnuu of a \rvrr. Hv wi-i^rblinx the Uttct ' 
HTi-ncor or Ifm HXtcikt the pr»««iir« ran be r«^lal«d. fur •• noun at iha 
is AD iipirnrd pmMur« |iTVMt»r than that of ibf wMj;ht upon :l. it 
mill wBtiT eicspes. A rKfnw r tfTte* to n^licri- Ih* pniMuro, fc« ' 
it ii optniil it aflinds a pA«Mg« for t)ie efllux of tiic o-airr w ifaa i 
linikr H. 

A mutt tiiiporlnnt part if thn tcHtlier collar n. thn tiiveiiltin) of «l 
by Itraiiinh n^movwl the difficu!tir» which bud Ihtii pxpcrienndl 
inaklng thv lanio ram vnrk vrnlcr-Ti)rht when MubiniEtMl (o gT<rat 
Hum*. It omimiila of a t'in:ular pi<-cit of slimt leather, Batunlcd ' 
oil (•> M 111 bn impervious to wuifr. in llio teuli* cf whiph a L-i:i.Ii- 
hola id cut. This piece It bent, >o that a am^os of it rvpn-.'viiU i 
rovBiwii ir, and in fitted into n jrroove n mode in tli'- oftrk nf thr n-J 
linder. Thi* ooUar Mvf conrave dftwnwani*. in pittporlioii m the | 
■urn in(!ii)«iH it til» tlio mon- tiffhtly Bfe'iiiiul tb« tain I' on onv ride I 
llie nwk of the cylinder on ibc oth«F, nud qnito prevent* any tmfi 

Tbn prpMiini whii'h rjin be obtnincd by thin pfvai d<^Midi> nn lfc« 
TL-laliuii i<f ibe piatoii P li> llint of tin plxUin /i. If the fonaFr li>* « ' 
trsnivi^rs'- >Brtiua li'ly or ii himdrvd linii->* «« Iar)tL> ad thu latter, iW { 
iipuard prnuun- in ili'^ lorffe piatun vil! bn tifiy or a hundiyii 
tlint ('xi.t(<hI upon Ibti xiiihII oni'. Ry uii^aiis ')f tliir \fyvT M ua additl 
advantRiin i* obtuiuetL If th(^ diinancc from tlii! fulcnim to lhi> 
wheni lh<^ pow(-r i« nppliod i« Ato timM the dixtjui(;« IVom the fulrruui W 
tli<^ pirton p, (ho prvsHiin- on p will bp tiro tiinef the pownr. Thu 
a nmn net* on M vfith a forcn of sixty piinmls, tlin furee tranw 
Ijy III* piston p will be .'WO pound", and thy force which tends to 1 
thi- pinlnn 1' will bp .'J0,000 pounds, BuppiuitiK tlia Kuctii^n of P i 
liiiiidreil tim>M< ihnl of p. 

The hydraulic pr«» is used tii all ciwm In wbieli invat prmwium i 
m]iiinid. It ii uM-d in pressing Hot h, in extraciin); l.lm juirv nfl 
root, niid in i>xpre»niii^ oil from biimIk : it ul»u 'ervea to It4t the itrea 
of catinnn, of ilrnm bolliiri, and of rlintii cnblos. I'hn parta ramp 
the tubular brid«* which span* the Mp|i«i Strait* weiw raiM>d by i 
of an hydmiilic prcm. Tha cyljiidpr of tlii" iiincliiDe, the lnr([p«t 
hw f<v>-r been eritiMrucled. waH nino feet long and twuiiiy-two inch 
inlemnl diami-liT: it wai capaMi' of niisiiiir a wiiight of two thnuMiid.1 

l(K). \7ater l*Tel.<-Th« icrrlirr Irprf la an applieatioil of the conditiom 
of rqiiilibrium ill commnnicntinB vciwls. It con«t>lii of a metal tub* 
b«>nt at botli end*, in which are tiU'^i glan tiibeit U and 1^ (ti^-. !i9). It 


I fltoMl on ■ uifod. aad wM<r poured ia wnttl it riMU in boUi l«^ 
tlu Lic|aul ia *t rtKit, tlin bivnl of llin valfir Ui Wtli tuW u tfaa 

tit If, thpT MV> tmth is the tttino licirizoiiul pUmt. 
inMnnnunt u ami in h-vplliiifr, or liiotrUining itfiw mueli ouo 
1 i* kiglwr thMi anotfaer. It, fnr euuuplti, it ia <l«aiiwd to flail Ui4 


Fie. 5H 

Di* favtwcon tb« h«i|ihti of B tuiil A, n UvtXnf-tlaff w fixed on 
' Uiw-r plAcc. Thi» rt*ff con»i*t* of ■ rul* fonii<«l of two ulidintr 
I of iruod, %r>A Mipportln; n pit<(« of tin plate U, in the oentre i4 
•tiidi tii*m i* ft mark. Thi* ftalT being bn}tl vertically at A, an oWnror 
Mnal it tltroBgh lltp 1»t«I al«ag the anrfacM D and K, i>nd dirvrtu ih* 
-fcalte In TaiM or lowrr tho tlida «ittil tlw mark i> In lliv prvlongsiioo 

Kg. a>. 



t"i«. »'. 

rrf ill* UtiF I)R Th* h^^ht AU in tbnii ni''-a*ured, Mid, militTactinfr iC 
6Mn ttif hni^lit of til? Wei, tin- )i*tKli' ''■r il>^ priini A mIioto B la 

ml. •iiiHI leval.— Tli^ ifn'rit Uft'tt both mnn' d>^lii»tn and mom 

' [>n Uii> waltrr IpvuL It caniiua of a glaw tube, Alt Iflg. RD), 

. ilvcuneil. tLMLt,l!ielub«. intMadoCbciiiKairue cjlLiiilor as U 


m LiqtiiM- 


KKBis la be, IB in fad 8%btlT cnrvnd ts oncli a iBnnneT that iUui>i«i 
ore ofaiHrpIcof vi-rv IniyKnuliiiH; il islilktl willinpirit iriih tliecxMpfiM i 

'irabnbhl.'nfnir, wliichli-iiilKtonocupythe lii);hei<l |iiirl. Tbntubebpl«nl| 
ill a bniMH cnw, CIi (61;. ilU), which U m arranged thai wli«n it U il fti^ 
pc^rfuclly hurixoiitAl {xuilion Oxp bubble of nir i« «jiftetly butwagn iWl 
iwitiw DinrVod in ibu aim. 

To Inkc Irvi'U witli thi* appamtua. it b fixed 00 a leteMope. 
vii3> (■nni>Rqii>'iitIy tie plnred in a )i<>rli<>nial pnsitioo. 

IIU, AFMalMi woUa.— All imlural <»U><ctioii* if waU-r ««««D|ilil)r1 
tflo'lnncy of wBt'T 1" tind il» Invpl. 'I'buji, a (froiip of Inkiai. «acb 1 
^ral lakM of Nortli Aiiu^rica, may be regatiif lI aj) a number of rvMtkl 
miunmnicntion, anil cnnM-fiut^uUi- tli« wnten U-iid Ui mnintnin tbo 
li^i*l ill •11. Till", t'H\ i* Uie riwe with tb« «miwof a rivor Nidlbei 
Mill a» ihv latiiT in on the tuwcr icvt] iho riv(-r coiiiinuallj' flam 1 
ttt tiin *en aleiig' 11* beil, nbich 18, la fact, tbc ni«4na of «on)inu 
bolwwri llie iwo. 


Pcrbapt 1I10 nioni striJiiiit' liiatitnee iif tbiti cliut of ualunil pbmwiMM' 
in tlial of ni-trtiiiH welU. Thrsn iri'lla tlprivo their iwiik' from the (HH 
vim't? ol' Artui», wlirre it lia* lon^ been cuHt'iiiiarv to di^- tht'iii, aiid froD 
whpTiiw thoir \xsv In othsr pwla of t'nuicp imd Knmpn wb» dnrii.ii. It 
M'enip, huwever. that at n rery remote period well* of the oanie ldl4 
w-iT diip iu (!hinn iind ICpypt. 

T" uiidfiWftiid ilie theory of tliese wells 't iiinst V- premiflpd ihat lb* 
■tratn couipo!iiu}[ the earth'* iTU»t are of twii kindji : the ono purnimiUR 
to wntAT, Ruch a* mnd, Gravrl, ntc. ; thn others intpiriiiaable, such W 
clay. Let ii« 'iippofe, I lieu, a ueo)frap]iiriil biMiii of firealiir or Icaicxtttit. 
in whirh the two iniptrnt-iilili' laynn AA. lilt (li([. 81), rndoiw hetweMi 
tbpiii a pj-rinnohlp Uycr MM. Thp niiii-vp-iilor falling; on the part of tbt* 
lojrr wbii'h ooiiies to iho surfnce, ivhii'b is faUeJ tbi; outcrop, will flllei 

Hsil^h it, nflil f»II<i*iBe tlie mionil full of lh« graorA will oHirti m 
rut haJIciw uf thi- bavin. irhriiiMi it pjuinot mnapv <iwin^ lo the inipvinii!- 
itUt itMU abuTt- uiil b«tow it. If now & vi-rticnl holc^ bp nitik domi ia 
Iki «atrr>br«ruif; rtratnin, ilip vitart tttiriag U> n>giun JU letel will 
|f«a ««l ti> ■ beiffbl whirli <|«|Mnd4 on the didt-ivDcw betvpt-n the kvpU 
ftHm iMterap Bnd or the ]W(nl at wbich tfa« pptforntioii i* luadr. 
Tk witen wbii-li fMd Arteoim it*1U often rorne (ma: a di«i«ic(- of 
er KM^ntj mile*. Tbe d«ptli wicK in ilin«T«nI pUcm. Th* wril 
Gmolle i* IWO feet drvp ; it sivRi Rfifl k*"'"!' f^ wntrr in n niiaiit**, 
it«nw of ihr itnqwM and nuwt nbiiiKUnt whiL'b lia^ bmi ninJc. Tbc 
ilum (<f ibv vali'f u 37° C. It fo)|.iwii ftom tbi- Uvof litn in> 
af Impfntturv wlili ilie incraMing <lepih bnlnwiiio •'itrface of ib« 
lliM, if thi« mill WMO 210 feet d«Ti'T, ih* walM wnuH h«te all 
yvRiuMl * umpentur* of •tS' C, tbM ik, thnardina/v trmiwratiire 

BonUBt IltllKK<K^ ix i.wt'iw. 

ion Vraaanr* aiippartcd by a b*dr inunarsetf la > Ilf|iil4.— 
yihn ■ K)lid i* iaiineiwHl in a Itqntd, «vtixj {inrtion of i> tiirfnro i« ciiib- 
jkaillid la a pmrppoilioular preaaimy wliJcb IncRMM with tlii^ dppth. If 
iHiaafinp all ih'on ptwautM ilrcompoied into boritntital and Tnnirnl 
PKaww, tbn Hnl set Miv Ib ojuilibriani. The T«rlii:«l prt^iim ar« 
nlrnniuly unt^ual. and will load to movo the body npwaidK, 

Itet tu iBiagine a rnlw inuiumed to a maio of watar (fl^. 9i), Mid that 
hn of It* odi[M are verticaL The prcMur^* 
lbi> fimr venirftl facn boiDg, cl««tly, :n 
, w0 niij iinlT ci>a«iJer tbe pni*«ure« 
I nu tha horinwta) facea A and II Tbe 
I ibiiTBiranl* fcv a coluuin at water. 

I ba<v i* ibi> fniw A, ami wbme h<H}rht ia 
ID, Iba Inmr fare [t in praw o d npwitnU br dm 
Mtbl of a raliimn uf water wboar bajM' is the 
W iUell, and wIkv height is IID (Wl), Thn 
Mba, tbimtira, i* itninl Bpwardn by a force equal 
W the iliffeimev b«<w»Mi thaw two poiwur.-*, 
■biidi bniiv i> niMDtfatlT equal lo th>^ weight 
if * eoImsB (if wat^r liavtOK the Mni<i baip and 
.haMBW ke^bt a* ibii eiilw. Cimtr^miliy fAi> 
pmmrr li efvat l3 lAr Keight of Ihr 
' of wairr dupJbnW ty (Ar imiin^mf Afii/y. 
W« aball tnadilT rm- from Ihi.- following ren->iii.t; 

i in 8 liquid ifi prmmd up««M» \iy a i-\iov ••'(luS t/i thv irri/lit 

i-ii;. fr.'. 

Illlt t'VBFV liodj- 


OS uquiDS. 

of Uw JbpWml liquid, tn m liqitul at not, let w Mppo* m 
of it of nny (tivrn aliAp'. tf^niia or imgulnr, to bacaNiM 
without either iaiovaH! or iltM^viiw of v»1uibo. The liqiiU llUM 
dilM will rDMain at rot, ajid th^mfotn raiwt bo acied tipon lit a 
«qu«l to its wfii^ltt and acting v«ctii:ally upward tkmugli iu 
gnrity ; (at othvrwiae motloa would immM). If in llic pUcc tf 
•alidillml watiir wr imigtM* a rolid «f aiMtliM oitbabuico 
lliw Hftiiie volitiiM anil afaape. it will nwMiMnlv KicMi« the taaw 
rrtMu tbo niRaiuuling liquid aa tbp Mlidilied parlton did ; hem-'?. 
UltiTr, it will (tMtaiu tbe ftmmm of a forc» M'ling ii^rlically ii 
Ibraugh tbo ocntrv nf )iTa<itT of the di9|)Incod li<iuid, imd ii^uil ut 
vaighl of tho diiplari.-il tujuid. If, &« alnuul ininrinljlT )ixpp«iu, 
Uquid iw of utufonii (li-iuity. the eenln of gravity ttt l\ie UlspW'''!! Ii 
laeaiu tho criitro of Krarily nf thn inimnriwd part at the bodt 
l»ini/¥ui/tvuiilmnly. Thl» diUinttion t4 (onictinit^ of itupcrUmM 
laKampIc, if a*jil>en> isoompoaod ofa hMuitpbcrv uf irua and anolbcrof 

I centra of trntTiiy wnuld nnt ooincidu with its geomi^irical ovntrr, 
'Vlt wvrepUeMi under nalrr, tbf centre of inaiitv i>f tbe displaMd 
would ba at the gMintntrital (wnttv, that in, irill liitiv tbo mob* 
ai the cenln- ••( irniviiy ••( thi- tpfacre, if of uuiromi dencily. 

104. PHael|>la »r AraltbBatfa*. — Tho prmwdin^ pnociplc* 
tliatriiry b>iili' ininu>r<i>'d in a liquid la aiibDiilUc) to th« action of 
forcMi; inniit)* wliidi Irtiili to lonrr it, and tba buojraoicy of the It 
I wbirb tnndi In laiiw it wiifa a fotro t'qual to llio w^i^ht of th* 
' dieplaeed. Tli« wi^i^cLl of tliv body ia cither totally or partiaUj 
tomn by tbiit buoynucy. fmni whirh it i* concluded that a hoA/ii 
m a Hqvid lotr* a /uiii nf il4 irtifAi i^md to fAr Wtv/M ft/ Mr 

Tbia print-iplc, which ia llin h«ai» nf tbn tlMunry of rminvrM^ arf 
rioatlD)! hiiiliex. Is ('ulh-d the pniiciplp of Aii:himnl<», nflcr ibr disovmn 
It ia iliowii i-xpi-riuir-iitiilly by monnii of llin iyrb-oMtatn- baiaut* (fif^.M). 
Ilila iH na iii-dinnrr bnlwu'e, each pan of whicL i* provided with a hoak: 
tbe betiiii I'tui be ruineil by iiis'iiu of n tuolbecl rw^k, which U wodnd kf 
a little piuion, (,'. A mtch, 1), hohU ilio nwk whun it 1>m beMi nM 
Th«> bfMii heinj; mined, a hoUuw cuppui cyllndur, A, li auiipinid«l to nu 
of tbo pntM, nad below ibia a >o!id cyllndrj, H, wboan volama )( cudli 
equal to tba capndty of ibe fmt cytioder; laMly, an eqiiipoiae is plan> 
ill the other puu. If now iht hollow cyllndnr Im IiUihI whfa wator lb 
«iqullibriu[i) ia dintiirbod, bul If at iheaauie lliue Ike bennnia k>nered m| 
Ihftl the »oll(l cyliiider H b-K:<)ine« iiiimorM.-d in a VBwi of watfrr plaoei 
boiinntli it, the Dquillbriiiiii will h« rvatorcil. lly hnlitfi inini«'ned iq 
water, the cylinder It low« h purliou uf its urei^-lil equal lo tbal nf tbn 
watvr iu ibi^ cyliudet A. Noiv u ibo capacity of Ihr cylintltr A i* 

:ylilHltT A i^M 



to tl» *olinn« of lh« rounder B, l]i« {irinciplo whJck ha* 
Ui'i liitwii i« proved. 
BMUnmakUvB cr tba *«lana or * b««y — The principle 
Im AMttMwB « mcOiod fur obtAiuittg the viiliun^ of > IknIt of 

«, pioridad it M nol ■nIvMi' in wator. Th<? Wv i* niupfinikid 
thifid to U»B hvilRMtatic bolitncw, ud U w«iKk«I lint in tlia 

,„_ In iliMillnl wUer M 4' C Tlis hm of iri>ifrbt U thn 

.' tlM> diiplim'l water, fnMii whirl) (li« voluniH uf th« dispUceil 

itttdilv mlruUtcd. Bat Iliu rolumn is mnnifcjitly lliat uf 

,' itnplf. Siippo"*. for fiamp)", IM KnunniM i« tlii* lum of 

JU* i» oaawqumUr tbf wnii^ht of Ibe (iisplannl waUr. 

j known that a iiTannni> i* tb«- weiKht of a cubic rc-ntini'-t^r 

r at 4* : cimaequHiitlf , iIm vnluma of tbu l)<>dj iiuJUMMd la I6B 


IW. Sqatliftrlnia of a»a>lBc bvSln.— A bodr wli*ii B«llll|^ 
I on bv (■-« futviu, name)*, tla wvii^kt, wUi'h *eU VHrtlMUj i 
Fvud IhTimtrh iumitronf in«vitT,wiii tW KMilUBt of til* Boid ] 
wlitcb 1 10:1| arts i-^'KImIIt apward ihroujih thecentMaf gnritjrt 
, ttuid diipUccd : but if tho bntly in at lut tbotc two force* mnft h» I 
•rt in oppoiiw diKctions ; wiwiKe foUow the oanditiatu «S • 
'^brium, aaitmlj ;— 

i. TV Jloalutf iody unuE Aptat* a infuuiM of liquid nlnr 
<f Irn/i fA<it vf thr toify, 

». Tir trnlrr af graeity of lAaJhating boify mutt 6« n (Av nrawi 
Uml linr ivifh that of thejiuiil iJi«ptortil. 

TliiH in iig. IM. if C; \t thf ct-ntrr of Rrnvity at the body mA fl 
iiftlivdiitplHCvd flui:t. iIiniiDoGC iitii^l be vnnirol. rinm wb«« il b I 
tbu wi^ight uf the builT luul tb« fluid presMire will act in 


F^. 01. 

Fig. C4. 

difpotinnH tXtma tlii> Ntinie lin>-, aiiil will be in «qiii1Jbriiirii, if equal, HJ 
I* eimT'nii-nt, with nrfiTpnci! to tho iiubjcct of the pfv*ent artidn, toi 
of lliB line t;0 ^^^)■illcel^ n» tli* nxi* of lhi> imdy. 

Next lot it l)n enqiiiri'd wlidlitir till! i><|uili brill in bL' Htftbl« or ( 
Silppow ill* body to be liirnvd tiiroU)[)i a aninll niijilti (fig, GC) nl 
the &xi» tokii n poitition iiii'ltnt^d tu tliH verlicul. Tbu ouiUc of | 
of tlio diaplHFod fluid will no lonjfir bo ti but soiiio olhi-r point O'. 
»incLi tbi! fluid preiHun.' »vU verl.ipally upward lbr>nirb H", lis djr 
will cut tlifi mi" in noriip point .\I', ivhiuli will (rfiii-ridly hnrn dil 
, poaitionii ac(vmling m the IndiiiHtion of the nxis to lh<> vi^rlical U( 
<ir HiuUlcr. If th<3 imifle In iudtitinilrly small. M' will hsTO k deflaili 
|io«ition M, which nlwnyR Adnut« of diitenninntion, and is caUmI 

If wc »uppone M to bo nbove C, Bn inspection of lift, fifl will khow 1 
wti«i lb* bmly b(i» received an iiKipflnilirly sniftll di»pliicemeul the wcijih^ 
■if tli* body W nod tile riMuIi-int of tbc lliild priwurcs It tend* lo brill 


b» hnij back lo it* or>7UBl podtioo, thai ik. in thia cm* tli« rqailibriuni 
|*l»Llpf«C.'i, If, on Uincnnlr»nr, U U bnlow C, tlin forrM tend In rnuf^ 
bf axi* ta lif-TiBlv Jkrlhn- [n>iu Ibr vorlJal, an<i the cquitibciuni is an> 
UJ». IlencA Ibc raU, 

m. TTf fiftiHiirmn trf a Jhntiuy boify lA Matitir lualaUf aeronlmg tu 
)U flHtovHfn u dioMr or Mav lAr (vnfrp a/frarily, 

TW iMrnuiiMlioa "'' Ui? ineUPcntn- luin nuvlr hf •fTortad «xc«pt by 
■MW>f ■ Minwwhiit dilGcult mntliviuutiml prcNWO*. Wheii. Lowvrer, 
ike fatM iif lli« iintiii.-r**d pari of ■ body U iphfrien] it <*n he nniiij 
IfCcnBonl, tot dnw the flaid pnawin st ««ich yatal coawr^w v* ih* 
IWn, «im1 roDtiniiei to do to wlwn the brxlv u tliKhtlj dupliu'pil, Ibeir 
iBOllmt miisl ill all omm pnn thiDusb tho C(>litT«, whicb U l.bflmfnra 
fti invUorntN. To illiulnit>f tliU: Icl n tjiburicat body lloat on llie 
Mf^ie of « liqnid <fi|t. 417), Ibm it* rcntrv 
if lintitv and tlit- metnct^Diiv botb coJiu-idUitt 
wHk the ^onmntrical crntn! (.' ili cquili- 
kriun u Bputnil l'02| ; siiv (iippn*^ n fimaU 
hOTj bod,T M be b*l(3)«l «t 1' tbo auniatit 
if tlw ri-jliuftl dituiM^irr. Thn cmlm of gn- 
tit» will BOW be nl M111P point O abi>Ti> C. ' 
CMnquirnltj tb«i (^quilibriiim i? iinBlahl^i md 
tk* ffharv, Ifft to it<*lf, lill iDAtuiitly turn 
mw ukI will rmt wbra 1' n the biror em) 
rfa T*ctiial diaoMler. 
' Oa bmMigwtinfT tbn poMtion of thn nictari'ntrr nf n rrylindnr, ii in 
(boad that vbm ihv nitii> ol tb» radiii* t^ the height i» ccvAl^r tlinii n 
tMtain quMBiiiy, Ibe poutlim of stable equilibrium in that in which th« 
ttf* b tiiTtlciil : but if it be li-w thim ibut qiiuilily. tliM equilibrium 
i> MaUo wbdi tbe ui> l» biirixonuL For thin nnuon iha slump nf 
t tlwr ioala lMi||[th«ui!, but a thin di*c »f wood HontA flat u» the 

Huio* al*o, if it in reqaimt to ainkv a n-liuder of mivlrratH Innjrth 
Ittf wth ita nxi^ verliml, it ig mNVMAry to load It at the lowtr end. 
By M dotnfr it* M'Utrr F>r (^i lly i> brought bclovr tb« mcMccnttn. 

107. C«trt»BlaD diver. -TliA dUK-rront ellrrlt nf (iiitpcinMoTi, imnipmmi, 
ml Aiutiinit arr rv)iri>daMd by lOMns of a w«ll-)iDoim bydrattatlc toy. 
ihc C^rtrman ditrr (tig. I)6|. It 4!oni>jil« of n fflitu cylinder nnarly full of 
pataor, OB itw* V'p of which « bt«*i cap, provided with a piMou. i* 
LriMlinUly fttii'd. In the liquid (hem U a littlc> pon-i'loiii ■ijcuri* ii- 
tHthsd to » biitlnw ^w Imll. ii, which .'nniitln* air and wHtvr, nu<i 
halu on thti aiiHWcv. In (he luwci juiit of tbi* iwll tb<^rt' in n liitic Uf,\a 
tr wfcicb wwt«r cjin cntar or Mca^, ncnjrdinii ni lhi> nir in the iii- 
iBfoiv "' i™* conpTMMd. Tbe •juanlili o( water in lb* ;rlnbn 

F,(t, fl7. 


<w uqctns. 


U Mcb, Uwt irtr liulp mort it ivqutrHl la nukrii muIc If ik| 
be uli^iilJy louen-il tlig air U rntnjiivvMd. >nd tliU 

iMOMiiUtcd to tbu W«taf of the TOMitl I 

Mir in til* bulb. Tlie eooMqnwc* w, 1 
Mnall qiimulity nf wMter pnaetratM in&t \ 
biilh, wkirh tbi>r«A>r* becMDM Lmtkt ( 
■inln. If the prewurc in rrltcTrd, tlw : 
tlip bulb rxpond*, MlpcU lh« MCMtof* 
wliii-li hftd *fltM*d il. nod the •pfNiatMl 

ti<iivlij^ter,riMiil«thpi>iiTfM<<>. Tbe«K 
nMf iilMb«ni«l«i,b5 rvplitcioeUuil 
piatOB bj a pimT uf xlirvl india rnbliOT, < 
il Ughtly tind ovnr 1h» moiilli. \Vh«a i 
prewed bi' tlie hiuid ibe snai^ efliwti are 

108:. 8wlmmtaclil«Aaar*f flahVB.— llo* ' 
IibIim Iiuvo nil ■ir.HucMi-r Wlow ibf tfim. 
which in cftlli'd Ihi- nriwiaifi UtiiMrT. tb 
fich eon i-'oiinprFH or tliUlf this at plo 
by nifan* of r iniiviilor nffDrl, nod 
Ibt niuu)? cITiM'ta lis ihon? Jiwl dcwrlli 
ihnt it, it fun i-ithf r rii* or nink in wnlT, 
^^ __ lOli. ■wUnnUiu.'TIi^ liiiniMi body it 

ItHhUT, on tli^ ^^-b[)ll^. thitn an nqual rolnnwrf 
"8' ^ VAlnr; it riinimjiwnlly ffontion th« siirfMclBJ 

■lill beltur in Ma walor, wliii'li U brrHri^r tbnn tnth wiiler. Tli<> difililhjr 
in (n i mining ronaiita, nnt uimiich ■□ Hontinir, h* in li[i>(-|)in|7 tb" bDadaibflT 
wHtn, lO aa tf bivnthi? frvt'ly. In iiisii tb« bend n bLwrii^r ihaB tkt 
lownr pMt*, nnd RCinwiqiimitly tnnit* tn link, nnd bnnf« iwimminn in to 
art wbicfa nx)uir(>* (o tie kamed. Wilb 'inailrnjH^de, un lli« ■.■imlnrv, 
thi- bend, Wng Imi Iipbvj tbui tbi- pintwor purt i>f tbe tHxly. rrmtuu 
nbove water witJioiit any •ITort, and ibue nniinaU tli^wrcre mrtm 

iPF.cH'tr omvrTV— iiv»Hri«i;n:ii*. 

no. S*(*nnln>tl«D «t ■peoUM KfAVltlaa. — It lias bwn alraady 
expluiiivd i:.'4i il^^it i>i>' hp-'dlic gjnvity of a hndy, whether aulid «c 
liquid, U tb" iiiiinW nliicb vxptvMPs the ndatitiii uf tbu w«jfthtaf ■ 
(^vvn vi>liiiiiii of lliii iHidy. lo tbu wcig-ht of tbo ^aniu roliuno nf (ll«lill«0 
wnti^r at a lviu|K'ratiire of 4°. In ord«r. tber-fi'K, (<> colralat* tfce 
gpunitli! grnvitT of n budy, it Ik «iil1i«i«i<t to dctiVTiiiinu it* wHjikt and tiMt 
of Ml oqtial v>iliiiiin of n-nlut, ud lh*n to dtride the llrM w^^'it' b? t^ 
KMotld ; tho qunticut ia tb^ spocilic gravity of the body. 

Tliiwr metbods aiv cnmmoiily uaMl in determiuing the xpeoific |;Taviii«i 

MnecifK CHAvm-. 


ilidi^ tad liquids, Tii«>c nm. In, ttM) ncdiod iif tbe bjdrasUlic 
Bi.'r i 'Juii. tlua of lb* iTdnniKUir ; and iid, ihe aptdfic gnritj: 0M&. 
I lluv. iii'wi>T*r, depuul oa tfcn muui priMapU, thai of flnt wiMrtatA- 
dut wKiffbt. iif a boijv, and ihtn thai cf an i!qua) Tolnmr of water. 
I flnt apfdr Umu metliodi to ilotcRniBiDg lh« fpaci&C gtatity of 
, and iJi«n to lb* «|iecifi<' gravity of Uq«id& 
in. Mpmeimv crsvltr af B«llflB.--L ffgdmdalic btUMtet^—To obtain 
■ *[trriUi.- trmitv iT a ■oliil li; ibe bTdroMatic balance (fig. 43), it U 
bad in mii, uiil La tlipa MiapciKlcd to tlic book ol tbe balMBM 
I MJlllwl i° valiir. Thi^ Iom of miitiht wlikb it axptrimcna ia, »e- 
' to .ln;liini«ln' princtple. llip nvisht of a vulmne of valvr ■•qua) 
lows tnluiiia; (ximaqurntlj, diTiding thn waijirlit in air bj' thv ioat 
[««icbi to watrr, ibn qtiutivut la Iba apedUc gta^it; required. If P >> 
bt ij tbo bodf in air, P* iti vcigbt ia watnr, and U ita npedfic 
P — P* bMitf t]i» w«(gtit of lli« dispIncMl wat«r, wr harn 

tt^imri'nd tbol lboU)[h tiui wni|^ing i* pntfiiniwd ia air, vH, * 
kintr. ibo qiEuiiii V rtquipnl !■ tin- wutgbt uj llie bo-ly in mobb, 
KTVHt accunu'T in m)aircil, it ik anc ww ajy to apply to tba 
tnl wniylitB • C^rrn-IMn fur IIm Wiii^tit 
' UMquaJ viilunir* of air diiplacrt] by ibi^ 
•nit tliF wHi^blA ID iImi olbnr a«l» 
It ntay aUn be miaHiPil lliat tin- walir 
ivbicb budtr* uro widgbcd ui, iirtctly iprak' 
i^ di«tiUnl water at a alandaH iiwiporaitm. 
i). KeLiittm'' hydnntitifr. — Tbi* apparatiM 
ecM»U of a bolli'w nwlallic <nlindi>r B 
'Ilk' i'^*l, u wbicb ia lUcd • cotw C, kuuM 
■ .til l^iiiL 'rbr.i>bj<!<1 of tbe latter U to briiv 
vity brlow tbu nivtHi'i.'nlrv so 
r;)Hvtli<alwilb itnaiiii vurtiral. 
Al iba tup i* a alviu, termiaalad bv a pau, hi 
«Ueb b placwl tbo ■iUbAukt wboaa uptfcilir 
FnrllT i* t'l Ik ilpti-niiiMd. On ihv at«ni a 
•tanilani poinl, o. '— niarkad. 

Tb>> apfauvliM Blaada partly not of tbi> waliY, 
mi tba drat mey t» to awMnain 1li«< meifrbl 
«hkb nuul Iw plaiwd in tbo pan in onbr to 
mail* Ibf byitiv>i»i-i''r *itifa lo Um aiaiiilatd 
pttat ft Lx-t lliia Kuiitbl bp l£'i iftaiB*, aiyl let siilpfaar bo the- iiub- 
Mmbb wbiMii apvcilic ||Ta*ity 1* In bv dHtenniiNd. Tli» nviulil* art- 
■W mnavad from tile pan. aiid replaced by a piece of Btilphui vhicb 
«ti|fba IvM ibaii I3& gnia*, and w«i|[hta addad until tbc bydro-. 

i'n;. ea. 

88 OS uqvtw. [lU- 

atHrr VI tiffiia d^rRUnl to the MniKliud o. If, f>>T iiut>uc«, it hu bn 
ntc«*Mfy to rtdd A-t |rriiin», tli-' weiglit of the ■iilpfanr )• ondcM^ 
tbe (UffvKDW Wirp^ I'io nii'l Tji) irraina. lliat U, TO )(TUms. ifi 
thiM dcti^minnl thn wi!i)rht of tlw sulphur in air. tl ia aov 
IWOMnwjr tn MoerUui thi^ weiglil uf an equal toIiiiiki of wrUt. Tti 
tbif, llio pit'ce of sulphur U pUo'cl in tho lowpr pun C nl m. 
»Mi1«d in llw figiirv. Thp whole weight i« not rfiniiirpd, Dnntti 
Ib» hydcnmntpr no liinf,'<-r irinki to the iiUuulon! : thp lulphui, bj i: 
■Ion, ha* Icwt a p«n of iu woiglji •v^iial to ilint nf ih« wain dilipl 
Weljclita HIV wJiiifl tb thc! iippi-r piui uniil lliu hvdnHOt'Ur aLnb 
lathe atanclAnl. Tliii) wifi-hi, ;t4'4 grniun for nxaniplc, npnuBnti 
weight of the Toluino uf wntor diapltiL-cd ; tbnc i*. of tht Tolnm^ of 
■.■4)ual to th« vnliinid nf tii<> *iilphiir. It U only nccoMuy, thrnrfor*, 
divide 70 ^r»ln«, ihv weijctit m air, hj 3i-i gn.ia», and th« quotient 
b Ihe (^dfit'innTity. 

If tho bodr in quewtiim is lighter tbui witor it l«nilx to rim to 
aurface. and will not nMnnin on thp l<nrer pan C. To obriale \\m. > 
ninnll mDvnnbtc fnar n( line wire ia luijiwlMl mi m tu picvent thn aaoal 
of til* hnciy. Tlie exiicriiiipiit in in other r'.mpi'eM tlrn mnifi. 

11:!. SpaeUlG cT*Tli7 naak.— Whvii tbu spi>afie frmvilr of • 

*iib«tHni-ii ill II i-tnti' of [w>wder i» f-iiiiire"}, it fan In- found nio«t conTMU- 

(■ntlv bv luruiii •>( ihi- Bpt-i^itic umrity fliuk. Thin in strum nit i* a riuiill 

diuli with n Inivi' nopt litloil with ncanifiiUv ground bIrm stopper. The 

•topper II* ["irfuraleil aloug^ lU niis, and tliu bore Is eoiilinu'.il bv ui''8in 

of a ihin tuW which cipnndu into a tubn of grpntcr dinntcler, lu sliowu in 

the figure. On the lliiii lube ii« a mark a. atid nt ench weighing lb» 

Hask ia HllL-d with wntt-r tjcnotly to thi.- ranrk This in done by fillinj 

the tla*k when wholly iiinler water, and putting in thi! itoppor while it it 

iuI]nI^r^L•l). 'Wf> llnxk and the tiil)e are tJieu couipl«t«]t 

lili.d, and the (|unntit_¥ of wnlor in ckcph ia rtvnioTrd 

by IdolliufT paper Tii tlnd tlie »pei?itle gravity pntc**! 

ui fnljown. Knving wi^i^-heil lb c powder, plaw it iuoM 

of the pipftle pun*, Hiid with it the! llo-k tilled nxuctly to 

a and PHLvfiiJly dried. Then bnlnnoe it by placing mial) 

nlioi, or irnnd, iti the other pan. N«iil. tvuiove thr Haik 

atid pour the pnwdrr tntu it, wid, on bpforc, till it up 

with wntor to tbo innrk a. On rvplacing tlio Ilank iS 

the irale pan it will uo lon(.*er balancB tht- eliol, nin** 

I iu' powder li«« di»plnwd a volume of water equal to 

iij own voliinie. I'lai-e wei^ht« in the He«]u pan along 

Vi^ To, with the lliisk until tliey balntuN> the shot. Tbw* 

nx'i)fhl5 ijive ihn W"i]iht o( the water diaplaeed. Then 

tlie nreigllit of llie pi'wdrr, nud the ncighl i-f an ciioal bulk of watar 

/v/oy ib»)im, iu fljjiTifii.' (rravity i* determined aa^rettiw. 

spicii'tc BBivrTY. 


tpiBUnI in ilii* dclvRnin&lJiMi to nmovn tbe Imjm of klr which 
to tha p(iwd>r, uid tmdiily iiKmnvs tbn qtuwtil;' nf wmit 
Tbi* i> RirMtoil hf placing th« bottle rnidet tbe ivMJTvr uf 
up, anit •MkiiMiD^. 

aBI»a »otabt* IB <m,t»r.—lt tbv body, wbnaa uptidSe gmvhjr 
l|pi«rniiii<-il br ui; nf Uicw iu«tl|od4. la !Niliibl^ iu wMtt, tit* 
i* tiMde in miim liqirid in vlucA it i» mic loliiUe, mick » 
ic, i>r naplitbi, lb* «p«rilir grsvin of whicb u known. The 
ivilT ia otilainMl tij tiiiiltipljrin^ lln- nauiW otitainnl in Uiii 
ibd ipucilii: inkTily of Uio liqidd awd for llio ■tntfrmina- 

nuunple, a dfUmuaation at ibe •podfic fcttv'tty of 
i h^ b^pB nwl« in naphtba. For «qual volame*. P rvprwou 
it of Uw pOUiMnm, ftliktoftbenapbtliii.iuid 1'" Uuit ofraUrr; 

Itly p, will be ibc sjivcilic fTBvily uf llit? siibttailfe iu rpfcrcDCc 

M, and L^ tliv (pfcilie ^titr of the naphtha in NfatoDM to 


The product of ibow two IWtlcois |v-. i* th« HpKiSc gnvil^ 

•tan» ooaipared with water. 

loninliigr (fan «[Mpiiio gntity af pninuti i>ub«t«n<iMi, th»y ftr>' 
bnfnn- bfbig imuoi-rx^d La wBI'.-r, wliid: nudon them itnpt-r- 
lotaivn withiHit Rllnring Ibcii yaJvm*. 

frnatjf iift^idi at itro lu «im;inrrrf iri'(A JitlilM nvtfr at 4° C- 




. KiflOB 
. 20*»7 
, !»■»« 

. 113M 

. s-ers 


. 8-363 
- r-81« 
. T7*|i 
. 72BI 
. ttWJl 
. «-TI3 
3-131 to 3 SOi 

Flint plaai . 
StatiiftTj' tnuble 
liock crystal 
St. (inbin ^laa* . 
China {H^nlain . 
SL Suttm poitplaii) 
Naiivi> «iilpbur , 
ADibncili.' . 
(^nmpact co«l 
Melting ico 
Oak . 
FHin . 
Velio w pi III' 
('ooimnn poplar . 

. 3-3a» 

. sew 

. 9-488 

, a'WR 

. 2146 

. aflfW 

. i-«o« 

. 1-aw 

. 1-078 

. 0-830 

. 0-852 

. O-Ufi 

. 0-800 

. 0-057 

. 0m9 

. 0-24t» 



114. •pMU«K>««Uy*tU«>Mk— L Jf«iMl«<(iFAjidi-«iK4tfvb 

— FromllM punfthiP hjitiMtetir Ubwwabodv UKU|Miaid<<d,«i 
■hit Bqmd who«v nfitite gnritT k to ba detenninMl. rierta no (h 
«C<hHl: fiir uMfl^, • hall of pl>tiii«m. Thi« i* ifann noM 
wd)[)w4 in «T. la dixiJlMl -wtfvT, aa4 in Uk liquid. TbelcMCf' 
of Um bodr in tlia* two Bqctids ii nolad. TbcT Rpnucfii ptif* 
tb« wcichta of t^Ml nlaMM oT iru«r. Hid of Ui« given Uqw 
iiWOiliKiiilll il U 011I7 I'oe— fy to ilindB tlia lecaad at tkfeD ' 
SmI Ui obuiB ihit i«qiiir«d spciSe ^viir. <^ 

Lot r be Uw wci^t of tbe pbtiamm ball in air. P* i> vni^UV 
P" itt v*i(rlit in th» (Tin*! liquid, and lot D be the npffifie i 
MMi^I. "ne wrkAt uf lb* «U«r ili«pl«0(id btr tlie 
V-V BW) tbat of Um) Mcoad ti^rid i« P-P' bom w! 

li. FaHnmiiiri Jljvfrainirfn-. — Tliis iBMrunwnt (D?. 71^ 
Kichobott'a hTdrDOiHcT, bat ii tnaile of |rl«as u n* la bo WMd 
liquid*. At it* lowir utlvBiin', iiun^ul at a pan. il ia load«d 
MUll Imlb rtuiUiniag mwrut. Then is a atandanl mark on Ui« •, 
Tha wni^t of tke iutruDiantiafirJt accunuljr dnlcrminixi in a 
then ptaoed In wnt«r,aiMlir«igliU addvil l« iIm •»!« pnu iiiiiil tbt>i 
ibe aMoi is ler«l with llin vah^r. It followa f 
Aisi principle of tlia oquilibnuin of fiOMliqf 
that tbe weijrhl nf llw IiTdroawttr, Ugalhi 
thf wirigbt in the aoalc pui, U oqnal to ths 
' Il '^ *'"' vuluDM of the diipkccd water. In U 

II mannnr, the weight of •n «qiiAl Tolurae of tl 

!■ liquid it detpmiiipd, *ad Ih« upccific ir ra vi Pf 1 

Il ^T dividinji the laller weight hr th« runner. 

[/ J NeitWr Fahn-iilieit's uor NicbulMa'a fardi 

friro luch ncrumle re«ulU a* the hjdroMMie 1 
lii. fjHri/lf yrarily Jt-uk. — Hiic haa 1mm 
dmcribed. In drtrrminin^ the (pedfic frr** 
liquid, th» flank i* Unt wnighod wiptv, and U 
rewinlv, Htll of water, and of Ih* piTun liq 
th« wi^ifiht cf Ihp fla^ tm fubtnictnl IVooi 
wnijllits ihiiH obtaiupil. tlic rvsiill repniNi 
reigUla of equal voliiuip* of tb<! liquid, and of vntcr, from wh 
■pecifio gmvilj' in (ibtainrd h_v i^iviMon. 

1lr>. On tba obavrratlan oftemp«r*t«tte In uaoertMlalnc 1 
jT*»ltl«».— As llie vciumc of a ^cdy incntmiii wilh ihi' ti>iii[ 
sad a# thi* inrrrCLv variFu «-ilh diflVreiil dulvlnuo''. tlll^ Apccili« 
of nnf gii'en bodj ii'uot vxaclly tlie Muir at dilleicnt icuiporatiu 

Fig. n 


sttcinc oitAvn-r «f luuium. 


J - 

. IfUl 




. 1-043 


. .HWO 

m . 

. i<eo 


. n-iWi 

imtljr, ■ mtUid Ktcd U-mpniatutti U ehowii tot IImm daUmuaa- 
Tlial of w«ter, for exAiupli*. liu hrta mfulv al 4* C^ for nt thU 
ha* tfac gnaUct dcuilj^. TIm (pedfic gravitie* nf otker bodiea 
niMid M bn tak«n al wroi but «> llii* b^ not alwajrg pocaible, 
oamctioos nnut Iw nmie, which vc aball ccoudcr in Ui« Book 

gntritM of /iyiiKb of sm, fum^mr a/ )n>A /Aof e;^ wotrr al 4? C, 

la-fiOS DiMilhxl «at<9 at A' C. . 1-000 

., MO^C. . o-(ie» 

Olirooil .... 0«16 

Oil «r ttirp«ntinf< . . 0*70 

Naphtha .... 0«47 

AlmoliiWftlcoIiol . 0403 

Eiii^r .... <na 

Va* *r table* of airtciae Kr«*lU«a Tabic* r>f specilio gnrity 

if oiiitt^riMW applkoali'XM. In iiiiiiF<rtil(i^y t!ie Hpcllie graritj 

Kia aflen a highly dialinctiie rhnrutcr. By racma of 
flc frraTitMaUi* weight of a hoAj m»y b« cit!i-iilni(Hl wben itH 
wa. and coaTanttlj the volane Tthtn its wi.-ij,')it is known, 
a ii«iw to explMuing the la»t-ni4inliont^d um of them tabic*. 
H well to iiKmlM a ■tatumeut of the oannuctiuD «xj»ling twlweeii 
bb units oT length, capid^, and weight. It will maniEratl}- 
knl for this purpow t>> dufine that wliirh fxihlii hotwmD the yard, 
pairad avoinlupoi*, nncc <A\Kt mi-iuurL-s stand to thcae in 
nlauom. Tbo yaid, cfininkting of 9>} inchnii, may be 
I aa the primary unit. Thmii^b it in MtmiliiiUy an arlnlrnrr 
it i* d*t«tautn«d by thia, ihni tlia nimplo ppniiulum which 
in uadllatlMIt !■ a neaa MHMud at Lotidou im lL« ivtt Ivrvl, Is 
indita l(Mi|r. Tbc galUm enataini S7T-37'i ruliic inrbiu. .\ gnXlon 
led water at thtt Handatd leaiperaliiiv wn^|i« 10 lbs. avuinlu- 
70,000 graiiu troy : ot. wbicb cotom to tbo mom tlitng, ona 
eb of wabv wnifbs 2^3'ii grain*. 

fVrnch sTtlein ibi- mt^n' b lhi> primary unit, and is •>> choten 
WO.OIKt muter* aro thr i>a^b of a quadrant of the meridian 
r pnin t<t the equator. The nwler contatna 10 ileciuiHtan, w 
imetprd, or l/XKI tniUinwlma, its langth n(|ual* 1-00% yard*. 
ttf tbm maaHiia ot capacity i« tbe litre or cubic dL>cim«lM. 
of w«i)(ht ia the gnuiune, which i* tbn weljiht of a cubic 
rof diaailled wator at4''0. Tbe labgramiEiu omtaJns 1,000 
iir i* tbn iruifhi cS a •Jeoioi'^ter of diatillod water nt 4* C 
mr »i|t«l» lfi-44:i^rain*. 


If V ia (be niinitKr of ttAw eentinelen (ur ikcimetm) in ii 
QMMittty of diMillod vntpr nt 4' C^ unci I' it* weight ta |.i iiiibii i 
kitocmumM), it U pUiu llial r=V. Nun cuondvr « imli*taM«i 
vpMJSe ffMvttT !■ I>, rvcrv <nibi« n>ntini«ier of thin ■obMaaw tdih 
M mudi u D rubir c«nlini»li>r» of waier, kiid th«t«fare V 
<if tbi* «ub«t*nrD viU wMgh m mucb aa 1>V' cmtimelfTr* 
lleiK* if P i* Ih* wni^il at thm «ub«Mncu in fnnuDM «« 
P™I>V. If, h'>we»<T. \" i* tli« volumv in cubic incbM, and PI 
WMgbl in grains wm »biiH hsTt. I'=2-'Si*-Jl DV. 

A> an piciuii]ilp nc laHv calciiluti* lh« iiit^nia] dianteUr of n . 
tub«. Mnrrun- in intrndiicixl and tbc Irn^th and vi>ight nf ibr 
al t' C. are n^iiralvlv d^l^rinined. A» the i-uliiiiiii is cvUudr,'-' 
h«»e V=»i-7, wlirni r i> tb^ radiufc nnd i thf Ipitj^b of the 
mitilRf U-m itnnrp if 1> if th« uprritic (iTavitj of rai-reiuy, Mil f j 
wriirbt of tbe foliimn in f.-nuiiuw, w« hnrv P=«rVD, and tbonAn 

If r Hint J are In incboi And P In gnins. *r« sbnll htre P=SS3-WI 
And llinn'fDr* 



Id a Kinulnr muinfr lb# diamelor nf v«n- liii» mvtallio wirw cut 

11*. Brdromaters wtib varlnbl« voIubio. — Tbe bydrDoiFtNt i 
Xii^hnlwin nnd Fnhrpnhc-it nrf cnll«l hii'lromi-tm of rouitmtl nJiimt.U 
vtirioblr irc^/A/, l>e«iiiM- lb«^y ftiv dlwav" iimimn^ii tu Ihu huuu eit»m, 
liut cam' tliiferpiii Wfijtht*. There are abo Mydramiter* tf rarm U t 
wtltniit hut tif nmnlant ntx^tt. Thi>M innlnimonlj*, knuwn aiid^r tbt 
dilGn'Piit iLunit of aculomi^i-r. al(.vh"lnmelvr, InriomtUrftaA tarrAaraimttr, 
lar not uvd ti> ditfniiinn tln! upcdlic eraritjr of tho Itquids, bn* to 
Rlinw whi>tli<!r tbe aci>)t<, slcoliolfi, *oluliona of «u^t, etc., arv taorr «t 
!•■> conoemnivd. 

11*^ BMinnti'a br4rom«i«r— Thin, whicJi WM th« tint of ihfTC 
inttninK-iils. uihv atne a« a typ« of Iheni. It cuiiBiala i)f a iflaai tab* 
(fl^. 73) loaded Rt it> lower end with mnKurr, nnd with a bulb blow 
in ibo middle. Tli«itt4-in, tha «xU>nu(l dinmeipr of which it aa n^bv 
tm poMibl«, in buUuw. niu) th« acnle i* ntarkL>d upon it. 

Till) irradiintion nf thi> imtrumnnt dilTir* arcnrdiDg m Ihi* li(|n)d, tat 
wliii^b it ia to V iBied, in bvATiur or li|chtfr than water. In the HrM 
CEMO, it it V) ooiwIruRlrd that it idnkii in water nnarlj lo the tup of 
the Bl«iu, In A jioinl A, which ia inarki'd tviii. A aolutioo of fiftiwa 
piTt* of Milt iu pifrhtr-tii !■ purti of wntor in inndc, luid tli« ituUumeiit 


il in iL It Mtib to A certain point on ili« Hem, B, wliich is 
ji't; tli« distaoM iMawveu A and 1) U iliviikd inUi 12 e<iu«l 
M>1 til* padtiklian oaiuiuikI to the bottom 
tb jtcn. Sotuelimm) iku frraiiuiitiuii it an a 
pqicr in ibn wtotiur of tliu atum. 
Ij^fnDflnr iliiw gn^wttMl aatv BerrM fm 
«f • irnMtur ipiwLUc gravitjr ilun «rat«r, Mi'h 
Old mIiiw •olntMiu. Tor fiquiib Hghtrr 
valcf • iltflVreol plan miut be adD}it«d. 
look fof icTo, thu point 10 whicii tho «pp*r- 
in a Holuti'iD of 10 pajt« of mJi id 00 of 
tor IV he touk the toiel in dUtillcd watrr. 
lie divided into lO^wid contiiinsd tlio 
lo tlx! top lit the Ktie. 
fn^iWtioRi of time hydrotnetMH ia nntinily 
it|i<Dal. aad ikrj p<o n«iiber t]i« di^nsiiim uf 
lEqnd*, norlbr i[u»nltlk's diuultcd. Hut tbuy 
imj iwrful in tiukiajr niixliirat or KiliitioiM In Vig.''i. 

fnfan\m»: (be rFBuItu ibey )nto being suili- 

in ibc innjoTilv at cnar*. Far iai«iinc*, it i* fiMind that a 
■ade nrttp niaihn M" ou Uvauui^'s li,vdruju*l*r, from vthicb a 
lufactuiwT ran rradily jud^ vfacthnr a vyiup vbicb i* bainf oTapo- 
bat rpBcbrd lli« pttipvr detiree of conMOtialiou. 
>. Oa]P-&Ba«BO'a alc«k«lomet*r.^Tlii> in.^lriiniPtit il uanl to 
tliv (irvDgtb »f >|iitit>Kiiu liquDn; that U, lliv profurtihia «f 
alin>liol whicb tbi-j cuoiaiu. It difTvn frMii Bcnumd'a tiydiu(n«t«r 
I ibp gnduaiioB. 

Uixium ot abiotule alcoliol and lUntiUvd wat«T are muit«. eoniaJaiiiK 
i, 1<\ '20, ^ vie., jwr canL of tbo ftimw. Tb« alcnholoiDoitir U ro eon- 
ttnictcd iJiBt uben placod En pui« lUMiUKl w*tvT, tfav botumi of it* 
kixiB >■ ti^'l wilii thiT wntirr, and Ibix p<^nt is xcm. It i« next (ikL-tKl 
to a>Hilut« atcubul. whivlt iiurka lUD^ and llivii auci-tUHvcW in iiiimun.-* 
•if iliffirDt ativnKtbi, tanlaJiMiig 10, SO, SO, etc., per cent. Tb« divisit'iu 
thoa obtainrd aie u>>t axactty e<tiia1, but tbeir 4in«rt>ufH la not grnat, and 
tbav af* aubdiriilrd talu tea iliriiions, ttuh of wbirb markii an« per ofqI. 
•if abauiuui aloubol in a liquid. Thua a brandy in irbich th« atcobnKi- 
malar *utod at iS, would contain 4t* ptr oral, of abM>lui« aUoLol, and 
lb* >m( would be wato-. 

All tbuav dataraiaaliona are made at 1A° C, and for that t«inip«ratiirt- 
unli at* tba indioatiaM convol. For, utbiT ibis^ buiuff tlie oamv, if 
tll^ Muprfatura rian tli* liquid expand*, and thv al<:»lii>1(>ni«t«r will 
^nk, and Um cootnuy. If tbe 1«iiip«mttiTS fiUla. Tu obtint^ this i<m>r 
t ii^ai cocistTuctad a table which (at each pcnxuia^o of nlmhul 






invR> th« R*ding of Ui» uulrumvDt fnr eu-'h de^rr* at tvmjiminr- '< 
n° up to W^. When tbo r.xnet Mialnia at m nlcnhfllu! nixtar- 
uiwli', tlic tMii [Krai lire of the liquid i* firrt ileurainod. ud - 
point to whirh th« Dlcotio)om«t«r nnki in it. The niimb«» in '■ ' 
comupuniiiiiz to ibcw duU indiratM tlie peroeotBge of alMtiaL 
ll« (ri^ng ihi- p<>rc(!ntafn^ r4 alcohol, llii* U ettutt called lh# 

I JO. saiiDi«t«r«.— VirfiHtrfin, nr (iutriuiMil« for iadicstinjr tk 
'.'orilniT" <•! 'nil ("iii'iirird in ■ •olutiiiit, arc modn on thn priiKipli> at 
ci'iitwiniat id>:i>)i>.ili.<iii«'1<'r. Tbpy arei ip«dnal«d by iniineniini^ thni' 
piirn wntPT, wliicb irivi-i tbn tela, and ihva in snlatioon cxiDtaisiEa 
fenut pitn»<iit2iti>«, 'i, 10, id, *itc~, of thi* ««ll, and marliiofr uo Uic 
thr ('omvpotidiDi; poinlJi. Tbuc inrtnunoDla are w> far olijfxni 
ihAl tyvry wit reqnirm n ipsciiil initniniPiit. Thiia nnn grnduaMl 
t«iiuiion aalt would )cive totKllv fnlw iiidicaliuiiK in ■ wIuImid of nitre. 

LiMifmrttn and liaontetm arc nmilar initrnmimta, and ar<* timl 
inrMiuriniC tliv quuntitv uf u-ntvr nhlch id intividiin-d tnlu milk ur 
for the purpiHw of luiultrratiim. Hut their um! in Utniti^, bnr*uM 
dvitxity of tli<>«e iiniiiil* in v«rrv varinblc, even whm they are p«i 
nntunU, and an appHrciit frtiud tniiv liv rvally due to a bnd natOMl q< 
of irlni' nr milk. I'rinomrti-rt, which arc tit vxtetmxe m« )■) ni 
are blued <]□ tin- tnmr. principle. 

121. S«nalin*i«r. Thn JmnimHrr \% ten appnratiia forindira 
Mpei'itlc t'nivit) of x liquid. dny-Luwiac'e dfntjmetvr Jiaa the 
eonitriirtinn ai Iteniim^'i bydromel^r, 
iimduated in a difTi'rt-nl ninnnrr. RoMMu^l 
■iinctcr (fi}(. 73) \a of gn-iil uejp in toBuy 
lidc inveMigationp, in lirtrrminin^ tli* 
irntvity of a uiiaU quantity of a liquid. It hat 
the ■amr' form a* liruiun^a hydrometer, but qn lb* 
npper pari uf the Mem then? i» n unaJl tvbcy b 
whicli in plnciid the siil»tnnte to be drti>raiini<d. 
.\ mHrkoii the«id»nf the lube iodicstMa meaMrr 
•if a fiihip <vntinieter. 

Tlie iii»l.rimieiil ia *t> eotitlruclrd thnt it dak* 
in dinlillcd wnterloapnint, H,jii*l nt thebu«tMit 
»f ihe «teni. It in then filled with distilled iratw 
to thc> bei^'hl inetti'iired nn the tube, which indi- 
fBti* a cubic centimeter, nnd tlie point \o whick 
it now vinks is 20°, The interval bi-t«-o«n and 
soil divided into W n^ual piiT(% niid thiit gradna* 
tioD is continiiixl to th« lop of the *cal<^. .^■ thii ia of unifunM bar« 
each diviMcin corre*pond» t.i ;s gramme or (MM. 



WD tlie dcMiT of «nr Uquiil, bile for exjURpJo, the labo u filUd 
uf til tbfi mark A : if tbu il*iiMBi«t«r •ink* to S0| ditiaong, iu 
tb(H»xJO'S=l<li'i; tliM b to «I7, tfaiU. with eqml tuIuoioi 
: of water bohiii: I, that of bi!« ia lUSi. Th« (pMific gT«iil}- 

cBAptVM n. 

ixiTT, utiHtNHimr, Kivniux, AWonrnux, tnu miiiniTiON. 

'!:. C«ptaiu7 pbBBOBicnB. — Wbra nolid bodwa nv pk<ud in eon- 
■tti liqiuds, m eiat» o( pbenonmis in pi«(liic>->l €sll>.-d tirpHlary 
aiMaa, bmusr t]i(^- arc bi»t awn w tubes irhcuu diniuctm arr 
MmUe with Ibii dinmrlor of a kftir. TheM phmantena am Intatml 
) f^Jiiat andflc tliu henil ol (OfMlln-iily or rapiUaty oUnuiiM : Ihe 
Ir m{ucmUid u timt applied vo div fncc« whicii proda«« th« pitroo- 

W pbMioaHiiin tif n|ntl«ritr «rc « tar vonatw, but mnr oil be irfcrml 
^Mntml ainwtion at tk* liquid nialaciilM for sach ntlinr, mhI (■> 
UMetinB hetwevo ifaRw mo^eciUva ud *oltd bodioa. The foUowiug 
Ih* of ihexe phnnnDwaM ; — 

I « bod; in plai>*d In a liquid which wete il, for exniii|il« a flM* 


Fii. Tt. Trf. Tfi. 

Fij. 78. 


r, iJk) Uqidil, m i] not tuhjwt tn the laws nf ^rmviution, ia 
raid* agabtat tk<r aiden of th« aoUil, aod ita ■urfai.'c. iatitaad of 
stal, becoiMW iliglitlT oaoeavo (HfT. 74 ). If. «n the ftmXmy, 
nttd ia m> whicb iatiDlnioiati<nMl bjtli>>* );l&u hv UKircur^-, 
. i« d«pmM^ a|IUM4 tlw tide* of tiie noUd, ami muuniiMi a eont^x 
)hi W|m. « m lwl iu Og. 71. Tim aurfaM of th« liquid pxhibiln 
Kttmtlty or eomcxity ag»ui»l tlw ndo* of a tcmcI in nhirh 
itaiwal, aMOfding aa \hm wUa or* or at« not moirtraed hy the 


iHO ifpifnil when • uiW at \ 

la fvofartka m tb diuiMter is Ib«^ 1 

Mi 77. 
WIm Ik» v&M «« ■iMiM L i hy tin liqvid, iu Mirfam 

(if. 76) ; vfcn &* bA« m» Bot iifclCTnil, tiitm ia r ruaru i 

ifer- "•- 

133. Kawa •( tk« —bm * ■>« «»»r— »!■■ In eApUUrr 
Ctay L— c ka* aWm tafeamaatUr tkat tbe eleTatioa and 
cf 6faU» ia Bif«ll«i7 mhrt at* ggrii t d br ib» tkrptr roIlowiDC 

* ypiii Li« ww 4 i v a»i»<fa«<a-J— a^M ii i^wi(jif fm^. 

tkrtmU. «AMi(lr4Ma>Av4MM««n>W(HaMlwM<<n. 

^nT'itT. Imt it uOtpniJait t.f Hg ml at» mi d liicbuut i^tim UA*. 

Thrac lavi hoU fwA m lacttn aa Wfdl ai in atr. 

Whis liqaid* an ia ubca vUet tbi^ do sot moutPB, the 
if ia lb* nT«tw mli» of 1^ diaiMl* af tkt tulw*; bm for tabaa 
aanr dianKtBr the Jg pr iM OW igftmit OB the MibaUnon of thai 
Tot aattmix, ia aa ma tubr 1 mStimptrr in dianwWr, the de; 
mwrun ia I'SM aiUliiiPtet : but id a )>latiBuiu tube of the moib di 
the drprnMon \» 04&S BoUlinMlpr. Htmorvt tba depmsHoti (Irppadi 
the h«gbt ft the i.iMT«« aaewanu of the meRury, aial ihU brii^ht vi 
for xhe Kuoe tntir. arconliii); tm the nenama i« fanned during an 
iotf or dfwtodintr motion of iha Mercuial column in tbc tubi.-. 
rNolu nnder^uiodiScatioB tf ihai>ete«i7buii|>iir>' 

134. Aaeam mat aa> t aa al an fcawraan pwaiioi vr ia«UW 
aifliiiaa. — Wh«^ tirn bodim of anT fCITM ahap* an* dlpftttd in awH 
MialopQui capillaiT phvuoumia an pnyluotd, provulifd the bodio* ■ 
ruJIkicDtIv near. If, for i-XBDiple, two parallel ^n** plataa ara immcm 
ia wai4v, at a \*ty •aiall di«l»iK« fioui raeb uthef, ntXtt will rise betwe 
iJtc two pUtta in the inrcne ratio of the dintonee vhirh K^Hinii>r« tbin 
The h"i|iht of thn lucf >il for hot (tivnn dihiaiu-i' ia half wlml it would 
in a tube wkotie diamelur ia pqual to Lbp distoiuv bvtntvli tlie pLatiM. 

If the pamllcl plates are immcraod in niorcurj, a CDitaapooidi^ 4 
fitenion ■• prodiicad, aiibjort to th<> #aui« laws. 

If two glaaa platm Alt and AC with ibeir planea Tonieal amd i 
rJined tn ooa another at a uiinll niiifle n* repraaantad ID llg. 7S, ha 
tbeir vqJs dipped into a liqnid wliirh weu tbem, th« Uqsid vilt ri 
botwotn iIkui. The elevatiou will be greatest at the line of cootact 1 



from tbcnoe gndullj lew, tb« nufsw Uking tbe fonn of ui 

hj^vihalM, irhoM' wjmjiUitcdi arn rai^ioctiTttly tbci tine of 

of Um plaica. flBtl ttie line ii) whiok thu f\Mei cut the 

of wUor !>• p1a>'<Hl nilhia a (vmira] glniu tub* wbOM Ugls 
land Bsu bomodlal it will Lavv a Aincavo meniigfUb $.1 tncli end 
And will tond lA luaTa towanli tho vcrlrx. Hut if Llin drop b« 
it will b«r« B r^Qvcx UMOHcua «l tacti end (flg- 60) uid wilt 
le from tfaa vertex. 

R« 79. 




[AltrKirtloa ma& r*pBl>lan pTedae«d ky capUlArU^.— I'hc 

uid tvpoletoiM obAcrtvd bi>twcvn b<>dit'> ll'intiD^- Oij tlit.' -iirrun 

Mta dna to f»pilUrit]^, ftnd oic nubjvct tu t)u- follmiing Inn-i : — 

two Boatia^ ball* liotli tnoincnnil Iit the liquid, for nx- 

Dpoo mlcr, Me •» hmt tJiHt tli«i liiiiiid tmrfuci.- Iwtwei-n 

itbI, on nttnMinB take* finec 

effect U produced whnii neither of th^ halls ie moUtened, 
wilb ImIU of wax ou waller. 
HtJj', if oncnf tfae ball* it miiiirlaticd nnd iWodiernot, as a ball 
and a b*ll of was in water, tln-y repel i-Hch utLer if the curved 
at thai liqaid in tboii nw|i«otive neigbbuutlioodi intvnnRt. 
I tfcaae capillary phMionMoa' dtpend on th^ ciiucavu or convex 
m which xhr liqiud hmhom In cnotact wiili tiiu solid, a abort 
tfca of Ibe MMM whicb datamuDM Ui« fonu of t)ii« viirTatur« l« 

CTBlian «f UM enrvBtara M UqntiX aortkccdi In oanlaM 

TIm- fona gf the aorfacn of n liquid in contiii.-t with a«ulid 
•ID tbe irlalion betwe«in Uie Bttriu:lion of the Bulid for the 
of tfafi niulual attraction bctwaan the d)ci](h:uIcii of the liijujd. 
|b« a liquiil mutrciile i&g. 01) in cnnUtct with a»ulid. Thia 
m actMl afOB bj thnw Iqikim: by gravity, which aiiracta it in 
of tba vertical mP; by the attraction of the liquid P, 



oai uitfitf- 

wbieb net* ta tho dinccioa ia¥\ tad by th* ittartioB of tb* 
wlik-li u ex«-rt«d in tk« dbectloa mm. AccMdia; lo ibe nUtiif i 
•ilic* of iImw fonn, Uieir nnltaat em lake thnc poriti'i* :—■ 

I The rMullsBt ia b Ike direction at Ute *«tlMl mU (Sf. Hl> 
Uiit coK till.- lurfikce n U plnno nnd bonMitlal ; (or, boat tlu < 



.— '- 

F>g. 81. 

Fig. BS. 

of ihf oquilibriiim nf liquidn, ihn lurface muM be papendii 
furce wliii'b xia upou tbl^ uioK-vules, 

ii. Jf tlir loKt n inriviuca nr V dimiiiishni, th« rmuttaot It ill 
lliH wifU- ""'I' (lig. ^^) : in ihia case llio eurGice lake* a i 
prndioulai t» tntt, luid bt«oina* concave. 

ill If tbo tmrt F iiicf»uw,or ■• diinini«he«>, Uie RBultant Bl 
tb<- ditvelicii nil! <%. fVi) wlrhb the &ugl« IViF. and tbo 
cominif iMfijiMKlictiliir (u tliis dlnrtioD U canTrx. 

Fig. 8i. 

U7. lafluence of tb« corrattira on capillary pbanai 

Th« elC'Vniicin >ir iltpnuoiuu of a liquid in a capillaiv lube dc 
tlie couroTity or i-rinvf xilj of the meniMMiB. lu a concara 
abed (fig, tvl), the liquid ujoteciiles iinj Bunlninpd in Ptjiiitlbriii 
IbroM aciing t>n thorn, luid thnj nn^n^jiKt no downward pivasure on tlu 
fmor lavL-n, On the I'untmr^, in vtrluv uf tbu molecular ■ttfaction, I 
net on tliv uuBKst infi-'riur U^iini, t'cvtn which it i'liilonn that ilio fnm 
OB any IflT^r, nm, in th» itituriciT nf Ui« tiibfi, i« Im* than if ihm i 
na iu«uliicuB. Tbp i'onwqiit<UL'i: is, [hut tho licjidd uii)thl Id roa is 
tub« until tbn int^rnnl ptviBuro oti thi: liiyi'r. »u>,tt isjiial lo the prHt 
lyt, wbiub »i.'t« vitemaUy on a poiul, p, of tlm taioi.' kjcr. 


Ot» nuAuaco* ia cdiiti^x (,fig. 85) equiUbrium exota in rirtm 
fcculw foroei actintr aa Uia tiquid ; but m tlw bioIwmiIm wkich 
ii|ir the rjmcv yUt, If Uicro wara no molccnUr actiuo, do not 
r neivu^ nu ■liractaan on the lower t«7cn. OMinqtitaitljr th* 
n mj I^wr na. Id the ia(«rior of ilie lube, la greaUr than if 
flta m*tn fiUod, for tbc moltfuUr forcM w aum pavecful 
hj. Tbe liquid (Htgkt, tlMmfoM, to aiak m tW tube until Uic 
lOMinB «a a layer, mm, ia equ*l to Uk ext«nutl pmuun ou uijr 


M7 iif upilUritjr, one of ihe mtxi diflicult in pbysix'*, ran only 
I eOBipltitrly by nutbcDiaticill analyaia. It baa vugii|ji!d ihi* 
tt the tBoM cntiimit mMbanaticianii, partirulnrly (IlaiiNut, 
MdPOMKia. Aawa bave «MB, the tlimry (U'LOviiitsf'ir tbeeleva- 
UjiiiMJii* of liqBid* not omljr in tubes, but iil*a between paraUcJ 
mI pIntM. It b1«o MpUia* ike alIni>.'tii)iM and KpuUion* ob- 
hvMD flMtini; bodif-i. 

Ul«*« aBptUatT ptunaaaenn. — TH* following foct* an 
> iBanv whicb am csutad bjr caplUarity :— 
» eapillaiy tubn ia inuoMtcd in a lipoid which moiatcn* it, and 
Bdnliy icmoTed, ifae column of liquid iu lh« tub« ia seen to 
' tkan wkila tlie tube waa immoncd in the liquid. Tbia aristv 
bet lliUa ititf adbena to the tower extremitj of IImi tube, and 
nnf« mMibcu*, which ooucuni with that of tbe upper meuin/uii 

• anna reaaon a lH(utd duw not oTcrllow in n capillnrj' lube, 

kllw latter may bo ^hortrr than tho liiiuid coiiinin whicii would 

■ b* fovnwd in It. Fur when the liquid KBubrjs tbr bip uf tha 

ppiwr wrfaer, tbonith prerioud}* ccmcavo, bcciimcA (^nnrex, and, 

wnwaid prMinre b«coaee gT«at«r than If the aurraw w«ii« plane, 

iing mutioa otaao*. 

can oftni) mot* mi tho nirface of water without linking. Thin 
ny fbeoMikanou ca ua o d ky the fact, that a« their feet ate nut 
! ^ watar, a deprcanw in produced which b««p* tbmn up in 
'%lit. Similarly a aeiHog D««dl« g«nlly pLic«d un walur, 
Uk, bacaaae its ■iirfaim, being oovercd with nn oily Ujvr, dona 
M watted. Ihil tf wmhad in iJcohol, or in potuah, it at ooce 


uta rapilUtitr tha Mp tu<« in ptftnta, that i»l aacwda in the 
■miB, thai water ritoa lu wiMd, tpouge, Ubuloua paper, >ugar, 
in all bodiM whiiih poawm poroi of a parcaplibla nut. 
nut aedion. nnder the bead* of endMniuee. at^orpticn, and 
f WB ahall booame acquainted with umc uew plioiumiutui wlik-b 
c^iUarity, and an> often coafounded with it. 


ox Liqinne. 

BSiHMiioKi, xrmiioN, ABsosmour, axdimmiiitim. 

I'iO. Satfoamoko KBtf aa»sDi»BO. — \\'bea two dtObitM | 

arc arpimtol bv ■ tliia {intntu paitili.m, •'iihi>r io<)t^«ni« or offi 
funviit MiU in tmm «*ch liqoid tu the othvr : to thwc mmo 
jaaatatrntUumoteaiii Momnaieurttmparu\e\y giv<qi. Tbew teniu, 
ligtAfy intptttt /rvm inilhm.tndimimlM/riimiril^onl, wM«tinliiitti 
bjr M. Dutruchnt, who lint lirvv uttpQliiin to thaw phNionmt. 
■im; bo well illuHliatud hy niruiii of thti mil/tmnoiiifltr. Tlui COH 
K long tube, at the nod of wklch a meiubriuious hug u finolf 
(Sj!. t^l). Th» bAg ij> then tiUcd with r i^tmnt; »vriip, or lOBa 
solution d(in>c-r thuii wuiirr, Kuch ns milk or AlbumvD, and in vaaam 
vatvr. The ill II id Ih found hTudunlly to rim! in ihei iiib«, tOti 
which mny nttiiiu Nttvcr&l inchca: nt the sniuv tiinf, the Icnl' 
liquid In whirh th<.^ oiidoaiii->uii-l«r in ioimcrFfd hcrntuM lam 
follawn, therefore, that »oni4 of the dXtTiiid liquid hu poned t 
tl)« iwinbrMir uid hwi inixvil wiili ilia intL-mal liquid. Thi>a 

liquid moreorer is found In I 
tome of the inlenial liquid, 
two curr«nt« have heaa ptodu 
oppuait« dircotion*. 1'ho Bow 
liquid tnunn)* that wlikb fa 
iu voluiiiT^ ill cniia4tni>ar, and IIm 
in thn oppniilc dirrctiDD U M 
If wak'i h plni'ed iu Ibc htf, ■ 
meneil in fj'i'iip, I'lido^moM I 
duc*:<d fruii) the WHiFr tuinu 
svrii p, and thv liquid in th« intorii 
niches iu volume while tli« level 
extprioir i« raiiicd. 

The height of the «»ceat in 
dcwnicimeterviuiva wttlidiJIcrait 
or nil vogisubln 8iib«taiicM. I 
thai wliith. (ur tJie mum dew 
til-' pitiftti'sl pownr of rad««ni<Mi 
nlbiiiiivu bH8 lh(^ hijibnt powe 
sniuinl eubslanrrn. In general, 
bu said 1h«t endcwiDOM tako 
towards the denior liquid. 
Mud ether form on exception 
they behave like liigutda wk 
With iciiJ*, accordinn m they an mott 

Pis:. *« 
deiuer thu wat«r. 




ibn endontOMeia from tbe viil«rtawudBlbe«eid, or fruin the add 

liag tn Dulr<M-h-t, it b BtCMury [or thf production of m,iat~ 
: i tiwt tile Ui]uid9 ba iGlTerent but cnpibln of niixiDg, m ulcuhn) 
, mtrr; llcrr U no *ndotimM», Cir inMAHiw, vrilh water nnd oil ; 
tW lK|ai(U Iw of dlflKrent deniitici ; oad iii. that the meiabmnB 
b« ptnorabl" tn at li-juton^ oj'the SuVtaocM- 
tsRcat thruufrh iliin i&oi^anic pUt«a w belate, but eontinuouf, 
■I^HW DMBibnaH) OM npidlj* docoinpawil, nnd eodosmoM then 

I wdl>lcBowB biet that diluta alcohol knpt in a poroiu v««mI 
< eootcatntml, d«p«iKl« Od «<iili>8i>i<n«. If » mixture of &Lcohol 
tWMsr W kept fur mtaiv tiiaa in a, blnild^r, the voIudir diminii^R*, 
' it (mcooim miicb yijim comccDirated. Th« niM<jn, duubil«<«, i% 
idui bbrdilet pennita the eiidoamoM ot wfttoc nlhct th>»i tbnt of 

**4 ncllMd i» Dot adapted for quaitlilalive mpnsuri'tuppta, fur 

I not take into aeoount thr hjdrontiitii: pri'nUTn proHumd b^ the 

JoWj liKJi pianiinf«i llie findoctuoau i<t Vftrlous liquids by 

binit the bodin dift'ujwd, Ili> mUn thi^ rndttsmoiic afmealrnl uf H 

thp Duwhnr vcbirh pipnuu'* h<tw ninnv parlii bv wi>i|;hi of 

> ibrougfa lli# bladder in virhau^ f i one part by wn^;bl <.•( 

HBbMaaoii Tbo following are mdw of the nndoiinotic cquiralmti 

I be dewnulncd : — 

C«u*tie potaw . . 31S-0 

Sulphnric acid . 0'4 

Alcohol .... 4-3 

I oT fodittni 
I of Biagtwatuin . 




> alnfonail that Uie<f)doanaoliceiiiural<qit incrwwA* vUh ilie t^mpera- 
■ ; aad that tho quantiliRa of ■ubatauuiu which para tu pqual timoi 

fb tba bUddor ara ftoponioDal to tbv- itn-ngth ol' tbn »>)utinn. 

IV). BiftMlaa ttf ll««l4at — If oil \» p»iu«d on water no t»Dd«noj to 

IL !• otMVTod, and cfvn if the two liquids bo viultntiy nRitahsl 

aa allowtn); them to *taail, two Mrpaml" lajor* ar« formed. 

I alMlral and water iba ca*n it dlSiirvnt : if alcuhul, which in «peri- 

' ligbta, be poured upoa wat«t, the liijuid* (^dually intormix, they 

I ialn oiui aaatber. 

law* of Ihia difluMnn, in which no patoui iliaphra^iu iutvrvenM, 
bwo ratDpletely inmli^al**) by Otaliain. The mdlhod. by which 
Ik Utmt uxpArinwmta worn madr, waa the following, In a glaM tmmI 
titjinmy Bln>ul TOO nibic Mutimetnui nf dialilltd water, about 100 cubic 
oMifaatraa of thv lolotiiin to be exaaiinMl wh« car«fiilly added by m«an« 


OX LtqinM. 

of R (upiliniy tnW, ao u to Form « lajar on the bottom. Aitt* ■ 
inivrvo] of iitu>'. ^iir^pimTo ta}vn wok okAiUj dnwn off ^ » ^ 
Rod thoir caiitMitfl examinud. 

The gfMiirnl i^m\U <■( thtud inT««tig8tiaii* may bf> thai ataui : 

i. ^^'hlrn 9>.>1iilio[i> i>f llj'.- <nuie nulMtnnco, but of diflcrcatilmiilth^ 
takpii. tlin qunatilW iliifmnd in oqunl iiinn> ue proportioMl H 
Rtn>u)rtlin of thi^ snliilion"- 

ii. In liu' cniie of Knlutioni contiunins «)iu1 wripfatii of diBsnnt d 
HiiDOM, tlie qiiantilipa diffumi Ttirr wilh (he MtUK of llis MlbtMH 
Sftltnc ■ulwtADccii may \>v ilividM iuto n niunWr of efmdiffiuiiir fiw^ 
the wtm of ilitTu'ioiii of rach tr^up l>«in^ mnnncled with llie f>Ilitni 1] 
nmpte numeric*! kIbiIod. 

iii. Th* quantity difTujiuil vnrint with tht^ tcmpnnttum. Thiw tdi 
thu rftiv of diirii'ion of hvdmfthloric Bcid at IS' C. aa uoity ; >t -tS^C 
i* 21 S. ' 

i». If two "iihulnnc^' whii'h do mit rnmbitip bo tnixed in mltti 
they inaj' )ni psrliHllv oe]iArat«d hv dilTii^ion, tli<i tnora dtlTiMiTa i 
ptwinii nut moat mpldlT. In ■ome Comm thnniul dnyimpoaqtMB • 
maybaeOactml b; diffiinitin. TliuabinntphAtoof potiwnumudeeaaff 
into free eulpliuric acid and 8ulpbnt» of potaMJiini. '1 

T. If liquids b» diltitensutislAnoo will difl'iaie into water, contuilli^ 
otli«ir auh*tiu]ri> dimrilvcd iu> into pure wntnr ; but the rat* ie 
nxluond if a pirtiuD i>( ihu dilluAtii^ tulMttiuM b« alnndr praaMit. 

Tb« follovrinijr tabic gtri's the npproximnt'i timpii of vqaal dll 

llydinrliloric acid . I'D Sulphate of magRMium 

Chloride of sodium S'8 Albumen , 

Sugar .... 7-0 CanaruH . 

It will bv svKU fr<)iii thi! abuve tablL- that the diHnrnnon 
ral«# of diffusion i* vnrv prat, 'rhtis oiitpliRtn of niagnminni, i 
tnrutdiffuiiibleaallDeaubstAiicps, dilTuflMsevi-D timet unipidlyui 
and 14 timca aa rapidly an coramul. Thiw^ Irut lubatanciM, like 1 
liUcii^ arid, ■taivh, dexlrino, gum, ntc, con*\ite a class of «uhit8i 
which are thanicl*ri*i>d by tliuir incupacity for Ukinf^ lb« crratnl 
form, and by the mupilapnoui phnmirtcr of thnir hydrnlM, C'lniidp 
flt^lBtinL■ a^ tlieljpe nftlii" elasa, ftrshani ba8pKipoiwd)ocall them ml 
(aoAAq, gtiKi), ill coulraiiiHliiictiou to the fur nioir ca«iir difltai 
vrj/glallvul «ul>*tnnc™. 

Graham hux propiiafd a m^lhod of noparalin^ bfidiea bawd on I 
uiieqiihl diiTiiaibility, which hn trftlU fAWi/jii*!. Ilii diaJiirrr CMMKtU 
nag of guua pr^rchaover which ia titrvlchwl while wet a alieet of pn 
m«nt pp<'r, foriuin^' thus a vu^ael about two inchm high and 
laches in dianielor, the bnttom of which i> of parrbmcnt paper. A 




in tliA siiMil tolaticm tn 1m dUlvKd, lli« whole is fUwted era « 

«l ronuinin^ « \rrr \u^ quuititT of vaW. In thn eourw i>f one 

I dan * muiv or Itm eoniplM* iwpiknitinu will faA>« Iimd eflnettd. 

I mlntiMt of u«nio«« acid mlz«<l with variinu kiaiU of fnod r*iidily 

be |iriM-MM ha* TKoivH luporlant applicatioM to lalxirauin' anil jiliar- 
>dcal pHrpoKi^ 

» fnrtbtr inninnatino od tfaU iiabj«cl thn ■iiid^'iit i* ivf>>Tri>d lu a 
mcnplplii Hnicli* on Ihu ilifltuioD of liquiiis in iha tbinl votiim« 
f*a'it IHrtiemur of (Th^wbtr^. 
ISI. BaAaamvaa ar ■>■••. — The plMnom^Da of vndotniom an M«a 
lii(rh drffTPe in Ihc cmr of puioi. When two diflctvat ga»m ■(» 
it«d br a pnnxM dinpliragin. tui cxrliang* ukM plntv bnta-rr:!! 
, bihI ullimaulr the ooinfosilioii of the jraa un both aidwi of tliH 
ia tlxi Mmn; bnt thp npidJty with whi^h dilTfrrat fliMnn 
lato «ach other undnr tlirac cinrumvUncea TBriM t'onsiderablr. 
I Uwa rp]rulMinif tbiji phnooin<nnn bAT« hot>n inTtmtigntcdbjrUraliain. 
HI* exp«risenU Uliutmte it, two of the moat inun^sling; of which 
) tbe foUoirinff :— 

L «laM rrlinii«r tk*«A at «n» end is Hll<<d with rarboiiir ariil ffiui. iln 
«Md tlnl ornr with a bbtdder, ntid the wholr> placed iiud^r a jar 

^V• s:. 


<l hjdrogen. Diflbrinn talwa place between them through tlm piirouii 
£aplinr»- ■'■'' *1*)~ the lapae of a OoitHin time hjdTOffeti tim pwund 
tllrna^rh tlMi bladdiv into tha cjlindrics] tewal in raaeh Krcnti^r qiiaiititv 
than tk> rartiucitc acid which ban pa»ed out. *o that tha lilodder ix-coiiipa 
trrr much diilnadnd oulwardi ififf. ft"). If the cirliudur ho iUIpiI with 
ii' i.'cm "id tbe bell-jar with caitMnic sci<l, tlio r«r«r» phenonietrm 
will lie produced— thn bladder will be dialnidfJ iiiwarr<« (H^. hK). 

A tithe about 13 iarhee long, cloaed at on>i (uid bv a jjIu;; of dry planter 
at ram, i« Hticd with 6ij kj'dnifcca, nail ite open rml llicn iiiiitier>'ed in 
a iMimT faKtlt. KndinnuMof ^ bjrdrogeD tawurdu tin- ait Ukm plncu 


OK LI4Vtm. 


_M lapjdlr ibat a partial nmum i* pToducnl aod niCTCiit^ iW a 
ube to ■ bcifclil of ivTnnl inchn* (1^. IW). If mivm*! lacb tnW 
■liUcd with dilfpreat piuM, and Allowed to dilTiiMr into llie *.» b >> >!' 
IDBiilwr, b the wnc timn, diiTKrcnt qiiantiliva of tbo vorioiu .- 

diffuw, (itiil nnthnni fiiiind thtX thi> Law rv^-u. 
lIivM diffiuiituH in, that lie /iirrr of Jift 
inrti-fh/ iti f Ar nj/mfr roofi oftkt dmmtin «^, 
TIiiw, ir two t(<8mU of «qual npscilv, raa 
oxxf^a and livdnij^pii, bi> iwpanitF<l by > 
plug, (lilTutinn tftkoi plitro, nnd »iXeT th' 
loiii? timu, fiir vvvry uutt part of okV|;ui «1 
piuMid into thf bjdmgnn, fniir pnrl« of h 
liiiiv jift^Heid into the oxvg«ia. Now iko 
hydroKi'D bdaf; 1. that o\ oxyi^cn ii 1(1, 
the forc« of dilTuiilciii is inri>r«e1r ns thn 
tmota of thwe nuuibun. It ii four tiaiM ■» 
iu tho OUR wiiicli liiw iV thn d«airit7 of A« 
y.VI. SnulonandTraaaptrBUOBAr 
^'ig' 8". Effiiiioii i» Ihc t-rrm ajiplipii to thn phdii 

of tbf piL««)t^>> of ganv* into vhl-uudi, 
miQUt« Bpnrtiim not iniich niont oi Uva tbnn 0-01.^ tnillimeter i 
iIiiM4r, in n thin plfll" of iiiota] or of tilnu. Within tlii* limit* of 
parimL-ntjil i^rToni, thu ntcn of elTiuiou ut' diltcreut gaaw oobcidc 
tkotw of thirir difftudon. 

If, howi^iiT, the i^Bws iMue tlirongrh long, fine capitlfiry lubwi 
TMiium, tlio r«ln of effluy, or the reloril^ of trmv^iiraliim, i> bde| 
of \\w rail' of ditTiuiiuii. 

i. /'(T Ihr lamr i/ai, the rate of lranj<piralion merratn, nthtr IktMfl 
r^/val, lUriK-ll'j an thr prtiinaifn i thnt in, ixjiisl ToluniM of air of dilTHtol 
dcnnilivM rvquiri! tiincji inipm-1y prLiportioDal to thelf duueiriM. 

ii. WUIitiihri iif n/Hiil iHnmrffrit, thr voliinu tnoupired in t^uat UvM' 
in mivraely iii Ihc lrt\glh vf Ihc htlir. 

ill. At the trmprratnrii rur^ tttr traittyirtitum Lpcvmca ji/ynTr. 
IT. TTin rtitf iif I nm'pinitiim u imlrimiilrul of the nuitrrial af the tot*. 
13.t. AlMorpUon and lmblbltl»B.— Tbi^ words abttorpliun and 
bibitlon nro iituiii Alnxut pioniiieuuutly in pbyaira; they iodicate tin 
peoetmlion of a lii{uid ur u iriw iTiti> a pniMim bndy, AbwiTplion in u»i 
both for Ii(|uid>i nud |^<-f, whilf imbibition is n-slricti'd to liquids. 

In pliyiiiolo^y lUi iniportsnt ili'linclion i* nindn biilwrrn 1h« twowonb: 
Hboorption uieanfi ibi- peiiclratiun of u foivi^u nubatiuici.' iulo thn tiuMM 
of ■ livin(( body, while irabibitiim rcfc™ lo pniinlration intn b'.iditw di- 
pri*od of Iif', whctlii-r orguiiic or mil, 

194. AHaorptloB of >>■•■■— Thu aurfures of ull solid bodin* ei«ft 



'vm tm Hw hioIbcuIpa of gmM with vlAxb tlwy «re in conittet, 
nattir«, tb&l iliojr bv<xune covered witli a moro or I«m tbidc 
Milaurrfyaa. Wbcn a ponHW body, whirh coOMiiUL-ollypmwnU 
m1]> ia m—w d wirTMO Ja propurlioai to ita liio, in |iljc#il in a gan 
UT tba (n«*t diminution of vntiuii* wbich Mi»iie« iiidiiiitM t^at 
it quanliliM nf giu are aWrbedi 

hbnuifh tlwra ia na abMrption (uch a« ariHi* frnni cht-micol 
IM bvtwora tlH> fittld mud jnt (as •riUi pbuspbunw and 
lUl the (jtuuitilv L'f LiLH iib«orb«iI iJi not entfawlir drponiinnt on llie 
nuUrioiu of tbi- ailid h:-dy; it i« infliMoiced in moie uiiMUure by 
^ BatUN botliof (li0Bolidaud tJivgaB, Of allbudii-v baxwnoil 
IM llie gnatMt aloorplite paver. Ouc Tolunin of tliiti sub- 
tile onliiuu7 tMnpvraliira uid prMtun atnorlis ihv foUuwin^ 
«f gia>- 

80 ToL Corbonic oxid* . 9-4 voL 

nkadd as „ Oxv^vti . frS „ 

* „ . 66 „ NiUogen . '"* « 

bfd b^drofn AS „ Hvdro^n . l-7fi „ 
lad . . S& „ 

loqitire power of pjan cliaTcooJ in lialf ad much aj that of 
Tbe cbarcoal maili' fiMiu parkwood, which in Tfa^ porous, ia 
>tn(i aeitli-=r ia grapbili^. PIhIuiiiui, i[i tlic liuvljr tliridcd 
v «i plnliaum «pon^, 1* wid la abaorb £50 tinm ita Tolume 
gw. Mauv otlief ^tons subatnucM, *ucli oa Tu««noh&um, 
Ik, ntc., aM aUn bigbly nhaorbent 

>a«rptl*a loplaiita. — Abmrption tab*« plac« in all parta of 
Uil lai'iv <ap«-inll,v in tho roullela and by the IcAroa. Them 
ath, in llii> fonu of wator, carbonic acid, and anunonia, tli« 
djoem. («iban, aiiil nitrogon nemaMr}' for lh>* gruirih of tho 

•nd tbu aall9 which they hold in solntion. ani abAorbcd by 
I, by n douhli- pirocna of cnpillirity and oDdosmuw. Tbo lap, 
len slaborMod i>v ibn plant, incrMuLn^ in denaity tnwanta lli« 
;, AWM tU Mceniliii)! direciiciu to UDdauuoM^ Thu a«cvDt of 
aba pmnotod by tl» vacuum which the exhalitiomi tiirougb 
ktod to pradii««. Capillary action c&n only raiio tho li((iud in 
iiO> ; it nuinut pmliwe a curreot 

•a«*tt«n la utmala.— In the 1i>w»r anitnab whoto ti«uei 
only of onUtilta, Dutritino id aocuiupli«hed an in ptnnta b; ab- 
1 (stdiMiaom. 1'lwt aheorption by which aoms of tliuae auiintila 
rf in in ri^uJity uuloKUMe. 

Hoimabi alM kbaarptioB m mot with. Madder ad- 
r t 

nm-wUd tkei 
me, botk wUd mi 


fuhahMvtnd. All 
in mdet to be 
t, an not abKntiad. 
e into an emoUoai 
iM. And Dt. Lim i 
I into an emalaka,) 
HD ita being moie i 

at, and alao bj JcfMaLJ 




OH 6A8B8. 

ntnritKTiM OP •ms. anospiiEaE. n«nniir.Ti>R«. 

!•• MM in * eOBtUat aUt« o^ Kpulidun, in vtrtui! nf which diey 
lh» moalperfwrt mntiili^, And art coniiaiuill} IviiJiii^- lo uccupv 
ir apWOL TluB ptOfeny oT gUia U koowti by tin.' namno rjjuan- 
/mmwh, or rladic forte, from which tli^t- nr« ofl«n called rfottie 

> and liquiiU bare M-viTal propitrtwi in cnmmnn, aod wiiie in 
ihej BMU to diflpr aro la rvalily oal^ dUTMeiit tlrj^n;!!* of thn 

pnipanjr. Tliuis in buUi, Ui« pnrtidM ■ra capable of moring; in 

piiw&Mlyi in liqnidii not quitnCr«cly,aviti^t4>a certain degree of 

If. Both am oompnaaibl*, tliouf h lit ver; diflen-Dt ikgm;* ; if a 

I and ■ ([a* boili axut nndor a pTcamue ofooa atmnaphpiv, and IImb 

fwaai ttv 1m douMad, tb« wai»r i« conpraiMd by abitut th« ^j^jj 

, wUla tjie gu ii coaipraBni bjr inie lialt. In itcoRtv thprn in a frmat 

wat«T, which la ihe iv)xi of liquids, ii> about 800 timpa oa 

Uw type of ffoMoiu IwdiM, whil-o undut a prmnutu nf ono 

The prop«rty by whicii gaiuii arp ditniiiKiiitlioil ftuiu liriiiida 

■cj to inil(fliult« expaiulon. 

ttio •olid, liijuid.aritiiMnui form aocnnlinK tn the iwln- 

of tliA OohuMTe Bad rrpulMTfi forwi" iTH--n«d b*iw*^n thsir 

In lUjuida tli««a fcwom balance ; in gaoH rep uUioii pn-pumJo- 

of preaaniTO auJ of T^ry L>w frmp^niiuipa, ihn forci" of 

' ba M) far incnraacd in iiuuiy fjaaM that th«y are convened 

, aod there ia evcvjr Ka»«n for bnlicria),' tlint with mtUL-ii^nt 

> Uld cold tliDT DUKht all be U<|ii«Gt>il. On tht* other hand, lienl, 
the foTW <jf repul*ion, converts lii)uid», »iicii m wa(»r, 

, and rthwr, intv tbo wnfunn «I»l« in which they olwy all ihe 


Rx cum. 

laws ot gMM Tkis a^rifcni 8l«t« o( liquid* i> hnoam In- tlie i 
MyoNT, whiJu gVSGd uw bodW nliicb, undur orduiary t«in]iMB>iuc t 
prtMBK, iMnaia in Uu> onrifoirRi slaio. 

Id dcAcriUaf tke propMrtlnt of gaatm we ihftll, fcv nbrioiuKuMna. I 
sxelumvi' rcfptvncw lo ntiu<»pb«^c «ir a* thnir trpoL 

138. szpaajiiiiitity «r KkM«. — Tiiib propenj of gMM, !-'< - <'" 
dencj to •Mumti cuntiimallr ■ RTviitcr raliuue, u pxlubilml Iry im ii.' i 
tb« bnowing expvrinieut. A bl»dd«r doMid hj ■ «Uip>cock unl ■.i-Mj 
kalf full of ail is placed undsr llie nceiicr of tlie &ir puinp (fi|t-t 

ami B vacuum in pr(iduMd,oa wk 
bladder imuit^tatety dliMndli 
arisiM tram the fact that 1L« 
of nir i«pel «ach other and prnw i 
the «i<l«« ot tbe bladder. Under i 
tmrf conditioiM thui internal i 
ommUorbalaDMd tiv tli« air in ih»i 
«dT«r, wbicli exBiU an ucjuat aai i 
trATY prrjviiirf. But whitn Ihia ] 
ill ivwiiwil by exhauBiiiig tbH 
till- internal jiriMuro b«»m<« et 
When tut i« Hrlmitivil iiii<.> tbo i 
till! bladder rtwuoius :(■ oripiiuU (nflk*^ 

lao. OomprmlbUltx «f i 
The Fuinpi'r-i^ibLlity '>!' jrwca il 
dilj iihnwn by the pn^rmalie ajr 
(lit;. 91). Tlua DuninaU of ■ rtaul | 
tub» elnsad at nni' rnd, aiii] 
■irilli ■ tigrbt-Ultitig »olid i>lsIon. 
th* Tod of (ha pi#lon it preswd, it muviu dowu iu tiu- tube, and i 
becomes compreeeed intu a maaUer Tolume ; bin, a* Minn a« ibe foi 


Fig. W. 

Tig. 91. 

f tha air regaina 1u original volume, and tho piMtoo me« lo it* 






140. TVolBbi cr *■••••— Kr°*)i ibcir nUmuio fluiditr utd expu- 
tlj, e»»n tin-m i" tm luiiiillu'Wifal by tbc force of (tnkvity: ih*; 
cLoa pMiM irriphl, likvKiliiUaiHltiqtiidi. To allow tlits agtsH 
•.^SarA quonn uip.t>-ilT u tiil:i'n (fig. It^), tlwi nfd of wkkb in 
I «iUi M slopcuck, mlikli )>«niiPtii*Bllv clotm it. 
1 br « hirb it cui bfl ponicnd lu iiii> plair iif Um iut 
Thp (ilube b tben extu>iMt«l, soil ib wpi^^t 
1 lij BMABti of « Hdkate IwUnc*. Air in miir 
in enter, and tha globe •gBtn ireiglcd. The 
III in lb* nMtnid ck*ft will bo faund to bo ftiMipr 
I bi£M«, and if tke capBcii; of tlii: rMwl !• kvowD, 
• will obriou*^ bs tbe weight of that nlotne 

« nodiScKtMn of tm* nutlial, anil iriili tin adop- 
df Mmfn praraalkrtM, tbfi wtijihtflrairaiidof Mhor 
bat hwn di.-l«nBilw4: 10(1 mbic iQcb^H uf iln aii 
Ui« onliiuir^ atiKwphcrie prcBura nf 30 in. ancl 
•t tbe trttperature ol IC C, wnnh 31 gninat tiM wue 
VBIiuu* of mbiiDK; acid fa noder the aanM etmitu* 
'IkMM weiflw 47-33 ^nuiu ; lOOciibio iiMlw* of hjdro- 
|PB,Uir liltblxcttrf all irsMm, Weigh 2-14 ;nMiw;aiid 100 
nhic inebM of liTdriodic acid iraa weigh I-Utgrains. 
tW trnHa nt Uie d«4i«ilj ot air at (f C. and .10 iucbn 
iiire In that of watrr at O" V. U (bund to b» aOOlSOU, In other 
I, thr latli-r ii' 771 timrM lui hoovf M tlw former. 

Vr«aMu«a eaert«4 br Kb<m*> — Oaasa exert on thmr own niole- 
■nd on iho aidca of ve««l* which contuia tliMu, pmuurH which 
U (tiiwUmI Ijimb two points of view. Fint, no may iK-^tMi Uic 
it uf the ^ ; aotniMDjr, we tnav tnkn accaiint of ila weight. If wx 
Kglrct tlie weight «f u}' gMM<i» man at red, anil nnly coimder 
b H^i*lve loiw^ it will be wen that the ffmarim Auv to tbii fotra act 
*ltli ilir_ Minn Lil«iMlr on all polvta, both of ibe inM itMif «id of lb>* 
■••■I iu wbir.h il in cuDUliii-d. Fur it u a oKamtLry MOatqueEOM of tbe 
ilwlkitj asd perfect flaiditT of kimw, that th« rc|tiitsiT« fuiea between 
Um ■iiiIw 111* ia tfap HUBp at all jiuiuU, aud acls o^unll; in all direcliona, 
Tbi* principlr nf tl» tquility of the prewnra of ftM» la all dirrctioiu 
BM]' be BhowD eipcrinii^tally by nicwia of nn appanitua tcwmblintr that 
b; wbieb tb« MUne ptioidple w deanonaliatcd for liquid* (flg. 41)). 

If we canoider ibp weight of anj gai we «Im1I rm ibal il giim riie to 
|i— eiin which ober the wnie hiwi na Ihow pnnlufed br the weight of 
U^aidi. Iict ua liuiigin* a cylinder, with iu aii* itirttcnl, MTeral luilo* 
higb, ekaed at both nidi and full of air. Lui lu touiiidor an; unall 
pMTtiM ot tha air axlawd between two boriMmtal piano. Tbia portion 




KM( wataifl tfc* «ieij(ht •( all Ika air afcoi 
fa) tlw ife bncMk it, tni HkMiH »ikt 

wUefc wtwwi hi tmiMtaA psiat n adu«ctitw ju -lyht Tay^ |ftl| 
■uCmc Tkn tW | »i>»m » OMtwMM (raa ibe top of tba eolani t 
baa ; at aor (i*m larer. It m eqaallr oa aiaal au&cM, «nl K | 
aaglM In iImbi, «Attb«r titer an horiaB t al, vvnlnl. or iaelioad. 
pwiiBw acta m tlM «U«« of ifce vMad, as4 un ut «nal1 cw&m i 
«%mI to tJM wviflit of a mI«bb of gm, wbow 1mm u tbU mrtMt, j 
wkow bn^ in 4iitaiMe ban tba ramBit of tb« oolntno. Tbe i 
iaatotadiywilwitof liwliapeaadJiiBcnaicMof thawippottdt 
prntUad the bcigla nnttM lk» mud*. 

Fnv a saaD tpaati^ </ fH the p ma wM due to ita wvigkt an I 
iwJgaHrant. aad nuf W ap|il*ct«d ; bat for Ur^ qiiantiti«*, 
■*™"f''" , till! pwM TW atv cowadMaUe, aad muU bn aPoiPad I 

le. «h« ataaa— fct>«. na a— paiMiaa.— Tho atnovphan li 
Uirr of lir irliM mtTooBda on ^loba is vrwtj part It paiialna i 
rotatorr nMtMR of Ike globe, aad fNNtU t«Miaiii Uxed nilii()Tvlj^ ta \ 
trial ol^Mta. b«t for local dnanrtaiKa*, vhidi produoa windu, i 
eoiiMaaitl; diMBrbtng iti pqnilibrisBn. 

Air WM r*xaniod hy iha aadtntii a« on* fd th* fonr «lcnM-nt«i 
[idiMiuatiT, bow«i«r, ba* abown tbat It la a mixtim of oxyRvn asd I 

Igaatain tb« proportioii ofSO'S rolnnea of tba fbnnrrtorO-2i 
' of tb* t*tt«T. Ry woiiibt itMMUtiof SSpaitnof ox]rg«a to 77 


Tb« atmoapban alao contMn* a rjuantttr of aiiufioiM raponr, 

< witb tbe tenptntHK, ibe aMton, tbe locatitv. and tbo d)r»ctMi<if | 
' wind*, ll r»rtbor contam* a >inall ijoastitj of knuiMniaoal gmi, aad 1 
iiin 3 lA pnrU in 10,000 of ita Tolanie of carbonic acid. 
Tbc auhaaic arid ariara fnim tli« mpiratioa afaninuU, froa tli* pi»- 
^CMM* of comliiMtjrin, anil Ctoia Ibn docompnution of ot;^aiiic aabitJUieM. 
M. Boauo^BuIl hoji tniimat^ that in Paita Uw fotlmring <|iiaiitiiiei nf 
ntrWiir acid urn (iroduncd cvnrr 24 houn ; 

Itv thf pi)|iiilntii)n naA by nointaU 1 l,AnS,O0O cubic faot 

Bt pTMcaaea or coinbiisiion . . . 02,101,000 „ 

1O3AXW.0O0 „ 

NotwitlisUnding this ennrtooiH nmtiniial pruductioii of carbonic add 
on the lurfaott of thu filobv, thu i-oinpiMttioa of tb« aliin*pb«i« doM nut 
rat^ : for plnntu in llio pnicnu of Tv^otalion decompoM the carbooic 
acid, aMiTiiiUliii^ ill'- ■.-■rbi)[i, aud reatovUi; to tbo atinosph<<ri> tli» osTgMI 
whinh U bcinj; cuniinuallj* i-aiuauiD«d in tbo pmrcanrn uf rMpimtion tai 

14S. Atmoaptiertc preantre.— If ire ne^lw^ tbp perturbatioiw U 

TRE AmMpnutE. 


I the Umuefhttr i» Mibjcct, u htiatf iDcoiuidcnble. we nw; ronadpr 
I ■ tind «« oft MTtabi depth, MinnaiMling tke xanh on aU adtw, and 
r til'* MOW p w uit M if it wne a liquid of tery xnall deoMn. 
itlr the jimutnt od the nnttofanai* cntuunt >t • p«vnl«T<>L, 
; Hiiul to tbm wugbt nT the eolmna of •Uncaplxve nbore ihat level 
r kuht:OaUl eectioci U the imll of uu. It will act «t riglit mglaB 
h'Aa ^wfiwB. wlMitcTCT be it> pontiiin. It will diminiah u ire memi, 
1 tetwew M we detcend from tliit lereL ConeeqaeDtly, at tlw Mue 
1 Ifaa aioMMpbRnc preanro* on nneqaal pliine nufafB* will b« pto> 
I In the amu ,tf ib»« miAeM, ptonded Ulf7 Iw maU in |SOfor- 

I lu tbF kuiirbl of tbe atDMapllCKk 
Fin nrtnn of tlw expiUMTn fotcn of th» air. It mi^t be auppooed tlut 
I ■olewiliw troald espttod iBdvliniiel/ bro the jilaneian rpare*. Bui, 
i|Uupuiti(a ■• tile air rxpanJi, its cxpaiudvi! funr« dcerroKS, and b 
' wealnaed by iba low tnnp«nttiire of the opper regioiu of thp 
b«rtr, to tfakt, at » oertab beif ht. an eqaUibHiun U eataUidieil 
ibn BXpaanra ton* wbirh uppanttaa tbe tnolaola, and the 
\ of gtavitv which dnwi thpm ('>«■«]> the eeatn of the ««rtii. It 
ilfcaHfaie ertieliMled that the aunoaphent t> Umitod. 

I the wtjght of the aiMoi^harv, and it* decree** in dcmatv, and 
I tbe ni tr T a tiow of ecrtain phoMRieBa of nrUigbt, Eta htigiii baa 
ttAmttA at Aoan 30 to 40 ihIIm. Abom thai height iha air ia 
J* taiHftod, and at a hri|;ht of fJO miln It i< amuned that thtt* la 
\fnhrl rarinim. Fium cvttaia oWnatioM 
tir nailu in tbo tropkal RC4ie, and par- 
Ay M Rio Janeixo, oa tbe tvili^l arc, 
.lialtfatimatw the hetght of tbo atiBo- 
ai hdwecD 19A and S12 nulca^ ecm- 
, ^idflaUjr higher, then-r<ire, than wh»t bai 
I taeii brliiTTrd. 
I Aa H ba» bean ptwrioml; aUIed that 100 
ibldwa of air itri^'h 3t gnina, it will 
Bjr be cmeoivifd thai tbe whole auno- 
UMVIaaa « eouidetahlc preattm on 
»nrfii» of the earth. The triiiteiic^ of 
are i« abowa hj the following ei- 


I44. DraalitBc ferce of tb* atmoeplierc. 
—On ooi- "ii'l '»f a Miwit glue cjrlbd^r, about 
S BchM hiph, and open at both wiU, a pjcn- 
rf UadiUr [■ tiiH) f|iiitp ur-tight. Th« '>tlicT 
tad. Ihe M)gt< nf which i* gmand and -w^M gnaaed, ii pretaed oa the 
plito of thu air piuop {%p 03). As mod aa a Tttcaum ie produrcd in 

1";.-. 9». 

112 ON OAKS, [1«- 

titB nwNil, hy vrorlnit; lh« )dr pump, lh« bladiW u depcvMed bj ii« i 
WMght of ihfl atinaBptirro nbavn it, and liiMilly butsM with ft louil nftS | 

145. XasdeftoiT bemUpboroa. — The ]ir*ciHlis)[ experawM 
wiTTM to illiutrato tbd dcwnwitnJpnMiira of tlic atnuMpbotc. IK --•?• 
of Uie Mofdr^rg ifmup^rrt* (fig*. M sad 0C>, ibe iBTcntioo <J »iii .: u 

I Fig.»S. 

diiatfi Otto Ton Ouorichc, burttumiulcrof Mit){(l(.'bur^,it cvnbfihowDlltfl' 
tbp ptMHureacUin all direnliond. Tliis appanitiis rnnsiitAof inriilioUo'' 
bian heraispherpa of 1 to 4J incb™ diainetur, iht- I'llp^d of which •!» 
niad« to fit tightly, rnitt iim wi'Il prenjed. One of thn bcminiihifiT* it 
proTidud with a slopi'ock, by wbirb it I'Ati be si'r«wi>d on tbu ait puntpi 
and on thn other ihoro ii> a handK A? Inns' lui the brmiiphnmi cobIA 
air th«y can b<.- si^paniu^d wiilmiit any dilTicully, for lh(^ external piuMON 
of thn atiiiiwphefc is couulerbnluncwl by the i-lnstio (orrv of thn «r in 
iho iiilvricFr. Hut whnn thn nir in tlip ijiliirior it piimprd out by meu* 
of tho air pump, thu hi-iuinphsn'M ciuinol be M-p(irnt«d wttbout a po«t^■ 
fu! wfTiirt ; and iw this i« thi- ra«c in whntnvrr pimiljon Ihcy am b*ld, it 
follows thai tijt' ulriicifplji^ric prMHure id trauii milted in nil ditvclioun 


14tt. ToTTtealll'a eiperlmanb — The aboro oxporimont* dnoioiutntB 
th« exintiincv of the atmospLvric pfSMiirt?, but ihey give do iudicatiou 



^BiuL The bllDwifit; H:(peniQiiat, vliich v** fitst rawlr in 

tTonicrilt, a pupil or CMilon, tpvn* an exacl meatuiv of Uiq 
ill* atmoopbMV. 
^ tnbn U tnJcMi.ab'iitt n jKd 
I a (|UHl«rof an indi jnlemal 
K^-MJJ. ]ti»«i«leilatoiM.- 
I U quit* fiUad with mtteaxy. 
pure C b«iii^ diMed bj ih* 
^ taha k inrcrted, the open 
Id is aMmll ncrvurx tiongh, 
iUiMab ROWKcd. TIih tube 
I TflTtical |w«hion,thoM>lttmn 
It 4nks, and after oKilUtiny 
Ir. it finall.T Mcnca tn rut at a 
I, whk'h at thr l^vcl of th* 
^aOiacJuaaboTv tbomcv* 
pie tDMiffa. Tho imuvut; in 
(the lulw hj th* piMture o( 
(■phero cm the mcrcary in 
fh. There h no contivy 
fM thi: merctiiy in the tube. 
|t b duMd. Itiit if tha «nd 
[■ba bo opouil, ibe atma* 
rill ptVM oqnallv inud« and 

tlldM, awl the merrart- will 
Itrtl ot thnt b the iroii^li. 
rnriiown in bjdra«(aliot(OK) 
bclghta of tiri> «olnpMia of 
L «onmuiti<«tl(iB with «oh 

t'lg. uo. 

|ln«niiljraatbDird«!iuitin*,iiiid bi!ni;o it followa, thflllh«|)ii<uiirn 
n^bure U «q<i«l tn tli&i of a columa uf lut^ruury^ iht? h«i^ht of 
Diocbaa> lf| bwwfVrr, thn wcifthlof tkcatmoiiphomdimtiuihcB, 
fl of the coliiiBii which it r-in mnAin iuimI hIm diiiiinUli. 

!*> aspVrlnaatai — Pucal, wlio wiihi-d to prore that thi> 
MUtaini'd tlir luormry in th^ tube wah rrntl^ thf pivmuti^ o( 
ihttv. made tlio full'iwing cxperiiuniu. L If it were ihr 
lamn of nn^icBrr oujiiit to drwcaid la prnpnrtiim aa wo ascend 
pn. Ill- •o.i>Tdiii)tly t«<|ii««ted one of his nIaficNw in 
)ni««lli'* oxpi^rinii-nt un tbn stiminit of tlie Puy de Ddme In 
I I'bia wa* done, aad i: w.u found that ttio mnn'iiiiivl cotamn 
^3 tiicbB* li>w«T, tliua proving ibnt it ii ivally IIil- wnij^bt of 
ib<n« nrliidi aupporU the mwrcuty, Mnco, when tliii weight 
tl)« bin|;fat of ibd ooluiiin alio dimioUheK ii, rascal ro* 


114 Wl OASB. [1«. 

peaitA Torrimlli'* «xp»riiiMOt M Bdiwn, ta ISMy villi i>ih«r liqnldt. lb 
took ■ lub« doard nt <in« nnd, nnuijr CO lert lon^ and bAviiq; filMit 
with wHtvr, plMvil ii trrtlcslly Id a iwmel of if«l«ir, and found t> n t^ 
•it%tr flood in Ihs lube at • haftht of S4 feet; tbat ia, l:tD li ■ u 
high an memiry. tliit nine* mi^miTj t* I3HJ timM as bcavj a^ «*>■; 
Uiv wpifiht of tiie ootamn <)f water was exaHly «qna] la that of 
oolnmtt at mnrrurT in Tnrriocltr* oxpcR»ROl, and it vaa coDw^i 
the Mme brrv, (he pnuniin- of lb« aUaMph«T«, wbicli succoaiiTelj 
parrtod lite two liqaicU. I'awars other expcrimRnla with eil asd 
wine tntv gliniler nwilt*. 

ItH. Aaa«nal af tlia •toMapkerte prftaaiu-a, — Let uiawaoMtM' 
Um lube )Q llif abovn expFrimont it a eylindnr, ihn •vvtioii of vhkh 
«qMal to a «qiian intrli, th<<ii siui:f (ho height of the iu«n.'uriat oolnaa 
roond niinibeni is •10 indif«, the colnmn will contain W rubic inched' 
and an a cubic inch of inereurr WM^b* iM39-6 |Taim=0-40 ot a pimnd, (k 
prnuiirw of •Itch n rolunin ■>ii a tiqunn) Ineli of surface ta ci|ital to 1*7 
poiiuilii. In tvuiiil uumb>'n> thn preaiiire of the atm>MphRr« i* (afaen tl 
1<^ P'tundn on tlic- square inch. A E^urface of a foot fjiiaiv contauu lU 
iiqnar« inr.hi>a, nnd therefoc: the prr^isurr upim it ii eqiinl lo3,160p(nilM^ 
or nearlv a Ion, 

A ttai or a liqnid whteh acta in >uch a mnuDi.T that a aqnarn iMk tt 
snrfac« » exposed lo n pmiuiire, 15 piiunda, i* called a preeaiiM et Ma 
alimnphere. II, for iiLatance, the elastic fone of the »t««m of a bojhir iiM. 
grrinl ihnt i>ach square inch of the iatnmal aurfaee ■■ rxpowd to a pnaNM>' 
otW p->imd8 (=ilx 1^) we *»j it was itodera pr««ure ot «tx MtuHMpbfMi 

Thi! jhurfaoo of the body of a mail of middle aiie in about Ifl fqaue 
feel ; tiie p^>^«ll^e, lhnr>-ff>n>, whieh a man nupporta on ihe eurfaoe of hi* 
body is 37.o'IU pouiu!*. or upwardi of 10 tons. 8uoli an (^normou 
pipffiure iiiifflit se'>iii iiii(>oa>iblp lo be borne : hut il mujit be rememhffCd 
that in all direction* Ibcn.' are equal and onlrarj preaiiimt wfaick 
rounterbulnnce one another. It might also he supposed that ihe elfrct tl 
this force, actinff in all direeliona, would be lo pw>« Ili« body tojrBlher 
and criwh il. Hut tha Mlid parl« of theHkeleUmcouid n-Jiiit a fBr^Teit*i 
pressure: and tu (o the sirnndliquldn contained iniheorgaaaand veanl- 
the air hwi th>.> feme deniily lu the exlFTiial air, and canoot bafsrttn 
CfimprenBed by tlie alinoepherii' prewiire ; and froni whal haa been '►■■■ 
ahoHl liquida (SS) it i« clear that Ihiiy are virtually inioomprnMikl' 
When the etUTiiiil prenmiri" is removtid from any pan of the body, 
iiilhcr by nicnii* of n euppi[i)i vu»m1 ur by the air pump, tht prattiir" 
from williii) jfi senii by lbi> dirti-mion of tliL> •iirface. 

140. 9ISar«at klnda of baronivtvn. — Thn inntnimenl* need f" 
meMurioR tbn Btmatph'Tic ]ire»iini aro called barvnuirr*. In ordinary 
twioweteni, tlie prnvure ia meivnirwd by the boifihl of a column «f 

{ BABOUETUtN. 115 

.17, u in Torrimlli'ii ftXp«riiB«ni ; tbi; iMUMinnbt* wliich we an> 
lo diwcribfl are ot tUa kind. JIat there aw Wroinetcr* wiiboui 
|ni)t, otM (if whioli, tb« miatAA, U rMii(Hahle for it« rimiilidtv and 

> BlWBf kMTS^BWir. — Tlio ntttnt baromtOrecawta ot itKiixighi 

■b«dMcd RluiK-iTn-i,nbout ■i^Jinchn* lontr, HlWwith merciirv. uid 

ig tntu a owt^ni cnnUining the aune in«i»l. In onl^r to ruodfr ihH 

•tar iDot* poriAble, «iid the Tariatiocu of thu I«veJ b the cwtera 

ntpiUe wli«n tlia tnareuFj riana (IT falU in iImi tnb«, 

1 dUttent tonm h»vm be»a conaiructt^ l-'ig. 1)7 iv- 

itemwfonnaf thedMMnbuvnietar. Tbo appuMtiw 

i1»B BiahogaDj Ktund, on th« upper part of wliich 

It null! pwliuled ill iiiilli[ai!t«ni »r inchn from the 

r Ihrt BMVurr in iLo e'iium ; » Di<iv(»l>ln indnx, >', 

■ ibt Male tbo lri«l or the metvurr. A ilienai>< 

n (Im ndfl of thn IuIk indieatw the tcnqwriiliir 

III (« <nw hull to which tbit barotnetw it Uahl<^ ir 

K with all othen -it the luie kiml. Tho w-to a( 

ik doM not kliraj* floampond ta th« l*r«l of the 

tj in the ciiliftti. For m Um atiaospheric {imaurr 

jwa^D ih» Mine, th« l>ri|rbt oTthe nMreuniil column 

MMnatltm* mercurj ia fuKeil from the (iston into 

b«, •nd toiBi'liniKi bom th« liibn into thp eintum, 

I tn tho PM^odly of eMr«, iho frraitiiatiini of the 

Kw doa* not tndioat* tlMi tme hright. If tbn di*- 

tf the datem ta large, nlMit*1)r U that nf tbo tube, 

BT from ihia Murce ii lowenvd. Tbo AayAf of the 

Ltor U the dUtanca batwenn lh« lerala of Uie hi«t- 

4 Dm tuba and in tha daieni. Aa tha prcaaiue 

f the m-rrarr ^mrtK by it* wiii)iht at the baM«>of 

H" ia inil<^iKleiii of the (btni of llu* tube and of 

(OH), praiidad It in not otpitlnry, the h<»ighl 

bBrnowtiM ia indepMadMit of the di&un-ter of lh« 

el its *1>*pB, iMit u in?atacljr m tlM dpmri^ of 

With mTnirr lh)i atavi heixhl u ihtt lorel 

ia ifD'OS, or ia round numbcn> 30; indrn ; in a 

It wniiJd be kboat %l-7 feet. 

^ VffrtU** karo^tetar. — fMai'ii baromitrr ditfL-ri 

t Jatt deaeribad, in the ahap* of lb* cintrtm. Tlitf , 1 

I niMcm ia nuKle of tntbnr, uid can be rninod 
I \tj in««na nf % taww ; llti* haa tbn advanljiire, '''R' ^^ 

(tOBatant lirvel rao b* o1rtaIn«d, and ahn ilutl ib« iartmni«nt la 
portable. Tor in 1ntT«llin^, it i* only iiRee«Mrv tn TMae the 




tftUlicr ontU the meteniT, wkicb liaco vrith it, quitafllU ih» dtiitn: 
bwoiiMlOT om; UieB be UicUiMid, and pien iuii-rted, vitLuut aovlcv 
• IxibMn of air nay enter, or llut lli« shock of Ui« Baercur; Ba; 
tlia tube. 

Fi^. W ropnwmU tli« amiitiemMni at lb« faaroneler, Um 
vkich i* placed in • bnun caw. At the top of thU cww, tlipn m* 
IiioRiliidinul apprtuKS, on opp<i«ile uiltvt, to> lliat Ibe lict*») d 
iDiTciirT, B, IB inMi. The (cale on the oDne ia trntduatml iii luiUi: 
An indvx A iiinT«d by ih^ hand, |iivi«, br nieani of a Tvnkr, 
height uf tbo miavarf tu j^ uf a millimetrr. At 
bolUim of thq EMM) tboM u th« ci«t?ni b, roDl 
mi^rpury, O. 

Vig. ))9 obow* thr detail* of tbc ci«toni cb a bi 

Kul«. Il conMf>I* «f a glaM cyliodi^r n, whicb allom 

moKanr to be seeii : ilic bottom uf the cyiindrr wcV 

wilh iFRlbcr, »u>. wliich u raiacd or lownvd b; iMUi (f I 

ton-w, C Thia «crvw works la the bottom of a hna 

i-vUriIt, 4), which is Eastened on the gin** crlindrt. it 

tiic top of the i;i»tsni lh«n i» s huiJI ivon* pcnnMT. 4 

the ]K)int of «*lii(:)i ourtly curre>|ioDclii to thn mto on Ut 

wale. Till- upptir part of tho rist«rit )« clu'ied by biickAii^ 

(f, whieh in faBlened to tliB bMOUieler lube, K, and to a luW 

luiv in th« bnua jilitlc, which rovnn llii< cistern. TW 

atmiMplierii.' {ir««<<urv U trno«iuilted thruujih the pone <^ 

tUiK lenllier. In luoot; Ihi* bnromftai, tb* 

nuiffiiry i» fimt niiiili> level vilh lli« poiul * 

wbjcli in elfei'led by tiiniiiig tbo sen* C 

rithct in onci din-ction or iJi* other. In lUt 

iiiauoer llie dittftuo> uf the tup. It, uf tbs 

column of mercury ftum tlw irori' point «, 

gives exactly thn height uf the barumelet. 

1 02. OB7>Iiiuaa«'a ayptaoo bartfoasUb 
— The lyjilion linToitirter ix ii )>i-ut utsss tnhS) 
i)ue of tli« bmui^he« uf whieh i» much kmgtr 
Ihiui the oihrr. 'I'ho longTr hruirh, wbidt it 

I It fl^fid at the top, i* fillml with mercuij •• is 

11 ' Ihc iriatem bnroineter, while thn.'ihortiTr hmoehf 

'— — I - which i» ap^n, wrvps nn n ci'i^in. Th«<dllfo> 

\\^ • iice b>.'twve[i Ihe two luTeli ii> the hdghlrf 

' *">• the biirciiiicler. 

J''ig. 100 ropnuvntf the syphon hnrameter 

i'i(j. lie. 

Fir. us. 
[nodili«d by Gay-I.UBSBC. In irrder to render it more nvailnble tat 
U«T«llili;, by previ-ntins th« entrnncc of air, he joined tbi> l\rn bmncbM 

*tube; vhm Ibn UuCniminit U intirrtBd, the Uibo itlwaij 
n in f irtwi oftl* opoUttritv. Had airraoiiol p«««tnit« into Iht 
aeh. A mmUm thmrk, liom^nr, mijfhl Kpttntte the inereuirj 
I aono air. To AToid lliia M. nuDt4>u hv introducnd «i 
iDodifiemtiaa into tlie appantiw. Thn IclII(p^^ bnuieh is ilmwn 
« point, and » joined to a tnbe K of th« rorm rcproKntod in 
By Uii* TnmgnpicBt, if Mf pa«»i ei i through tbi^capillftry lube, 
«aau«U Uia drawB-oDi nxtremity of the \rmicft bmncb, bmt 
k* nppv put of llie cDlargemi^Dl K- Id A'v p>'«itioa it doM 

A» oWmttioiu, nara thn TMCimni i* klwnya -^^ 

W f»n of thn lub« ; it la UMiraoitrr Mail v n^ *" ~ '.T** 

Hvar'a barDmittiv llu aboTt«r liranch in 
Sarv i» a lateral npUIarr afprturu n^ Uiniugh 
umcwpheric picMum i* tfanuniltfu]. 
»Bi«tric hfiight ia d«t«inninni by idbniu of 
, wbkb have a conunan xero at <), tnnanU 
nf tbn UMagft hraiu^, an'l la* gndiiat^ in 
RCiioDS lb« oD« from O to E. and Ui« olb«r 
1^ Mthitir on the lubn itiwif, or oti bntiM tiIm 
IM to the Iubi>. Two dlding Tpmien. m 
ieaic ,*( of a tniUimolcr. Tbp total hn^ht 
■Dam AR, u iha ram of th« dialaaow Crom 


••«tt«a« U( MAMsa* t« barMBvMra,— 
'ling iMUODMlcm, HMTCiirjr ia clitxrii in prc- 
anj Dtber liquid. For brio^ tbi: AfnH'M ..( 

it alanda at tli« i«aM hoigbl. Wbfii Ihr 
■OOIMter alaiidB at »0 bclin. tbu 
nater would aland at alxxit Hi f»«t. 

^•a preferenn* bocauae It duM uul 

I gtaafc It ii nrwaiy that tho 

pur* and fron fram oxide : otb«r- 
larM U> ibo flaw and taniiibea it. 
' It ia iupim iti d«nntT b changM. 
ight of Uw> barametvr la loo gTr»t 
iienurf I* purified, bafom bning 
HMMlan. hjr trratmeBt wltli diltito 

K at the top nf thn tubr (fig*. jHt 
wliiclt ia rallxd the TurrKriUita 
tat be quite Ino ftwa air and 


Fig. 100. Fig' l"!- 

na Tapovr, for othfTwiaA intfaer would dafiOM die mercurial 

118 031 axau. [iH-i 

Foluuin liT ita elwtic fbror. To otiuui lbi»nMiil, • amall i]iunlin4| 
[iian itH^n-uty is pliuwd in ila tube Bad toiled for kome lime. It a i 
itlloneil In cnol, and ■ furtLar qiuuititjr, pterioiuiljr wunnrd, (ddtd,! 
ii boUwl, aiid tiO on, until iha tilba is quiu full : Jn tliis 
moaiit uir luid tliv ait which adiiere to tke «idi» of tb« tube pas ofli 
Uie meKurinl vapour. 

A biirtiiuei(<r is fi«e IVnm sir snil moislun if, whtai it la incliniH 
mHiturr Htrikni vritb ■ slmrp m«Ullic Huund Mguinit Uie lop tJ (bst 
If ihfre 1> Rir i>r nKiimmi' in it, the wund is deadened. 

154. c«rra«u*a for vB^iiisritj.— In cinti^ni bcrmuvtm ihatl 
nlwajs n cerlAin dcjitoMon uf tiii: mnciirinl column diur to ca|«Ili 
unless tho internal ktismolor of thn tube v\C(<tds 0'^ iDch. To 
the corrMtion duL> la thia dcprcurion, it is not unou^k to knowj 
disinft<>r of tbo tubr, wo Riu*t also kiKiir the \Mf 
iliv iiivuisuuB "(/(%. lOd), wlitcUTuiMacronliiittMlkl^ 
ini'uiicui ban btfoa funned duriup on SMCwndinit or ^ j 
Kir^ndin^ motinn of the mcrcurj in tliit lube. C« 
qiiriitiT llip Li^iffbi iif Ili« tueiiiscus iiiust be i 
by WingiiiK the painter t« ibu l«vi4 ni, nod Ilw« lol 
li'vi'l d, when tli« ditTsniicc nf the ri>adiiigs will ginll 
bvij^bt m/ requirod. These two loroi*, naudy, tfa« b^^ 
Icninldianicturnf tbiitubc.iind tbohnghtai'lbi'iaMiiM^ ' 
being bnowo, lito rviulliajt coireclioD cui t« lalNUSili 
of tlwfi>llowiD{j:i«blv, wbicb folio w» the ammgiMiient freqitaitly sdofMi] 
for ■ multiplicaiion table :— 

Fig. i(l2. 



in inehst. 

H*iglit«f8a|ict«efM*aiMU*IaiaehM. 'M 

0-DlO 0'0]£ 

0-OSO i oo%t 



1 ■ 




01 III 

0<M3I ;0-05ISo 
0-OI7C loOi'Sl 
0-0088 0-01 18 
00048 00003 
0'002» O'OOSrt 
O'OOI 7 0O024 






0-01 10 







In Ga]r-Lu»MC> barnniclcr the two tubeii uro madv ot tb« Mme dis- 
muter, so llisl the error muMid by thu drpriuMon in iho ouo tubn v»iy 
naortj com--fis that cnuscii hv ilio depreiwioii in iLt' otbpr. As howeisr, 
thA mminriiii in tho one Iiilie ia t'lirtiicd by n i^tilumii uf mvrfury mlk an 
iwc«ndiiig moli;'ii, wliilo tliat id ibn other by n cnliinin wIlli a dMcandiag 
motion, ihuir briKbU will not be the smuih, nnd thu rt-uiprucal uumflltM 
will n^>t bt- quite uincl. 


oonvetiMt nr i«ni^r*tara. — In ftU obaMrUuns with 
ett, witatovor bo Onir coiutruction, a cnrTVCiiou uubI tic niadi' 
H — p w lBi*. Memirr 0C4itncts tad expaiula witli ilitlerait Ivmpera- 
It bnoi ib dcBMljr diai^o, Mid couxNjut'^tly iLo barotudtiio lioi^-hl, 
' tU* hrl^t b ia tiie mT«n« ntio of Lbr dtriiMty uf lb« meniiirri 
tibat f'lr diltcKfit aliiMiplierie pnanmB thr nii'TcuTiitl rolupui miitht 
Um Mais bMfbL AooonUofl}', in <«rh obM-rvatiuu, Uie beiglil 
I Biart bn ndaded to a detMuiutc tvnipurMUM: iliB cboke of 
I tfuitt arliilnrr, but tluit of mcilting itv \m alwtyt ailoptnL It 
I k» MSI, in tbe llook on II(>«I, bow tlii) tumctioa U wade. 
) Ibc kid of UbiM wbicfa bavn boon |)n^piir«d for lliu purpMO, ^r 
lit mf Uir buvniclM U rMilJIr ivduMd lu tero CentlfnndH. 
L v«rt*U«4MlBtlMbM«l»ol'tbobu«aMt«r.-WbaDtbc bwD- 
' b obaernd Cor mv«i«] i^y*, iu b«igtht U fouud to tuy in ihv mom- 
p, not obIj Ann ow daj to anotiier, but olio duiintt (bv Mune dnf . 
•xtvnt of them laristiiMiii, Uwt it^ tfaa diffenno* betv*«n thi^ 
: and ibo lt«*i belgbt. in diOcKnt in diSeaant pUeM. It incnoMa 
I iha «|B>tor lowud* tbo poU*. Kicopi under oxtraordinarj dr- 
Uie gratlaM vwuitona do nut lutmd tJ uiUiiuekrrv under 
I aqDUor, 30 under Utr tro^ of Ciuicor, 40 in Fmnoc, and 00 at 3S 
I tram tlni pote. Tbe fteuMA viinatioiM aru oWrvod b winlu-. 
I daify itiffU it lb* b«i)[ht oMainod \>y dividing thv nian of 
UTB iioiirly obMTTatidnii hy S4. In our latiiudw^ the bwomotnc 
bl at twea tuiTCopoiid* U> tbe oiMu dailv beijflil. 

manl^ hiaykt u obiauiad by adding logotW thi- mi^iui 
f-4iify h*i(iti tor a inoBili, aud divtdiotf by 80. 
1W M>WH fr«rfy hfiffM in ttmUnriy obtainc*!. 

Emits tbe Mjuaiui, ihn iiMaii attiniaJ buiflit at tb« Wei of the tea te 
, or 3B^ incboa. It increewi bom (he c^uaior, ami bctwi-vn thi^ 
I SO^aad 40^ it attiiinR a maiimuin of 0°"7tS3, oi .10-04 bcbo*. 
fAi Ivmv UdtadiM it dtdvaw*. and in IVis >l doM tiut «xc«ed O°'70U8. 
TW gamtvl aiaau at tlie kvel of tbe ica ii U*'7UI ov 'I3-W inches. 
Tht Meaa nmiibly beifbt i« groator tn winivT (ban in tununer, in 
■ooMf i^noa iif ibd ooulet almoapbtm. 

Two \aa4» o< vanatioo* an- ohwrrcd in tbo banimoter: trt, tbe im>»- 
Jkdai tarittian^ wbicb pteHBt no re^nilarily ; tboy di-iwnd on Uio MaMoa, 
lb* diiwliim ii/thi witKU, andUMKeogTaptiicalpoMliou, audarooomnioD 
tn oui -llmatfT : ^ad, tUn Jaify mnatietu, wkieh U« produced periudicaUy 
It fnitain bnuni of tbe day. 

At Uicoqtwtor, and bctn-mi tbn tropic*, an act^iilMiluJ larislions ar? 
nWnvil : but tbo daily vahalivna lalio placv with audi regularity Uial a 
Wiiwiii may ktic to ■ certain extent u u, otuck. Hio bainitrati.T mnka 
tnm miimj till towinb foar o'clock; it then riou, and rMchea its 




nx (iJUK*. 

mauin«B at tkfut u^ o'nlor): in iht vnaaif. It duo ipia 
nMliN n ■.•Tumi miuiiuuni luwiudu four o'dodi to ih» BOniiBg, 
wcrnnil mnximum at Ian o'clock. 

In tho t«i»{ii-rat«< kium then are hUo datly rariatjonti, but 
t1at«ctod witii diDiPulty, atioe ^ej occur ia conjunctioa witb 

Tbi' lioiini ci( Ihc- majiiuia aui) minims appear to be (lie ■ 
rlimatii*, whaicver be Ih*' latitude; thny merely vaiy a littl* "ilfc 

Ift7. 0««a*B ef barattMHc vailatlsBs. — It \* obarrvnl lk«t 
coune of lilt? Immuii^K^r i* ^•^nomlh in the oppaaitc directiou t>^ 
th« tk«miciniL-tcr; that is, that when the tcnpcnitare riao tbc 
fftllo, and iw« nrjia: which indicjitn that th« barrimeiric lariuii 
any pvvn plru^i* nn> produced hy t)ii> eipanMon or contractian Of 
and thiireforit b_v il» rbniigciadpnailT. If thr tcmpnratnro wiff 
thrvxit'h'.iiil the wlji>l(i ■•uli'iit of the alniMphpii', no i-umnld 
prodiicnl. luid, nl ibc snmr btighl, llic ntmoapbprip prcawufo 
pv^rywbeiv th« Mimw, lint whnn anv piirtion nf tJie atinmpbere 
wnnnur thiui llio ntighbrjuriiig parts, lU Bpwilio gravity i« it 
and it riiww and pmuiu nway thmatfh the upper rcgiitn* of thn atnii 
whcuc« it follows that Iht? prewure ■« dlmliiiiihed, and th*? biLTOUMttfl 
If any portiun of Uii< uttiKupbore rctniufl its li^mperalum, wUla 
iieighbfiiiring parW bpronii- i-hoIpf, the mmf effi>ct in proditoedj 
thin ciuK-, too, the dcnaily 'if the lir«t-m<?Dtiuiwil portjcia in IcM tha' 
of ihn (ithnni. Ilrnce, mImi, it iiflunlly happens that an ■■xtraoH^UIJ 
of the baruuicti-r nl onL- plucv Is i'uuul<'rbHlaut.-ed bv nil uitraordinHJ 
At anolbor plnu.'. With refer^nr.e to the dnily variutiotw, thtiy afipcar 
result from tb? etpHiisiong and (-iMitracticQn which ara periodically pit 
duci>d to the ntmoiphcK by the h«tt of the Kun during the mlaltM 
the earth. 

1G8. B«l«tl*ii of b«ram«trio vorliktloiia t« tbo M*M At I 
wcftUier. — It hib9 heeu ob.spn-ed that, in <iur cliinntc, Ihn bammMarJ 
ftiio wuiher is ^'iJcnLlty above 3fl inchi'n, and i« bflow tbii poiM 
thute is mill. HTiuw, wiiitl. (ir ntunu, and id»u. that I'ur any given aumfel 
of dnyn at whinh ibe hnronicCr slandA nl !HI inrhoa, then> are u 
fine aa rainy days. Froui thia coiiicidiiuce bblweeii ihe faei^t «l 
barnmeier and the ntnlo of the wc^alhcr, the lollaicing- indication* 
been marked oti the barkimeter, counting by IhJids of an incb akure ■ 
hUow :S0 incbeii : 

Height. State ef the weatlnr- 

31 iDchei Very dry. 

30| , tSottlpH WMthar. 

30^ „ FlneweaUier. 

^^^^^H BjtnoMEnKS, ^^^^^^^i7^^^^ 

5^^^^^ S"*** "' '•'• ""ifcw. 

^0 VaHable. 

^K .... lUuiarwind. 
^P . Much nun. 

Ihe buunieiw m an indtmUir of tha *lnto of thi' wentlier, wv 

Ml** tbM it rvolly only Mrve« to nivMurv the ir«<ight of the 

K ami Uui it only riat* or 

n wdgbt mcieBHu or diuii- .^k 

nd Blthongli a dianttv of fiSlmH. 

ibe prauare, they are not '*q' 'b?^ j| j 

oanoMted. Tfau oojoddenee 4~ ,tf 

m iBal«oro1og;ical coaditimu ^fl ;> BK 

ft our rflmate, aJiiJ 4>«a not lip ^r 

»r. 'riiftt a fall in th« baro- / 

lall^ pi«MdM rwD in our i 


u canaed by lli« poillioa of f 

Hie wiith-waat wind*, wfaidi - \t, 
>d cMwqwMl.v light, iiMLke ^'^' XT 

Ktcr fink ; bat at the Mne ^^ '' ' ' 

tli*T beconw charged «lih ^^'S-.:^ 

•pour In crominji th* ocsao, ^BpR^^L 

r u* run. Tbtf winili of tlii> ^KplS^^^j^k^ 

nortti-nat, on ll»o contrary, ^l^fji _/'^^BF V* 

ar and denaer, Hake Uie barv alHi ^ fHrn^ Jr\ 

s\tmA •» Ui*j wily r««di ui> tB^C_,. tf&sB' ►If^ 

ig paMed orer raat coiillufais ^fss^^a H 

•Mi>nrdi7. -^^KF 1 

t)i« bwotnelfT liwo or gink* ]^B 1 

ad U, tiir two US' thR« dayi, ■BR^f V 

Im hvbUhv Of toward* rain, BTSJ^JI 

B fmwd 6on a iitmi Dumber M^^Mi 

atbiM that the indicationa ^Win' 

ntranpty probabl«. .Sudden '■*' 

{■ Mth»r dirtctioa indtntM Yig. 108. Fis- lOt. 

icr or wind. 

Tlaal b«ronat«r.— 7*ha icAn7 \iammrtrr, which wnf invented by 

a Bjrpkon baraan«t«r, and ia otpecially iiitriidMl t^ indii-iitH k<io<1 

«athor (6g. 103). In tbi; ahortirr W »f ihc nyphnri ilicrc in it 

kh rJMV and flilU with the mercury (fi(r. ItM). A strint; 

to tbl* float paMB* round a pulley, (>, uad at ihf olhcr end thatj^^^^ 

h^ P, SOtMwh«t %ht«r thiui the float. A ii«ulli> Bx«4|jri|^^k| 


ox GASES. 


•f uUtj" KMTM niuud R ^thJiiaU^ ciit'lu, on wlik'li iit mailiod tariM,n 

I maTAn-, etc. Wheu tiio pivwurv r&riai lbs lluni Mka or rw i 
'nova tho nmllH miinil lo thii cnrmponding poinU nn lh« aoitt. 

'Die b))miut^t(4s oriliuHrilv met with in bvuM>% aiid wbicbtni 
iBtathr glautt, kit ft liiit kind. 'I'iiny nrc, hnirrvor, of tillle nw, fa 
rMMTiiM. The lint ii<. tbut thi-j hiv Ufitlior vvn d«lii'att* nor ] 
theit iuilkntioni. I'h* ucimd, whii^h ap)ili(>9 «iiuiI1t tn nil ' 
in. ihM t)io>« i-oiiiiiiciuly iu uuc iii ItiJa outititrv ura ihhiIh iu Londoi^l 
tile indicRtioai, if they im of taty talu*-, on) cnlv h> for « pbn < 
««me l»v*I and of tlio fiim«c1ininiir erudition* m I.cindon. Thiuti 
nii-tM irtiui'iini: nt ii curliiiii litijihl in Loudon would indicate ■ 
AMe of wcalhffr, but if n^ninvvd to i^hooti^r'ii IIlll it irould sland ] 
inch lt.>»'rr. uid would iudicitto o dilfvrait elaCi* of woatbitr. Ai I 
piviatirn dilTiTti with thn Icvrl imd wilb )irii^[iKpbicnl (vnidiliMM, ill 
nerrwiiry Iu tnliv t)i««e iiilo iit'iMciiiI if exact dnin ftre wbuIimj. 

KHX SatermlBttUon oflietgttla by tbe iMuomater. — Siiiiv tbel 
iphi-rir prcwiire dwrti**!'* ft" wi- ftn'tnd, il i? ohiioii" liiHl Ihe ' 
will kiiL-p on fnUiiijt ni it is lakvo to * (irmtcr and gtvMnr h«| 
fact vhiclt siiggfttU n vrrjr nwful niiithoil of dtrli^nnining tlie itifl 
betweeu tile cleiulioiiH f>( twu Blations. sui^h •» tbv ban; ud aimitidll 
u iiinuntidn. The mcihod may he explniiiiHl aa fillown. 

It will he Myii in tbi> noit vliapti-r ibnt if tbo k-mpi-raliira <lf < 
Miclujed portion of ait euntinupM minsUiiit. it* volunii- will varj- iiiT 
a* the pivsaiin; pvr ^unre ini^h. That i' t:< wiy, if wf doiitdv ibv | 


ire slinll hftlvL' llie volume, Tbis fiu't is coinmowly called ] 
nml Mnriott«'* law. Hut If mv bnlvu the vntiime «re ma 
double llie quantity of air i[i each cubic iiicli, or douU* ' 
ilcnaitT of tbc nir, mid hi on in any prtiportion. ('on* 
tbt- law U «qiiivalHiu in thixi — That fur acciiwtAnt teinpentotfl 
the clonsity of nir is [jroportional to thr preaeute per »iuiwe iadil 
wbifb it mwlainn. 

Now Huppoiw A Hud It (Gfc. iM) to r«piiut-til two slur 
t-liat it is mqiiirod lo dRt«rniiii<i the Vfrtiinl hi>i)ihl «f 11 
it hviafi borne Iu miml lliAt A and B art nut nM'eMHriK i;^ liit, 
name vertical tine. Take 1' nny point in AI!, nad H n point all 
iqnall dislnnee abovn P. Siippnuit lh« pressuri' p<>r «]ii«rp incbofi 
th<i DtmcupherH at P to be denoted by p, and nl Q let it tel 
diminitbRd by a ijiinntity dpnot^'d by ifyi. It is pkin lIiM thit 
diniinuliott Pi|iial% llie wi>igbt of tlit^ cotunin of air lielwws S , 
and H. whcue isectiou is one iqunrii ineb. Hut, lince the donuty of IImJ 
uir i* diructly pmportional to /i, tlii- wuight of a cubic inch of air willj 
mimI J^i where k di^uuteB a certivin qunntily to be detcnniiied ixn-l 
mtuiT, and g tbe acci'lemtini; form of gravity {10). Ilonce, if vt dowH] 


J -i 



bv dx. lb> pn«iift- will be iltmut»hoi] by I^Mj^, nail ir« 
tliU (aL-t *%«bimicaUf by ibp >r>}UBtk>ii 

mll>]uiomi kl^bnical prccew tU« ItuuU tu the conduNoa ik»t 

dwiMlc* Uiiibe*)Hilof AB.iuicI I'nnd I', thRntnioupbcrkpivnam 
B iMpPCtiTi'Iv, thu l<VNritbms ht'ing of lliv kinil i-nllrd ' Nupii-rian 
»' Sow, if II and 11, m* tie hi-ighu of the l>arniiii-t>'r nl A 
livclr, the tempenUiue of tbn nirrcury beui^ iJie wok nt 
liaM, Umot rada •quab UiU of P m P,^, and UiMcroK 

to diripnailiH it aail ^. 
IbiM ibe force of jnnnly i> dinVrvut for {ibicec iu difftront 
f will <l«prnd tipuii ibn lallluili- 1,7:1). It a found IbMt if ^ ii 
l«ntlag fum of gntitj in luitudo p, and/ that force in IniiiuJp 

*°^ r+MOaSBco*^ 
ba* a di-Xiiitv nuiiviical t nine. 
'ntu wbat biu been >tiil>!d abort! it will b« tttea tliiit if p in the 
of air at « leiup'WliiH! of f C, miijer Q (be [>n«»iire exerted by 
tibM of utetearj, we aball have 

pfN«n tbat it p,i» tb« dctiai^ of air under the mnie prcMiire ({ 
w« *faiiU bavu 

baa a ileliDil^ niimoricAl TaliHi, Tberofon 

f # ia tli« dMMty it meiciuy, and if tbe Intitude in 4fi*, we aball 

Q = a9 02.e/| 

V — fi) ^ 

- # • ■sKnja+-') 

k# ia the ntio wluch tbe d«iiHty of dry nir at a tempomture tf 

tltude 4A^ under a pteaiira vt ^Oti iuehes of uierciirv, btiara to 

•tT (if mercury at O" C., and thcrcfoK f^-^v U a det«ruiinalu 


•I S 


ox outs. 


X = 30fl2ia. .-(I+0-00SS8co»2«.){l+«0 l«*w 

Tlw Talu)> of •> i« fl-OOnf-tU, vhich i* neortr «^nal to y^j^, If «ti 
atitutr iIm- pi'nppr Talu«9 for rr-r p^. and clinnj.'!! Ibvlotrnritlinw inio coanoll 
Ic^rilhmf, And iniioiul of < uw tho ini«n of T nnd T,, ihi- u-iupmnm 1 
Kt tlKT apptraud lowifr «tfiliuii», it will be fuimd tbat 

X(iiif«i) = eo;M'i(i+o-002mc<*2*){i+ -1,^x1 ' ' ' ■ 

«'liich ii Ld Phce'a bftKniielrie formula. In \is\i>g It, it mu_ : _. .-.u'.m- 
Iwred ttinl T nnd T, nri' ihc tom|KniIUTca (in ihc Ontigrkdo ihtmocntu. 

■ ttiid tlinl ]{ luid II, art- tlie Lei^hu of llie barometer r«iiucrdlAO*C 
1iii« if A ii ttt<? lUPAiurtKl heipht of tbe bammirtrr nl iho loirerniliaii 

' w* liitvc 

If ihv Urls'iit 10 b« metunired is not great, one oWirer ii enougk. Fx 
jTeHl'-r hfliBht* Ihc a«piit lakes some tinit, luid in tho intorral lh( pM-l 
KIT* iiiMV lun'. Cnnjetjiiontlr in tliin cdw tht're mu*l be two obMia^T 
tini' nl each Kiuiion. who nifik» simulianeoiu obfcmttioiui. 

L«t ni- Ink? the foUaniiig einmple of tbe above foniiuU: — Su 
that in Ultlnde 05° N. at the lower of In-o iitatiua* tbn lini^t d ll*l 
biuflnieter wert* .lO'OflS inchi^, and thi) tpmpotntiim of air awd in* 
" lr°-82 C, while ftt the upper the hsighl of llie hnn>iuelrr wm ; 
iachtv, sad the Ipnijieraturenf air and nicrciiry wns 10^-55 C. DfU 
the heig'ht '•( tbc uppiT suition nbove the lower, 

(1) Find II and H,; vii, 

11 = 30025(1 -'S)= 20.040 
n,=2«-230(l-^) =28188 
Ilpnce log 3 = 1-47012-13 - 1-45001S5 = 0-O3Gfl20e9 

(S) Find 


(S» rind 1 +00O256 cos i>* 

8I11CB OOOn.'M cos 130°= -0002GO co» 50» 

= -0'001fO4 
therefcr* 1 +0-002nfi cob 2(.= O'tlHR^uS 

Eenc« tlie requinnl height in feet e(|iinlii 

e031flx0«ift355xl-OCC74xO02M2e88 = lC7I 
It may be ewily provi-d that if H nnd H, do not gn«ily differ lh» 

K»pierifto Ifl^rillini of ^ equals "^^^. U for lostancc U e-iuaU SO 

toriK Axn bakiotte's lah. 


■d II, BqoftU SO inclM*, ibe rasulliBf error irituM uoI ex«««J the 
of tke wbohk Acoordinglv Tor buighta uot excordiii^ SOiYi tt. 
witiiout nuicfa ertor nw tbe fbtwulik. 



Myle MBA lKarl0tt«'a law.— Th« l&w of tlio cooiprawibihtv 
vfnn dUiiovermi by Boyle •uU MartJtte 
oiUj'. In ciMi>«]unico it i* ia Kngland 
J nlkvd Bi^vlo* law, acd.uii tli« «-jii- 
Uiwlit'* U«. Il i> ai foiluwa: ■ /'Ac 
trr rfuwrwwi y fA« miw^ M« mhintf of a 
ochJry <T^ 1^ M niww/gr at Ma pftvrun 

tir b roriflad bj moma of an appantuii 
anoOtM Me (fig. 106>. It cannlMa «>r a 
• niba fixed lo a viirttr«I support ; it i' 
b* iqipvr pan, and Um uilivr uod, irliicL 
iDta a tliort vailicsl leg, it clo*ed. On 
ttr l»g tiicfs in a aealc, wbich iaclkJlm 
pchiM; Uie anla a^iwt llie li>iig h^ 

I haighu. Tba >tav of bolb aMlu* ii iu 
boriioatal lino. 

II i|iui]tliy of mittvrf b fourth iulo tlit^ 
liMl it* lerc! in bnlh branelica \t at, 

effBCled witlMul much dilllciill^, Tbc 
la abort loir i* lliiw luidor tJio urdinary 
irie pmMiuv. M^rcurj ia thm pound 
bni^ tnlw until the vuliune of thL> air iu 
br tuba i* ntlaced to ijno half; ibat u 
t niincad Croai IU Iu I>, an bIid'O'!! ia tliu 
tf llw baifcht nr tlK< maTGuriiU cnUiititi, 
MaaaMiwl, it «ill U> luiuul exactly v<{aa\ 
t^kl of iba iNiraiuoliTT nt tha time of tlic 
hL The pr<4Hin ul tb« cohiniu L'A i- 
aqual to an atlMMplMiTn, «bicb, vritli iliu 
trie preaaure BCtiu); on tbu BurfHCe of the 
tl C, inaioa two atmoaphere*. Accordiniily, by doubling ibe 

lbs Tolamvof tb« ga* ba« b>fca diuiiu)ab«d to one 111 

U moKuxy be pnund into the Inngvr Inwuch until tlw 
ftir in rnduoed lo cma-ttiint its od^ol Toliimr. it will hn foiuiil tin 
diitiuiee tntweea lb* leT«1 or Ihn iwo tube* ■* equal lu two lisrai 
columiw. The preaaan) i< now ibn-e Htnuwplwm, wliiln tho toJi 
rmluml tn niin-ihird. Duloi^ and 
h«Vfl T>>rilli-it the Uw tor ur up to ^ 
uplivm, by mnnnfi of «i appw&tns •■ 
til tliat whiHi liw been daicribed. ' 
The law nl» JHildii good in tb* c 
pr»MUTi^ of l«M thta oae atnoRphcn 
iwtaUi'Ii thia, autaary u pound 
gnxlnntmt liibe iintQ It \» alMiiit tir» 
Ttill. the r«t being aJr. It ia tiwn in 
in ■ <l»(>p tr»ugh (vmtnining nMTCur 
10"), and luwrpd until ttiv Icrcb i 
mtirruTT insiiin and outnido the tubs a 
iinai<». luid tlie ioliuni> uotnL Tbo I 
ihnn miwd, m rcpmsrntixl in ihp fignn 
tbi' luliinie of the air ih doublnl. 
hpi|cbt nf thn mrmir)' in tfan lubn, nht 
niEicnrv in tli>^ troujch, in tln-n fuiind 
piocllr lialf llip hdfctt of tim Iwto 
colnnin- Ai-wrdinglv, for hnlf Ibe p 
lh<> Titliinip lion Ihwd (Inubti'd. 

In tli.> cxpirimi'til with Miirinltn'* t 
the ((Tiniililv of nir ivniniiii ih< 
drtiiiity muni obvinuslr inrmvr a* ita ' 
diniininhps >"xj iVTi»«rf. The la 
bi> <^unc-inti-il : * /W Ihf nameti 
it-iinfi/ '■/ <■ ffo* u frmporli/mal to ilt ft 
I JctitL-. lui wiittT in T70 liiiiM n* hon 
iiiid'T a pii-wiitK of 770 atiuaxphei 
wt'uld be B» (Ii-nw a« wmor. 
ill'.' last fi.iw yoRTs liiiylf'ii Inw wiw niippiMej 

V\-i. HC- 

I'lllil nilliji 
abmluti'lv trii-- for nil trasi-!" at all prpiwiirrt*, bill IWpntt*. 
amtniil thi- cumprvwibilily of jwi's. cbluiuiKl twulta incm-npatib 
tilt! Law. \\v l-iok two srailiiHlt'd g'LiiNi tiibna of tho aiuiiii l«ng 
filled niM with nir and thn othn with tlii» (TM to be Pxaminad. 
lubefi weiv placi>il in the stiuie ni»rrnry trciiirh, and the whole ■)) 
immpnwd in n »lTnnc glars pj'linder filled with water. Hy mrn 
piston moved by a prn.'W wbicli workrd in n fuip at thi* tnp of a c 
tbn liquid omild be jiibjucti-d ti) mi iutwa-ing prwsurc. and it ci 
it^n whether the cumpreiuion of thp t«c t(w™ ww tha wnw 



roseinUrd tlmt lucd for eummicis tli« ooniprM^ilnlitv 
It (fig. 47). In iIiH nHMWt l>t>pii'U founil that Mrkouii- ncid, 
eU«1 bjdmgiea. utiinufiiii. wiiJ cvHoofKO. are inoi* uomprmwibta 
[MT: lirilmfctn, vhirh hu ih« ume cnnipmiibilily an air up la lA 
I then lea cotnpnwabU-. Vcnia th>-w eip«riiu«nto it vrw 
1 iW Um law nf BotU Mill Slnriotli> ww ii<i( K«nor>]. . 


oiporiiiMill* on ihn nloidie fnnv iif mpoim, nuloiiR nKl 
had occmUiu to tat tlii? nccuiw-; iir ItoyU- and Mirioltc's \tw. 
MkiJ BdnpUdwHeMotlylltKt of MariiXle, but tlicap\iaT8t»> hail 



ox OAS£S. 

Tbe gu to be C)>iii|iK8«eil was contaiMd in k >U«nf( gUtu tvif.dT 
(fig. 108), about six fi»t looj; and doeed «l the top, O. The prnwof 
WM prodticii'ii lir • rnluinn of incrcaty, which rouU be iiiciv»>-i <-' 
n hdt;ht of tW fi-et. eunUined in nloug verlintl tube. KLy fonu'-! ■■'■' 
Dumber of IiibM ftmily joioiul by good KCvxtjW u to b* periWl; ti(-in. 

Thu tubes KL auil OF irora bmnMicBlly fiitrd b a boriiKinlal in 
pipi>, DE, whi<-h fomi«i] pnrf^f k ninivuriikl m^frvoir, A. (>a tLo tuf c( 
this rrwnuir thorv wat a force pLtiii|), BC, hy wbidi luerciiry «oU b 
formi] into tbc! npp«mtus. 

At tli« ootiiiiiviic«aient of th« mprrinient, the vohiiDn of tli« art 
iho mnnorai'ter (IIM) WM obstned. BiiJ the iuitikl prtmuni detrr 
by addiii}( lo th« )irwMi]tn of Uip otniaipht'Jv the bnif{)it of tlw 
iu K &boTe its level in II. If the lei'd of lb<i uw'tciin' in iIm j 
hsA bwn nbnv^ tlir IrTvl iu KL, it would bnro bvvii nm'inwry to i 
the -.bflmyiKo. 

Hv nicjtns of thr puuip, water wa« injeetiM] iiilo ,\. The me 
beiinr thfU piyweii liy llio wntiT, ram in ihn tiibr (it', whoiv it o 
pciiMi-d thp nit. Olid iu ili» tube KL, whtrv it m(m ftvelv. It va«> 
then ueo**«ii'V t-i iiii'n»iiif thi- volume of the aif iu GF; th*- bnf^l 
the mercun- iu KL iik've rhe level in ("F, lojiPther wjlli t}i* preauMt 
the nlmoiphiTe, win tin- lotnl prL-wurw lo whieh the pui vnw cxfomL ' 
These n-et- oil ihn cI-tiik'iiI. net'wuifti-j' for eomp«rina: dllTi^Kiit toIiiBM'^ 
and the t-orrnspoiidiii)^ i>?ti>pe rat urea. TIil- tube OF waa kopl oatddaiinr 
thi? expnriniont by a Bireiuii of eold wntnr. 

Thir long tube tvm nitni'lied U> a long itiaet by means of Btaptes. Tht 
indifiduni tiibci ■Ki'ti: iin|iporli<ii nt tlin junction by cordu, whii:h pwad 
round pulle_v»It and It' mid wore kwpt eiretched byamall buckets P, ■H' 
UuniriK 'liol. Id tiii.' iimiiti*.-r, eoi^h of the thirteen tub« having' >■'-' 
Bepitralelir coiinlerpoiBed, liie whole column was perfectly free, uui'^ii' 
■tniutiiig its wei);hl. 

Dul'^); and Arngo itive>tiffnt''d the jimMum up to 37 ntmoMphem^ tsi 
obsuri'ed that lliu volume nf HirHlwaysdiiuiuinhed a little iiiorv than b 
r<;quinM) by itoyl'^ and Mnriotle'* law. Hut, on tbvsr differraces ' 
very kiuhII, tliey nitribuled them to errors of ohseTvatiou, aud coadudil ' 
thnt the hiw niu pcrrfcclly exni^l, nt nnr tnto up to 27 ntino»ph«n*. 

SI. liegnauli iiiviu.iipil*d tlie wui" liubjwt ^vilh an nppB.ntus n 
btinjf that of Dulou;,' niid Anijio, but iu which iJl the noums* of «i« 
wen- tnVen into aceoiiiil, mid iho iibservntioiis made with remarkshl'- 
precision. EIl- exiwriiuouted with air, nitroRen, cnrbotiic ilrid, and bv- 
drogfii. Ilo foimd thnt nir tloei nil eini^ly follow Boyle and M»rii>l<<''> 
law, but expeiieiie^i* a greater i'<jiuptv>«ibility, whieh iuavain irilfa tbf 
preMiire : *o that tile liifli^reiio.' bolwiien the enl emulated and ilie obMrrtd 
dimiouthn of roliiuie ia gn'iHer in vfov'^'^" ■* '''* prewuv inctwum. 



Rffnanh faiuul Uut uitrnftra mu tilta lir, but i« !«<» oumprxwible. 

nair Kid <>jthibiu (»it*id«nbl? dvviHtiou frum BovIr bimI )tnri<i(i«'s 

, nfliLer uakil prMiunsa. Hvdrumn *l*n decUtni fn>iii Di>vl«> «nd 

ntl«'« law, Wt il* nnnpniNiUinitT diminitLes wicli iaorr«Msl presiira. 

I add de^lstM let* fntn the Ihw m proportion ■« tlic tmipo- 

■ hUfbor. Hi* U aiaa the com iritii otbor faMS. And vxjwri- 

I •bowa tiiHi itie d^'iaijon iVom tlie Jav It gr»Bt»T, in proponiou ta 

\ pw il DMrrT ita UqHL-fj-in); point : and, on tL« cininn*. ibo firtlier « 

li* &qa ihi* feiM, th* in«r«' clotvly doM it fi>Uow Ui« law. For ^w« 

I hair aul been UqauGed, tbv durutdocui ftoni the law are tnconnidrr- 

■d ma; be quit* Mgloctad in ntdLmrr pk7*iesl and dn^aikal ex- 

•nt«, when ihe pivMures are out gi«&L 

AypUeaUBBa «t ■ojla'a kad ■K&rlMta'a law.— Dbwr- 

loa tliip frilusiv* •••( pMttt Hf- Italy r>>ni[iHnibl>' «Mi ntail' at tli« 

t'sually. tlH'ri-forp, ia jr.ia iiiinly«'t, nil meaiureaieoU ure 

tti tke Rtindiutl pn^ntura ol 7t)0 millinipl^m, or '£9^ ini^hcs. 

tkeaMly lioDeby Mariolhi'sUw, fur.iibicetbeToluuicearwiuvenult m 

fjtmtiUM', V : V = 1" ; I*. Knnwing tLc volume ^' nt ihu ptuoun! 

I mMj calcalkle iu voluiuu V' at Ui« givuu tuiupt>nilitn> P', for 

Vi" = vp 


ft volume of gai to mea»(u« -^JO cuhir incb>->- nn-Vr r pw w uro 
what will bo it* T(iluni« at tlic itandiird jhtaiutv, TOO mm. f 

In fik* BUiDpr let it br aiilud, if !>* ia the dvfinty of a giu irbtru 
IW harau«1«r »laad< at H' nun., what will bv il» doouty L> al tha 
^■M tuopnaturu when tbu bnromctLT itimda nl f 1 mm. r Lrt M bo tlie 
taMEf tbegaa^Vila Totume b ib« flnt cM«,Yit« volume in tba«wxind. 

I DV = M = ir\' 

-. D _ V' 1" _ H 

•' If - V - 1^ ~ if 

Una, if n' denote 700 mtn^ wo have 

thnaitj nt H ^ (Dennity at itawlaid pmuure) .rrr. 

103. iKuio^taro.— Monnmetm are ineirumeutt for UK-A^Tirin^ thu 
tauka of gaiea ot rapaiin. lu all wanonivt^T* the nnii diowu i^ thn 
fnmm* at ooo fttnKWpbvic or 30 incbea of mi-iciin' at llie dnncliird 
t"(n|icratun.-, whitb, m wo liave eeiifii U nearly l-Mb*. to the luiiiure uiL'h. 

ItM. ibtaometor with ooavwMod air^ — Thit miUKaNcter u-ifh 



= SSf> cubic inch* 




P mV in tnnoifA nn Mnti'}tIp*M laur ; it rtinsUu of n gliM tat* 
SoMid at it* uppiT nxtri'init}-. rhiI MM wilh dry ur. It if 
qa«nl«d In a small iruo box miitiiiiiltig iiirrc-unr. tir k litbulnic, j 
■ttin lidc (^fig. 10(1), thi> linx L-i conni.-cli'il with thx rldwd remel Gcab 
the g««or rapoiir wh(in> t^^Mon U to Iw mMuumi. 

In tbn p»duHlinn of Ibin muuortKrtcr. tbr quanlitr nf aimnl 
|]i« tiibii in »ueh, thtit vrlim tbn Kprriuir X communicslM ftcdjr] 
lb* Mtmoi)ph<.-iv, Ihv level of ibw tuMn-ury is tho Mmu in the 
in tho ttibiilun-. CnnKsiuentl;, >t tliU IrvoI thn DumW 1 la 
uii Ihn m-h1>' t>> wbicb tht> tiib« is RffixixL As the prramre 
tlimu^rb tlip tubulaiw A incKiuos, lb? mirrcury riacs in thr inba, i 

irri|thl Biiilnd tn thn tAnxion tt 
(«mpr««»ed tiir. ia vi]unl to Ibn i 
pnrHun.-. It woald nni)(*qn««d 
ineurrwl to nmrlt tirrt alinoip 
tb« iiiiildli! of tb« tube; for me$' 
vnliun* of thp nir la iviluf^ to i 
Ito teiujon in pqual (o two atii 
ntid, togctlii^r vrilh tho weight 
int-roiirv raised in Ibe tube, U 
fom morf. ihnn ■«'» ntmoipberM. 
pmKiiiii III' thv uninVr is« little! 
ihrt miildlf, «t KUch ■ Iwjgkt tlitt ' 
vla.4tic for<-p of tlio oudiprnvcd 
tOBelhur witb tbi! wi-igbt of th« I 
ill the ttibv, in <<qunl V> twn ati 
The exact (loailivu of ibe nusiboaj 
4. rto., on thr mnnnmi^tar icnle i 
bi.' doii-miinod by cfilculAtioci. 
liincj ihi« iuiuioini?t<Tr i* madA 
«liiw itilx', BJ> ropn'>*iit<^ in figr.' 
Thi" principle in obviou-'ly the vsuic. 
UK. AiiBral<l burameter. — TIlii iiwtriinioiil dfiivriilAnam-' l^'iitik j 
riri'iimstfin™ thnt no li<[uiJ i" iis'd in its cimnlmclion (u without, nfk^ 
moLit). r'i^. 1 1 1 roprcsi'iita nne nf thp forms of Ihpsn inKlTiutieDU(i1 
atriirti'd by Mr, Tmi-IIh; it cniiMSla of a cjIindricHl mettil hox,ox 
of ftir, till" tcf of which is madci nf thin comiKntnd ninbt), an 
thnt it rodclilv yiiOds in nllornlions in tht" proMuri' of ibe attniMpher 
Whnn iho pn-Mure iucreiu"'^, thn top in ptv-Bi?cl tnYrnnln ; when i 
conttnrv it dni-niiwji, tlip rln"licily of thn lid, aiiU>d hy a >>priu^. ( 
movn it in ibi- oppiwit* dinTlinn. The.ic molinni ore tnuundt 
iJpJiculc iniilliplving Ipvnr* tn nn index which niovcn on a iir»1e. 
inmriiiiiMit in fcndtiaU.A empirii-nU* hy cwn\>titittif_ vt« indicatiosi 
diffvn>ut pnMfurr» witb ibooe of »n uidiiuu^' mBTrivriA^jiiMMSBi. 

I'ig. loa. 

Vli:. fl'X 



Tbr' HwrDid bM llin ■•IvuiUav of Mag porta)))*-, ud cfla I>« con- 
" of fork ■felMMT'Mluiodicatv tlHidiflrn^cviDptewnre brliTMo 
fauflit nf Ml onliMirT 
■ad the ftraiiail. li 
mucfa iwtd ia (!»• 
:nirh«igbt« in niHin- 
■imiU. Bnt h ia 
la til iiot oat nf mpair, 
V w)m« ll h«a bem 
ted lo itinU wia- 
of prwiim ; Mid il« ia- 
naii fruni timr to 
ccnnp«ml l^iMiaiM 
Mandiud laioiaeier. 
n. ft>wa ar ta« 
•r (aMa.— If « 
icalinn i> opi-ncd 
two cloMd vnatol* 
iBiair Iff, Uwy ■! 
in rn BiW. what- 
W UiriT .Ujimty, ud **'e- '" 

Imgar or aborlcr than tbe mixlare ia mmplvte luid will roDtifin^ i<i>, 
dkoiucal aelion or wwne othvr rxtnini<cii» rauie idTi^tvi^dp. Tlie 
hkh irxtfTO ih" mixttire of rmm maj' Iw iliuii suW :^- 
) Tb* inistutv takM placo npiilly and U homo^rn^oiiH, tlint iih. t^ai-b 
1 n( Ibe laiitUN cnotaiiiB IliH two jnaM iu tli>! biliiic |>r<>]>urtioii. 
IT ttiR fm.m sM'enillT nnd tbn tnixturc hnrr lh>i Mint" Iit-ciipeni- 
and IT th* froHia ipremllT aiid lli« inLitiire occupv [ho ntiic votuiur, 
tJiP [uri- Miin: pn unit of upa oxPTtiNt hy tbo miilur*' wilt •■qiinl tlin 
ih' ]miMMm« per anil or ama «xi>rUHl liy tli« jint<M wi^rAilv. 
thr wiwnd Iaw a rrn Kinvcnii-nt rurtiiitln oni be «amly dtduccd. 
',,r^ ff ■ - . . bw tliH >(iluin" frf wiToral ((it»«> iinder prewiTH of 
.... raapcdirdy. -Suitpan th«w gaavs wlien uiixcd t^ have 
V, aadur a p ro waw P, Iha t«nparBlon)* bning ih<T lumn. Ily 
aarl MariMlv'* Uw ir« know ibnl r, will occupy a Toliitiie P iindur 
p,' provided 

Vp,' = «•,]», 
anrilarl* V^,' = r,j», 

nil M* pa. But iTQ learn frnm the above Uw tliai 

P-r: + Pr'+ ■ ■ ■ 

Ij ToUowa tlial If tlie pirwiuv* an alj tbo Dame, tlie roliuuB 
torw f^mnCr fA* aiuw of lie MTNwa/i* ro/uiiiM. 



132 ^^^^f OS ojuits. [IW- 

Tke Gn-t law wm dumra experimenUlly b)- BertlMllct, ini mrtet 
of nil appnntut rvprcwnted in fl|C. 113. It cohhsm if twpglsMi (rlnbc* 
pTavi(|i»i n'ilL MOji-cock*. whirli chu be H'reweil ooeua UwiotlKr. TV 
u^ipor f[lobe ww filled with h]^i)mf(vii), and lh« lowe* one with cwbmoc 
wid, irliich bas ii tiiuM ibe (UrriHit; of hydrofiau Thu f!Uih» btiUf 
liRirn &:tr<l tci|f<!thcr wem plnoed in the c«1lai« of tbn I'luu OWtntM;, | 
And tbu aloiiH:oc)u ihrn open^, the ^lobe couininln^ liydragM b«ii|i 

iip|H!nita«L llonhoUct faiuid kftet IM 
tiinr thnt ihe prcwucv hail nm ckanpd, 
(till] that, lu *pit« of the diJVinvtii« b dM- 
■tty, till! tRo i^nees bad bcoomc unifonnli 
DtixeiiE in Ibe two gLob««. ExperinwDB 
mtulc in tlif »me iuniimt with other j!»^ 
pnvn the »<aine TPsultB, Mid it w«« (ou&i 
that the difluiiiou was luon? rapid in pa- J 
portion 0* the dlfiWrnec botwcca tbedmU ] 
il"»f wa« (CTWiter, 

Tbi> an-uiid Inw may be demnnatraUd If 
pmeinginto a timdiinted tubfi OTer meicutjti 
known voluiuc's uf )i»B at kuoirn prcsaiuW' 
'I'lio pn^Miifn ond vcilumo of the rb^ 
inixtiiru luv thon iiii>a«iir«<l, aitd found to 
V in ncisjftiotitc with the law. 

OiMeuiM iiiixtiu«« foltnir BoyU anJ 
Mariottf'alnw^like aiinptc )niBca,w hs- ^*ii 
pmv«>d fur air (Irtl), which in a mii:'-Ti' 
uilnn-pii tutd oxy^ti. 
107. Mlstnre of Riue* luid liquid*. Aba«rpll»a.— ^Volct Ull 
nitiny litjind* pOB*>'>« ili" pri'jiL'rty of iib»rirbiinf I'uder the mat 
ciidftiiions of pn-ssuvf and Uniiwralun.- n liquid dws not nbaotb eqlil 
ijiiuulilic* (if dill-'rcnt giufs. At 1ii<^ ordinAry tempi' mliirn mi4 ptw w l* 
wnt'-r diBjohv? ||;~ itn vohiiue uf bilrogpu. ^JJj il» vuluiiw uf bxrgco. )» 
uwu vnhiiiiF of rnrhonii:' aHd. itiid -I^IO timeji its volume of nmrnoiUACal gW- 
1'h<- wlioU- Biibject of inv ali8i)rplion bad be«n investigated by BuDixi- 
to wboi*e work* the ntudent is referred for further iufoniiation. Ti' 
ttcncrnl liiwi* of frfls-Rhsnrption an? iho follnwiug; : — 

1. For the aame 'l"f. Ou' wriiic lii/iiid, and tht tamt trmpmHart, St ' 
IBtiffitt of j;ri« iihsiirlifil ii projHiilioiial to Ihr prriaurt. Thin iiiny al>n 1« 
exproMi'd by i<nyi]i;j: thai ut all prL-»urm the vuluine distoUed is the nuif . 
or that the d<'ii''ity of ihi^ pi» ubticvbiMl i* in a coniflant relntion with tlitt 
of the cili-niul ffuv whin-b ia not abai>rbed. 

Accordingly, when th«p!TJ»iirediiiiiiiishe», tbuquanlllyaf disaolvodo' 

* fJasomclriv Mvlhmh, by R. BuiiMin, Iruiiiiliud bv l)r, Kotcut. Waltoa lU 

n-. -. ] : 


rusMint oof ttootES is ai«. 


IfaiMtntiMi i>f a gw br plnccd ondor tbc air putnpnad nvneuum 
reaipd, the |;*sob«ir« Us es|ttiiBi>'« ri>rr« and eacapeo with rlTervtuwcnc^. 

II. Tha fiMiptiffr ^ 0at atiorbeii u grtmltr rAcH Me Umpcratire t* 
war J Uikt ■■ In my, nhva tbe fUftic fonw of lh« ^na is 1«m. 

III. T^ qmmtilf of yta Khkh aH^aid etm itittolrr it indtjitrtdtnf «/ tkr 
iltmrw mul of til* jmaalkji of aliur gatn ickieh it maif aJremlii hold in w/u^mr. 

1h evexj ftttam inixtan «*cli fsm i-Xflrcisw iiiv kkihh prmture aa it 
mold if it» Tnlmaa oecapiail tlio vboU fpiuv ; sad tbe t»t«) pRMim i« 
|mlt(>ilteMiiB«f (be bdividiulpT«Mai«a. Wbeu a liquid win contact 
ntb ■ ipuHHu nUtuti!, it aliMNba ■ certain port uf «icb iraa, but ]««• 
hiui it wiiuld it til* wholo qiaot w«n> occupied 1:^ «acli nn*. Tbv 
{■■atilv of pach ^as dJMolnd U proponioual U> llie pr#iuuti> which lli«< 
UbMrbcd )pw i>x«Kiici iSaur. Fur iofttMDce,ux\geu fomis <j[i1t aboul ^ 
^ qiUMiilTnf ur; al>d mt«r, in ordinary coiidilioiii,abitaifa> nxactljr tiie 
MMB ijumtiiv of usjrgKM aa il vuuld if the alniu>iihcK wvre entiraly 
Imwd of thi» pu, luiclar ft ptwsuic equal to ) that of the almuajifavn;. 




lfV>. Ardunisilea- prlaclrle «pplt*d M saava. — Th« prMture 
Raitni hj gaao* on hodia* inunarmd in them in ir.uitiuitled equally in 
U dtR<cdiaBi« » liM faMfl tiwnt hy 
im axprniaMutt with the Ifagikbuig 
«ailaphcv«*> It llMiinton toiUivn 
hot ail which haa hoM oaid abmit tbu 
^•Uibnun nf bodie* in Ijiiuidi 
pfiia to budie* In air; tbey loM « 
art t4 tWir weight uciual to that uf 
it air which iboj di»|>Uo«. 

Tl^ InMof wnij^t inairitdemOD- 
tntnt by (UMIM of th« AitraaKipr, 
rhtch «nn«i«tB of a aoalnbiMUU, at one 
f whnm eitrwnliltita a (oiall It'aih'ii 
tri^ht il aupporled, aud at tUe 
Ibnr ilwi« ta a h^Uow copper aithara 
if. ilSf. Id (he air the/ exBdljr 
titan one another ; but when they 
in |laMd nailer tbe rt»:eiver of l!i« 
it fntp and a vacuum i* pniduoed, 

Kg- 113. 

W ifdwro Btilu ; thvn-bt thoirii^ Htmt in nmJit^- It U hea\iei t\i&n 
fca anaJI JUaAo «*4i*«. /iwan^ U« Mir u <rih«ti*l),-d each bod^ w 


Otl (USES. 


no^M up l)y the weipht ol the air vbicb it dii^UMft. Bat 
fhttf ioiniirh thrUt^^of ih«twi>, tu woiftbt luidergMa moMi 
diuinutiou, nud tliiw, th^lu;^ in n-olitr the henrier bodj, it 
iMured br ihn ainnll londi'ii wpiylit. It maj bn proved ky mesM < 
nppHnitqa that tlii* kwi i-i eqiml lu lliu wviftht of ihe dit 
Kir. SuppoK ih« rtiliiiiKi of the uphcTv U 10 irubic ihcIm*. 
w<ii){hl nf ihia v»liiiiiti of nir iit S't irruina. If now t)it« w>-igtit bui 
to ihi' Iradi-n trfiirlit, it trili ovcrbnlancc tJic iijibon! in nir, bo 
oiiiPliy hnlancn it in variio. 

Til*' principlt- i>f Areliimocl*it i* true for boiiiw in air : nit tl»t I 
■ail] n>Hiiit hnilii'A imninrwHl in liqniil* npplin to thrai, that )», that 1 
• btiily is h<avi<T tlinn air it will sinli. owing to lb** vxtvaa of tU ' 
tivAT tho htinTHncT. ir il ia M honTV n« air, its vmifrbt will 
npoiuiterbnlKiici.' lbs briMynnov, anil tb« bodr will Itnat in ih<? ati 
If thn biiily is li^rhlor than air, thn bimyanry of tho air will pmrut 
tli<^ biii]y will rifK in tb^ aln»uplu<rv until !( reachna a laTvr of th«l 
dptwity ns it,* nwii. TliP Curve aT tbf iultuI ia equal to iliu rxam i 
bunyancv nvcr tbt- weight of tlin body. Tlii* )« th» ivMOfi wfcr ( 
vapours, clnuds. ami nir bnllouiui risu in tbe air. 


lOR. Air balloons. —.1)1' hnlloont nrn bnllow opbi-nt* made of i 
lilfht ini|)-'i'iii>^abltt iiiHt--rifii. wliicb, wbi-ti tilled with healMj air. aithi 
liydrnspji aiti, or with roiil gas. lisH in thi? nir ill virttie of their n>IUi«j 

They •KPtt: tnvcDtcd by ib« brotbora Montfrolfiet. if Annonay, and 
fiml e\]>eiiMH'iii was mado nl tbnl plarf in JiiiiP I"'':!. Tli"tr 
wii» a )<phpn' of 40 yatJ# in eircuiiiftir>'rii-e, Bii'l u-cigliwl "1I.K) p,>ti 
At lh« liiwiT part IIktc wn.i nn npiTliurc. and n unrt cif hiuii w«» i 
pi^dcd. ill wliifli tlrei wn* li||[hl>.-d tn lipat tlip inlirnal air, Tbp 
Tom \t> a biiitht of S,SOO yanbi. nod iliruiIeMi.-ud<?[l wltliout anyardd 

(-■horlp'i, a pmfpjwor nf pbynirji in I'nt^^ siihitiiutiHl hydrnj^n 
air. Iln bimii^tf iiiwi'iidr'd in a ballouii tiif tbis kind iu 1>t>(%inbt!T 111 
Til*- uw of li"t nir biillomn wa« cntiri'ly uivvn np in coni>pi]n«iioc 1 
H-nMM nccidmla to wliirb tliev wen- lialil". 

.Siuov tlit^n, ill" nvl nf linlloiminK has \\n-n irrL-Btly iMlcndiN), and 1 
n*rinil» bFivt- bcpii niadi'. Thiil whi.'li f ray-Liisaw mniim in 1801 wi 
in>»>t rvmArkablf for thu fnctn willi wliivli it ban enricbi^il acieiipc, 1 
tho hcijfbt fliifli lii> allaini'd— L'.'t,0(Xl frrt nlmve ibe «■« IpvpI. At 
bi-igbt tbx linMiiictcr (tpti»-iidT>d to IS'lt iiii-bea, and the tbeimonwtH', 
vrhirb vaa HI" V. on the irrmi'id, was degnfe below »cro. 




lifeMihilH' rvgimt, tlie HrtncM ir*s Bu^h on UiadavoTCftv-l.uiuMc'* 

Bl, tliat bv)^n»elrie rabtaocVA, »acb m p*l)«r, parchnwnl, «tc., 

ilrinl ami i-rampM m it tber bad liit-n pJnccd ncM the Uro. 

napinliun aail drrulBtion of the blond wi>n> Kic^eralKl in c(nu»- 

nf tli« ignmt ttmttetino of ihe air. (Ihv-Uiubmi paW- made 

pilMOiiM* in » ninnte, IbUikI or OB, the Doraul niimbRr. At i^U 

boifibt tba lirt h*d a nfjr d«rtc biw ti»(, and sa abMlul« uleac« 

Cni- 'if ibi- milt mnarknbliT rrnvnt wCMita ww miuln bj Mr. Olaiob^r 
l.i^ Mr. (VkiifII. in a larjn balliMMi bi;)oatn>S ^ ''"^ Intti.'r. Thi* wai 
illixi wiUi 1NI,0(K> riiliu: ftet at tanl gM ( ■!>. trr. 0*.17 (nO-.1M| ; thfWvi;Kbt 
«f ibf I'laU srait <>.•■) iniunih. Tht^ Hfrceiit look pUtv at 1 p.m. ini 
iSlfu^Wr A. jaul : at 1° 28' Uw.v bad rr-ncbml a hoiifht of iCt.JM fimt, 
■oil ui Rtetpii ininittM attvt a hejgbl of Jl.OOO r*^l, iltF* t»mpenitiit« 
W^r - IfH : at !"«>' tfany wrc "l 2*I.W)0feut, wiib the tbcraiomripr iit 
, - 16-y. Al 1° ftS" Uio biiighi flUUMd inw3i>,000 tool, and ili« tpnipiTfi- 
fan> - lO-O C. At iLia bvufat tbe tan^liou of tbe ait vna «» ^-ivBt 
^■d tlw> raid BO iatcnM tbat Mr. nUi>h»T (abtnl, lui'l iviiiM nci l<>iii;or 
IjlMiiii 1 1 Accordiiif' to an approximate 4«itiiMilou lli« lowi'nl bHr»nji-tTic 
balfHil tbi-y atlMited waa 7 inchca, wliicti would corrct^tond to n bvigbt 
rd 3ft,(W0 u> 37/100 fwl, 

170. Can*tracU»* utd m«aBC«meBt •( balloona.^A baUi><>n ■>• 
Bwd(^ ipf E'lni; band* nf lilk wh-ihI lugnthcr and cDVcrcd n-itli ciuiut«houo 
ivniah. wbtL-k rvtidom ii uir-iisbL At the (up tbi^ti* Im a Mt'oty valre 
riuned t>7 a iifmiiK. wbich the iwrannut c«ii npnn at iiicnHtiv, br mconii of 
a Hird. A liitbt Kirkur-work boat t> fiiiii[)>!Qd^i1 bir mean* »r cnnl* U) .i 
DPt-wnrk, whi<-b pnlirriy earrn thu balloaa. 

A halliKin of iltH nrdtnari' dimnniiona, whirh ran cjiiry tlirvit |innHiti). 
Walwui 1*1 rarrl* btirli, I'J vanLi iii diiimrtrr, uiid it'i Toliimv wb(>n it Ih 
«|mte fnll i*! aU^ul li-^ rnhie. ynrdiu Hip baUonn itiurlf wi-igh* SOO 
pniMUt ill* a twjao riot. miefa b» tbe tvipe and boat, 100 poimd«. 

Th« baQmii i* Rllffd aitbnr witb bTdroffcD or with cual iia*. Altboitglt 
lb* lattnr !• bratier lliaa Ihe former, it ia gicinrrnlly pr«rtnT»<l, Voaiim* it 
b di g «p » tr aod ninm eoailj' obtninvd. It in {iaw(>d iiitu tbe balloua IVoin 
tW ir>* iwMrviiir br mnan» nl a flnxiblv pipr. It U important not to 
fll tba Wnmn qitit^ full, fur tb^ atnioqiberic premrnr* diminirhM as 
UiiiM (tig. 114), and Ibir gni. inadn expanding ill i'onH-<itirnru if il> 
'- iiM, teoda to biinl it. It i« aufHcii-iiI fir tbc lurrnt if ihi? wvl^hl 
liailiuwd air cxrrtdt tbut of ib>i bnll'xiu bi S iir 10 )>niin<li>. And 
Urn ftirvB n-main't cviiuUiat m Ionian lli« balloou i» tii>t tjiiitr di*l«nded 

El ifUatalii-ii "f 'be air in the iuti-rior. If lUe atmoiiibrric prcMuro, 
WHpl», baa diiuini''ii<-d tu nne bnlf, tlic m^a in ibo bnllix^ii, nccurdiiiK 
jJiF and ittif'iif'f U^; A** d'tabkd lU I'oJuiue. Th» \ o\u)n(^ ot 

1r l3| 

OK OASES. [in- 

tbe air diq»Uo«d b theivroie twi<w u urut ; but, sim* its d«iuil; b« 
bccomit ooljr on« hM, i\\n vfijt\it, ui<l L'on4t«|iiviiiiT tb« npir«nl bnojHi?, 
u« th* Mioe. Wliaa uuce tlie liimciud ia i-nrnpl^li-'lv diUted, If it r«- 

tiniin In riw ihn fomt of ibi> unci 
li'^etvoaei, fur the volume uf '■!- 
dinplni'Rd nir TPmoiltl the uune. hi\ 
ila (Itfusitv diminiabM. nml a u:^ 
ttrrivoK At wbicb tba liuo; 
ei|iul ti> tlwi witi^hi of tfat) 
T)ic ImllooD cua aaw odIt 
hi^rii'iiitnl dtmiTtt^iA, outiinI I7 iht 
caireata o( air wliicli pm-uil in Ih 
MnMfphM*. 'Ilia lU'TiKiilul know* 

bj lb« baroDtptifr wll■-lb(^r he b 
niwcndinit or deac«adiii|r 1 aiiil br 
ilie «aiii« iu(i*ni> ho liewrmbM 
hcif^ht which li« ba» re«cbod. 
hna UnfT fixnd to tli<i bout would 
divnti-, bv tile [loeiliou it tnliH rJAtf 
nbnrn or biiluw, wbcther the 
IB de>et'iidiitg or KMiondJng. 

When iba aerooHut wi>hc«to^ 
M-L-ndthe npeoi tbcvnivo at tb«ti^<l 
tlie bAlloaii br tiifuns of tfan mrf. 
n-hioh nllnw* fa* to i-scnpp, nnd tb* 
balloou ediilm. If he w&iit« to dfKvnl 
tiiffi kIowIv, or to rise ngtin, lu 
vuiptiM uiil bftg* of Mutd, of irhick 
ttii-ra i* Ml ampl« eup^ly in (be Oft 
The d««<:«iil U fncililntod bv fiuM* 
of K gTApplin;; iron fixed lo ite 
llua^ Wben oiuv lliia in fixi 
nnr obstMte, lh« bailout; la li 
bv pulling the cord. 

The iMily jimcticel apptii 

M'hii'li air luillomui bAve hitherto hid" 
liaVL- bwn in miliiary rwnonotiria^ 
At iho battle of Klmru«. \a I'M. > 
Miptivi'bdlloon, lliatlR,onehelcl bvaot'rd, wu need, in whidi lh<inm* 
nn obii-rvcr whu rrport™! llip niovem*nl* of the cacMur In' Di««n* « 
»iyrmLi. Ai ilii- baiil« of St.lf.Tino the movement* and diffiaeiiiaiw (f 
thn Aiutriiui trocipfi were wanliwl by ft oaptive b&Uoon. twd in the wk 
in AinvricMballoMivvK frequciitW uiei. Thswholc (ubjoctof miliWf 

Fig. lit. 


■ioK fawi bm-n tiwtol b two juippn Ut linui. nrnret aad lij 
■m BMUmoot in * renni mluiuo of iliv l4ur«9iaiuO J'Apcn M tba 
1 Eb^imms. Haay womiU Iutc rtantlf bwn nude by Mr. 
W lut tkv purpow of BtUiifr BWtcotologU*! obtenatMiu in tlw 
If i*po«u if dw KtootfliM*, Ail bBllooiM taa only b» tralv asefu] 
1 Uiejr tan bn jniiilad, aad •• rcl iill atl«mpt« wiujn with lh\a rinw 
MWplittelr fnilnL TlieK U no iHber eomvn At pKwnt tban to im 
> ■Lr, until tlii^m )■ • 
at wliicli Im* wore or 
]i« dmiml dimction. 
L rMr«eh«tB. — Tbn 

« nf tlin jinrncllUl'- 
I iX\an th<' HprDDiiai 
•if> llir bsllom), bv 
gr him tlw ni>f*t» iif 
date ^■^ npidilv oi 

X. It CiMUli'U 

circular pittu 

<fl^. HA) about 

in di^niFter. knd 

lib* IMiMWIOC of 

■pnwii iwt lilio 

itir uiBbmlla. In 

tm tbere U an 

IIimuK-h vrbirh 

ililitr of the ilo- 


pKiduis<iL, wbicb, 
niunicBteal to Uiv 

b.- ■Unp.roiiiL Fig. Il-V 

m tb--n- 14 M puBclintc lUtiwhrd to the Btt-work of thr balloon 
of a card wlUnb paiwM roiinil a pnlkj, and \n Hied nt ihi- 
to %h« boAt- ^^lion tbe CDTil in vul, the pnracbutv tauki. at 

rapidly, but main tlixvif iu> it bvcomeailiatoiKlcd, luntprrH-ntrd 



APriKiTm rocvDBit 091 T1IK rKOrKHTin or UK. 

172. Mir pnmp.^Thn air piinip ij> M inrtriinwiil by whirh a t 
cilu be {inNluc^ iu ■ uiveu »fiu», or THt)it-r by wliicb ur can b- ^m 
rktvflod, for on abaoluti- VBcuum ouinnl bn jirodiiorid by it* mcuit. Uj 
wai invenud b,v Htto vod Gu«ricke in 1090, a f«« Tcsrs after tlie in* 
tion nt the bnnioK-tvr. 


r I 

rig. 116. 

Til* air j»iiiLp, as now usually ponstniPlpd, niBT be dotcribed aa I 
in fifr. Illi, whii'h ^hovr* tlio gi'iioral nrrHngeineul, E ia (Ik iwn 
which tb" vui'uiim ill t»i be produc^eii. It in n brll siaaa, nwtinf on I, 
D of tliirh giiva, gTnnj\A pcrfi>i?t]y ^mmilh. In tlio o>utr« of D, nt Ci'^m 
ia an opi^iiiij^ by vibich a ■.■oitiniunicHlioii is miutf briwonn the inttnW' 

ApfAiUTTM roraoeo on tto pnopntnE* or aw. 


■ And of thp CTlindcn P, Q, Tkui oommunirction I« (riTeclnl 

|iip*» [uaHnir tiruiiKh line body of llit> plain A, luid rhoii 

" Ki rigbt anirle^ M dhcwn by Kro. Ko, in lig, 117, ivhicli 

bonxoDtBl MctioB of UiH oiadiiDc. In the cj lindt-ra— nhioli 

Jy of glsM. and which wc iinair ceuivutvd to th« plnte A— 

^Jliin^ air-ti^hi. Kurh pUion j* mitred \>j » 
1 Il,tunii--d bv 11 hiuidlp SI. Tliis IS Bhumi won? 
rtn Bit. 111^, vhich rqirNvnl* a viTliml lortinn nt' the itiRi'hinx 
. the I'Tlindrn ; hiirv II is th? |iiiiii>ii. iind MN ihc lniDdlv. WheD 
I down, nOB piitno ii niivii, luid ihn nthi'T drprcvi^d. Wbnn 
(• ravctwd, Ibv fbimer pUioa i« dupKMtnl, Hud thv laiivi 

iarilM> inacliln» tt ihin : Eftch cvlindor i» lltb^ wilh a vnltc 
rimd lti»t wtira ilji piMac ifl rniicd, i-uiuiiiiuiinitioii in nprnwl 
I ill* rt liadcr >ud tlin rvc^'ivfr; irhi'.n it i* ilfpr-^ood iIip miii' 
I ia ctuar^. Now if 1* wi-n- tiiuiply miw.'d. it vul'uiiiii wuulij bt' 
I*, bill M ■ commiuik-xtioii U opened witli the Kcoivnr, 
E pxpAiidf M> u lu lill botli ihe r^wivHT anil iW c^luidnr. 
I fittno hcfriiw In dHWvnd. the Himmunic^ntion ii c)oi*?il, aiiil 
rnr in tha rylindt'r »luni« to Ihe ruivivr. but, bv uwau* uf 
' nnnractrd tslt-M, Mcapea into llie nImiwpliprB. C-in-wiiui-iitly, 
!f»eliua wliiph Ihe air in tb« rowivwr ha* imdrTsraii- ii pcrnimii-'ot. 
I grit Kroko ■ fiinlKTr raref*i.*lt(in in pruilufpd : find m na, nt euch 


It is piRin ihM wben ibe nwradloD haa 
exieni ihi- utmospheric prp»iire oo the top of 1' 
it will \w vnn' ii'-nrlv ))HlHuced hv like atmotpherie p 
' trfthe other pisttui. (JuoiMiquGiitly, this MpnrioiiinM 
■.wine only ihn diir«miii'n nf the iv» proMiirw. It uj 
ftwo cvjiiiiicw are tuiplovwi. 

To u-iplniii tho action of iho rnlvca wn muot |to int< 
. Hmii))romeul uf ihe iuttriororilie c;iliii<iere u 
Hg. 131 nbown the ifetio 
denlt. Tlie piRlou is fiw 
diiw* (X Bml V), ncrewed I 
c-onipniBiiitr hi'twc4>n thpm 
di«ca (Z), vrliOMilluinL'ten 
tluHi thov of thi? ti?nsii da 
tliorongflily s«iiirin.ii n'itl 
luMigbt,lllouK)l with but li 
lliB i-ylindiT. To ihn centi 
is ^clvn'ud a piuiM.', It, to ' 

i« rivpif^. Th* piwe I) 
put ihu iuifrior of tin- cyl 
tiiratioD with tho rxtri-nal 
nic^atiua la cIohcJ br a v 
hy n dolicntc upriiifr ''. V 
uK.ivi'd diiwnwftrd. the ai] 
ia oonipnrMPi) until it foi 
cdpea. Thii inntant the i 
the vnlve ( fnllB, uii) in 
tprin^, And ihs prrMiiiv ( 
fruro coiuiiig in. The a 


Fig. 121. 
which is thi-n-'by kept 
twevn thi> cjlindor bnlow the pjiiton and the m^ni 
'CliM.fl by tli<? vnlve nmrkeil ti in lifr. 11^, anil fy in fij 
tfasdng ibrough the pialnn ii held hy friclino, wid t> i 
is kept froui bHiDi: tilled through more (hnit a v^ry am 
tep of the nylindnr. wiiilo the piston, in cintiuiiinR i 
•lideM over »//. Wbtiii th* pistnin descend" it hrinys 
which at oiicc puis oil lb" winraunicntiim betweuD ill 

173. Air pomp cBiiBe. — When the puntp faanbeei 
the pivwiiiv in Ihe n-iTivrr in indipiiti-d hy ihc dilfoTOi 
mercun* in the two le^ of ii irloM lube lK<ni like k ay 
ia open and ihi* other cloned like the haioiiietvr. Tl 
vhicli in Milkd the t/atir/t; is tiicd tn nn uprig:lrt 
under a imnll iiL-l! jnr, wliitli ('(•iuiuu[iieat«« 

eat«« witld 

^J *ntuw$ rocsDKD ox nu rnOFcnncs or ur.. 141 

*<'' -t. tMmcJ in tbr lubo ImcliDg fmia lb« orificu C b) tb« 
■ Hit. Ila. 

' "oauaairing to «ih«Dst iho nir in ibe rt'C^i^r. Ita i-Uutic fona 

' tfcp ww'jrfit of lim column of niercufr, whirfi in in iho Hfuwd 

**d abich (nOMHiiicnUt- Kinain* full. Hal M ihe piiuip in 

r w fliuic fofcv soon <liiniiiUht<i, biid in unnblc M nippon tfae 

si uf ilir ntmuTJ, vbinh links nod lend* to Hand nl ihn Mme I«t«] 

I hfra. Ifia aWlute xtteoaai could W produced, iLpv wcmld bo 

P|T <ia Ik laiuc kvcl, for then touU) bo no gircwuK ciitii«r on the 

u ofdr (>llier. Itut with thi> vxrv h<»it iiiAcbin«N tli« bird ia 

XboHtttbirtivth of tm inch hijtLirr in tho clowd bmocb, which 

' thtf iL* vacaun i> not ■baolutr, for tbn cliwtic ri>rc" nt tbo 

^■••qHl to the fPtmuM of* cnJumn of uiuii'urT' of that htiglit. 

Dt tbfi DurliiaQ on never ^rc mi •bwihite cncunm, for, na we 

■■^ thf «r beooCDM ultlRtAtcly so nnhri thikU whi-u the pistona 

I'l^ kttom of the eylimUr, tt> clnilic force cnnnnt oTnrroinr the 

I ibc Tklree in lb« in*ide of the puton, whiofa, iberefoni, do 

Ujr ta ahaol'ete THcuum ii aifo imju-'Uiblci ; for, «ince tlie 

■tltKkt^Under ii^ny, ,'{ thnt of the rvopiivr, only ^\ of the nir 

*M(bwWatr*Cl«<l nt mch utrnkenf the pi»tcn, and Oon«equenlly 

iSwiUtto axluuul nil Ibe Mir nbicb tl eoutaiu*. The tbearctical 

■'nkUHtiou after m pytta number of (troheii ii cnuly cnlciilnti-d ns 

y-'ljtl A dcftnte the roliini« of th« rcceirer, incliidiuff in that tcmi 

^19': iltbe TolniiM of the crlindtr between the hif.'h«l iitid lnwi>4ii 

irfchtfMlan, aad tM*ania fortheMikn uf di>itinciii?«i thai i)ie<reiii 

I nWw, then tlie nir wbieb utcupit-d A Man tb<- piston in 

lA+ltnfl^rit iiUllni, nod i?otiH>qiiciitly if D, it ihoden^iy 

■■rirftha firet alrvke ^d 1> tbeorigiuul denMtj^ wx uiuai bave 

K Aedmitjr at ttio end of the tecond trtrolce we iiarv for jujtt the 

iWKonlng Hill appljr to n atrokoa 

I m (wo e^nal c^lindrriy tbn uuiie frornuU ia true, but in tbia 
imadnsrii. Dpatmkea aud d4vmttr<)ki>i>(<qiinllTivokon he tnw. 
tabeiMis tlint (be fxbaiwtion ii nnver couiplelv iiinee l*. eaji be zeT<i 

I N iaiafioite. Uowa^'sr, a number of attohea not cxcenuvely 


hevi OH lli« formn' fixis Iim tnico as mfiiiT torth m tlul nn tb* Ins 
lii tlie prpMUie which nisrs tho piston in diublo] i an adiaattgr^ < 
h «»unt*rlmUnc«d by llw inconrcnipncB thot now Uw |dnaa«-iU 
ne oscillation for one Kvolutlou of tlie tiy-whc«1, 
I Til* mochina i* double nctiii;;; ibnt ii, thp pirton PP(nir.I3^)l 
BUM ■ vai-uuiii both io 8w>nijtng anil J««c»DiliD^. Tkis i* efl*'<^"^ 
BV rollowln^ ftrmntrrniHiiU : In Uii- pislou Ibvm in aTaltnA "l^ 
Ipiranb M in lb<^ urilinnrr macliiiic Tlic piM^D rod, A A, 1* 
UA in thp inside tlinre is a copper tiLbe. X. br which ihc »ir niak"* ' 
lacapi! ibniiigh ihp valvn 6. At ibf top of the cjliud^ir ibrr^ ■■' " 
Hood rnli'D, (1, upvutu^ upwitrdfk Au iron rod. D, works viiL -''' ' 
Bedon in tb*' piii>in, nnd tcrminntiu nl ita end* in (wo cnnloU '•^' 
land ■'.which lit b to the openin^v of tbo lube, BC, Icadinf If* 
JMMvor. ,-| 

Vat us suppose tliie piston deKend^. The valre «* is Ui«d rltmi, ''"^ 
»Tilv»*beinR opi-n, the air of the receiver piutcainto til* 'P*'**^°^| 
I {latoB, while th« air in th« npnce Vloir ibe pirton uiid((^*'^l 
apwanon. aiid miBii];.' iLe valve, cM'HpM b_v the tube X, whirfi r**"^ 
bnnlcatw with thn ntiaonphprr. When ihn pluton MO>n>l>, iht 
uii'tion lakes place tiirougb /, and the valve » being- cluwd. thi W*' 
NK-uifd nir raoapw bv the ralve n. 

"J"he lUHchinp bus n alop-encV fnr dnuble clliaiiMioii. ainiUar l'>*^ 
llreadr described (174). It is also oilwl io an injivnious tnanmr. * 
Ulp, E, round the md ia lillcd with oil, which pamw Into tht amit'^ 
jHicn bclweifii the ri:«l AA »ad the tube X ; it pnaaw then ini" ' " "'* 
I o, in lh« pi«taii. mid fori^ed br tho ntinnipheric prSMure, U 'Hi 
lintribiited ou the surface of lh« pi*toa. 

Tlif appivmlus is of iri-'ii. unJ can consequently be mad* of mud ■ 
fTvater diiciensionn ibnn th« ordinary miu^hine. A vacuum can aUol 
jmdiiced with il in far tet-e liuje and iu Inrj^-r appiiratus. 

17C. SpreDvel's >lr pampr-^prcn^nl hwidevit^^da fmmofaii 
rhich di'ponds im Ihe principle of eunvcrtin^- the sptipc lo be exhi 
nto a Torrit'fllian vncuum. Tliridoa and coii«truclion of the appuini 
at thus described by the ini-entor. 

I If aa aperture be made in tin; top of a bitromet«r tube the metcm 
nnhs nnd draw^ in air; if the experiment be »ii armntri'd ii- !<< ill^^ 
lir Io enter along with luiTcury, nnd that the supply of jm- - jr.;,!"! 
frhile that of mercury ia unlimitwl, the air will be carried ni-nv, and ( 
ncuum produced. Tlie following iit the niinplent form 'if tlie apiinniut 
S whieh ihiH action is ivnliu^. In tiff. l2-1c if in a gIsM tube l-tiirrr tiun 
L barometer, op*n at both ends, and connect.-d by means of india-nibbrt 
Mblng with a funnel A tiltinl with mercury and inippnned bv a rtand. 
Itnur)- i* alloired to fall in Uub Wbe VA « iat« niifulated by ft dtmf 


irruMTTS rovxtiEtt ox tac ritopernc* or aik. 


K[ Hwl nf xhe tube cd Ota in tho flftnk H, whirli liu • opoiil 
liltlv liighur thaa Uio Iiiver eod of fit; iLu upper part 
Mux to whieli a receiver II can bo tighttj fixod. Wbon Uui 
l'iiBfnd,tti» BrA portion of meicurjrirKicbriint out cliMM Ib« 
Iftnott Mr &vm eoU-ruigr 

ill tb* BHt-urv ia allowml 
^Uv exbsiiatiuii bcinne, 
I «Ui Ud^ of ibn tab« 
RJanturv IiaTinif • dovro- 
Mm, Air and merciirT 
itnafh tbe apout of ibe 

■U it abot* tb* bafia 
KlbtnociUT bvotlNtrd. 
m4 badr bam Ciom tAtuii« 
llbttil A lo b«i rvfMMMl 

tkf tube luitil tlie vx- 
I ii (oiaplot*. Aa ibU 

ifpmMbed the tudoMd 
na Am oMvurjr eylindan 
tfinudab. uniil tb* lovrer 

(rf fomw n ooBtimtoiM 
taiatwy about 90 toolkM 
naida tkU Mafe of tbu 
k Doiar u beard likr 
■ water hBntmer wb«B 
Im openlioit i» completed 
I eeJinas of tstomxry mn 
Kit, and a drop of nucoaiy 

iba top of the oalunia 
ndoMiig the alightMt air 
the bcight of ibe colun^ii 
IMIli tba bcigbt nf the 
r wuvarj b tbe buo- 
'ittcr word*, it is a baro* 
Mv Tonicsllian vacniim 

Fig- IV3- 

Bier R Tbia appantua biu been uwd witb fTKat "uoceM in 
la ia whieb a rtity compl«^ <Tibsiution i* reqiiirrdiw in the 
M of O^iaalor'i) labw. (See Book X. ClmplerM) It may 
■I^Moaljr cambiiivd with an exbrnixtin^ n^rinK? whkh rvmoTea 
r i«it <•( ib<i air, tli^exbauBtioa being oomplntml a* abuvr. 
■danaiDK pomp. — Tbe oondeDiin^ pomp u m »ppar»tULs Coi 
Ig air or ULT otliergnt. Tbe fona luuoJJv sdopkd in the 


ON flAttt. 

fal)n«-inp: In n crUndnr. A. of ixiull dUiooU-r (Up, I^IX tli«Ki(ii 
piHiuQ, tliv rod of wiik'li UiuovmI br tfa« hatiil. Tb« cjUndw U pnt' 
with A Kivw n-hifh fill into thu rucuiver, K. l-'l^, 135 Atm 
tumngviiivcit of th# i«lvw, which «« to eoiwtnictcd that 
vnJvc. o, optat tnm the outdldv, and Um lower nht, 4 

When Che piMuu detcpnds. Ihe valve o clntes, uid the eUatle fa 
tb« conipri^iaed nir opccs Uau rnlvtt «, which ihu» B]]own tbo cccng 
a)r to pn^ into !)><■ mcpiver. Wh«ii t]i« pitton nwreiid*, * elom I 
opnurt. Km) pcrtuili- the tiilruice uf frpsh nir, which la turn b«coiBBi 
prrvited i-\ lilt; diiwiMil of the pirtnn, and so uu. 
TVii.v a^jiorntux ia chiefly uw.-d fui c\iiLi^ti^ Wi^uid* Tciih guni 




> Hi* t-tapcotk, B, it onaiinrinl willi a rtiwtToir of the [fis, by 
lai'thn tube, I<. Tli« pumji tMfaausU Ifai* pu, lad totrm it tnio 
fDMl K, in wUiefc (be liiiaid ii entitainrd. Tho vtilicial gMeoiu 
I tTf mailfl bv loMiis of analoKoiu apfHiratns. 
''tt^. Vm* of Um *lr pomp.— A pmat tiiiuiT cxpcrimimt* with thv 
^ futp liBVB bpca lirvtiiy irncnMi. Swh M* ih^ mi-n-UTul rain 
"" , tfe full nf 1)odi«a in tmim (08), the bUdJor O'^X the buntiti^ 


(U4t, Ui* Mojirdobaig bmnupbetiM (.145), and th« hitro- 

IW/Mafdia n nKwi (%. 197) U All fxpeririienl mwl" with ihe uir 
^ nd *bow> tlt« oUnk (ok* of tbe air. It ih b tlntk rnntkiniiiK 
4v Md air t the nudt la cLmkI b; a cork ibmairh whicli fia*^» » tiibo 
Iftof is tbo iii^nld- Tbe AmIc bcin^ ptiif iil uni!«r tho Ti<Mvrr, a jot 
r iamni botu Uie top of iba tiibo m wxut *■ the air ia «u iFicieuU; 



ox GA$tS. 

Fi^, 128 rvpii<(*'nt« ui nxpdrinwailtllnslralJitgllipfiriict'j 
, |im«iini OD ill? Iiuiu^i bodj. A |;)iue Tcw«t, «pcu nt 

pl»C«d nn thn pint!' of tho nmchino, thn uppor end of Uio cylind 
'It tbe liauci*. aiid « vacuum Ja iiMd«^ The bund thcu bwDuiw 1 
Ihe wt-ighl oT tli« nttncopliiMv, wiil cnti nnlv ii« takm bkii; \ 
etloit. Aod lu thu olmticitT of tlio fliijil» i^oulHiiicd lii tli»oi| 
couiilrrbnUuci.ll b_v llii? wi-iybt vfituf atinosphcw, llic polw of] 
vweUa, and bUKid tcod* to cicape from lh« poiv*. 


Fig. 12B. 

Fig. 130. 

Bt luesns of the lur pump it ma; be *bown lliat ait, bv i 
mypeu it cimtBiiiB. is aeee*»iary ftir the support of combumioB i 
Fur if ne plnce ii lighted tnpar under thn rvc^iver, ttod begin i 
ihe air, the Uuuie becum^e w«ftker a» THrt^fiicljon proceed*, Mxl 
EXtiii)£ui8)iiid. Similnrly an animal foiul* and di«e, if a vncunm 
if a recxirer under nlucli il U ^kced. Ukmrntlui 

and birds d 

•J ifMiuna foimtD ok the nuoi-EiiTiKs or aui, 149 

M. fuirt tad rnptile* wpjiurt Ui« iitit of itir fw a math \oa^ 
^ loMii ««o liTp Hvpml dajii in T«mo. 

■Imimh lubbt lo frniiitnt tnay bo kq)t in vmuo Tor n loutr tini« 
•I titmljfli, m Ucy Me nnt in roiilact nith oxypnn, whicli is 
ta bnunntntion. Focid Itppt in iK^nmiimliT rl<i«iid cun, 

rtiei the iii Iiml bwn cxpflkd, hit« V-eu found lu frwh after 

jMn M on ttiB tirx ilnr. 

Jbr**! (WKnKUit.— Hem*!) rounl«in, which driiTN ila Dame rmm 
r. tlom, wbn livwl Ht Alrxanclm. I'M B.C.. di-pcmlii on ihe 
■^nTlhealr. Il oaiisialA uf a bnui dUb, IXliK- 1311), und of Iwo 
^■ka, 31 and N. Thr di»h cnmmiiniraK^ with lh» lower part of 
ib^ X, I17 A loflir roppr 1iib>.-, B; nod uiotiipr tube, A, cnnnvcC* Um 
)be& A tliinl tabepnoMthrDu^lh tbfdu'h intb^lnwcf ptrtoTlhv 
IL Tbia luh* btvui^ ht*tt Uh«a out, Ihe ^toliv. M. i< pnrtinUT 
rith WKbtr, tlw tube ia then r«pUe«d, and vnt^r in jHiiiTi^d inin tli« 
Ilw water fluw* ihmuf ti the luW, B, into ibe loirer |flube, and 
li« air. which a (ntvtd into (he upper glniux ; th* air ihua com- 
. arlii D|K>n the wntrr. Mid (nnl:n« it jtl out a* T^^rnwateil in Ihn 

If il w«Ti? ool for the tvpiManc* of llie atinoKpherc', and friction, 
ii wmM rise to a heii;bt aboro Iho watvr in tho lUah njiial to 
brMM of the IoT<i| in th» two globes 
XaMralttaM foantBin. — Tho inlmtn'ffeHl fmmlain drpeiKb 

lk« elanlic foroi of llic air And partly on ihn atnioapheriR pTW>- 

con^ta of a ffoppM«i) glaM globe, C (l^. ISO), proTidtii with 

ree Mpnllarr lubaluna, D. A |tl*M tube opirn at both cnd« 
at ooe i-tnl to th» uppet part of ihn ^loba, C : th« other «nd l«r- 
jtut above a littJe apettUK In lh« di>h, fi, which aupportu tha 

with whldi the glob», C, w nearly lw->-ttiiril8 fllled. mits 

tubm, U, a* ilinwii in the fi)tiu« : thi? tiitirrtial prewure at l> 

gaal la lh« aln)0apli*ric prmuniv, to)relhi>r with lhc< weight of thu 

Af wator, CD. w)i{l« the piclprnal pT>-4«un! M that point is only 

III* aim->fpheii>. Thcfr ciinditions prnrai) ao \an^ nn the lower 

trUai tube la op«B, that tt. mo long ti» air can eiiivr and keep 

C at ibu «aflir dennbr w> th« external air ; but the nppnntiu is 

•n that til* oriflro in tlie dtab Tl d^H not nllow no much nater 

lit a> U rHreim fioni tfa« tube*, II, in oonwiqui'iice of whii^h 

KTaduallr rim* in the di>h, and cIomi the lower end of the 

,\d the external air Mniiot now ■'liter tha globe, C. the air 

twUtuI in pTOpnTtiim lU the liow c>>iiliiiu^. until the pnuuunt 

ilanui nf wat'ir, CD, t^tr^thcr with the tentiun of the nir 

> gtubo, \a equal to ihia «xuraal preMUre ftl P ; thv fliiw 

nilf (topa. iJ»t*t wamr MMioaM to ffow out of tbo dia^i, l\\« ' 


ox <Mfl». 

tubo AboK'iaiv-'ipeaiicun, nir enter*. Mid ibe flow { 
OD. a* bin; m tli-riv U water in lb? tflube, C. 

181. TlM ■n»bon.— The sjpbuB i> a Vnt tiiW i>p»n M 1 
with iini-qunl kpi (tig- l^SI). Il U Ul^(^d in trunirrrrinc linn 
ri>)loii'jng iiinniicr; Tlio >Tpb<tn i» flllnd "iili nnvue liquid, irnl < 
onds Iwiiii; cl'it-^rl, i[jti vliorler Iva 'm dipixsl iu the 1i<iui-3. m n^ 
in li(r. l;il ; or liii' *hotl<;r Ic? bm-inn Iipni ijippfd Jin llir lJ4uiiJT 
Is Bslittu^tiHl liv applying the niouih at D. A Tucuum b ^ 
duiwd, the U(|uid iu C riwi nud fills the tubs in MUMtquioH 
fttcii'Mphcrii: jimuurt!. It will thp'ti mn out thinagk llic nplu^ 
■w the nhurtcc viiJ iliji? In the lirjuid. 

A <yphi>n of thn fonii iw^reiteiitcd in lifr- 1-^ i* um4 
ptvipci^ir <>: th'.- li'jiiiil ill the mouth vnuld be ulijectiiiiMlili 
31, iinttib-hail I'l lU'' Iut3)^>r brftiirli. ntid it i* Sll<<il br clonagl 
Mi<l suckiu^ bi I.I. An pnlan-euiii'nt, M, noiilen tbe pa w i i ge otUQ 
into the mouth morv dilKcull. 


rig. ui. F>e- ist. 

T'^ explnin tlii* 1t<^w of vr*tRr fiuin tito •ffhts^ IM luuppd 
anil the aiion leg immersed iu liie liquid. "At pattai* then m 
C, And t<inding to miw tiiv lii^iiid in thu tuba, la the Ktmntplitric ' 
niiiiiiii th<> lieitfht ofth^ coliinm or liqiiiil PC. In Uk« numunr, t 
•UM nn ibi' end uf tbo tube B. is the wi'ii'bt of th« aliuoapbeiv 
preMiire of iho rolumn of li<]iii<l .\lt. But a» thin kttor eo 
locRer ihiiii CD. the fori'e aelinfr nl ]) in l«i» than thr toKv act* 
and onwijiinntly n fiow tnkut pin™ pn>pikrtional to tfan d; 
belwtieii thesu two firroM. Tlir- Auw will therufure be more i 
pinportion lu tliu dllli^rcnci.- i>f IctuI iiKwnen ili« aperture 
aiir&ee irf the liqiiid In C, i» Rreiitpr, 

l^i. The Uil«ni>itt«at sypbon.—In the inlcnnitl«iit 

lire I 





ri^. 13i. 

ritiNaoliBiwm. It h Mnngod in • T«iiel, en tlial the iboner ha 
P^vAf ktloni of lb« rtavl, while th* loNgvr l«g po^e* tbrougli it 
' ISji Bang M tiv ■ ooimImii Mpplj- «r 
t>, tir biel gnilu^jr tj^v* both in tliP 
'udiellwKilwtntlMliipof tlio STpbon, 
> il GQi^ (Jhl «*l«r b^giiM tn fl<^<r nut 
> ^fnaiiu h iwnuif eil ao tliM ibe Aaw 
pbna M tncK npid tluu tkM of tbe 
If — ppBea th* TM« i i ,nA coowquentlr 
I Main ia tbe YmmJ mtil the rhattm 
twlMlf«rdipH in ih» liquidj Uie ^- 
I (bn Hdiplv, Had thu lluw comm. Bui 
■•I I* (wiitinoallT M Oom the nine 
tb« laid <{(nlD tixi), uid tlio nuiMt 
l«f pbmonM'nB in reproduced. 
Ttc HiToiy o( tlie inUniuueBt n-phoa rjEjiLiiiu th* lutunl inl«r- 
tetMi (]triairi> «liieh ore fowid b taaay K>uIl<^i«^ uid of which ibcra ia 
% aceliiuil exftiuple xu-xi Gi^lMwiuk tu Yctkafaiti!. Muiv nf the*e 
^tiap fiminilt water for •uTcnl dsj* or nuollii^ and Hwn, rA'^ .<topi>io)r 
lir ■ runuD ini«TV,il, ivmh nicomiBRiie*. .In otlien tb^ Bow utopt^ and 
neonSmcui icrenl tiuwa b an lioiir. 

TbsM piMfionMiui «te cxplainni bv sjvmuiiii; I'lai i)ivt« an> iiiibtDr> 

wtdA fnwitaju, whicli u* niorw or Im* dIuwIt liltinl by ipriuin. nod 

vUeh mn tb«n •ntpticd bj fiaiuiea lo occtuTiBg >n tfan graund m to fcnn 

■a iairTKiiitriil »T|>tiiin. 

IfCt SlAr*Bi klsd* of pnnai**. — Itmipt uv mnchlmu «blcli srrre 

in^B w»i«t eititor bTinciioD, hvpruuui*, or bybMb HErcufotnbiiwd: 

I u« fi:ii>wir[iinitiT ilirided into i-Hiariw HJI ptwiiu, /vrce pmnjii, nnd 

I aarf/erru^ piniipi. 

•■MIm pmDp. — Fig. 134 nfirmraU n moA«\ «t * *iirli>>n puinii 

1 M i« u*od in In-turw^ but wUch ha» tbo mine amnp^mviit ax ili« 

in common um. It canaiabi, Ut, of a jfAiM rgUitdfr, H, nt ibc 

L iif which lh«ro vi > talrc, 8. op«iiiu^ ui>«-Hnl') : 3iid, of a rnetioa 

, A, wliich dip> iaiu the Tnwrvoir froni which wntcr in lo be taiwd ; 

. of a fHtau, which u moved up and down faj a rod woritcd bj- a 

P. Th* ptakni i* perfonl«d bj a hole, the u]i|>m- ap«rtun ia 

I bj a talvH, Q, optning npwanl*. 

■a the piaton riMa (ram tb« buttuni of the cyiiodi'r, a vacuum in 
balirw, and tiM) rmlvo U u kept doacd by tb« a[iiicapbi>ric 
V. whi)i> tbc air in lh« pipt-A, la i->in««qai>ncaof il*aln*tii'ily,raiMis 
TaltD S, Kiid jiiirtially paav-i into tho cttiiuikr. Tin? air b-iiiir thu* 
anM, water riMW in tbc pjpo unlil tb» pro*siirc of llic liquid cntunin. 
tCVnhn mitb ibc loatiou '>f ihu rarrl!<d tur irbiob tvmaiii* in tbe lubo, 

lai W GASES. [Ill- 

MiimterlMiUiicci lli« presniiv at Ihr Btmoti^ttetv on th« water ol lb | 

When Uif pUUm dyitunJ*, tlw ttiixe S i.-Immi br !t> own itc?Sfc ' 

luid pnitvntii t]i» tviuni t' At i 
ftjr froDi tlie ^'liuder bio ik ' 
tube A. Tbn ur Mimprnvdlf 
ih« pivUiD opus tbe lalip U, lil] 
i-H.-Bp« > inlu tho alnMcpliiriv tfl 
thi>pipR(;. WithneKMidrititel 
of ih'^ pi^tiju the unic acrini 
piu-nonic-nn is pMiiuiW, and I 
it frw ptrjhTO till- vritt«r 
llie CTlinUcr. Tho c8i»ct b Mvl 
roiupwliAl rancllfiiNl ; durinfc 1 
dcnvnt of tlip jaxtaa, Ibe 
S dofcii, and Uin wstiY twwj 
Titlio O. imd pMSM sktirtf 
piston, b_v whif h it i« [»U-J " 
ibn upprr mnrvoir D. T)wf«Ji4 
uow no mnrw air in tbe pBUfti 
imil tho watnr, ffltmiil bj tbr d-l 
iuiik^h«rir pKMiire, ridtuwilbtbj 
piitun. pi-ovided tbat irhcn it il 
thn ■iimnitt of iu ooutm 
nol uiotw tbnn SI fe«t abOTal 
luTiil hT tbr irntor to wliic^ | 
tube A dip4. for wo bsve 
(117) that H column of wati 
thi" baight in equal to the ; 
rig. lat. juj^ of tb» •tmoupUnn', 

In practicit tbr hi'iffht of the lube A diwt not often tiiMed 36 U ! 
fiMtt, fur, ftltbuiitib>< siaintipharii- pro-t^itir^ ran xupporL a higher oolonih J 
thi- VBciium prodiiciMl in tlic b«m?l is not piTrfwl, owing to Uia fact ■ 
lbi> pifitoii iI>>M not til cxnctly on tbn bottom of thit bitrtvl. Bat < 
tbtf witter btu piLMifil the piston, it 'm Ib« a*C(^udliif- tuKu of tbn hXU , 
which MJiw it, and tho height to which it can be brought doponibootfct | 
force wbii'h inurus tbi> piston. 

liiS. ■aoUan and rere« pump. — Tb<^ action of thin pump, a inoJi>l i£l 
which IN rep^>«^l1I>^li in li^. l.'t.i, doprnds bnth on exhauntion aiiAtm' 
piwrnm. At Itin blu•t^ of the barrtil, whorL' it ia coiiiieirti<d with tbn t4l> 
A, tb(>ro i* a valm, S, which oprti* upwanli. Another vslvu. O, up^nini 
in (be sauie diriK?tiuM. clom>s tho n]M'rtnr? of a coiidiiil. which piuurs fraa 
n bolvi «, n»M the valve S into n vpmcI, M, whirh i* called llie air 



Fmw thi* dumber tliei« b MKulior luh«, D, iip irliiob tlw 

K^ womt of the pwtnu B. wlitdi i* solid, the wnlnr rii»« llirniigb 
A inio lli« (ami. \Vb>m (hr pUton «iak«, Uie mlvi! S dcMM, 
«ut«r U loKi'd tiiroit^ the ralv-u O into tbe ir«crvair M, end 
t«ac« iDU itui lube 1). Tiir li<!ii{ht ta whicl) it mu be riU(«ct in 
deptnilt tdelf on tb« iBi>ltv« forvn «luL'h works tlie piunp. 

p hdM D worn a prolimimtion of tbe tub^ Jno, tbe flow wdiiM bn 
Dntl ; il would Mkt' plave nhiru th« plnton iltawuJnl, aud would 
■via M it wcmilrd. But hrlWHm tbtw tubM lbrr« i> nn ininrrAl, 
gr vMaaof tbe vrio tb«< K ^ CT Tcir M, mwum a coiitimiou* flow. 
iir (btwil tn(u the rewrrair M dtvidM into two pnrU, onn of 
g in D, pmwM ns tiuf wunt in Ui* rMorroir bj it* wsi^bt, 
idliM', In vinue of tbiH pcv^aaurn, rima in tha nsicrvoir above tho 
(if ibf lab« I>, coniprnMni( tli* air abon. Comrerjucntly, 
fblen Mew»di , iltd M tongvr farw» the waWr into M, th» Nrarth« 
H 3 

F<i!, W, 

oat <uu3. 

rlroir, Inr di* pj ow w it ht» roocivod, (mcu od U» 
Ip? tubs D. until ibc piitoo o^b duKoiidti, •» ibNt 
rir* •avtM*'— Thp po-inripU or Uie imetiaa 
liml In tliH case or iLe lii-draultc from, And »1« 

TIm lira tog 
mod*] daacri 
llie baneln 
whii-h i« to 1 
npratMta ft 
chine Thw 
I'inv 1' ami I 
are worked 1^ 
it] tlM li;!«re> 
P' is ndwd 
and water i 
Wliwt it ii 

ihriMigh llio 
thii tub* of 
of till- Bit cliimlwr. wliitw tUc other llt« im* llie 
rido of tli« ^>^>f ihoM is n tube, W, to wliieh thn I 
taetaa oC the pr«Miire which the cutnprvued air ii| 
OS the wnter ■ (trong jet in forwd tbmutfh the del 
■Mt b any direction. Both piftou mm m fMn-nod J 
oso in famed down thu other rliei^ ooviwquvnttv 
ioto the nir chnmlM'r without nmmlinn. 

187. Toloelty or eflliu. TorrloetU's theoij 
an ftprnuiv nimif in thn boltoiu ol' uny vusael, gjiJ 
particlf \<{ li'iuid ou tlw mirfnci?, willioiit rcfpr 
bwii-ath. If this pnrti.-k* fi'll frwlr, it wouM I 
the tiriiiri' ^qunl 1u thnt of anir otiior bodj fidlij 
bet1m^u (h<! I^vul uf the liquid ftod ifae oriBcfl 
billing bndii?ii, ii \'^gh, in wbicli ^ ia thfl acr^lpi 
A the hvifiht. If the liquid Iw msintAiD^d Ht \ 
by ft »trMiu of wBitT Tuiiniud into the vi-iScL 
hu (■■vnji'^il. lh>> pHrtic-liu will follow nno nnoij 
and will ii'UH iii the foiru iif a strvniu. Sif 
Wiually in nli dirnctiann. n liqniil would iuniJ 
Willi ih>- iwine velocity, p»vid«i tlii> d^pth ■ 
The liiw of ihp *»!ocity of elllux wa* dis 
be enunrinlod ai followii. Thr rriifitp of 
fn^y Jfl'D's Ml/ teauht haix on itucAih;/ i 




'^jut at (it tmrfart. It ii nl^bnueiillr cxprcwed bj tiia 

inn diftciJf from Uib law, tlui tbe velocity o{ tIBux deprnda 
pt «f ik oiiliee below ibc ■utEk*, and not on llii- nnl.tire uf 
, nmvgk utiftcM of e^iul um aail uf th« mul*^ drptlt, wattfr 
i^ voaM iMue wiUi tbe Mini? Tcloci^, tor althuiijtli tha 

t^ hnw liqnid i« greater. ib« wei^lil of ih<> •-•iliiuin. mid 
djr lb iirMBUW, ~U gn«ter U»x II follows fu^(><^^ that the 
it «fi<ut an directly proptutiuiml to ths aqoBie root* of Ui« 
Hi* crillcei. Vi'aur would iwuo froni aa oriftni 100 inchM 

mab^t wilb ten tiniH Uie Tvlocitr wiib wkicli h would 
one an iftdi bcluw tbe ■arfncc. 

utitiu of watFT which it«ii« froni orilicm of dill<-i«nt ueaa, 
ady proponieeal to Uie aiie of ilie urilW, prortdiKl tbe level 

Mdaflof tb« Jet tuna lateral oriilMa.— Frou ili<> principle 
il tnUHmiadoii of fniuurv, w»i>t Ucum bom au utitice m tlio 
nel witb tbe tame volodtv iw (roiii an «[ierliiie in the bottom 
U tbe aaiM depth. Earb [unicle uf n jitt iuuiag from tha 
*tmi begiaa to noro haritontallj' witb thn relodty above 
bitltiatance dtswa duwuward br tbv force of trniiity. in 
uuncr at a bullet &teA froin a gun, witb ila axii liorizontal. 
iDVii ibat tbe bullet deaeribcf a parabola nilli a TAflical uiia, 
wlag tbe nmtlo of the gun. Now tiai-v tach pnrtivU of th* 
u tha wumt e«rve, tbe jet itwlf lake the [larabolic forui. •• 

a nmadted, that in txvty parabola thnre U a cenain point 

ben, and that tbe 

RtbcveftoX tulb<- 

bi IMglutude of a 

I . bukK tbe Mino 

|fc« di«UBi» (rata 

I ibedmunEireiiiM 

pitwlu of a cbvle- 

%cspabl«of proof 

■iiaataucb below 

De itf tbe watnr ia 

iBo*. .\oeordingljr 

led b; watrrcoiB* 

ificae at dllTerMt d«pUu bebi 

own in flg. 1S7. 

|kl o* tbm iat.— If • jet imiiing from an nrifire in a vpriical 

u tba •nini- vcUcity at a Imdy would liave irliidi fcU fruui 




r* 137. 

Hu lurface, tolce dlfleieat 



th" >uTf«M of tlia liiiuid W tk» oriHce, th* jet ou^lit to rise C '^^_ 
of ihr liquid. It jom nol, however, reath ihU; for tie Ljifc' 
vkirh fall hinder it. Dut bf inclining tho JH kt • wiall ani^ y^ 
trttixai, It rvMhM 4bout j*j of Uw tbeorelical bel^l, Ih? difTr^v" vV lb" 
due to frictinM and to tho mriiit«nc« of the air. By cxpcriiiieit' 
Dtum th« truth of TonirxJU's law bu b«ni deiaanitratnd- {l>^ 

190. Q««attty oC •■nx. V«Bk MntnM««.^lr «■« mpp^^ ' 
tUnm of ■ viimrl oiintiiininir wnirr ti> Ik' lliin, Riut tbn orifin tii iitf'^ 
nniall tin?U> wbiH« Mva t* A, wu mi^hl tbiuk ibat tb« qiiaDlilr in * , 
K iliKlisr^ pnr v«onJ wnuki bn (tivpn by tbo formul* Av* 
iqn«« Afttli pATticlv luo, on the Bvirrni.i-. H vvltwUj iM)ual to •/^v^- 

I thin i* by n(i lu 
Ihr MM. Thia may he vxplaiued by wfrrenco to Bg. 1*1S, in vtiiuh 


partidai iiMo frum cocb point of tho orillcA. 

But thin i* bi' nc m*^ 


ivprMenbi an orifice ia tfan bottom of n rfiaat>l — what in teue In liii> "r^ 
b«!ng eqiutlly true of m oriltoe In the nd« of thai vcmcL Krnry paiwh' 
above AB MtdMvuun to juwa out of tlie r«w«l, and in M doing tifrti > 
pnanmoD tbouc near it. Thnw thnt inue eenr A and B «x«ft piLiMUu 
In thr d{rMltnn« MM anrl NX ; ibote neiir the oratre of ih* orifte* i> 
th« dirwliou KQ. thosi' in tho intMmndintP porta in tbe direcliooi FQ> 
PiJ. In otttupqutniv, tiic waltr n-ithiti th» i^mco Ifjr in uB«Ue to 
Mcafe, and that which dooe rscspc, iiutcod uf BMnuiiin); a cylindrical 
fonu. It 6T»t contiMctii, and labea the form of a tnuicat«d cede. It w 
tcmai that thn «<ii.>apiu)i: jvt coutinuM to cuulract, iintU at a dtittNC* 
bom the oriliiv about I'qunl to the diamalOT of theori&ce. Thli pKttf j 
tb* jet in cnll«d ihe rma amtractit. It U fniind thnt lh«ananf itil 
1^ r^ aiiinllut M>dion i* about J or 0-1)2 of that uf Ibo oriiMt j 
" Awordingly the ittiv value of tbe rfSax per MMod ( 
*\ 1 /B ' giyen appnixiraatclv bv tbe fonuiils 

E = ftiKA ^ 2jfA 
or the ortuo] Talu« of E U about 0-<M of ita tiranlM \ 

U>1. Xafliiaiioa at tubes on tb* qaaatlty of e*u> 
- — Tbe rtMult pii-'n in the Wt articlp bii* rfft-n-ncv to u 

Fir. 13A. apettun.- in a thiti wall. If a cTliiulriral nTottiieit ellJTi- 

tubc> OT iijulagu ii>hl(4>il toihe Bpnrturo, the amount uftb* i 
dSIux bi couidfnibly immiuwd, and ia aouo ctat falb but littlo abort ftj 
it* thMNticnl BiDOunt. 

A ahoii rTlindrirad ajuta{i><, whoM length i« from two to tlin* I 
it* dinnirliT, ha* twi'ii found to incivaiie the efltui per second to i 
O^A^^. In this rum, thn wntir on entaring tho ajntnffa foisa ■ j 
eostracted vi-in (Hg. 1^>)). ju«t an it would do on iwning fredy kto tb-1 
air ; but anfu-wmrda it nxpiuidn, and. in cuntequenm of tlii.' adbMiM ot 
tbe iratcf to the inttrioi nirfaceoftbettibo, hn*,on leai-ing tbeajula^ i 


Th« coBtractioa of 
IT ui (kpennre w 

Fig- 139. 

t "^J qcAjmrr of trn-vx. 

^Oimpttln ibn Ikti of the iwntMctrf win. 

""■"*• ijol^ c«mM ft p«nuil vftcumn. 

^^ll'*|M««T llNf point uf pVfttMl 

»U flittd with It Tcrticsl lube, 

'MfiifvUeb (Utw JnUi natoc (tig. 

i« t«tj (lui nbtr iwn in tho VMtica] 

SUapltaitbelonnqf sconicfniMiim 

' li^ Md b at the »pertiire. if thr 

• m* prapfirlv diouiii, Ike rfHux pT 

: mj bv nunl to OViX^/'Jffh. ir tfai- 

r««lof a frmlmn of n eotic ornuilaMc 

hf littod lo the oriflm, the cfltui 

I Mil Anther ii»a«M«l, «id bll tctt 

idtrt rf th« Uwnretiral Amouni. 

VhM the ■jutip) haa morv (ban ft cBrtdci 

,aomuid<a»lilrdiniitiutii>nuiki'jipliw« iu 

MMBt of ihe ^fllux, for «xaiii{ilt.' tf it« 

b 48 limn it* diameter, ih* efflux i* 

toOWA^/^yA. This ariaM from ih? p. |^^, 

,tfcat «liai B'ater paww aloog cvUnilncii] 

, llw rMutanm tncrMM* with iIm kagtL Thi* cflbct irjil bo bcA 

b;t tha fi41ioir!iig BUtemeot. If in fig. 13U. wu Buppom the 

I lo b* replacod by a lube excoodinft >[<• dinmutcr in Ifngth hy a 

liiniu, at li-aat, ib« efflux per wcon'l E, will be r«lai«ii t» Ih&t 

I Ibe ^iilag« R W f^f^B abore in a mnnnr^r npjinixiiuatoly ^ven by 

(isBiida E,^Kx7'S7<(/|- whM* 1) di-notos the iliameicr of the 

Mm, and L it* tragtli, iliia* If lh« dlameier were I incb. and the lt>agtli 
MO fp-i, itw ellux fat toeoaA E, irould bn aboqt onu-citihth part of E. 
Tkia noolt it tne of water at ordiaary t«nipi>raiur««. Th« ivHiHlnnM 
wUch gin« rii* to thi* rotult ia called tu/itrattHe friclion ; it is iiidcpea- 
AMt of Ihif nalarial of ibe IiiIm, ppiTidc>d it \» wn roughnncii ; but 
iifMHb m a coiuidonblu Av^tw oa ibv vtMuidty of the liquid j for 
iiM<»«i»i. ic»«oU watar cxpcriniCBii a ftv&trr niiiataace than lukewarm 

IW. ratw AT tb« JM>— After ihn cnntract^d rein, the jet Iim thn 
km (if ■ •uti'l rod fur a ahort di«Uni:#, but llim hejcia% la Kpimte !uti> 
fafN vhkh ]iK«eiit a pasaliar appoanuice. Tli«v smiii id form a Knius of 
nam) and nodal a^KUMl* <iff. Ul V Th<^ ventral sef^ieoi* komkhX of 
dfDp* BitvndMl in a l><Kiioiil>l diiwction, and ihn nodal tpgmeiit* in a 
diriTtiut) And n» lh» vvnlrnl nod n<id^ M-ginetil» bate 

(!(. US). httwttamS^ 

If WKKfT W COAtUficd IB I 

rift HI. 

F* 1*3. 

mnmed, for it U expended In forciof OM tiie water; but U i 
ill* otlur ndo : and if th* TMtal mra nwTMbU in > horiMat 
it wouM mare in a iliraciiioii oppcMii« tbu of tlu iKuing jeL | 
luttntad bf tlie appantiw koomi a* tb* j^ifrinw/liir twiwi ifrf . a 
miff (flg. 143). Ii ct>n»i«ta of a glaa* Toaeel, M, coolaljiiBg ^ 
Myable of moTiu)^ nbuul Sta rertical aii>. At the lawor.j 
% Uiba, C, bait horiiuntaUj in op|i4*il« directi^uu at 
the T«aMl wet* tnii of wnttT amt ibe tubm cIomI, the i 
•Mm at C wiwlil bolanr-c t^Rch (ilbnr, being eqiiaJ and ttCIUi^ in 
ditwtioiu; but, b«i»g i>[>en, ibc vram run* out, tbu prw*^ 
OMrtod on ibe opnn part, liut onlv on th« oppodto ndn, iw iha 
BgUTt^ A. And tbia pnusuro, not being DeuiraUi^ )>j 




1« a iWalaiY moiion in tbo diroctjaiiof tbe aim w, the 
^vUdi infTMoRj wiUi iho bi^r^'lit of the liquid, and th« iiio 

'*■ watn- wheel anil tli« reaction macliloe dcpenil qd thi* pnn- 

ICoUi.n^' bn'wwkf also art on th« Mmo prindpU: tliM in, sn 

nacilou fmit tbc h«iil"d gHM which imue (torn atxmitigv in 

H ibem lunii-kti in th« ujiposite diivi^iiuii. 

raMe wlM*l>. Tvrbta«a. — Wbvn vcMer i» cdotiBHoml j Bow- 

■ aghoT t(i n Ivn-er Itvel, it vohy hi used aa a mutiTo pmrar. 

idKlMl bf lui-HMiof im(</- trA(*t<: thai ii, wheel* providr^ irith 

BoaUbtwrdii at ihe eiKoxalvnaw, naA on vrhicli lliv water 

(mMon or bj impact. 

tam is a thIjmI pUiu round a boiiiontHi asU, and am 
Idnda, HMlmAirf ud AftnAof. 
wb««b th« float-boanb an >t right anglon to th« cinntni- 
of tbn wbiwL The lowtat lloat-buiudj urv iiiiiiiFrH->d Li Ui<? 
whtrli ftowt with ■ vtlnci^ dopenlin^ nii tlir hciebt of th<i fall. 
'berU BM applkuble when (lie quAntiijr uf water i» great, but the 

■bf vheeto us uwd with a tmail ^ UHniiir of wai«r which hne a 
n, a» with anial] OMMiiitaiu *1i«am>. Uo the circtunfctEiu^ i^ the 
tlvmi nr buckeu ot a pwuliar iiliap«. Thq waii^ faiU into thx 
« tiMt nppvr part uf thu wbrvl, wliiab b tbo* moved bj the 
ol tbi water, and a* each buckvt arrivra at tba lowMt point of 
toll it diadiargita all the water, and aaorada empijr. 
htrUtf ia a boTtianlal water-wheel, and ia similar in priudple tu 
irwolic tiiumiijaet. B>ii instead of ttie honxonlal lube* there 14 a 
IB, craitaining curved vertical walla; the wntvr, in iaiuint; 
one. prtMaiiifr a^in#t tb««e wollti, e\«rt« a r«tctioD, and 
lit whiocl about a vcrtictl axia. 
bavr ibe advantage of hi'in» of 'moll Imlk far tbeir powvr, 
* Fifimnt for the bi^^beat and ihet ]ow«»i full*. 
jtue uiKivr* vatkfd hv a fnll at wati-r, it in of the atmcwt im- 
prvTcot tb« wat«r frwn ai-ting oo ilie iiincliiii-^ W titipnrl. 
W tu pnvoBt the great loo* of power wliich inalinaysuccuBiuut'd 
[wi I ■{ imperfect]]' da»tic bodioa. 
Marlvtlv'a featttot II* «•#, — Mnrii>ll<i« battle prvuKnta many 
fSnett lit tbi* Btmoapberia picaaure, and funiiidiPii a meana uf 
a coDaldtil flow flf w-at^r. It cciuiiiita ot a Inrge narmw- 
ln, in tho noch of which tbm ia a ligbiljr-dtiLng cork (flg. 
tliia a lube p aww a, open at butli end*. In tho aide* of 
ar« tbrve inbuIuiK*. t*ch wiiii a narrow orifiee, and. i 
\b cliaed at will. 




'nin bottle nod the tube h^iug qait« tUltd wilh wAter, !' 
irbAi iril) be the *fl*ct of <i|iRnm({ (Utrcttii'oly imo i>f th<- 1 u i 

and r, Mipponng, m tvprMwitod in toe 6% 
_- tliat the lower estri'uiitj uf jr b bet«'«l 

I tiiliiiliim> A unit <*. 

V i. tf tli>^ tubuluTv b U open th« wairi il'm 

^^^ AUt, and thn lurfncc idnka in iho tub« f uitil j 

^^ \_ ii la on til* ftftnie level e* ft, when tho 

^r^ _jil «toj», Thi« flow «i«» from the Hxcew i 
pr«Muiv lit Ih" point •■ ovi^r th»t at ft. 
)iriiuurr nt t i» Uie Mtau ok tli« proeenn < 
Rimmiphfliv. But when cinso Iho lord ia ' 
Miuie Rt ft ftud at ', Iho «lHiix oonwa, fai tk ' 
einiMphrric prriaun.' on kU potntx of thi? M 
hurizuulal lavtT, hr, U tiie ittanv (HO), 
ii. If now the tubiilure ft It cloted. ani e < 
PiK HI. opened, no ■'flliix taliRii plan-: nn the coatnifij 

air enters \iy thf oriGce n. and water aaecadlt 
ihp lube r/. B* hi|;h m ihn Uver aii, nnd thioi cifiiilibrium !■ rotabliabed. 

iii. If ibe orilieea <i nail ft ere uIofhiI, and r "p-ni'A, an «nBX barcfl 
rnnxinnt \elocity takf» plnrr. iu> long iw this li-vi-l n! the vuer 'a »• 
below the open enii, /, of the tiibn. Air I'ntiTK bubble hy bubble at < 
nnd tnkp» Iho plm^e of the water wliirli hiw llowcd out, 

Tn order to aliow that tlio •tllliix nt thn orificn i^ is cntiHtant, it ia I 
>arv to (letiioiistrule lliut the preuiire on the horixoRtal layer ck Is ■!• 
vqual to that of the ntnionphnro in addition to thu preesure of tbr i 
U. Now eiippo»e that the level of the water ha« "unk to the Ikjet i 
The air which hn.' pcnctratud into tlie llnak supporta ■ pnwsure oqa 
that of (he stiiio"ph'<r» diniiiiiahod by that of the polucnn of Kqidi^l 
or H — pn. In virtue of its ela.itidlv ibis preiuure i» tt&UHniittMl Uj 
laver cA. Itiit thi* layer furthnr ■iippnrtx the Wdiffht of a rolna 
water, pm, no that the pnuaurv at m ia really pn+Jt — pn, or H-| 
that into nay. \l+h!. 

In the »aini' innniier it may be shown that this preMora la tlw I 
when the Ipvet siuk.i to ft, and so on as long lu the level is htghn ' 
thn npertiin^ i. The premure on the layer cA ia tliirnforv <m>atMiI, tnA 
ooiDiefjiieDtly the velocity of the efllu.x. But when unee tlie lerd ia b«l>)W 
the point I, the prpssurc deerpasi's, and with it the vfloi-ity. 

To ohtnin a ooniitftrii flow by means of Mftriotte'« fifwh it is filled with 
wati-r, aJid the nriliei' wliicli is below the tube / is opened. The rapiifitT 
of Ibo flow i« proportional to the aqiisre root of the ht-ight. U. 





rftoprcmoi', rMrisinov, ixn BCPtEcnov «r Mcn. 
0«4»ei of Bo»Biii«».— The Mndv of *auikd«, and that of llin 

I ot riMlUC bodi**, form lIlF ■>1|J4WI oftfMMrfHK. 

I eoMUm* aooodti willi Rfi-remv to the plntiuntblt ftoljngs tWy 

to ntctte. Acoiuliai i* onnrvniMl with the qumtllom of 

tnamiLMiaa ami compaxiMn of aoitoda. To which may 

Xbv ylisnniogicnl qimtina of the pnrMrpttoa of found*. 

SwBd mn* MfllMr— SuimJ i» a peculiar woMtW excited in Um 

I nf h-Kiing b; llii; vihnUitT mutiiMi of bodiN^ wfaoD ttiia moiMn i* 

. to (h« nnr throuffh an niasitic tnadiun. 
I BOOBil* ate nol idmlical ; Ih«]r preaent diRw^rai hj' whirh thry 
I dfaliBginahMl, cMapaiod, and their idatioiM d«imnui«d. 

mn dinlJnfviiiiad from imum. Soond {wupertj u calkd, nr 

mamii, i> llut which prodticn* m ouotinuoiu rniwtirm, *iiiil lh<^ 

taliw of whirh nui b« dMetmined : wliilv uuise ii i-iihr.r a 

nf too nhorl a duntlun to be detCTratned, lUin th« Nport nf a 

(ir "bo it in a confuard tnixtum of many diaoonlact b»iuiiU. 

■ tnlUiui of IhiuidorortbB noiw of lh« wavca. XcrrfthclnHi, tJie 

balw*^ aunnd anil noioe ia by tui sieatu precjae : Savart 

Atrm IhBl lh«re *r» r^laliooa nf height in the coso of noise, aa 

laa in that of aaund, and tfane too tnid M be n-rtnin i-ani miffi- 

' wall orgaiiiiwd to detcimiiw the nnislcaJ value •>( th>> aound pro- 

I hf a mrriaice rvHiap on the pavemeni. 

«f *•«■«.— Sound i« almya tfao ntfull of rapid oaeil- 
I EnMrt«l to th(> mcdMulfli of ein^tir budiut, wheii Ihi- ilate ol' 
of tbeao faodiM ha* bonn diaturbcd <>ither by a ahnok or 
Soch bodiw land to te)nin thnr lint |K>Biti>>n of equllibriiun, 
reach It aflar performing, on each aide of that poaitioR, very 
1 TJbtaliMT motemunta, iHe amplitad« of which qnKlilj' dgCTtMC*. 
A Wy which prodnnwa iiHimf i* rallert a mmwva* body; m Uttd*T- 



r mMiw K movemuat to or fra. Th« FKoch ribniliont aft vith^ 

tvibntionii, an otnllatiim ot pArHfion U th* nMnni<n)t of Ur t{I 

mol'M.'uli! in onlv oot dlnttlon : ■ iAmiUv or cwnplrfr altmfaia ca 

lh.1 nwillnlion boih b»c-kw»nU and furwnrd*. ^'ibfaliocw tn- wij 

robwTvt^. If a lijEhl pf>wd«r i* sprinklnl on a body whicb i» in 

^nryidliiin)! n luiwicn! uniiid, a belt jar held huruontnllj in ihe hi 

«iaiiipli«, a ra^^d motion la impartiKl to ihe poirder vitick irndtrn 

the vibrntion* of the lH>dT: aad ia lh<! taiue uiaiict^r, if a AteUb 

be •iTiiftrfly piillnd and Ipt ^^'r <^ Tihratimi.i nm appanTK to iba oy 

IW. Uoumt U a«l 9i«p«c«tBd la nM««.— Tbe rib 
ilaatic bodici can ooih produce ilie tcosHlioQ of aound is i 
intcrtMitiou n{ a invdiuin intntpnuMl bftn^'eQ th«i Mr and thj 
body, aiid ribmtint; with it. TliLt lu^tuiu is usually tbe 
gMO*, vapours liquid", and *iliiU alio tmnunii noiinds. 

TKe Wioiaina I'xpcriniuiit ahowi that llie pnomca of a 
nadium in n'-rrunry for tha propagatinn of anuad. A wutB 
eU. wbicb ia coQtiiiiiallT iCrock by a amall lianuner by nmnal 
work, or an ordiaair musical box. in placf^d undnr tbo rMvivor ol 

pump (Ra. l-U). ^VtloD^aathe 
ia full of ^ at tbo ordinary | 
tha sound is tnuuouttad, but ia 
don as the air is exhausi«d th 
bcoomct feebler, and is iiB| 
a vacuum. 

To ensur* the suMyas of i 
mpnt, rtw Wlwiirk or mu 
be placed on vaddtng ; for ( 
Tibratioii* would be Iransnil 
air tliroujih the plate of th» mai 
'200. sonad U propacatM 
elastlo boCtm.— If, In tbe tA 
;>i'rimcnt, nftcr the vacuum b 
niadr, nny vapour or \[ti» W ti 
liie Mutid of lb« bell will b< 
iliDwinK tbnt found is propig 
itiU itHHJiiuu as in air. J 

.Sound is ntio propnsiit'd i4 
%Vbpn two bodies strikp a^ali 
other uDd«r wstur. the shocll 
linctly hwrd. And tiUn at the bottom of th« wni«r CMij 
sound of roloea on th« bank. 

Tho condiii^tibility of solids is such, tluvt the aciatcbiajiof aj 
«iid of a piece of wood is beard at th.- .Jthpr ond. The «aP 

Fig. lU. 

mrAMTioii or sodkp. 


Im nil, Uini «t tiifbt, wkm ilio «r U applied lo tbn ^rouod, the 
icfknea nr any oihei ooiw st itrut dinUuicro i* hennl. 
BL Vc«p«(wtt»B Af MmMd tB til* kir.— Id orttrr to liiuplif; 
i ILkim ••! til" pn^ui^iiob ^r twnad in ibe nir. wn i>iiiill flmi rnn- 
rthr rafK in wliicli it a propifialrd iti> cylindrical Iiiliu of iii<lrlinilc 
I«>i M>', 6g. I4U. !>• a uibc filled with nii at a euosianl |in-«- 
laod Wmjtemnm, and let Tba • puton OKiDaiing fspidly frvin A to 

R«. IW. 
bra I bi> piston p>w«i fnMu A (onit coraprMSM ib« air in lli« tuba. 
I itt EdBMvjaHiici* (if llii' invat <oiiiprH<ibilitf , the coudL-tiMtion of thv 
< nal Ukr- pUrr at oar* tlirniigbniit tli<^ irbde Ivogtb oftlio tulw^ 
i^ within a d'tliua lunflli nil. wlii<rli i* called iJw tmuhtufd ic<aiT- 
' tLf tnW UN liL> mppoced to he. diridod tnto lrn)cthi iv|unl in sil, 
■d racli or ibwv lejiglli* >!itid«d mtu Uren parallet lo lliv pifli^D, It 
IM* hr (biTirii by colcuUtion, that irheu the firnt layiTt uf tbu wave oH.' 

Ln, Hfi'. and ao 00 from layer (n lajvr la all piit< uV Il'll". IfH'". 
Ihp miiilpiwcd ware advancM in tlie tube, each of its jiaTIi baTins «iie> 
CMiTrl/ til* Mmr drgrro* of Telocity and ruadniKitioiL 
I Wiwu the pbli<fl teliifaa b the directiuu oA, a vncuuui in ]vodurvd 
lnhiixl it wiurh caiuei an ripanKna of the air in i-onlaot with ila po*- 
kAor bn. Tlir am layer upandbg: In [urn brings the firat to iU 
Iplglaal ttabr <rf canJwmitinn, and anon boat laj^er lo lavcr. Thiin, when 
ha pbton ha» rvimnn! to A, an f.rpaitilnl leatr in produced <if the tianie 
Inptb at the maili^nxii wave, and dtnx-ily rolluwiiig it in tho tiibit 
■W* lh>7 arv propagaicd tngvthrr, tho comMpoDding l^era of tho twn 
iHna pOHMMBif «q«al «ul coatnuj rolucitiva. 

' Th* whok of a condearad and 4'j|pRnil<-d wari' fiini)» an undalatiou; 
A|| h^ mn tmdiilatjim comprehetida that pitrt uf tbu column of air 
^■M daring the backwanU and rnrwRni^ motion nf thf< piitnn. 
WmbmfOt of an wulnl-liim 1* the apace wJiIuh suiind trnvi^ne« duriug 
ft BMrpli'tt librntian of the body which produccA ii. Tbii U-ii);tli is 
Mt b prupurthin n* th<- yibraiinna tuv mom rnpid. 

It ■ [mnnnaiit t-.< muaik that if we coiihJm a single row o( panielM, 
*UBfa whenal riM ix^fupy a1iiu> [nrallel to lh« aniii of the i^ylmdcT, fnr in- 
tauv.thaaEslai]^- AII"tli|:. 1411), wenball tiud llir<y wiIlliHlt^iMpcctiveW 
Ii Iba MHM) iiintiuil all tho raiioiu tnkidli«« which lb« piston has hml 
iMsaaidlaly while uadlUtiiig fnitii A to a tuid back to A. Sn that if 
Ji filT. 30 Ml' M-pfoaeola tho Unirlh of ode undulation, th« eurrad Una 






n'PQA will iwfimieitt tha nrioiut vdodtiM which all lh« pHun IhJ 
Ui« Une AH' have naudlmfui^ : tot inMauoe^ at tfae tauwi t the piftaBtri^Q 
nlvnod to A, the ptrticle at M will be mntiag to tht> ti^hi ^^H 
a rtHodtj npt^waited by QM, t)i«i pnrticl* at N wiU lio morjig H^^l 
li^n wilb n veldL-ilv Rpn.'wnl(<d hv PS, aud M on of tho other pufi^^^| 

Wh^n *n tiiiiliiUc»Ty inoti'in it tnui>mittail thnm)tli a dimDuk^^^I 
motiiNit of vaj two paiticlw nrv said tii he in thn min« fiArttp when I^^F 
particlM tnilT* wilb «qunl irlncitiu in ihr Mtno diKiClioD ; th« omB^H^ 
■n Mill to bp in opposite phaam wh«a the pariiclw more with theM^H 
velodtio* in oppoflitc diiDcdona. It b plain from an iiwpwrtina of fir.i^H 
that wh«ii any twi> parlicUa an> twpnrnlAil hr a di«taiice «^iul 1 < -• ■■■ I 
oudiilatian. their inutioiu an.- alwav* iu opposite phkici, but if '.ii .r .^ [ 
taiiiw equal* fhn1i>nfjth of an undulation thoir mntion* aroinUie aai' t 

A tittU <v>nHtJtmti»D will tliuw that iu the cmtdeutrj >r>ii» ibr a m^Jt 
dpitgacinu vrill Im tpvol***! at tliv middli^ nf tlw wnrn, and likevitrth^H 
the (upcndtrrf kikv will be mo<<I rar«4l«d at ila middle. H 

It tx «a nnuT imnsition fmm the theoiy of the motion of aoaioa^H 
wave* ill a cyliii<l<T ii> that of tbnir niotioDa in an uiilBGlased niwU^M 
It i« rimplv Dt-nmHrr lo npplj in all directiunn, to <«ch m«l«eul* of ll^| 
vibrating body, what hai biwn aaid about a piiion moveable In • l^^| 
A McJM of dpberirnt warca alternately <yindi?nM>d and nrelied >• |i^| 
duRod around each ci-iiln! of dixtiirbiuiDP. An tbi^ia wavee am coniaiatlfl 
within two Ronmntriml xphnrical tiirface*, whooe nuiil gndtially incrMMl 
white the len;^h of the iindulatlon reinaina tliu xnmi.', thvir iiinm inMMHU 
with Iho diitance from the cciitrn of diMurbuioe, an that the auflitoif I 
of tli«< vibration of th? nioletriileij gradually leaaetii, and the iatmrilj I 
«f tho found duniniaheH. I 

It i* them aphfiricnl wanu, altftraately condensed and cxpwdel.1 
which in bpinjr pnijiBfrdti-d irnnMinit Bound. If many poinia am fi^ I 
Iiirbnd nt tbn tnuin llnifi, a >yst<'m of wavca u produced around *tA ■ 
point Hiit h1I t1i-.-Ae wnv(<4 aro transmitted one tlir»uj;h the othsl 
without ni(Hlifyiti(- i-ithrr tijeir It-ngths or llicir Tclucitiei. SometlBml 
condnniwil or eTpnnd"d wavni coincidi* with other* of the aune nalsiel 
to produce an effect eijuni lo their Buin ; somrtimen (boy ni**! ndl 
prmliicK lui effect nqunl !■> tluiir djffurpnco. If the anrface of still wvUtl 

Lbe disturbed at two or more puiula the coeusl«ni-e of warw boooniH 
Mniibin to tlii> ry■^ I 

iO'i. Cftnaoa wbloli laflnenoe tlie Intenalty or aottBid. — Many] 
oauMu mollify tlie fnivi^ or l!ie infftitili/ of tin' tniKid. Tlu^vt nri', ihedp-l 
tance of the •oiKiniiii^ b'Kly, tliti ani|ililude of the TibratioiiB. Ibe denliljrl 
of the air at ihr place where the loiind in produced, tho diraclioa ofl 
dia currents of air, and liu>ilv, the pmxintiiv of-'iiheraoDOTOuabudieK. I 





ij nUtfAdAnKI Of tOL-Xir. 1€5 

tir umM vm t Mf from lU tar. ThU Uw ho* been dodiiC«d by 

rion, trat it BUty br obn driiioiiitnit«(I <iX]ionin«DUU}'. L«t lu 

' KVHtaJ Munda itf equal iaicoMty, for ioMaiiFe. UJl* uf the name 

:niclt hy bunnun oftlie Nun* weigbt, fallio^r from equal heights. 

«i t .r 'if tb«M btUa an ptacad at a dUtanon of W rania boni Uic oar, 

«bi nr at a dutaaoe of 10 yatib, It la fuuiui Uuat tbe single brll pra- 

4u. ■ ■ a aomii) of tb« mow intMudty aa tba four IwlU ■track limultaiie- 

•ru^v Cvmr*{ara\Xj, tat&tmV\» tho dtataDM the inteoaiij of the sooiul 

far fiMirlii. 

dkiance at which aounil* <sn b» board dapnida osi tbcir Jsteiiailv. 
Tbn wjnn al a vuIaiiu m St. Vincent vriu liMrd at DomFtva. 900 miloa 
'. atal lk« fiiii^ at Waterloo vai bcaid at Unvnr. 

n. Til ulMuaty o^ fir MODuf uH-rnun u^iU Ur amplHude tf lAc 
r ^(Ar Mwonwa iaoy. The coanectioji bntwi>L-n tho intoiuilir of 
I wiuDil anl tba aaa|ilit«da of tbe Tibraliooa, Is i«adily observed by 
aoa of ribtuiiig eoida. For If the vtiAi are aoiae^'hat long tbn 
aikiH ara peiMptiUe to th« eya, aad it i* tern that ih<> aaond » 
bbr in profatrtiai) m ibe ampUtttde of tbe oacUlatioa* dncircaMa. 
jiii. 1^ iiitimmljt 9/ loiaid dtiitndi tm AtdtMihf o/llifairmlMr plae^ 
} aifc'il U u ftroJic^ As w« hare already SMin (ItAf), wlim no ulurum 
. by dockwork la pUced under t^» bell-jar of the nir pump, tbe 
, Wmnea vMknr b proportion a* ihn air ia rar^llrxt. 
I liydmitMi, irhicb U about ^ th« duDBity of air, wucda ar« mucb 
r, allbiiugh tli« pn>Mure ia the ■amn. In cwbornic acid, on thec«ii< 
,wba« deiauty ia l-6-jSi, aoundf at« luom iaienM. On hifih mfluntaiQ*, 
vbm the air ia mncb rarefied, it i* nectnaary to spcnlc with wmv vflfort iu 
wdartobulwani, and tbediachargieof agmiproduceaoiLly a fcvble sound. 
ir, 7W <mtiKtiry of mumd it niodffCnf (y (A* n«oMon e/' fAi- atnuitjArrr 
.^dArJinrtitm <•/ lAt nW. In calm wtiatbar foantl ia alwiiyH Wttcr 
ptOfa^atad tban when tbEre 11 vtiimI ; iu tbe latter cmp, fur nn vqiial 
4fataw«, aoind ia oaoc* iBioMe in tbo diiMlion of th« wind than in the 
naOaiy dipsccjoit. 

T. IjMtly, HMu»rf M itTaiythmrd 6y the prarioiitf/ of a fuiin-oux luify, 
A attfaifr B■a■ll^ to Yibral^i in ttvti air and not ntMir a Mxiodiu^ body haa 
W a T*ry fwble aound : but when it TibmtH nbovi^ a ■minding box, 
aa in the caae of tbo violin, (Tiiitar, or vioUmcelJo, iu koiind >» luucli more 
Tbia aciiea from ibo fact tbal tbe box and the lur whirJi it 
I tlbralo in aniaon with tbo atring. llcaoe tba uae of Munding 
I is atrinvred tiiHtniinMii*. 
t08. AFP«ralM* to alrvBKUiea aonod.— Tbe apjMntua rcprcaentrd 
ia If. 147 iraa a*^ by ^varl U> ■how the jnfluenco of boxes in 
aiiii|lfcaiiiiig aound. It eoaaiata of a hciuiK/iJjcrical brAwi Teasel A, 
wtiA ia aet ia ribfttiai fy amjw ofM Uroog bow. Neaz it there ia » 


hnllow cordboAnl evlimlvr U. cloied «t tbe further end. Bv lueM*^ 
liHiidl" this cyliodcr ran bn tumad oo itn ■uppnrt. m oc tfl bp iocIlH 
luiy jriven Ai-gKV Wwiwdn lh« vmmI Tlie crlindvr is AxtA on <• **"| 
bv which niciuui it tnu bt> plucnl at nny dUtniiM ftnm A, Wht< ' 
vv<vfl ia nitu!<^ to TilimUi tfa* nreogiiimiDgi of tbe toaoi a vmt f' 
Me. But tlie Bouiid loM* alniott til Ita tntcBHt; if rhi- fji'"' 
tiinifii HWBV, luid it bccociiM (tni<liin1!r wrjJwr Trhpii the cylicul"' 
muvi.ll to u )rft«l<rr di^lanw, abowiu); that ihv olrvugtliciuu); i> in* ' 
vibmtion of tbe air iu tha cjliuder. 

Tb(- cvlind^T li i* mad* t^ vibr«t« in lUiianii willi llie bnia <«'" 
Adjusting it to a rarisic dqitb, which u effected b; niRlnsg w 
alid«< into th« otht^. 

Vitrm-iiu BtatM thai in ilie theatres of tie aueient* twonwl ' 
vMwnlii war* placed to itrcniftliefi tha rnicv* of tho flcton. 


ng. 147. 

SiH. iDflnaaee of tnkea »■ tt« tamnanUaalvn ttf aonad.— Thv ll* 

that tbuiuti^iwilri'f sound di'ctvnsc's ininvrwc priiportion to ihc ■qiujet' 
tho distnnre d(ws ikiI apply W tbe cafle "f tiibt-*, v«|H-dallj if (Lij ■« 
slni^bt aud cyliudrii^iil. Tlii! soiioroa* wnvci in that caw are not piift- 
gttteA in the fonu of iucrcnfing conc>nTTical i>pbere», and aound nui b* 
treiwmill^d tongrpnl di>ilnitc>'>vitbiiuiiiijv !ien.'L'ptibK' nllemtion. 11. But 
found that in one uf the I'nrin •n-nUi pipei, 1040 yneiii loi)|f, tho •mbm M 
ao little of itx inl«nidty, that h toiiver>alii>u couM be kept up at tbe tai* 
irf till- tube in a very low loiie. 'I"he wrakcniinr of ■nuiuj beoooBM, hoit- 
ulesr, peK«ptibl« ii^tubet of larg« dianivter, or wliutu tlie aidaii are rougb. 

rtwarr or »ux» ik oases. 



{■tf *t taauoitciag Muuib wno linl u.-wil :a Eii{[l«>il for 
tlM tbfjr ooiuut ot uDotehouc tubn* of kdiaII dumelw 

■ •WNom lo uiotiior. If* penon spnbRSt ocie «iul ut tb« 
ilii(im]j bawd b^ * pmon at tlia otli«f •od. 
ilbi*f«xpBriiiiaiuil is end«Dl ihni a moniuiinicAtion nuiv 
t*«a tvo tamw by iiimn» of >pF«kiiu,' tubes. Tbu Telocit}! 
tUdMtinftMCOtid fttl64C., MihatadiMUicnof OOmilwr 
vnmA in (bur misuiM. 

i* noft inpOTUnl ■ppliMlUnu i»f Bcouilical prinriplrt u tho 

ll <«MMt« of 5 cj'lluder oC hard wood tdioui a foDt loii)i ami 
d tt 009 «nd, and in wliicb % longiutdinal psMitK in bond, 
hi MlbMCOpc it ktU agutwt tlio diwMcd pnn of tbc body, 

» hatd •gainM tb« oDim. The practLwl phvudui cau 
daiam tf iolanal cantiaa bj the poeuiior «ound omitted, 

rtMngtbemd kf icWMaee. 

ffltr or ■oBod In t**<*- — Sincu tbc propHpmlicvi of tKinotuui* 

liuL Buuiiil nrijuirrd a c^rtaiD tine for iu tnuimiiMion frnm 

iBOtlwr, u i« *eeD is muneToiu pbetican«aa. Fur txumplc, 

Jkuadn la only hoard mmbo time after th« fiodi oi li^jhtniiijir 

, althou|(fa botli (licaoundand the litcht an produced Htiiul- 

h1 in like numar w« mw a maauci in llie act uf ttnUaog a 


J of awBtd ia ait Iwf often been Dte auhjeot of experimental 


leconrto <^ the direct nimiurf'nj^Dl^ niu infidv 1>T Moll aiiil 

I lSJt3> Twfl hilLi, near ADiittrduii. KoDlijobcrct and 

, ir»» ckoam u aUtionii ; t))«ir divumci? fr^m each other ■• 

IgtOKnnotrieall; mw 57,071 feet, or iieftily eleren nulo*. 

Bk<I al sUled inuvnla mmnitniioouilT at mcfa »tatinD, Hiid 
h vUpiwd betWtfvn wein); the fliutli aud hi-arinj^ thu sound 
' chnMOonetm. Thii time could be taken as that vhlrii 
lUfd b> travel between the two nations; for it will hesulxe- 
tkal light tako an inappri'dnble time to tmrol between ih« 
», Intrududng oomctioos fm tlio baroinotric prtteure, 
Ml h78To™''trie Mate, and eliminating; the inUuctica of th« 
id Vna IWk'i rteulia aa ttcalciilaled b; Sduiider rta d<T 
US-Tti feet a« tiie tolodty of sound in one stcnnd in dry air 
n rn im of TtlOnuit. 

• of toiHid incMaaca vith the inereaae of ivmpeniture ; it 
■lad for any tempeiatuie f from the fumiiila 

Ke velocitjrUO^C, and 0403005 the coeBJdeotof eipan- 

IfiS Acovxncs. [a 

hion for 1°C. ThU amounto to an ineratw of ii««rij two le«t r<«< 
dcjini) (Vnti)tr»do. Portlie ■unetemperatanitifuiiliipeiidenlof th*4 

,Ktj of tbe wr, and ooRMqnmtljt of Ot» prnwuni. Itu the Mae tot 

' suie t«iiip«nti»» vith tU oounda, wlietlier lh«v b« atronir or woak, i 
■i^ubi. 31. Dini fnuaJ, in kin Gxperinuaita on th* candorliTily tl t 
in tabM. tbat nht- ii a w«ll-known air wa« plaj«4 «a * Bute at J«u I 
B lubn 1040 yimb luu^. it wiu liiMud wittuiut nltcration ai tiM OthtClj 
from wliieb h« conduil*!! ihnt ili« Tolnritj nf diiTerml WMindii Utbel 
For the «idp reiuxiu thi> tuiiv pluyud bv a band is b««rd at b ^nat i 
lauM without nlii^riition, c^mpt ia inti^nritf , wbidi ooM oM be IIm I 

[if •omi! tuuuds travelled iiKiro rnpirlly tlian otbura. 

Tbia (-nimot. hoiri'vcr, 1* aduiitted as uuntrmilly tnin. EanialiaWtl 
a praCuutid mitthpninliml invi^«tiirntinn of the Ihwc of Ike ' 
aonod, bu fiiiind thul tbe vi<liX'itv of a aouud dspvndii on it* i 
and aci'uMin);!/ thnt n Tiilcnt nauiid ouRhltn bn propa^ralMl wilki 
veWity tliBU a ^rntliT uiie. T)ii» concliisioD 18 conlLnui>d bv an i 
tiuo inadit by (.'nplnin TaiTy uu bis Arutic expedition. Puriug i 
nractioe it wm fmind by pi^noni itBtinoi^ at acoiuiderablv dutaanl 
thia guna, that Uie report uf tbe caimoti wm heard bcTorc th<i c 
fire given by th* nfficnr. And mom rormtly, Mullet nude 
exporimentti on lh« vetncilr witfa which «oiind ii propo^tod in i 
olHiervinK' thv timw which plnpu'd before blaBlinir* nuuie at 
vrtfK hvaid nt n diKtaoce. tie found ihnt the krg:er th« charge of I 
■Owdor, uud tbvrefore the louder the rvporl, the mnrc TBlnd 
traasmtMon. With a rba^ of 200() poundu of (rnnprmdrr the ' 
wai 0S7 fi«et In a eecond, while wiih a charge of 1S,UU0 it va» 1314^ 
I the aamo tiniv. 

MM. Bravais and Martinii found, in 1644, tbat sound tiaraU^ 
hd tame velocity froni the bone to the suninit of the Fauthon, ■ ftni] 

' the anmmit lo the. bnae. 

Mnlli^t hau iuvevtitnited the rulocily of the tlHoamiudoD of aound : 
varioiiii rocks, nnd find^ thnt it i» na follows: 

Wet emid 82fi ft. En n -wad. 

Contorted, «trntiiied qiiMt* and eliite rock , lOftS „ 

OiacontiniioiM granite 1306 „ 

Solid granite 1084 „ 

The velority of irannd vnries in dtfTerent gasM. Diilonir eau«ed orjM 
pipaa to suiiud by iiieuiH of ditfurcnt gaset^ and found thnt the vdocitii^ 
MUnd nt tcrru wus lu follow* : 

Cniboiiie acid MO ft. in a sKuni 

Oxygnn 1040 „ 

.iij- 1003 „ 




rarhoiiic nxidc 1100 ft. b a SMoiid. 

Ilvdrop-n JieS 

son F^raalM tor caJ«aIaUat tbe rtioeltr •> »aua4 In «>«•■. 
-Fur raletilduig ihv vrlvnlv uf (•»iiid iu ^ilw* Ncvrton gt\r ■ nil» 
L«>Iiu» u tbe foraiaU 

I rRprcHUiU the telocUy of the •oiuid or the dbtiuice it traceU 

:. r i&» eliuticity nf tiu> giw, ind tf it# d»a«itv. 

fiVBisU esprcivM Oiat Ihr vtlaoitT uf llie prup(4,itiJDii nr fouod 

u dirrtt/^ a* lie ujuart ifat of Ote rloiiieitif of Ihf iiaii,a}iJ iarmtiy 

afnMit rvtit <tf iU drnrtCy. 1< fiillowti iLnt rhv trlucitj- o( aoiiml in 

uailer m>7 pc ww re, fov allhougli tbo dimtidty incmwR* with 
ytMsiuwi ill* dniMtT inrraaaw in the nmu raiio. Ai (juiio. 
Ihn mam [irmM ire U unlv ^fl'^ indm. tlin *«li>citf ia tbo iuhr iu 
• Um M-a leivl, jiTOTidn] thr trnkpcratilK^ i* the MMIB. 

If f br t}iF furci? of (cntvily, h the bsroinetrii; hei^'Iit n<iuc«l lo ihr 
^M |) pf»liiT" n-m, nod t the ilcimcy of mercanr, hImi >t xtrhi, il it dear 
^t tar ainu luiJrr iW alEDCvphurlc pnssute, e=yi1; nd for xvro 
tinn<m'i fonsala W-oinai 

lt0« if «v vappiM) th« tninprraturn oif a gan to intTDiu* from <y to f* 
hTulnmnwiD imrcaMi fn'tn unilj at tm to !+•( at (, • hting tlio 
,1 uf cxfMuiuoiu of thr k'Od. lint lli« diMiMlj' vnriu UitcikJ; aa 
ka vdIuhu:. tbuvfoM d brcomoa J-*- f 1 +a}. Iltoicc 

.■y^(i + <o 

TW Taluo uf r, nbtaini^ br tbU fonuuU, arv li>w tliim ihn pxpari- 
malu. IjapJaiv' u«;n>^ ■* " naHXi for llii'' (lim'tvpaDiy the 
IpvdBcadbjrprwuN in ifce coi»l««ia»d wavt-si (wd. hyccnridMntiofw 
•« lUa idwai, PouMo and Wot have found that Newtm'a formula 

it tv W wrillm P : 


-, (• 4- •l)-j * b«bg th« apocilic boat 

'ihrpuluracoiMbiiit pmiaui«, and f' ita appcific lieHt for a cc-nxiaiii 
I Book M. Wtten Ikn miMllfied tlie rvsiilu vidcuktcd by 
■ bfiDsk agFW witb lb* expdiniMUl r«*ii]lii. 

Timfkjmeml naMin (or Introdncing tbe eonxtaDl into the Gquatinn 

!^ tb lelochy of Mxiod may b« iindentooil horn the ft>llo*rjui.' con- 
^MualkML W« bBV« alf«ad;r Mm iliai iviind it pnijMgnWd in air bi a 
» of altcTKalr caaJmmtiaet dt>J nrefiKtSoat of tbe tityen. .\t eocti 




bcMt » avolnd, moA Uui li««t inprwn* tht f tastirit; i 
bu Ui« r^UUj witk whieh tarh caa(l«o*«d Uyer ut* on ibnnvTii I 
I llie i««Cutioa of cMcb Uyer. Um Mme mbmdI of beat itis 
' wm dAvuloped by Ik* rondvBMtiaa, wil it* riwtidtv U diuinufaad I 
cooling. The «fiect at ihia diminiohiMl eludciljr o( the omM lajl 
tbe Mcae m i( tiw ^luticit; of ui luljumt ytmto bad been in 
the n^iidilj with vthlrli ikio laiur would vxpaod upon llixi dilated < 
woali hf grrjUar. Tbu> ubili' tho Average leiii|i»raluK of the 
nnaJlcrrd, both the h<aliii; which incnt»t» lb? flailkilv and tlw* i 
which dimininhotit eonear in iacrearing Tolutttr. 

Knowing the veloHty of toand. w« <*ii r»l(iiUte •ppMixiiBatel; 
fiMwicQ at whidi H u pntducvd. Litrht traveU with lucb vtlocitT I 
Tike IhuJi or Ibe tnote aircoiiiiMuiriBff ihr mpnrt of a gun siajr be \ 
•idcccd to ht Ken nmultauMiuil.v with lbs exphMJoa. Counting 
rttte uuuibM of teoondii which clap« between M«ing the B**h aait 1 
' tlie »uiid. and mulliplvuigthiiiimmber by 1130; we f»i the i 
I fiMt M wbidi th« fTin is discbar^nl. In itie muuu way tfac dill 
r tbundvr may be Mtimati"!. 

307. Valeclty afsoaad In ll^oiaa uid !■ avIKU. — The vch 
•Ouod in wKUT wnn inviMij/nliil in I^J7 bT C.'olliuinn and i^lunu. 
noon^ twu hoatn at k kii>jn ii di'lanot^ m lli« I.alF uf Genon. 
•upportnl a bell immi.'iK'd in witlvr. end ■ tient lever providnlati 
wiliitthaniiutr'which Mrix-b th<< bi.'U, and at the other with a lighted 1 
■o arran^d tlint it ipiiitrd •»□!« powder thf moment the bainnt«ri 
the boll, T" th<' "'iMnd luial wi» nffixed an eiar-tninipel. Uw 
which won in wnlcr. wliile the mouth wiui applied to the •o 
observer. « that h<' roiiM muoiuni thn tiinn b(!tvrMB th<- AmIi cf 1 
Hid lliu arrii'Hl n( rununl liy till wati-r. Br liitu niHhod the rnln 
found to Im- 4T0ft fiii'i in ii nwond nt tiir trnipcrntiiM) S'l", or four 1 
M great ax in air. 

The velocity of oound, which is dilfeniDt in different liqnidi^i 
nlciilnli'd hy a fornitiU tuialn^nua to lliat fiwa aboT« (3(KI)m 
c«ble U) pioes. In this way ure 'ihtaitjcd the number |()tmi !■< 
following tabic-, .\t in the rnn> of );AAes llif velocity tari*e witb 1 
lempentiire, which is thereforv appended tu eai'h case: 

lUrer water (Seine) . ].r(X= 4714 fL In ■tMxal^ 

^_ " .1 ■■ - ■ 

Ariiltciat sea-watur . , 
Solution of common wilt 

„ „ chloride of calcium 

Absolute Hlvobul 

Tiirpontintr 34 

Kthtr «aOl 


= WIS 



= 4706 



= 6l»i 



= 64ai 



= a8i» 



= 3970 



■tsnJCCTKIX (»' tOVXD. 


tA» a gcMnalraJa, lint dmttidty of wUd*, m oompuvd witfa UiedtM^, 
melt If Ifau tlut of ii^okla, ud eoiu«qacBtljr tlw ptopagatko of Maai 

Tbc dllfauM* M w«U *Hia ui aa RspmioaoBt by U. Ifiot, who round 
thai wkea a b*U wat >tnick bj a biuiiin«r, at <m tad of an inn tube 
fUK (mt hmiTt two aaunda wrrn disliiiL-tly beard at the other end. Tbe 
tal of tb-Ao WM tnaHii(tt«d by the tiib^i itelf with a telix-ity x -. and 
Iba ««nod by Ikn mcloaDd air with a known Telocity ■. The intcnal 
{^Iwvwn tb< maad» was Sfi a»mnd*. Tho viiluc of j- obtalMd fron tbe 

•lii>w> that iht TiJodly at mihhI [u tht tmhe b betvcui 9 and 10 tixnea 
irn*t ■* that ill air. 

tU* cIm* of phcmawMia bok«i|^ tbv fact that if tbo eu i« held 
a n<k iu wbitlt a blaatiny U briny maili' at a dittaooe, two 
■eporti an biaanl, uoe tnu>*nilti«d ihruugh Uiv rucli to the oar, 
wAn liaaMHittKd tbnMigh tho air. 

relndtj of anaod bn oibet nlidi has also been dniennbcd tbM)r»- 
\y by WcflliMiiii by twana of ihtdr eocffici«nt of nUtticity. 

li>Uowfn(talilegit«ailiaT«locity, eipnvMd iu feet pet Mcond:— 

4030 PiiM- .... loeoo 

&;i7 Oak .... 131683 

W.W Ash .... I.T3U 

. lltUtl Eliu . . . i 13610 

l.'i470 Fir .... 16218 

. iiiKw Axpra .... le&n 

I *«lndt} b tba diiartkm of the tlbrvs wi« gnMut than acroai them. 

•f BBBBd. — So long *) (ODoroua warm are not 

lad in ibatr mouun tb^y aru pnip>)nt«l in tho form of nmcHntric 

■; but wli«i llit^y mvHt with as ob«lauI«, tlmy follow the KcDoral 

t at ilMtir bcdin* : that ia, they trtunl upon tbamwiKc*, forniiog new 

wai n. wliicb NMm Ui OTaoaw tnm a Mcond MMtre oa Uw 

r ada of th« obstacle. lUa plNuameDOO oewtitutM tko mflectioD 

lis rrpmH-Dta a niM* of mndont warM t«<lMrl«l from an 
fV Taking, for niam|>l«, thv InddL-nt wave M(M>N, unTitksl 
the wstn A, Ui« CDtre»pondiii|( irtluctod waie la tvpivix-nled by 
me, CKD, of a etrcli^ wbcoi- a-nliv a iBiatmi bi-yond the obatadr 
« A i* Matv il. 
I(Miyp(«Dt(*of tlw i«fl«ctiiig Miifac* h« joined to the mmomaieiMAn, 
if the papeadicuWCi/'fa Jr/zU/on tAeaurlWv of tliu body ^ 





Angle ACH i* c*ltrd tli« oi.vltr of imddam, Mid ibe angle BCII, fiem4 ' 
b,v tbe prolongaliuti of aC, U the angtt of rrfirdinii. 

w^ — ^ 

IIk? nrtluL'tiuu of lutuud is Biibjtct to the tirii fnHovrin^ Inva: 

I. Tlirr riwi'/ii' of rrjlrethn it rquiU to ihi angle of inrn/twrs. 

II. The intiilntt unifirmit riij/, and Iht r^ected rtn/, ort i» ikt t 
plant ptrjtfndicalar to tJit i-rftcctiag itirface. 

Fmiii tbvf iawp it follow* llini tli'i wnvewhbb in tlin ti^N Wp*" 
p«^iit<'d in tlii^ Uiri'Clixii AC. tn1<c* iIil- dircclion ('it Bft(7KSMt>U^•l 
\\ial Ml iiWrrfr plftp^d >il It iicnui, W^iili-'i iW >uund proceaduif hV 
thr: point A, a H-i.'tiu(i nuuiiil, nbicli ui>ptitni t" ctaiip from C. 

Tlip iHn'H of the relleclion (>r 91111111I niw th« mnie a» tbo«e f« UiAt 
Nnd raiiiniit b<ful, Hud iiiiiv be driiuiiuit rated bv *itiiiliii rxpprinitjiS, Csr 
of lh>' himpl-'Hi of the«« i> miule with CftniiiKntn mi^^1nl (sw duptil 
on RHiIiniit HcBi) : if in tlie ff*ii" of one of iliesp uiinvm ■ m»tA k 
placeid, ihi< (mit placMl in the focus of the KCotiil mirror hean tbe tickill' 
ven diaitiietly. evcii when the mitrorMueaiadiHtancvof Lior 13y*i4a 

'2Ui*. Bcboea and rea*aaaeea. — An echo h th« n>petilloti of B NOOi 
ill the air, in:i--(l in' Uf niHiTiion from *i">ni* ol)«lacile. 

A vciT »horp qiiicli Boimd i-iiu pniduce iji t-cho when llie rrflwttnf 
SiirfHcn i* ■'>'> feet tli»IRnt, tiul fur nrliculnlK pounds at l«ut dnuhln tbil 
diBtiili(*i> i>; iict'ewiarv. for ittiiMybeeiMilv Hbown that 110 nnu canpnuMMIon 
or hvRT dixlinctly niort ibim Hvc irllabk'^ in n wciwd. Noir, m tb* 
relocity i"f *oiind Bt ordionrv temporntiinui in«y he taken Hi 1,135 f««tb 
r« Mcond. iu n tiftb ■>■' liiat time soimd would travel 3^5 fwt. If Ar 
tcflei'ttng «urrHce i* II2'5 feet dislAiit fioiind would trntrel tbroairb Jtt 
feet in eoinp and retiiruiua- The time wliieb flnp9«« b<^lw««n tbe ailiea- 
lated and tbe r''llecl«d «iuiid would, tbcror<nv, be a lifth of a stvond, tbt 

■ nnxcnon of eoL-jm. 178 

Kud* would ooi intettm, nad the rsdeeUd Mund would be distiiitily 
ft A jMiKin »pt«kiag iritk n laud rair« b front of a rctlvRtor at 
btanoe of l)?'fi 6«1 can only diarJnguUb the 1n»( Te(lK.'i«l syllable; 

t) *clio U aaid to hv uimatyiMain^. If tli« i«ll«etor wrtr at a dia- 
of two or ihme Itnm 1I3& f^t th« oehowinild b« dlugtUiAn', 
Kkn ih» diatactr* cf th« rrflMting *urfM« i* Iom than 113^ Itwt, tba 
fct and UtB ni(t«ct«i muikI are confounded. They csnuot Iw livani J 
but tli< HMtaA ii itTcngthaaed. This u what ii uitl«d ^ 
ia oAvo nVnn'i^l in lai^e rnnmn. Hani walla ai* very 
lapaatrjr and hnngingn. wliii'li arv kHd rvflccten, deaden 

I ttAota are lliow which repeat the uime sound wreral timea i 
> caao wboD two oppiMitc >urfacot (far example, two pamllel 
ai*«ly reflect aound. Tber4 an) Khi><?<> which t«p«<st the 
or 90 tuMB. An ecb^ iu the chutvau of i^moneita, in 
m wand 90 timea. At Woodstock ih^K ia one which 
Ht»&om 17 toSO^UalilM. 

i» tki bwa of the reflection of aouod un Ihn wimn aj> thoo; c{ light 
curved Mufacee produce ar<iuttie fori like tki^ luniicoui and 
! Cbd produced bjr eoDCarn rvBcntor*. If n puri'in itnndina u-aAt-t I 
I p(a fariilg* spBaluwith hi* face turned Tnwanl" oue of lli« (iiets, 
. I> i«priivlunii near the uch«T pivr witu such diiitiiK.-1iii.-is that 
can be kept iip in a low looef which ie not heeni by any 
\ ia the iDInnnrdintc v|iacea. 
Tvt » aijuBre room with an ellipticAl c^ilinff, on tlin flrouad floor i 
|Im CoBHrratou* dea Aru ut Metier*, b fari^, wliiob prvteula thia I 
Hint—"— in a rvuiarkable degrw whan panoiu utand in tha two foci 


B* iKl Berely by aolid ■urfaca. «uch a* walla, rocki, t^x-.., that xound 
IwrteA. tt U alau relU-cii-d by cluutU, and on pawing intn a layer nf 
ti greater deutjlv ilian il* own ; it is nliwi furtb<!r r<;llcct?d by Ihe 
Idea of miM. Wbeu tlie weather 14 f'lgufy, Miuiiile und<>rg'> In- 
iinkblo partia] rntlectiniM, and am tnpidly dmiMvi^d. 
yhBiprriitg i^lcriea ai« formed of sruooib wnllx hnnn^r n c<nutiiiu<>iis 
nd btnk. Tlia uiouth of tbn ■pvaki-r b itn.-sL-iii'^ tit oiih point, imd 
«ar nf tlie bearer at another and diitant jk-Iiil, Iti this case, the 
ndiaMmenalTelyrrllcctDd tmmoDe]Knut to the other until it reitcbpn 

llMfcr^t parla of the earth'* lurOice are tineijually hnalrd by the eun> 
tas ta ibc ibailivH'it of u««a, empnration of wntvi, nti J other cauxca, lo 
It b the Btniiwphere there are Duiiier.>u> ascnding and deerendinff 
nwti o( air of ililTerwit deniritv. Whenever a sonomut wave |«im« 

171 'icoosno- I.1N- 

tmm n nwdium ra nnn dpniitj' intOADolli^r it iiudirr^r"**' parlial rcAcdhB, 
which, ihuujrh nut iCromg cnoujth to rutin an echo, dUdnctljr wtalnrf' 
tho dtmcl aoiinil. Thin U donbllM* the rawan, W HuiubiiMt Kitior'-' 
wh; nund Irotvls rurther at niirht tbui at iI»t iime; eran in tb« Sccnk 
AiMricJUi fonsU, whnpo the unimah, whirh nm nilwit by day, fiU lb] 
ntDKHplx^n? in llit- ni^-lil with tlioii«m<lN of I'onf uu>d aoumt*. 

^10. X«(V*eU«n ot aaoad.^ it will bn shown in ihn unquvl 
rrfraetiott it llie cliaiifCf of ilirvL'tiua which lifiht and heat i niiiiliwo ) 
paMDK from onf modiuni In annthnr. Sandhauaa ba;< fnund 
■enomue wktm arn rrfracleil likf Vifchl and heftt. lie «<iiiaIr<Kli^ g a WW J 
laiiMM, bv filliu); Mpbi^rical or li^atinuliir nolWion enTelopM witk i 
aoid. With mvelripefl of paper or of goldlieat^ra tJiin ilin nttmeSm 1 
•oiuid u DOt percEptibto, 

Sondhniim nit ciiial M^enln out of a htgp coHndion haltoon, mA] 
fa*ti>n«d thi-iii cm thi> two ludcu of n stieet iron rin^ h foot in diantrin; I 
M to r»rni a hollow bii^onTni lenii nboiil 4 Jnrhru thirk in tha 
This nuilJlln.1 with (^ulxinii^acid.Hiida WHtfli wan plfu^ed iii th^dinetfai'^ 
of thf ax'i* : the point vine then sought, on tiio cither «id» of tb* itat, A I 
whith thi.' *<itiii<t y»i- inixil Jiftlnellv heard. It wan found tbal wkMI 
ear wiu n-moiod frcm thr mis, the !oimd vaa taicrvW percppttUe; I 
thai at a crrinin point on the axial line It was vi^ distinctly iMvd. 
(Jomcqui'iitly the 9uiiin>u» wnvm in paiwnirfniin the lena bad DonTcifJfd 
rnwarda Ihn aii«, their diredion hail bMin ciiiui:»<d ; in other words, ikir 
hadbtwn fefract^d. 

Tho rfrrnc-iion o{ Hound rany bo PAsily dcmmistnttnd by mnntia of mt 
at the very thin iniiin-nibk-r bnllnons. ii»ed as children's toys, inflaltd h 
narbunic aoid. If thi> hnUoon he BUed with hrdrogra ni> focni V 
deltictml. it nets like a ennvex lens, and the direrKmce of tbe lajpi u 
jncrewwl. iuntead of their being cun»ur(!Td to the imr. 

^B buffd both on the relleotiun of Mund, nnd on it* condnelibiKly m 

^ tubM. 

Tlie npz-iiking tr-i'ttjul, «« il* name implies, is used to render ifce Trfw 
audibla at trmat dinlnniMM. It ronaim* of a slightly conical tui or bw* 
tube (flg. 14fl),veryiniirh wider nt oneendfwliiEbi* cnDftd Ihn ArT).*^ 


Fia. IM. 

vustiRCMKK-r nv mi vdmiikr op vibiutmss. 173 

M with ■ tDi>aUt|riec« at tk otli«r. Tbo Urjar the dirn'oiiow i 

mt tliB gTiMdBr I* the dutnoiw at which tbo Toico it b««nLl 
t&en k hmaII}' ucritKiI to iks mifc«mt« leflratioiM of Mnnruiu 
* IfBm tbo ii»dp> iif tbo lube, bjr wfaieh Iba wafm t«trd motn bikI 
ti»pa«iB • dirt^tion pumUal to tJio ui*orthi> uMtntnuait It hn->, 
nr. bBBO ulijectnt 111 ibin txplanNtiiMi, tlut iJia loundt emitt»it bv 
^kini; tru-nprt hth not ntnm^ rob-ly in tb« direotjon of ibo axi>, 
I (U ilinctiiNi*, tb«t ifau bell would uot l«fKl to ptodiicn pvallellMu 
I )«oii«i>iu> w»VB, wbrrc*! it crrt«inlT trxaiu ci>Mid«MUe inSuoicsl 
■mtbenini; iUp acnind. No Mttabctotjr upUnatiiw tua bn-n fntea 
liA*t orU»- twlL 
r Mr titrmptt i* uitnl br ]i*T«oiw n lio ntw linid 'i( bpATnig. It n . 
ubIItbii itii4Tt'-diipen)iiitg1ruiu]>el. uid cotimii of n t^cniinJ in(>t»lli<i 
•-D1- -if wb<Mi« <-xImmittM, Uimiiwling in a hril, maAii^ llii* iviiuid, I 
tlw oUiitr Ptul is itilr>i<)ur«d iiilo ibe eoi. Thia inflrumrnl U th4 

of tba uptalrinir tnimjirL Tito bnll httm a« m<)ii[li{ii<'i->.- ; lliit 
nM tbM M>unda mnitn;ir (raiu (ba mouth uf tba purran wiia 
rbmw •nnnds nra tnnniultcd bT n wvin of rotJmiiin* to ll« 

of tli« Initnp*'!. •■> that tbo ««Te», which would become giestlj' 

111. Mv cnnrpolmtcd oti thn auilitory nppnrntUK, nud pr»dii<-» • fur 

i>dt«t ihHD d)Ti>i)^-al waftii would havo doDv, 



RB«aii hnr*' bennderiiifdriirnifii^iinnK thn Diin>lM>rnf liiiniiioiw 
ndiiift to ■ |ri»M> ■"«nd, — fur fxaniplc, Savurl's whwl, the nvrni, 
d'a wrOmhI, >imI lb" phomiitOfrnipb of U, Scott. W> will hnrv 
r lli(i tir«l ibnw, rwrvin^ the ilrnnnpliun cif Uie pbonaut'igrapb 

■ diaptrr. 

flftvmt^B M|»p«r«ltL*-^ .Vitiwrl'f lotJitnl ii'^vJ. lO cnll»d from tbs 
' 4U ifiventiir. U iid j]>piimtui> bv which the Bb*"lule niimhtr of 
iiag to ■ pivi'ii iiot<- ran hv (lrl^rniiii>-d. It ciainMa 
I fraoie in wbidi Iben are two whwl'i. A and H (f\g. IfiO) ; 
^r wh«Htl, A, \» tntitkMUA with th« toothed »hr*l by muoDs of k 
a multiplying «l»ecl, thereby cauMog the loothnl wh«*l to 
ilh KTMtt trlority ; a cnrd, K, U lix«d an tlio fmiu«, and, In 
r, )hf< lonlhn) wh««l Mrlkua agdn»t it, and n»w« it to vibrate. 
! brtnir atrtiFk hriveh tnoth, niaku lui many vibration* a* ibifto 
At Ihn (ido ol Ik* ■ppatatiH tliort U an indicator, H, wliick 




'fri>'M the number of rcvoIntioiM i4 tlie irhe«l, Md ea4iMiqii"nUv tk 
Dunibpr oi Tibmiinn* in a iiivon time. 

Wh«m ike whs*l is inured nbwly tlio «pp»™te bIiocL* ^gniiut lb 
..cud nn) durtiiirUy hrud, biit if lb« Tolocitj i* gniliMUj iiwTttund, tbt 
Hind beconiM higliet aad hiffhcr. Baring obulnml the aouad wtar 
nbcr of Tihniiotiii ia In bo dcIrmiiiiTd, tba rpvaliiiion at tb« wbe«l 
DtiiHud with iho Mme velocity r>>r a c«ruin uuinbvr of ae«ind& 
''■mniber of tunu uf ihotoothnd vrhprl II ii then rend oD'oo tlioi 
Mid Ikia multipliM by iii«i uumbor of I«etli in Ih<» wbiM'l giTM ibe 
Ruiubvi' of libraliiiuD. UiridinK thiii by ibu corrvKpondiog number 
wrondji, till! qiiaiiciit iiivi-* tbe Dumber of vibrations por •pcond fur 
l^veD iKiuud. 

314 •jrrcBi— Tho lycMi in an apimrntus wUicU. liko Srtvnn's vIimL 
H "■"d 111 mi-nsiiiw thn nimibfr iiT vlbnitinii* of h bndy ii> * ir^\i-n time- 
Tbc iiunit- 'Mri^u' n'a< )iiri-ii to it bv il4 iiivuntoi', Cnjjiiitu'd Luiuir> 
boi-niisi! it yitrlcfs sniiiidii iincl"r wnler. 

It ie, made i^i^tirvly of biaju, T\f. lAl repr^wnU it filed on tia 
tftblo of n brllijwi, by wiiich n ciimininun curri-iit of nir can Ik «* 
thpingh it. Fiji*, l-'iS nnd l'>^ chnw lb-' intiTiinl dntaiiii, Tli* \ltt 
part ciniristit of n c^ylindrii-nl Ihi.t, O. eloxed by a fixed |il«[e, B. On iU«- 
plnto n vnrttcnl rnd, T, Tenia, to whic^b in 6xed a diw. A, ninvinp «idl 
tlu- rod. lu Ibe plate B there are equidi»tNnt rii'dilar boles, and ia At 
iliKv A. nro Ml i^qiinl tiiiiitbi'r of holi>> of tlip ibiuv iiitn, luid tli* *■■ 
i{i«liuiee from ihi> eeritrv a" ihuse of th» platp. Tb^x^ liules are Mt 
petpMidiculur to ibr diie ; ih-y ant all incliuL'd to tbe tminc i-sU^t in li« 
Mme dirertiiiii in ihn plate, nnd nri' inclined to tbe uim^ ^xienl iii \h' 
(ippoMte direutiou in tlie diH', ku tliat wlieu ibey are uppo«!to cacti oite 

iniAti-Beiinn' of the vimiiEB or vniKATios-f. 


in liav* til* appoannam n epre»ei i teJ in imu, fiir. 1^1 t?«ni>«^u«it]n 
hm • comiit or kir IVMn the beUow» rMcli<!« the lioln m, it strike^i 
bfaalr a^niBsl the uiIha of tlie bolo i>, Boil icnparlit to tlie diwc A a 
^ttorj moiiuD in ib« dirtrtion a\. 

Jht the «lu at iiiinpliiTii]r, l«t iia fiiM auppuer? ihm in Tli» moniable 
ir A tlwni am vifklwiii bakai, and in thi? lixcd plaiv' II on) v <id«, which 
Ht owi of iha appff holm. The wind frotn iji" Iwllon'* Milking 
piaM tli« ndiw n( iho latter, the moivablc A'laf b^^n> ti> m1iii«, uid 
• ^tc* tivtwr«a two nf it« COOtWUtlTC bnln cl(i«.-a tbu hole io tb« 
'mtt pitate. Bat ■• tW- di«c conlinuM \a turn ftimi if nrqiiirmi Ti'tocily 
^^elM aic sptiii oppuRiu nacfa oiliirr, a new imputiv is jiriHluL-nl, and 

F)|r. 1^1. 

Vig. !£!. 

a la. Oaring a cooiplota mrnlution of the disc th« Inw^r bole i* 
i^OMu tiiBu iipMi and dgblMn timet cIoMd. A ^rii^g uf ■Kluxi't mid 
l^fp^fCi it tbu* prodaMd, which niakea the air Titimtc, nnil uiiiintitcly 
Muta a ainnid wbi-n tli« sncMmJTa iiiipidi^* nre oiiJficit'iitlr rapid. If 
Mflnd plat*, lihT tfap nioriii? difc, lian eigbt««n bulM. luii^h bnln wriitid 
i^lMelj prodncn tbe mmn nlTerl a* a wparatc niin, tbo ■niinil wuuld hu 
H|lfli ui tiKM aa inbnar, but the number of libtaiiouB would not bo 

b '«iliw In know ihe nurahn of Tibrnliom cnrrwixindine to Ibc found. 
(ndsriiL. it i« ner^marr to know titv iiuiiiI>it o( rtvolutioiui of ibi- dttc 
Ahatnvxvi. Fuf llii* puqwur an ondl*"* cTTf-w on thr p^il T tmn'initA 
tbadtwa in a wbe<-d. a, *itli 100 t««lll. On tlii* wbevl, it-bicb niovcs 
**M» Moth tnt tjery urn i>f ibn Hiw, thrm i* a entcli. 1*. which at each 




CMnplelc revolotiMi, nov» nac inanh oi • MMmd wbiMl, h (fig. I 
Un tbe siia of Uivce wbeeU iImk u« !«•> kmiIIm trrhkli nam 
tUaJi npnMBRled in (jg. ISl. t)nc of Ibcsc indien Kivoa Uie i 
otf tunw al U)« dtK A, Ui« nU)«r lh« number of hanilrals ti 
Bf MiiMlw of two arem, U md C, ihn wh««I n cna bo uncooptel i 

SfaiM Um mind nws Ui propurllon ti^ Ibtr vehNrUj «f Lbe diie A,i 
■ wind is farced Bntil Um doMivd anuiid U producad. TIm mi 

I kqil ttp for • cerUin tinte, two mtmilm for «Kaitiple, and tlM I 
Faf buH» raad o£ Tliw nninber nnltiptiMl b;^ 18, and dirided ^\ 
. iificalM tb» nnnbcr nf vihrMiana ia a atcnnd. 

Wiib xhe MOM velodty llie trma gim Uw Mme Miuid in ur i 
wah-r: thoMuni- i* Ibn caaeirith all gaat*, and it appcaiw, thcndai^l 
•Dj givHD tomid deporids od the number or tibraiiona, and nol 
■Mluro of tfaa tmuidm); body. 

The buauBg and hnmmiiitr noinf* nf cettftin inuMto i« not vocal, I 
produced by tctt nipi J llup^iiii^- nf Ilit- winfca BKauiiit tbe air or tbs M 
Tfax •t'n'ii hail twi'ii ingriiinmly nppHnd to munt the cfilonly at I 
and ulnti unit thus pn^iiuviJ, which Js otTMrlf"! by bringing it into ' 
with thi> otmil. It hsu> thui bivn found that thv win^ of a jinat 1 
lbs rHlv uf 1<^,000 liiiiea in a Mnrcind. 

214. Bellowa. — In ncuustica a Mmet U an nppamtu* br 
wind in«triiinmtii, *\k\\ a» tho mttiU) and organ ptpM, ar« 
llntw«vu tlii> four \v^% of u tnblH lliifre b B ptur of bctlnwa, S (6^. 1 
which is norknl by mnrui* of a pedal, I'. I) ia a n-arrvoar of Ab 
leather, in which \* »\>ikA (hi> nir fotced in by thi^ bellowa. U\ 
Munrroir in pivisMl by mi'BU.'i of wciifhta nn a rud, T, moved 
I hand, the lur ia driv«n through a pipe, E, into a cb«at, C, Ki#d m\ 
I table. lu thiif ch«at there are Rinall hoIe» cirecd by InUhnr VBlTn,i 
can ho npitrifid by prcanng on key* in front of ib« box. Xh* tvvm i 
' ftiuudin^' )<i|ie in placed in one of the«e bole*. 

SIfi. Xlmlt of perceptible aonsda. — Iti-fore i^avart's t«a 
phywciRtii ii'uiiiiK'i) Ibnt ihi- I'nr could iiit perceiTc a aovnd whea ' 
number of iutij^Ih ribraliuiia wbh below H'i for d(«?p aonnd*, <ff i 
18,000 for iicutn Miunil*. Hut h<< hbowni that lh(w limit* ■Ktw ma 
too olosiJ. and ihnl tliu fni'ully of porcfiving nouiids dcpnnd* nttbf*«] 
thnir inti?aiily than njt tliolr hiritcbt : an that wheii extrvmo aonnda i 
nut beard it ari>'-> from l\\u r«et Ibnl ihey hnic not hrvn praduofd i 
■uflidnnt inli-aHity to alleot ihp nrinui nf hf-nring. 

Ltjr incivniiing the diameter of tlie tiutbed wheel, and e:in*nj<aall*J 
tbn uupliliidir anil inl-'iuily uf the vibrnlinnii, Savnrt pnshrd iba Hail' 
aniitr uiunda to 4(^.000 iiiii)ili> vibralions in a My:oDd. 
for d«ep »aund», b« tubftiluUnl fur the tontiied irherl an imn 

MKAftintutST or TitK amuR or nniuTtoxs. 


frat ImfTf *litch fo-olveil en • liorixoDt^ axis ln>tweqa two 
nden pUtM, »haitt 0O8 of nil 'mrii bom ibc bar. At eAen a* Uia 
ml. > Rrmvi RHUUi wu froditotd, dno t» lira dUpUnvmont of tiiii 
tbi^ Dinii-.« Wmw •cericMtnl, tbn aound bFcnnii? I'uiitintiouii. 

C*f and <biif(«in)[. Rv tlii* bim»> Saimrt fonnd, that with 14 to 
I Tilirntion* in a M«onii, tba car pvrceiTsd a dialiaut but vrry de«p 

H>pn>tt. liowpier, wlio baa lafM^j;U«d tint aaine Hulji(^<.'t,(IUpiit«<« 
toaiilu am t>i tbn linica nf daap aMinda, and holdn tiiot nu wmnd 

• thai la nwde br Lmw tlian 33 aln^W liliratinnx pr «u:ciiiid. On 

f band. liE bnld* that ncutn aoumla am uudibla up to thaa« 

BiUti)[ 14 79.T0O taii|tl« vibralinnH jiit ancrind. 

»mham«ra cnrhle D•lb•d.-~^\1lCTl Die tyrm or SaTtTl'* 

UHil In il«larniiiic ihv rxatft tiuiiiWr r>t vibrnlions camwpondiii); 

nowid, it ii niKVflMry to htinff the sound which they prodnca 

with the tnion Miiud. and thib cannot be duoo exactly unleaa 

a iati t o bav« a piMniMxl vnr. M. IlubauicIV ymphic method ii 

IW Aoncmcs. 

TMT »un|ile uul «xact, aiul fn« (imn Uiu difficultr. It cowiritiit 
■ flan point U> the body oioittintt tho iiyutKl. Mid cwing it la 1 
vibralinn* on s propwiy piv|Mn:^ •lufacv. 

Tan nppoMtiu coiui)>ta of ■ wood or Bctal CTlindor A, GiT.1%f 
• nrtioil MinC, and iumr<d by a kiDdle. Tlw lower piui of lb I 
k KR* •nfuUiuii in u lixnl out, *> tbat anxirdiiiic «• tbi- linadli^ i*l 
ttota I(i(\ In tiulit '■r fruni rig;fal to ii>fi, tli<> cyUiider i* niivil nr ( 
ItniiMit tiw •:\hn'\vr is rolled it Hhprl of {Mivr corcml with bu i 

Fiv IJA. 

film of lnm|)Wiii'lt- "n tliin film tlip vibrntion* rpjnulrr ih 
Thi* in plU'i't''!! us fclk-ws ; Sujipi.iM' th« biidv wiuitting the not* li> be 
n'.f^! md. Il is hi^ld (irmly at chip end, and rnmi'i Ht tbo olhnr ■ Bl 
tioiiit wbidi ifnui'.* tin- aiirfafp nf tli'> cylindel". If thti md i« nul4r I 
Tibraiv- nnd tli>» ■•ylimli-r i> nl ri*»t, llie ptiinl would drm-rilie ii short liM 
but if ih'' i:yliiiil''r U lurtiRd tbn {Mint prodiicr^ nn iiiiihtlnfmg trM 
raintainiii^ »^ iukiiv uiidiilMtii'iii* ni> llit> (iriiiit hufilniu]'' ti)>rntLoa«. CM 
sMuenil^^ thi- iiiiitili'T 111' vilmaioiu cuo be couiit»l. Il rfmninsonlyl 
ilrteiiainv tbi- iIhip iu wbieh ilii? »il)Mli"iiii witm niml''. 

ThviTt Axv >*n«fiil wnymjf doiiif.' this. Tin.- iitui[i|<?(it U rocmupan tl 
curve tmo>-d by th» vibmliiiK md with ibnt irncnd by a titniax Ai 
i^i), which j;irwnlin.'»iiiiui!ibtfrof viliMiioiipi-rspcoiid, fiir^xunipll 

rurSMAL THEUI!) in )H:»K. 


\tiait proD)! uf the foik it ruRiUli«<d wiib a pivot, wliiiJi U plaou! 
with tiie ItLmpblftch. Tho tifik nnd tii« rod aro th«n mt 
I tofttiuir, Mad eacti ptodiMe* it* own iiDduiaiiD^ InuM. When 
cii «Br<Jlnl it {■••*¥ b}- ooontLu^ ilir niiuiber of vibrUiatu 
in tb« Mmu di^Ioooe to il«l<Tiniii« llie DiiniW uf 
1» piT «ricaiiii bv thn <<la>>iic tud, Supj>oi*0, for iiwtmce, 
ImitiK fii'li Diade liiO vibraiion*. wbiln llio m) aauio ItK 
>'ow wn klroulr knnw Uiat thd liininir ft'fk iiuLhm an« 
I ia tlir ^ pan of a srcDiui. anil tlierrfurc luO Tibration* in l*J 
But in till! HUiic time thv nid uialtn* 165 ijbnilioua, 

th makes oae vJbnlion in the luyiy i^,t "f a iwci^ad, and ihcru- 
nIiM IH^ Mtconu , ., or I-jO vibratioo*. 


CH.\PTEIl ni. 


! irrQpvrU*a of oiwitoKl tOBttt. — \ diuipto muni-al toiiu reaulti 

kentniDuuiin riijdil iitoclirijiiouit ribiaiioii, proridixi the. number oT 

rollit within ill* t«Tr wido liinita meniioui*il iu tbi- liiat 

^(XlS). Musical xmm am ia tarml caMi* cpni|>i>und. The di»- 

||««Dcu ■ aituplf and aroinpuuiiil miulcal loiii>n'ill lie 4i)tliuucd 

chapt^. Tba Innn vieldcd by a tunit>(( fork fumiahed 

tvaaiiuuic« box tt fimplri lliat vivlded by a wld« stopped 

M* bj" a flute, i« Duarlj ntnpU; tliat yicldi!d bj a mtuicfll 


, Uitirt liaviF tliTDo leading qualitiua, namelv pitrA, intmtilij, and 

lor fJour. 

fmifh el a muaieal tone is deUttulned bj 1L« numbor cif 
I per MMood jiald*^ bj Ilie hoAy produciuK ibu loue. 
I mimmfy ot tb* tone dep^udr on lh« rjiml of thn Tibmtiona. 
iUt vh"R ibe cxlcnt ii ^'nntrr, and leu wb«<n it is lew. U ie. 
M«rir (W e«a«lj propnrllonal lo the l/^nnK of thu txVeiA •.•( 
>of tli« Tibrmlioew which pnviuw llii- l-jiie, 

tiwhrr, or wliat niaj- bn (vinvi'iiirntly culli'd ihe eolour, ia that 
aaalitv of tone wkich dinliufciii^hi''' a unto wbon mundcd on 
Mit, (nun ih' »ain» note when •juiidt^d on 8iifi|.lii>r. Thu» 
V nf lli« tnbli^ Slave la sounded ou a riolin, anil on a fluu, 
I will lui'i* tbfuum- fiifrh, ibat is, an' pn/iiiievd bj ihe Slklue 



Biinibcr at >'!bniii<tD» per nemud, uni) lh«j maT h*\e tli«i wun^ i 
and T«t tbn two tini-i wilt lint« i*ij distiact ^ua]iti<-^ UibI ii, I 
timbiv or colour In tltlfi<r>^»l. The cttiiw u( tk« p»>Cttliar colour of < 
will be roiiKiilcrpil Ulcr iti thi' i-lupler. 

SI8. Mnttcal lattirrala. — I-'^I uj> mippniut thni a muticiil tnnii, i 
for thv itBk« III' fmiiiv rtliTPiii.-u w>^ wilt deiiuln l>v tlin letter C, i 
<la«id bj' HI ribmtion* por (pcond, uid lat tm fitrthcr «upp«* i 
other niu«)c*l <i>n«, X, i» ptodiiced hj h vibntttoiM per (iwuid, ■ 
Rrentrr thiia m : then the iiilrrviil from tho nolo V lo tbc note X ia 
ratio H : m. t)ii> iulirvnl bf'twfrn two ndtva bning obbiinnj by 
nut by nJitmcfiim. AIiIioiikIi two t-T morv tonro mKj be t«| 
niiinpnl. il by no nironn follown that when manAfA toHTihrr tbirj-j 
due*' n I'leiiHumU? M'liKalion. On the (^onlrnrv, iink-M tlicy aiv i 
th^ ri-juh is hnrili, mid ordiiinrily tlin revonip of ptcwiumblo. Vi'» 
tlwrpffn.' li> euij'iire wli«l iioln nr* fil t* Iw *oiin'l«'d b.<gvtli«r. 
wlivn luuncal tono ore i;oiii|>anTil it ia found thiit if they kk Mp 
by fta inWrvai of 2 : 1, 4 : 1, ntn., tliny to clowly ivvmble one i 
tlinl ibiiy rnny for most pitrposm of music be coniudenid aa tbeMinel 
Tims, siippiun r to alnnd for fl miuicnl nolo producod by Sit tihri 
]iiT wcrmd. Hiifi then t' and r so cloiwly reautubl* ouu Knothet ■■ I 
cnll<id in music: by llin nanip nnmo. 'rhn intorvnl from V, tn r »< 
oriim, and i" in naiiJ In he an ortacn above C, and couvi-tw-ly C an ■ 
Wow <•. If we now cfiLiidpr munirnl soiindj thut do not ditfrr brat ' 
oi^tnvu it ia f"Hiiil tlinl if w* lull"' tlirtw nn\f X, Y, atiiI 7,, tv^iiltrnK w- 
Kp>>i-lit>']y froiri rf, y. and r vibnitionn [".-r riecoud, thena tlirec not<4 wlifa \ 
•oundcd logpthcr will bn cmioDrdnnt if ihn mlio of ;i : q: r rqnali 1:5:1 
Thrne aticli noli^ form a tuirtnmiie li-itid, and if euundi^d wUh afoarAj 
note, wbieh Iji the octave of X. const itiit"' what ia rnllod ia mnae a i 
rhonl. Any of tli<> uotvaorn ehiinl may bealtPTwd by cine or uiot«i 
witboul cliHtipins its dialini-tivu thamcti-r; for insUinw), C, E, O, i 
am n chord, niiil C, i-, '. g, form thn name pbnni. 

If. however, iht? ratio p; q: r eifuidn 10 : 12 : lo. thu three swnifa tf* 
■lifrhlty ditioiiHiil. but not nn miii-h bo nn lo diaijualify thtim fmm pro- 
duciii^ a pi CH" lira bin BL-nniiLion. nt leiut under c^UiLn circamataoc*- 
Wh^n lhe«i> tlin-"- noi-'s nnd thf oitave to the lower am loiuided log^lhc 
thry cnntlitiiifi ivliBt in uinKic in culled a mmor ch'irJ. 

itV. Tbe muloal aoala.— Tho ■rrie* of wtundi which eaauera * 
jtivirn nolo (? with it* ortave c i» called th« diatonic n-alc or truiui'- 
The nol*pt eomposing it are denoteil by the letten C, 1>, K, F, II. A. R 
The sQile in thrm continiii'd by InlcluK thn octave* of thm» notM, nanwiT 
(!, li «. /, !/. a, h, and n^jain th« octaves of lh>'«v last, find no on. 

The nolen are bIh" denoted by namo*. \it. do. re, mi, fa, tal, la, ti,4>- 
Th» rclftliona «xiiiting between the note* an- Ih'.-ee :— C, E, O, foro » 



tnad, O, K. <f^ form • in*Jur triad. BDd K, A, c, form * in^or 

C, n. Mid V bail-. Tor tbU mmom, apedal ntiuvr. beiii; mIUiI 

awJ*. iIm (mik^ <A>iihimim(, Mill *iA-a9aimaiA, tsA tba tlin* trixb 

ItBK, (foMMAiif, Mid MiA-rfMinnnN( Iriiuls i>t cliord* KifMctiTotj. 

imstlf, tb* nunwrinO rvhttont between ib« uo(«a uf Ui« ««lc will 

Mrr«n bf ibe tbive ptupurtiun^— 

C:E: O:: ■!:«:« 

:B:SD ::4 :»:« 
F : A : SC :: 4 : & : 6 

I if M d<u)i>t«9 iW nnnbcT of double vibntionB concipandiiiK to 
MU C, tbfl number of «ibnUioM comfpondinff (o tb« rentaiiiioic 
I will be gjvm by tbe fuUowins Ubie— 



]■" O A R f 

{<!» ^w |m V"* -"' 

> iat(v**l» between tbe micivMiT« noUu bring TMpecttT«l_v — 
CloD DtnK EtoF FtiG filoA Aiolt BUi. 

• in ■■ * to ■ ■■ 

1 ■ il ( 4 I ti 

It will fap oliMnvd thit tbere tra bm thrm kiada of inti'rvals, \. f, 
ntd \X: "I tbaa« ibo two former ma cnllrtl a (oNr, tbu lut n umufniv. 
Tba two loBM bow«T«T uw not id^iitiokl, but liiftar by mi iotertxl of ]j, 
whicfa i* uUed a tmmntt. Two aotei nliivh differ by a tomnM can bi- 
IwlU/ diatinguishnl by aii ^i^ufaiml tai. Th« bl«tva] between tlir 
taiSt! aod miv «itu in ilminiiiaatod by tli« pHitiuiiof tbc? Intternotcin thp 
wile ; tbuA (be inl»rTBl frcnu C to (! in ■ nftb. Th» «-«]•> vn )iaT« now 
eowadcnN) in odled tii« mnjar Mralc. as bi^iii;^ foniitKl of nuf/iw trioda. 
If tbo mianr triad wrra Hbttilutml for tbi: ninjnr, a acnln would b« 
iaiiMud tbal could be Mrirtly called a mnu'w Kule. A# H-alei) srp uaually 
writtas, hoiTvTnr, tba ajnwdi^ wate !■ lO furnmi that tbn Ionic bi>iir« a 
■daor triad, tb« domUMiil and eiib-dominant b««r ma/or iriAilii, wliils iu 
Am Atwdttiy ■cahi Ihay all tear (rmot triuU. fnictiually, iu nmsiral 
NntpOittiiai, tlip dniniiiant triad i* alway* majif. If ih? raniw ^iipu 
ibvia ant ■aatmnml it will bv fbuiid tbal iu lb(> major ■rtili; tlin interval 
tmm C to E eiinali ;, wbiln in lb* minor acaln it nquaii ". The foniier 
biBmJ i» eallHl a major lliinl, tb<- Intlvr a ounrT Iblni )l-'uce the 
W^ir Uiird viivnia tbe minmr third by an interval of JJ. Thii interval 
U mHihI a acmituiHi, thnufch r«ry dilEer^nt rmni tbe intiirval nbinc i-oIImI 
^ thai nam*. 

iltoBnlpt(idIaca»kniof tlwBunibrf nf niolni, and tbeintfrvnla butweeu 
thiB, will 1m> fnuiHl in an article by Mr. I':lti^ tn lol. xiii of llm /Vw 

i^-___i j*r*- RafotSoniig (p. t)9), ' ( >n a l>«rfiet Miuicnl ScaW.' 





K Jiatoo 

390. Oa ••mlWD** aaa vb acalaa wltta aUareat Imtbo 
"ill be atro frim ihi' Is't ■rtii'l*' that the icrm'Mrtiu tune*doea ^ 
a ooiwUnt intcrrml, being in ooe cue MiaiTaleBt lo (J and in uiuitKi 
u. Il L« found cooTMikut for the pKrpoM* oT mHiic to Inmduce 
iBtanntdiat* to tb* mtmi nou-* of ib« gamut; UiU L* dtmr bT ii 
ot diiDinhbing tboM oote* by au inicrral of *>. W1i«b a aoiv t^ty Q)i 
iacnasiil hy tbis iatun'al it U md to bo ibnrpcoetl. and ia driKitnl brllti 
■jn>buH't,call«d-C»haTp;'ibftt uCt ■>C=||. %Vb''nitudi 
by the ume intrrvttl It U ««id ta be flattco«d, and it repreamted 
I(>,ralWDt1ni;'thRit»B-knti=H' Ifth^eftictof ihisbo 
It will he fLiuiid ih&t the number nf notua in the aciOe froin C Kp 
haa bran uii-rmM^ fi-oin lena to tv-onirxiim noliw, all of n-liich 
euU]- d)tt)afpii*bed tjr the ear. Thiu,reekoiuagC tueqiuU l,ireh«) 

G Cf SV D Dl Eb E «tc. 

Ilithcrli] WD hare made the note C Hxt ttmic or kry iwle. Adt 
of till- l«i'iilj--iii]i' distiacl no»» nbnTe-»iwntioned,e.g. <i,orF, nrCJ.i 
mnv Iv niiub thu kvr note, and a ncal^ of notm ooiuuticled with 
nnc« tnit Tlila will bn f-nimil logivvriae ineachoMoloawriMitf 
■onip of whivb nrr ideutiuul wilb ihoM couta'mod in lh« wriee ofi 
(' il thn kp,r aaXp, but Riciit of ihnm dilfcn-Dt. And of coaiM tbt 
triiiild be true for lh» iiiiuor «c«le M well a* for ihn ni^jor acal^ 
ind.-ed fur olher scalps wlilch limy In.- coiutnicti!il by meauaof 111* 
niciilnl tiinilsi. 

2-il. Oa mualoKl temperamsntr-The uumlwrof notra tbat 
frnin tin- rnnatnirtlim of tile Kale* dowrtbcd in the laat article ia 
[Uiius:h) itiiicli uiii>(iiprove(iuit«DnmKi)ag««lil(>inlbepnuiticeaf: 
itad parti rnlnr!y for music dtaipiisl for iu»lriiiii'-nl» with 6x»d 
Bueb as tlie pittiiofort". Arroniingly it boconiei pri«nii?«llT important 
rpduw Ihr number of notes, vhich i» dotie by Blijflitly nltM-int; tbcir jiut 
proportions. Thi» pnif»»s i« called temperamrnt. l(i (•■nil^ring tb( 
notH^ bowevEr. ui«re or \r.m di^niiitnce ix Introduced, aud ikcoirdinji^ 
aevpral dilTprenl if^Ivni* nf ti'mpntmncnt hnvi' born deriinl for rMtdariBf 
tht* dlMoiiance as alight tw poMibli-. 'r)i« tivleni usufilly mloptod — It 
]«aiit in inti-nlion— in called the syiti^m of e^ial temprrannd. It 
cuD«l«ta in tb» niibstitiilioii botwcca (', nnd <' of «leveu tiutM st 
nqiial int'niiU, ench iuterval bi-inir. of cour»«. ih* tn-elflh mot <rf J. 
or I-0&9I«. Ity ihi» niraiii thn dialinctinn bntwn'O tho aci&tt'inca i» 
abolixbrd, iM tlint, fur cjmople, CS and DB becuiiitr the name not*. Th» 
«iile of tn'elvi' noli-t thui fnrnind )■ rnlM the riiromatir »faU. TloT 
<vinT« foliow!! that uiHJur Irind4 hecnme ulijihtlj di««onunt. Tbu* in tli« 
Jiatooic scale, if wi> reiTkon (' to W I, tl U (lunoied bv I'SiSOOO, aod 

psnrcAL TacoRT of hcsic. 


' -I- I annoo. On the mteoi of e<iual t«ni|>Fnitiinni if V i* imoXeA br 1> 

Xk* nawitT af vlteattoBa pr*dDClnt aaeh not*. Tb« 

*^wm> tvrk.— flitlwriiowR hava d«nc>i*d tbenumW of tibrationtconr- 

- - - ■ 1 ne Id tlw nole C bv m, ud bav« upI usi^ed kDy numerical vitlu^ 

' -1 inboL In (Ii* thmrj of tniiaic it U umiaI t-> aMjni HM double 

I'm* to till- tnkUUvC. Thin. IiuwpItt. is arbitrnrc. An itunrumi^t 

'■■am provided tbo intarvalii bctwi-nn tiw n>itM nn- coirscl, •■h*ii 

i-Uad by mij- niiaiber of tibrMion» ptr MMud not diffiBring lanch 

-.'M. Mocvnver, two initninirnU ue in tune widi one Miilber if, 

tauir aiiMntcl; fa) inae, tbey baT« ar^ ono Dole, for tBHaiict!, C, livldni 

fav IbaMBwasmbarof ribntlian*. Cuoicqurutly, if two inRtrunmnla have 

■ >(■« tbite («y C) in mmmon, ihcy c»n llien ba brciiight iut« luiiu joiuti}', 

b<r haiiaeibirir nmiUDiii}; nulu •qxtnlulrfidJustHt nithmfnTiDCn totbAt 

fuDdankmlal sole. A timing fork in an iattrunit^it jiolding a coiuiianl 

'Miund. ■nil i* xuri a* a ilandud fut luning luiuionJ itKtruiiii<iitii. -It 

*7raai>u of an «l«>-ii<: iiti>el md, bnnt u rL-pr4U4>ni<>d in fig. K>(1. It 

i» audi' in nbraic atlier hj dnwiiig a bow acrow Ibo und», or by 

iki^ <«« "T ibo k|pi affMnBt • hanl 

t, vr by rapidly «imr«liog thi? two log* 

of a Htivl ^)d, ai •kcnm in ibe 

TliB ribretioa prodncfw a n»l« 

i* alwayii tfan Main for tlw mum 

ii|i fiiik. Tbo noU> ia tircnglheoed tn 

Bg tko nintflir fork on a box open at onx 

, tmUri ■ r i mu MUi o fcu-. 

ha« Wd nmuulicd for mine j'Mi¥ 
1 BPl enly lia* iIm f\Ub at iIm tatUDg 
tlwl ii. lyauvrt /nkiA, bma getlis; 
IB thn lary^ tlmatrcii of tlurnpi-, 
1m that it u tK)l lh« Mmo in Ix>iid<>tL. 
, Vitaaa, Milan, etc. Tbli i* • source 
inMaTMikAM both tocoQipowr* 
mowr*, and a oonnutHon iraa ap- 
lo Mtablbli in Franca • tuning 
t4 onifnrai pitch, and to piepu« a 
rliicb voald terve aa an Invari- 
In an-orduiCB with l)ii> rvcoiic 
I at tlinl httdj, n mtruuti timing 
hai baxn «<talili»ked, whloh in i!aiiipnU>rT on nil uiuaical ««tab> 
ia Fruicit, and a Mandard Itas henx drputiitvd in the Connw- 
•Uvt if Uiuif ill I'arlH. 
li pR<«gB» 8*0 nngiv ribnUAum pfr»feoad, tad giriM th* ittftodnrd 

' fnat 


Hg. U6. 


nttU) a, or the a ia the tj^liki «UTe. r-mMquMill}', wilh vtttttto^ 
ttaniarA, th" niiildl^ C would revtilt from 2fil donMe libralkin* frt* ' 

22X &n eMBp«nB« ^valsMl t»B*a asA barrnvBlcm.— WJ'^'^j 
fivcn Mie (Mj C) ta noDBtkd nn mn^t inii*irtil ini>Wiini*«l>, n^ 
tant ■Iciw it prodiKnl, bat ■ cerip* of tonM, cmIi bein^ of Ibm Ij 
tli*n (bfl oM pn<o«>lin; it If 0, wIimIi riMjr b* called tb* , 
tone, if dL-notn) bv unit^. lli« wt>i>1a wriM U givBU bj ibit '""'h' 
I, 2, 3, 4, li, t(, 7, nlc,, in other wftftl*, fiint Iho ptimitTy C i» »-"^' jjt 
ihpa lu octavi* WivMnM aiidiMi-. Ilieii tKu fifth I" llial oclav(>. thm '^^ 
•MottH i>rtovc, then the third, liflb, (uid n nott- lictwpcn the Milh ''^ 
»pn-nlh to ihw »«eoni oct«T0, and »u 'in. Tli<?«» '■■■■iindsir tnn«»^ 
i-nJled Ihe hnrmamca ot tbfl priin*r7 to»r. Thoiij-h TiirhlH in conip»(ii^^ 
with thn priiimrj' tima, Ibiy may, with a lilll** pnwticf, bn haani, fltt^ 
the pniuary tJioe ia producMl un iiMwt musical int-tnimmttt nhm.W , 
inrtanrc, nnn nf thn lowar iiolm ia ■oiinil'^ on Ui* pi«nofnrtA. Vot 1 
g>i[t|»ui of •■\i>'tJMi»ntHlh' ptuting ibe pr««iqic(> <if Uw ban 
distinct ton--*, I>n>r«Hor llrltnhalti cottatnictisd an inMnmeati 
rrmiHoiKri/iobr: Th« {<ri]idpl« involved iniLaroDftrnctionialhia: A< 
111' air rnnlninc'd in an open tcmmI, for <-xamp]» a bottle, vrbra r« 
vibrate, I'vidx in viwld a certain nnte, and mnaequentljr when tbat I 
ia wu»d«d in its Dcis^hhaurhoud, to alrenglJKni it. A lesiMianee gloktl 
Iflawi |[lobe fumiklicd with Iwo opening*, ODa of which i* lnn»Ml 
the origin uf ihe noitud. and the other. b_v mcansofau indio-Tiibber < 
ia appliod to tJic via. If tlu> tone proper In thu tnnonaocn frlobc dUil 
aniong^ tlin harmonicn of the compound tone that b muuiM, it i* I 
strengthened by the g)tHn!, and thereby rendered diatinctlj andlUa. 
Further, othnr thinB* biiing the uunp, th<^ note proper to a |rin«i fItAej 
■Ifpetid* un ihu dtanieler of the );lube uid that of (be iUHui«*d1 
ogK^in;;. ('iinnrqiientlr, by meann of a wrim of aach t^bca thil 
whole serii's of liHMnonicn in a (riven touipiund Ion<4 can Iw i 
tlidliuctly audible, luid tbeir exinlrijce put beyond u doubt. I^ 
I lelnihoiti'* n-jii-irphoj" nhnw that the diffi-miit mfour or qualilT of I 
sounds yielded h\ ditTereut iDiwii-til iirKtrumenta \» due to the diAcMl] 
inleniitie* of tiic hnrnumirJ which nccompany tho printory tnnaa of i 
Mtunds. The leading ruBullaufthoM reMMircbes bU the oukinr of toaadi 
may hit thua itatnl; 

i. Simple tonea, an thooe prodiioad by a tuningr fork with a rfMOMn] 
box, and by wide mvered pipei, are soft anda^euabk without nnjrmi^h- 
nras, hut weak, and in i\w deepnr ni>to* dnlL 

ti. Muiti(-nl ftiiunda aci.'ompanied by a ouriM uf hannonioa. aay up te thr 
itixth, in modorata i^trrniilh are full and niiuii'al. In canipiiii>>.ia wil^ 
simple luneti they Kre grander, richer, uud itioii* aonOTOua. Such ai* ll" 
•oandu of open orgim pip™, of the pianoforte, etc. 


Il' Ik mrtvn liMmooin am pffiwRt, rd in tbn itiu<> nf narMW 

(if IHMinrnrle HUinin (irtiok in ihe miJillif, FUri'Miets. etc., 

Uamin'iDiiiilinel; ■nil whrai « Krrater numW of bamionln> 

'■Ittit bnnonic* bFjood tbif "utb mi MT«ntb «* very dutioct, 
■■id b(««n« ihxrp snii rm^!i. If Ik** •Irong ihn bftmionits drv 
pifafiri*! Ii> tfai^ oiinicnl uwfuliivM of the nub^s. On Lht- cunlnn*, 
■• tarfid •> imptning ehu»rtcr and i>xpriuimi»n to thn niu«i<-. Of 
llMtmiMM (trinind iMtnioieDU, and luoM ^['pn^ furuUfatd with 
k «lr. Snoiid' in trlikh the hnnnoDics un ]iiiniiTuUtl}r itmn^ 
IkMby * pMuUcrij peiMtialiii^ characUT, «nch nnj tboao yielded 

I iMruideitU. 

Wiicn tiro rimplr lonri arc miiiuIihI toffntbf>r it in in 
found tliat ibnj altffruaicly alnfnirlbt'n nnd Kvnk^n niit- an- 
WImm tbk iano, thay ammid to £Mif with oar nootliM. Thi«niay 
UbhI ai feUowi: Suf^kw AB. in (iii. 107, (oV a row of parlU-leti 
iSmf Ihv ■nioid ; auppOM thr vibmtioiu pnxluctDg tUe oni! tune to 

Fig. i»;. 




fttad bf tha rootinnmia ctirrrd linn ; tban on thn an» hand ibo 
at the diffcnot pdnta of AB give llic WocitiM wit)i which 
«n ■'wwrfimw»iMi^ norin^t, an>), ontbn ritherhanil,oiii!b pitint 
iha diferant mlocitiM Kpr«*eDt«d by tbe«nnc«Mivn 
like mmanr let the dotted lill■^ nhow th« vibmtioni> whicb 
I ibi *p«oiid tone. And, for the nho of diatinctn<-iu<, «u[>[Hun thn 
af vibraliona pprtecood proJudni; tlio fanner luue to b« to that 
the laltor in Ui«' ratio of A : 8. Now Ipl tii coiuidrr nny point 
<rn at nutt npFUpioi th« poulion "S: ilnin' lht< oitlinate riiititiif 
icrrurr^- in I' anil die Utl*r tn <J. If thn tonpn w<m unuudpil 
tba Telocity of N at a given iiiRtMno* iinnliiiNid by tli«i former 
W P?>( uid that of N at thn aame inttnnt produced by the 
Id bu QN. dnn^Uf-nlly, a« tlirr arc sonadnd tngnthor, 
city at tbv itiven inatant is tltasuin iif thL-d-, or I'N-f(J.N. 
inatAnt we con>id«r the point n, it* velocity will eooiiLit 




at pn »aA Hg jtAatlf, but m the«^ Mr« ia oii|>i>miu diiwtiav, iui 
MOOiiQt irill i» pn — 117. Ilenre ibe nctutl TelodtT rMnlting 1 
cocxMteooo df the tvn tonm will W i&cliciiled bj' tb» nirr« in fl(l 
wbaw ardiaaiM »qiial ihu (ttlgubnic&l) auin of ibe ccimH|>ciDiIuii 1 
iiatM of the two eurivs in fig. {■>>, that iii,if AN,A>i, . . . rnprewot* 
diatMiCM in 1n>Ui flpiiM, the curve \» dficnbed bj ukinff RX 1 
PN + QN, ni equal lopn — ^fn. mict va on. This curre nboiirs br i 
OMvivn ordinBltui tlie amullAnTOux velw-itiM of liii^ dllTvKtal 1 
AB, aid the •UDOwatre Telodliot of mvIi {inrticli?. Coasequniilj ili 
tvpitmat* tha «ucc«Mini valocitio* coniiuuiiinttixl to ihn ilnim ' 
mr. An iiU[i«(.-tioii of the tifcure will ahow that the VFlodtiiea *l*l 
gmat, thm imnll, th«n ki^hC, nnd no on. the dram iwinx tint 
ntpidlr for a ihuri liinr, iheu fur k. short time neiirly broo^I to T-' 
•o »a. In ihort, the cfTcc.t of th« boatini; of tones on tho cumoxii: 
with ihHt i>f a ciitiliuuDua tone Is utriclly AnnlngnLi» to ih<t vSra pr" 
on till? vyn by n fiidtiifing w compan-d vf illi a •t«ady Ujtfat. 

It nmy V pmneii that when tvn nmjilc Conai an pTDducr<d hi •• all 
a i3i>uM<- iiVirKti')ii>i [>er second, tli*y prodiirn m — n b^nts p^ •troaiS 
thus, if (■ i.* iirodiiLW liy 12H, uidDhy IH double vibrntiutu psiw<oo4|l 
ihey will 011 hciing Hiimded to)[<ith(-r prnduce 18 bpatii firr wcoftL K 
hHB Iieeu (Mmliiiui-'il that tlic bvaCn produci^d br two totiM an> uo( aafiUt 
iinlcju tbi> mtio m : n Id less thnn ihi' raiin (I ; S. Ik-ncc, in tht (av 
r('pn.w.-Qi('<l by li);, lu8, ihou^-b the iiltvruntions of inteority eiift, thtf 
wtiiiH not b.' nudlblf. Also, if tho tonf» havL- wry difli-rwit tnl(»4n% 
thd intvunily of tbi.- bent la rery much dis^int^. 

Il it found thnt whnn boala nrc fewnr tbau 10 pot aMond or morr tkn 
ro [wr gM\>ud tliHv arv diaajnveahlsi but nnt to thu nxtont of produdu 
diwoM. lipBt* frim 10 to 70 per sepoud mny be rt'W^ed >a ibe touRr 
nf (ill diwnt\l ill muftic. ibv iiiAximiini of diminiiiiieit brinK aiuuncd whto 
about 30 bcntii niv produced p<?v shcotiiI. For ■■xaiiiplt', if r aad II an 
sounded liiiwlhiir llio •■(Tecl i» vfry diwrirdniit, the ialtrral helwwin th«e 
nuti.1 bi^iiit; II) : li>, to that tlit^ beat« ari> aiidibln, and tt><> numbrr id 
bp«M )>er MToiiii beinjr Ifl. On thn other hnnd, if 0, E, anit O irc lomM 
t<jgi-t)i<?r there ia no diMonan(-e, but if V, K, (), B am loundad Inpvthff 
the d'ncord i» vpri* marki'd. ninci- (' produt-M e, whii;h ie diBOord*oi with 
B. Il will bu n-marked thnt C, E, O is a major trind, while E, (J, B » 
a minor triad. 

A C'lmpiiijiid iiiinical Icme being composed of idmple tooo* repreaetitfd 
by I, 2, .t, 4. ■>. i\ 7. etc, doca not givo riBe to any simple toni^ capablr 
of pti>diirtii); an aiidihin bpAt up to the snventb, the iiixth and aercMtli 
Ml! th(t Knt that pruduce an audible bent. It isforthinrMui.iii Ihftt ib't* 
ia no trace nf roiiirbnevi in ft compound tone, unleM tbir aeti-ntb lunnoiiir 
be Mudible. 



««!« lo nprvMot gniphicall; it cnnipaiini] time ir« ahoiUiI proceed 

Acurveoat ef aimpkUiDMof dllTviviit tnt*ii«ti»in th« tnme 

«• V' 1'^ ■* coartmeted fraut two riiuplR tooM of eqiiid LmeDsily 

.1'-: iiT 6fi. 1& Iiu»ri'ileiil thaltliereBultiugcun'a will uki; dif- 

'»:< Mcoiilintt to Uie pnneDtv ot absiico of ditTcrpai hflraionii« 

'7 iliStrvni inuMiliei; In otbtr wocde, Ilie <vlt/nr6l ibe ooIh 

bT difTi'rcDt iiMtevmentt will drpoid apon the /nru of ihe 

I {undiiciDfi tli« (ound. 

0«nMB*UsB«l MB«a. — Bi-ndiui tlip IxMts produced wbao two 

I ButM nrr Kiuoditi together, thuni ii luiniher tuid dutinet ph«no- 

.wUdi nuy bo UiiudeaaiM: Suppow two napU tonci tu be 

is produced bj fibndoiw of fiiuCQ «xt«int, «nd of h anij m 

■tioiu per (iM«ad. Il Ima bmn shown by H«1mhi>lii that thty 

> a H>ri« of other tooM. The prii>dpel one of thrxr, whirJi may 

ollnl UtP dt/Trrmrin/ fniM, IS produced by m — ni Tibntiraw p<>r 

lu intscirity i* genCfallj vvrf ra«ll, but it in dintinctly nudible 

^raiA, It hw b««B <«]M the grate harmonie. u ircDurBllr ittf 

I ii laaeb lower thdn that eS tbe notee by wbich it in KmcMtod. It 

I wfpfMMd lo be cnniitd by tbo beat* bt'ComJog loii nniuinoug to 

bed, and RMilHM.'lii)r iulo a I'unliaiious sound, and thU «i]h- 

I counMtnuiced by ihn fwt ihiti tU pilch U the tanie m tbe 

MUnber. Tbe »iip)Ki*itk>n is •hown to be erronmun, first, by tbe 

at tba dlfTerentinl tmn* for inlrrval^ that do uoi bvAl, and 

i)j, by the fad tlial, uitder certain dTcuumluicea, both the beat^ 

1 lb* diff.Tpnrial tooiTi mnr be benrrl to([rthcr. 

Tke ylijrMcal eeDatllntlon of nioaloal cliarila.— Let u* lup- 
I compoiuiil iMiee to be aounded together. My il and (>, thvn we 
I t«u«ni<aof tonatMckooiMMingof aprimaijand Ju hanuonio. 
>It. denotio^rC by 4, tbe tvoBfrien, <».]:>, IH, . . . Mid 0,12, 18, 
Now, if in'Mui of producing the two nolv* C and Q. wv bad 
■l thn oclavH h^luw C, ire should hare prndiiciMj llit- M-rinit 2; 4, 
l(^ 12, 14, IR. IB, etc It i* plain ihni ihe two forum »vrie» 
^oinrd dilTur fioin the but iu tbe fulloitm;!' rwpvcta: li>) The 
iiiDP It it onittted. f&) In tbe cbm of the but terimi, the con- 
r inmiariDBtinMaUy decrease ia intensity, whereaab the two fonner 
, 4 and tl an? of tbe uum tnteoHty, 8 it oJ \aiTet intenuty, but thx 
\tm« Vi'§ will turnfftben nach Other, awl eo on. (<■) t'-ortain of ih^ hai- 
■ oftbi-ptimary iateooiittixl, for example Id, 14, not occur 
Ib Ahrt of thu two fomer •crie«. In tjiite of thaw diffcreiiciw, however, 
Iha two cumiMiund BOlea affect tbe mr in n lumiurr very ilunely 
manibtiac a nnffle conponad tone ; iii abort, tlicv cqiiIcm''' into a »intrle 
tui- wttb an artlflrial oAoiir. It may hv niii-d that jn iIil- cim- nbuvu 
Ukma C aad U ptoiverait oomiuui/aa tone 2 (thtt i$ 6—4), au that, 

I two I 





AticOf tpMliiag, the 2 u not vMitMt in the aeries pcoduonl hj I 
(i, oaly it eiUta id \etj ilinunulwd intenailr. The Nune 
will apfily to «1] potaJbU dtordn. for iMamplc in Iho ra*« at ibv oujvi 
C, B, 0, we liBVH a Urn* uJ utittcial colour rxprvtiwd b* th» i 
nm;il« Uidm, 4. 6, 6, 3, 10, 12, lii, 16, 18, rtc, tagger «itkl 
i-uuibiiiatiuu (udm, I, 1, 2. ll will b» r«iiiai)i«d tbai Lu ihe uMii 
thi* acrii'i there lue no ilissoaimt tone* intraduood, excvrpi K, 14tl 
m, 1^,tknd thin ditHuiatK^ will be inoppreciAblj aliglit, sbcp lt>Bl 
tliini liontiunic of 6, And ihu lU Ihi? fourth hanannic of 4. •» < 
ihuir int«n>itii>« will he difn-mtt. m oJhi wilt b* tli« inMultiM ' 
iiml IP. On iLd otliiT li*iiil, neiuly all lliu loiwM wbirli hna ane- 
romimiind toni' »m pniN-nt,i]uncly thrntoni 1,^,4, fi,(t, 8, lOt I 
plw* of I, 2, a. 4. 6, «, r, >*, ». 10, 11, 12, etc. In .liort, the I 
trind difTon nnly ftota a natuml compound tono, in thnl il 
m seriun at siiiiplB tou(-« of diffi'Kat intenailiM, Mid omita thcve i 
bcKtiag with iw neigh bourinK '"'"' would pnxluof diunnoDTc, foe en:,-:'-- 
7. which wiiuld bt-at with aud S; W, which would Wat wili 
10: Bud II, which WDuid beat with 10 mid 12. It it Ihb lir 
stMice wbii'h i«ndt-n> lh« major churd of vuch gn.'at impu(tM< 
hwmany. If the [MUBtituentB of iLi- Tijinur chord are ■imilB'i' 
CUiM>d, Dkinnlv ihife compound tones whoM priniorici' ani propoiti'ii'i: 
10, 13, 16, it will Ip fouud (11 di(r«r from the mnjor chord iu the fi - 
ing princijHd impccU : lat The primary of the natuml toD« to u>: 
approximaicH is v«ry much dp«p«>r tban that of tli« currup' 
major chord. (b\ It inttwlucc* ihu diffrrfittiai tonpn, 2, 3, .^ nai'i 
form a miyor chord. Now it haa alrtiaily b<'i>n reniarkud that wh'u • 
nmjor and minor chord are wiuiided iof(cihi-rilieyttrodi»linc!tly di*-- ■■ ' 
for nxaniph' whi'ii C, 1'^ (i, A.nN^nundrdto^Rther. Acrordinglyi i-- 
of the diflcreutinl locus funning a luiijur chord ah uwa that att denKnUn 
difeonan^^v eiial* in evci'v minor churd. 



SS7. Vlbratlona of anrlnKV— By a arinjf ia mvant the itriog <f a 
iniitinil iu>ilrijni''ii1. Hiirh atn violin, which in utrctf^hed hy n rcrlaiit fonr. 
and If commuuly of ctilf-^il or ie a loetallic wini. Thr rihratiou!> whick 
string* experience mny he I'ither Iranstrrsal or kmgiludinal, but prac- 
tically llie fotmer are alone important, TruHrvrrtal vibrattm* may 

vuKATttnis Of »ntix«». 


twni by 4nwiigt " bow ■rriwi ib« Mhf. at in Uw cam of tbc 
', m br Mrikin; tti*< Mnn^. «^ in ihr am- of th* pUno(urt« ; or b; 
r ikt-m Inttun-nwlr uid Uieu Ii-ttin^ Ui«ui go Muddualy, u in the 
rtbc iruiur uiil tbi' barp. 

■*— M *. — Tlio *MW«H<rr in hii «[ipanilu» by wbicb tfatt 

rikntioM of atriQe;* nikjr W BludiMl. It i« aIm caltnl 

. btouuB it baa gctiemlly only uno ftlriog. Jii addiUoa In Ih« 

1 coMut* of m thin woodui box to eln-iigtbL-u ibo luiutd ; on tbi> 

I tao llivd bridgM A uiil I) (Dk- lW)t ovnr which jumim tbit 

i «bkb ia cotniiioaly • mndillii! wire. This i« faateued M one And, 

bod u ih« otb«r by a wngbl P, which can bn incrcaMd At wilL 

I iif a third muveoJilH bridge It, thn Unglh of ibtit portion of 

t Bfairh i* to Im' put in i ibniliuii ctui ht allcml ■( pIpdHUW. 

t— mt ttt« tniuvvrse vllirBilont of ■trtsci.— If/ be tb<! 

lafaAring, thai i», lli<i viliniliii); jmrt bvlKt-vii two bridjp!B A 

[(6j. IWt), r tlitr radiua of the lUintf. rfiladcmilT, P iho «n-wbiu(; 

, aad a Ibr number of Yibrmliona per Micond, it is found bv colcu- 

'"Sr/V^ — .; "■ being the ratio of tin* cireunifRroooe lo 

Thi< fonniila i* liwqMcntly wriltMi n c= . x IHj^7 

I ■ lagth of tbe stnng ta wire used that its w«ig:bt would 
» a* (ha Mn'tching weigbt. 

I fonnula thn following lawn have been deduced : 

teiiiff rMUtaal, lA* lainibtr of vibrationt per teamJ u 

mamtmr of vArodoM pw mtmti i» imttrmts ■■* ^ ruMiu of 

■ HMmirr of rttrttimt ptrmtnd i» ifcmf/y « Iht tyuar* rout of 
I KtiffiU or touion. 

TV. '/%e mtmbfr «f rttrtritOHt per rmiilJ of 9 tfTMjr M MMfM^B 
njKarc rovf nf i'l dmaii/. ^H 

Thvw Uws Mv npjiltnl ID the constructiou i>r ittriii)(«d infltann^l 
which thi' k'u^'lh, disiiLi'l''r, Ii^n<4on, and *a)ittuin) of tli« MiJa^H 
choften, thnt aiirh nnd meh notn iimr he elicilMl bum tlit^. ^H 

:!30. irodaa (uitt loop*.— I-^I <i* inip]Mi«i> tbo tfrjutr AD ^H 
to bngin ribmlin).-. tht? i-iida A and D twing fixed, uid wkiJa illH 
•0 Itft ft point tt be broiiglit in rral by k stojh and let «« *upp«^B 
be ohh iliinl ]>art of AD. The put DR miiat now vibnOe ■bodH 
D iu> fixnl poiati in thr mnnnt-r iuillcHtvd \>y tbc iMMitinuon* m^H 
liliF'i now nil pArtx of iha <iimw »lnag Innd to mahtr « riliratid^l 
mmc time: iicfordiD>.'ly. tb<r pnrt bclwt^vu A nnd il will not f^H 
fdngl* vibrnli<in, but will divide intu two at tbn point C. ud iQl 
ibr! mBimcr ibuwn in the Hi'iin*. If BD wcrv ouc fourth nutt ofl 
^^ the pan AH would be lubdividud nt C nnd C into Ihii* vibw 

^^^^^1 D_ ^« '_- ~-S.' "-^Ji^^B 

pnriioiiB each ^qual to l^D. Tfa^poinis B, C,C,MPcnlli>d mmM^| 
puinU: the middle p'lint of the put of tlw string bptRMn w 
POiisBPTitive artifn in cnilod a luup, or ft rmtral sfjmntt. It irii 
Temarlml tliat thu rittiu of ItD : BA niiwt bo UiM of »i>inu two « 
numbci?. for exninpic 1 : 2, 1 : 3. 3 : 3, etc., ollierwbe the iiodivcami 
formed, tfiuw lh<^ tw>.> porTiriiid of thn strinp cannot tli«ii bv nul 
vibmte iu the auvaf time, nnd lb« vibrntion* will int^'rfure with *nd 
de*trny ono another. 

If unw Ku tvtvi bni'li to Hp. IflO, the p.sistrnco of ifaa node ftt C 
Im) easily provnd by bonding tomv light yavvra of paper, nad ]A 
them c'li the «lriiiir. Siiy threu ptecta. niip at C and ib« uthwam 
litcly midway bpiwnen B and C, and btttweeii C and A, The OM' 
eXpvrienciM <m\y & very *ll^ht mo^un, u\dwmiiini in iia pUce, the 

im UMM> mnsoimns. 

of * node at C i the otber two an vinlMtlj 
I tfaroim offihe Btriog. 
■raacal Miuif^ ribntoa bctwismi ^x«d poluiD A aiid It, iia 
wt qoite M iinipl« m might b« iuC<:rr«l from th<< nbov« 

In poiiil of tact, putul vibnlumn bm aooa ph)(Iui.'<.'J, and 
ed Bpun th« priiD*r;r vibnttioM. Tb« partial vihntions 
to lb» lialf, third, fourth, ete: pwt< of tho aCring, Jt is bv 
tl vibmioM that tho harnxinirs sr« produced which maeaut- 
iaary tipto dun to the priniAiy ribnttioiu. 
■4 lutTB^MBtB.— In lh» cKMii hiUirTto conidden>d tfaesMiad 
I the TJbniliiruis a( *ului bodivH, Slid tlio &ir only nurvoi an ■ 
Iraasniittuig thi^n. In wind uwtrunwnlk, nn i!ip oDnlrnry, 
MdiM of the tube atv of Bil«quAle IliivtinHM, tliu eii<:k«Ml 
lit b Un MWmnia bodv. In fact, the nubatjuico nf the tube* 
lafluenee on tho primary tone ; with piiual dim^iuuoiM it i* 
riMtbar tho tubea Atv at pltisa, uf wood, or of nicbJ. Thne 
hHt**** aimplT Ao no mnir than give ri» to diffbrdiit hat- 
1 imjwrt » dilKcTEDi colour to llie compound tone produevd. 
DC* to tho DWDnvr in which thn ur in tubw ii nuula to vibrato, 
■■taU are dirided into mvulA instrumpnta and rwitfiiwtrunieDls. 
rUb laatroiawata.— In mouth iimtiuuieiifB all parta of the 
! w fn«L yig. 1(8 repr«rpnt* the niouthpiwn of na orgao 
if. 163 that of a whistle, or of a fla^wolet la both figurte, 
n it 1* call«d the moatb ; it ia boro 
Itos tho pipe ; b and e arv Ibl^ kpt, 

oao ot which i« b<iT«11nl. Tho 
n i« fixed at cue end of a tiib«, the 
of which maj ba rither oppnpd or 
n fig. 162 th« tube can b« fittod 
dot fa; meaiM of the foot P. 
nfid curreat of air eiit«r* by the 
diikM Bgainat the upper li[>, and 

praducad which cauaca the air to 
ieia aa intemitteot maniivr. In 
rolMtMOa are produced which, lnma~ 
tba air is tho pipe, Make it vibrate, 
i ii tha reaolt^ Id order that a pure 
w pcoduead, tbw* too*! bo a certain 
twaoa the fom of the lipi and the 

tt tk* mooth; Uwi tuba hIiki 
i«r« a great leiijftli in eompariaoD 

imetev. The number of Tibredooi difpendt in ftaavl on lk« 
of th* ^p»> aorf tiff telodtj- of the cumnt o( air, 


Fig. 143. 



S33. BnTtil tiMtraai«nta>— In i«nd iBitratnento 
i<«)(iu< ku tliF' lur in vibration. The toogu^ wbick UMll 
OT of viood, IB niovitl by a cunvci of lur. Tbc moatbpieecaJ 
the tiiuaaoQ. thr rlurionvt, ihv cbi]<l'* trumpet, w« <li9«Mt 
of the read, vhicb, it diut be rniiarkcd, is svoii in it< ainplci 
Jcw'a harp. Sooie or^an [lipeA are reed pip^a, ntlien are mi 
l-1)(. IM rcprmnto ■ model of a xvmi pipe an oomnai 
]«01unw. It i> fixrd <ni tbe wind<hei4 Q of n bcllom, ri 
tion* of ibe n*<I ena bti seen tlir«ugh a piece of glata, E, fil 
nde*. A nonii'R hum, fi, ■iRiiKtlicnii the aotiod. 

Fig. 166 «bow« the rewi out of the ptpo. It ccanm of 
Ist, a rvctan^ai vroodm IuIm! doaed below and npm abort 

copper plate a- frrmitng on 
tube, and in which there 
dinftl apvnure, thmugh wB 
from the tube MN to the 4 
n ttiin etustic plato t cnOei 
wbicb is fixed at its up] 
■fhicb grates thv edge of 
dinitl apcrtum, neiirly clofl 
furvnd wire r, which pTosM 
longiie. and cim be iiioT«d \ 
It thui regiilalM tbe la 
tongue, a&d d« 
pit«1i of lh« nd 
ihia TFirn that tt 
liined. The rw 
placed it) the pi| 
a current of ajr 
foot P, the too 
pipwcd, it bcndtf 
afr>rdi> a panagt 
escapes by tba a 
being elMtic th 
gains its origina] 
F,g. iM. F,e. m. Kb. les. pj,rf„nning a .Ni 

tirlDB, BUCCl'SJTe 

«-loee» the orifice. In this waj Mmorouicwnves result and pi 
whose pitch increaseii with the Telocity of the current. 

In this reed, the tongue vibratos idt«niatrly before an 
aperture, mcrvly gnuiag the edges, as ia seen in tie bar 
Mrtina, etc ; such a reed i« ctill«d H_^Ye rrrd. But there ■ 
<Alled ffatiaff itriU, in which the tongne, which is Ini^r tin 


iwuy AKi> Loors or ax organ pipe. 



tlk««dfM at «afb iwt^illtUion. Th« reed of tlit duiOMI, 
iff. 166, M «n examjilc of UiU; it it ki'pt in iU plaw b^ 
Ml et Ik lipi. Tbe rMda of th<i liaulbov and LoiBoaD on aim 

IT ib« Mo«a 9r*dtta*d br um muq* pip*. — Daai«] BeniouiUi 

4 iW tbi taoHi iirgau jiipe coc be iiiaitL> to j'ieJd a cuccounon of 

pipMlj nrrioK the fotce of the cumnt of air. The tvaulta be 

t nw; b« IhuH alatvd : — 

K jipe u o|X!ii at the end apponta to tho mniitfapJKO, tb«ii, 

th^primu7 tonvby ItWecu.l^gTaduaUv inirrea^iuj; the tarce 

mat of air, obuia mMuMJT«lj the tonea U, a, 4, 6, etc., that i* 

• kirmmin at lli* primary tMa. 

ha pi|>« IB eloac^ at the end (^pc«ile to th« ntoathpiisce, thim, 

On primary tone bj l,«.-a can, bj jfradaaDj incnMlog tbo fiiKe 

mat 0^ air, obtain tuccecMTal; th« lories 3, fi, 7, «ta., that ia (o 

Bwrai AarBMnMu of ibe primarj looe. 

t hi added tbal if a doatd and an op«n pipe jield t)ii< name 

car, Ibe diNsd pipo nwl be half the len^h of thn o'pcn pipr, 

f rMfMta th^ am tb* aains, 

taa» Ii la ItnpoeaiUe to produce from ibu gincn pipe a tooe not 
in the aboTv icrie* rcapoctivRlj-. 

gb the above lawa ar« eniinciatiKl viih T«fvr«iioe to an ur^'ao 
' arp of coiir« wki at any oilier pipe of untfarm nection. 
R tba Bsdaa and lospa of an erfan plpa, — The vibralious 

prD>)<*cio); a miuical toue take y\»cv \a a din-L'tiuii parnUet to 
f tJia pipo — not ImufcTHil;, ta ia tbv ctum of tbn portiona of 
f atiio^. tn lh« former caao, bow«vi!r, m vi-ll a^ in tLu latter, 
pMia of NodM and btpi may b« produoed. But dow by n nwfr 
iidentood s nctiOB of Uie colamn of air coauuned in the pip« 
ipsrticUa Ktnoia at real, but where there arv rapul nlteraationii 
mlim «nd rwtfaelion. By a Uiop or trMrat ugiiu-iit must be 
I ■ wctkM of tbe cotamn of air toiiEHtncd ill Hn- pipe, nbum 
Ian of i1m paiticlaa of air have the trtvnti^ct a)npUtiul{«, and 
I« la IK> ehaajre of deuity. The wctian* of the enlumn of air 
ma, tnad« at right angto to ita utih Whnii thu column of air 
. bdo wvetvl ribratiiig portiona it ia found that th« dicUnee 
Oy two conaecutivo loop* is oouatant. and that it \i bisecled by 
K'« can now conridBT aeparatcly the cium uf the open and 

I «*• of tbe open pipe, wbat«Tei lone it produces, there ntwt 
It (!«ch vni, naoe Iba indoaMl oolunni of nir ia in contact with 
tboco poiuta. Wben tfae priiuatf tone ii produced 



ihfre will bo n loop kt Mob nnd, Md » nodo >t Ui« middle Medndlj 
pipti, the DodM knd loops dividing; thit «olunD Into (wo 4qnil 
Wh(<n ibn fint humonic (2) ii> produiwd, Ibcre will b« a loop I 
end, and » loop in tlie iiiiddUi, Lb« coluton htiiag dirided intojW 
parU bv thv alt«niati! I«op« nnd nodea. WbcB tin Keond btrmca 
ia ptndiiccd, the column of ur will bo dividrd into tic equal pail* tf ' 
alttMoalv riodw and loopii, and to on. It will be r»mftrk«d Atf 
iiuccf*«ivt' modcB of diTimion of the vibrating colomn arc tie onlj 
oNipaliblu lith thn altpmale rociirrenoe «I ^qiial iiil)»rv«ln of DOdM 
limps, luid wiib thp occumMicp of a livip al cai-h cud of tho pipB< 

ii. In the rjuw of tha rloaod pipe, ihrrc will itill bci a loop at the 
cut \a tbr uioulhpit<c«, but there will b« a Dod« at the eloeod Mid. 
tb* air in contact with a fixod iilop ntait bo at mt. Aacocdi^j 
(iuc«««sii<' modM of divUion of the coluniu of air moM bo Mm 
with thin imrniftomcnt, nnd it will br found tjint whMi the prinaiy 
IB prodiiovd, ther« will b* merely n loop nl ono end, and a nndn at 
nthrr. When the lint hnrmooit.' (3) in produiv^d, I.L<< i-oluinn ii di' 
inU> thn'e Kiunl part* hy Bltrmatr liHipi and node*. Wbnn the h 
hnriuonic (G) IB producod, Ui« columu itt divided into &W «qaal ;«rs.iid 

There are neveral oiperimentu by which the ezi»t«>nc« of ii>><!" u4 
luopa can be shown. 

(a) If a line meiiibmnie ia stretched ovor a piuli^hoard ring, and W 
■prinkled on il some fln« wnd, it caa be gradimlly let down m tube •* 
iihowri in fi^. 169. Now Buppom the tube to bo produring s muKal 
ri'ile. A* the membmnc deswrids it will be nft in vibnilion by li» 
vibrating air. lint wh«ti it reochcE n node it will cpasc to vibralo, for 
lhpn> the air Ie bI rteL Conf«<|tiently the grninR of wind, loo, will b« 41 
real, and their qiiieocence will iDdicatI^ the position vt Ibp node^ Oo tb4 
other hand, wbpn Ihe membmne reaches a loop, that is, a point vbrn 
the amplitude of the Tibrationii of the air attains a infi.\tDium, it will bt 
liotenlly aifitHl^d, as will bo shown by the agitation of tbe (train* of «t^ 
And thus the poedtions of the loops can be render^ manifeM. 

(A) Again, suppose a pipe to bv ounstnicled with holes bored n«M 
of ile sides, and thecia covered by little doon which can b« opened uA 
nhnt, as shown in lig. 107. Let us suppoa! the little doora to be(bit 
and Ihe pipe U> be caused to produce such a tone that the nod«* at* el 
iN and N' and the loops at V, V, V". At the latter point* tbe teaty 
i» that of the cilernal air, and conteijuenlly if the door at V is op»oe« 
no chaoH* is product'd in the note. At tbe former poinle N aiid N' lher< 
are alternately condennalion and rarefaction takin)^ place. If now the 
■loor trt N' is opened this alternation of density is no longer poMib^ (t 
Ihe doDiri^at this open point must be tbe same ae tbal of the cxUnilur, 


H^r A^' k«<eoin«* n tcwp anil tliu naVi ;i«Ided bj the tiibi! i« 
€A»ag<» of jlOU* prnducod by chiiDging the fin^ring of 
Mtnto^ oo« fnrtn of ihU Mp«rliuciit. 
, ut £^- Iti^f to b« • ptp« emitting k errt«in ooI«. and 
plugr, Gtting itie lube, (lUlMll^<i to th« end ofa loog rod 
t .Auv^d dufvn tbc lube. Now when tho plug U ui> 



^^^ \iM position, there will V • node in contnct with it. 

\i, )A tEToil'"'"? r>>rc«d down, Lh« uola yielded by tho pip« 

i^atoiniiR- ^"^ evory time it rnachM K poutiao which WM 

noda bcfont ita iiuwrtion, tli« not* baconiM the Mine w tli» 

_ j\«l(l«d. For DOW tho column of iitr ribntM m oxutlj 

isaimr ** it ^'^ befoiv tb« plug wm put 




(d) Vig. 170 Aav l))<i TnMimrr in whi<ji thn 
perimoDt ii patformffiL Tlii* fi'^-im nprvfentt mi orgMi pipt^ 
of wbtch u B eli«Kt P 6U«d with 
mnui* of ih« tulw 8. The gu tit 
coiun out in tlirw jela nt A, H, C 
ignilotl. The manner in wbich ti 
from tlie cheat to ilivpiMutofigail 
in Ihn iBiiillntt fiKun.', which U 
»*clJon of A. A circuliir hole ia 
aide (if the pipit and covnrpd with 
r. A piece of wood it fitted tnl 
M In leavo m huoU opitca bstWM 
menibmie. The gu paMM fron 
lh<i dirvction indieatnd hj tht u 
Bpacv bt^twee^ the ni«qnl>nii« and 
wood And M out bj thn tube in, i 
of vhich il is Igntl'-d. Now su[t 
tu bu cauncd to yield itfl prims 
M it i« Ni imcoT^rod pipe tin 
be A node at B. its middle pa 
qupntly there oiif[bt to bo npj 
di'Ttnly nt B; th««e would OMi 
bruno r lo vibmt*, «ad tbervbjr 
lUme Ml, nnd thi» is wbM scttii 
If by incren-iiiiK the force of t 
ortHve Co tbf primnry note ig pnl 
bi> n Irtoji, luid A and C nodefi, i 
lliir fliimn at A Wid C will now be cxtinguixhc-d, m ix, in ] 
the cue. But nt H, thure bnin;; do change •if density, the 
uumovnl, and the llsuit- cuutinuoii to bum ati'adily. 

By nacii nnd all of Ihnsn nxpfiriincnts it is ■hnn-n thM in | 
whether o]>en or clii»i'il, then- are alwava a n^rtaiu uuiubOT i 
midway belwron any two eonsm-iitiro nmif-t there ii alwi 
iimifral }i'iii'/, 

2'II1. SaplannUon of tbe aiisMaea of iMd** and 
■naalokl ptp«. — The existence nf nodes and loiips is to be 
the c<i-(^xiEteuce ill the Same pipe of twi> equal wavea tr>vti] 
Iriiry di red ions. 

Let .\ he a piiot from which a lerie* of waves wla out td 
Ifrt tho lengths of these wnres, whether of condennalion or n 
AC. CD, or DD. And let 11 be the point from which the aeH 
equal waves st-ta nut tuwnrds A, it must be borne in minit 
CMe of a wave of condenantion originating at A thn particle* 

Fig. ITO. 





liibBvbat ia a war* of i»ad«nwlloa ofiginBtuig at B their 
llk&veliiaB B to A. Now l«t ui •upfioM tlut rondeuatkm at 
Mllgribewanfrnai AjbogimiBt tlae wni«iLiut«Dl Uist «<]«iikitiM- 
Md bjr tb» wsT« from fi begiiM at D. Coweqiicntlr, mnridiiig' 
uin I* lh« putictM in tlie Use CD, at aaj inotani Um valoeilica 
iMm ia CD da* b> tho (bnii«r wave will W »|frAra(ed bjr th« 
• of (Iw e«m SPRT, while th-Mo due «• the wavn gnu) B viil 
mu4 bj Ihe oo-ordtnat«« of tbo curiv T<jrS. Tlivo, »Liic« tfac 
ml viih tlw Mm* nlocit^ and an M C and D nscpeetinly 

■B« batoBt, we must bare, for any Rulw^iwot itutaoi, CR 
Dr. If, thatafon, N ia tbu middle piriat bntwMO C and D, 

ha*« rti equal Ut ItX, and caowqiMDll; PX »({ual M QS, 

Mj, if tbo parlich: at N liauMiuttwd duly aoe vibration, iu 
tacit insUml wituld be in the opptfdta phiwe t« tbM of ila 

it tnamittod oaljr tbo other Tibatlaa. In otlicv wotAm ibu 

adU at atuy iofUIit t«nd to bo oiotmI with njud T«locitv in 
btdkina by the two travM, and lh6|y<toi« will tw prmuatfatiy 
hat point ij tbcnforo a nodt. la liki? nuuini^r thdra in a nodi: at 
1 betweAU A aad C, and aleo nt X" midway b^iwwii B aod D. 
to tha motion o^ th« remaiiiiug parlidai it in plaiu that their 
Tebciiiea will bo the (itlKebtiiii^al) nuni of tba tiriocitieii th«y 
acih birtaat recfrivH from the waiw w^^mtat^ly. Htncfl at the 
lieated \ij the diaiiratn thisy am trivcii by the ordinntoi uf tlie 
tL Thid curve mill change froai iiixaiil in innutnt, nnd nt 

thn tiiDB ori;tip«cd by the pa«<4^ or ■ wave of coudennlioii 
Ff>ctii>D> (niia C Ui D will occupy the pnnitioo ahowa by ihv 
N kSk. Umce it ia evident [hat particles uear N \ivie hut 
Igea of T^oci^, while tho*o noar and D cipFrirnru Iur)Co 
' Telodty. 

nrre IIK were produwl both way* it would nlwnys paM 
S' and N"; the pari, hownvirr, betvriHia N and N' nould 

ba om one aide and aomettuiM on the oth«>r clde of Al). 

tho partide* betweon N' and N hare, nmultaaeouidy, tirfl a 
Um difectioa A to Tl, and tlu'o a motion in the dtroction It U> 
WfticlM near havini; tho (frealrat amplilud» of librntion. 
r N and N' there will he alffnatdy the ipeateal rondeu»atiaai 



nk ex^nwtiaa ■ppGM to tho can in wfaick ABk i 
orpai ppr. A beiii); the cod wkcr* tba tnoutiipiwM it rfl 
wsvM Aom B luT* tlicir Ofi^ in the tvflectiun of th* M 
frinn A. In Ux pnrtfeulM- CWaco M id»w d , tbn now yietdtd li 
that isfentcd bj 3, tlut ii, tba fifth thaw ibv odare to tha | 
A ihaflnt wiphuintimi an obnoiwl; bo nppU<d to nil odi 
wbetbrr the ead hn opMiad or c loned. But in (Le Inltet cnai 
waT«« from Urn dontd Mid mint omnmeiKe nt n point diM 
inoulhpiera hr • (pan equal to one half, or thiw InlvM^ a 
tie. of the leci^ of a wava ctt coodeaialtoa or espnnnoa. 

$S7. ObamMnl bmraaBlown.— Th* air in an opett tobe i 
to gife a KMiDd hj iBcui* uf a Inmiaont jet of hjdroiTCEn, 
When a glaM tub« abovl IS inchM long i* bold over a I 
kjdrogen <3g. ITS), a note in prodncnd, whieh, if the take i 
imition, I* the fundamantal not* of tbn tube. Tbc miiinda, do 
froan th« auCT—JTn eiplosiuns produuM by the periodic om 
tbc attna«|AeTia aix]rj(i!ii irltb the iuutniifjetof brdrof^cai. "] 
M callnd th« e^anieai kanaomron. 

Thv phpnumi-na of the cboniieii 
and of nuiying flaniM hava been 
b7 Prof. Tyndall, whoao Leiim 
contnin a number of Terjr heautiiv 
on thia JHibjeci. 

The Date depends aa the Mt« 
and the Inngth of the IuIm: witl 
bj taryiit); the puailion of tbe je 
tho iwrifia of nntra in ibo ratio 1 
U obinlned. 

If, whiln tha luhe emits n Mrta 
voiM or the fjrnn (3I<^) be gm 
to tbo anme height, » aoon aa 
Doarly in tiniaon with the bun 
dnme bttcomes agitated, jumpa n 
and in finally stiuiil}' when thp 
ure in unison, If the tona of 
graduall]' heightened, tho pula 
commence; thny arc tlie optica] 
of tlie boBta (j^4) whiofa occur 

If, wlille the j«t hums in th« t 
dncna a note, thu powtion cX tbe tu 
■iHnd) a point in reached at wbicli no noimd in hoard. If D 
or the a^rea. or the tuning fork, be pitched i»t tbe note proi 


Fig. 17a. 


sitnrazD Axo wihd tKersoifzicn. 


^^Pm ymg, md eontinaM la tiog wen *IVr Uu sjno i* aili; 
""■Ji^grahoulin; at ao iucomct pitch, ntrn>.-t« ihi> flaiuH. 



il toMf;. 

iMaliuiuauli, — i!triiig«il iDuaica.1 initnuncnti: drpnnd 
> Indutka uf tnuuTPTH ribntioiw. In «o(ne, nuch m rh« piaao, 
Bib mt tatdanl, and Mch notu rtiiuirtii ■ lepiuiLle ■trio); : in 

aek M tfw vialiii ud guit«r> tlie luundi Bro varitJ by tbe 
I; nd eiB ba ptodnMil bjr fevar Hiring 

I fiM» Us TibntioDi or Ih* suiufn >m produmd b; tliu sUuko of 
Mv, wUeh u Bored bj a lericn of boot lover* nomniiiniMtiiig 
ifaja. The *0aBd ii slrengtbeoed bjlbe ribratiouAof the niriii 
111% b«4id M which tfao stxinipi &n> stn'tcbcd. Whenever n k«y 

■ Jiiy w u niMd wbicb fnliii when the linger w ntaoioA Crom 
nl atop* the vibnlioiM of itit^ currDjpun<tIiig string. Bj mi'inn 
Fall the dMnpwi can be aimultancauil^v roiuitl, aiid tlio Tibraliniw 
fi>r Mina time. 

vp ia a sort ot tnnAtJon from th« iiutruinmita with cooiitant to 
h rarisbU inuiidji. Ita Hiring cormipoDd to the natural uutnH 
lla : bjr ni«sn« of tlie pedalH tbtt l(<uglhB of thu vibmtinR pnrt* 
mgrt, inan tn jiiiiiliii ■ iibii[iii uid fliiti. Thn>oiiiid ixHtrongth^niid 
vsding bos, hhI bjr tba vibntioua of all Ui« iirin^p liumonic 
• plajcd. 

rloliu and guitar each Mringr ■:«■ Ijive a groat numlwr of Muodii, 
to the loBglh of the ribrating port, which \a dctcrtnined by thn 
<f tha flng«ri if thn l»ft hand whiln thn n^1it hnnd pUj') tLe 
« MringB thctnaelTiia. lu buth tliew! Itutmun^uta ihu vibrntioDs 
iiili(*tm] to the >pper hc« oS the Mundin^ txix, by mcnnii of tkv 
ir which the rtrlaga paM. Th«»e TibtBiioiut »re cnuimuiiiciiti-d 
l|ip«F to the tower face of the box, i-itbar by thendca or by ui 
ita |iW« called the tMmd po»t. The tiir in the Interior is Mt in 
bjr both besM, and the otredgtheaiiiK of the Bouni) U producnl 
W liaBHltuicoaii ribntinffl*. Thn ralne of thn inatnunent con- 
IV pariection with which all piMBibIa souiida an InteiulSed, 
Mida oMWitially an tho qunlity of the wood, and the mlatjie 
M of the part*. 

|b4 tnetranaaia. — All wind intitrument« may be rof^mMl 
ureal ty|>™* "f aonoroua lubw which have biMin dmoribpd. In 

(H the urnn, Iha notea anjixtd, 4Dd rwiuiru a wpnnite pi[x> 
rta; iu iilUi'ra tho note* am MriaUr, and arc pcuduecd by only 
IW llutev bom, etc, an of thi» dii»i. 

un the l><po* ^M of varioiu kiodn, namt-ly, mouth pipes, opi'ii 
^ Hud rev<l pipM with apetlurM of vnrioui ■hapm. ity meatiit 
0f«iitat can produce any note by both kiudi of pipu- 
■ 3 





Id tbft jM«, Um nMuthpiorti cawwU of a mmple Utt^ cttruUi ■)«• 
tui« ; tiM cuTTeDt of tit U directed b)r inetiu of tlu lipa, m> UmI il p^m 
tlm edg« of tlM apnrtnir. The bolM U diflnnat dbttiuices v* < 
citlivr bj ihttfiBgenor bj ktj»; «b«n one of the holu ii opnwd. • I 
in praduoMl in the ecncipoDdhig Uiyer of air. which iaodtfl<;9i thn i 
IwdMi of oodea aad loopt in tlie interior, and lliiu «Il«ta tbe aoit. 
whiatliair of a ksj U riniilarljr produ(vd. 

Tb« jnanrfwim p^ OLinutt* <-rf tnbei> of diffinvnt siiM i 
the ditkmit notM of thv ),'ajuut. 

In llio mmqirt, tha horn, ilir tmmhon^, n>nipt-A-pi«t(m, and oph 
tho lip* form the nwd, oud vibrntu tii thv innuthpiMo. la tfca i 
dllfereBt nolM an' prndnrnd hj nltirring thn diitanci- of tbe Ijpt. b I 
Irvmhime, one part Df thu tube 8lido« wiliiiii t)ll^ uthtr, ami the ' 
eta a1t«r at will th<? Icnj^h of tht? tub», ixcd thus pirxtuai hiffbororl 
nutea. In till! cantrt-*-i>ulon, th«r tube fonn»i>et«ntl coni-olulioiu; ] 
plaoid at ditfonoit dUtancM can, wbua plavrd, cut off 
with otber put« of the tubn, and ihu* alior tho lon^ of lb* vili 
fiolutnn of air. 


viBiuTinss or eous, pi-ites, »si> meuiulisis. 

340. VIbraUoB* of rad». — Kndi latA narrow plate* of wood, ofglia^l 
•od upucriaUv uf Ii!iiiptr«i ste«l. ribntti! lii rinue of their ela*tirity;Bki| 
, atringii ihny hnvn two Irindii of vibmtionn, longitudinal and miimnc, 
liu latt'!r are produced by flvinj^ tbe rod* at one end, and paannf; a bow 
Iftver ihn frw part. l^oR-itiidiiinl vibratiotui nr<i pmdutvd bvHiiD^lb 
pd at onj fiiTt. Hiid nibbing il In ihn liiinction of i1« It'netb with ■ pise* 
of doth >prii>1i!<'d with min. Ilut in tho latter ca»n thn cooDd b uolf I 
produi-ed wlieti tlie point of thn rod nC which it hsa Veu lixni it i 
•li((uol part of it« b'lifrtb. ns n Iinlf, a ibird. or a qunrlcr. 

It i* nhonii by onion In I ion tlinC fhf niwihi-r of tmrifrrfe vihratiaiu i 
M n pivH linif bj/ ntli mill thin pUifet oflhr tainr kind M dirreth/ at ltiar\ 
ttM-kntu, ami invrridy m t/w tquarr of Iheir Ungth. The widtli of tbs pbU 
doM not air<Kt tho number of ribratjons. A wide plntK, hownnr, 
nquiraa a ^matur fnn^n to «it it in motion than a nam'iw one. tt iii 
ot eOiUM, ondentood that one end of the vtbmliiit; plate is hn1<l firmh. 
In cloatio ti-A» of Ibo wnn- kind rhr number of loH^iltiduial n'troCMM ■ 
rfy ai llirir Ituyth, ichilciri- lie ihc iliamttfr aadfvrm of l/ktir i 



Ftf. 178 nrpnMBla an ixuCnuuent ifiTf«it«il hy Mm-loYf!, bnivcl 
OD tbR loDfitudioAl vibnUioa of kkI«. It couiaia of • jolid wooden 
ytdoaul in wUcii m fixvd 
«irBBt7 tkin dMl rodi, MMiia ool- 
«w) umI tftlian «kil«. Tbvy 
■i* of aucfa ■ laofth that die 

wUW thr a>l<-Qn^l •diM giro tbe 
kail Botek unl nini|>lirtie the 
cknmutic K*)e. Tlic ilMtrainpin 
b pl^T*' l>y rubbing the n»da 
ill tba dinrtloa of tbtor Ingtli 
kXwwM tba fiagw Bod tliuinl^ 

CB iwI wUJt [>owd«r«d i«*tn. 
n* Botn fmlnc'id n«enible 
IfanK (i/ a paadsaa pipa. 

IW fMBM^/bri, tbe f/io^, 
and ■> — 'rirf Aiuw, ri« eaotplm 
«f dM tnaanrae tibntkuH u< 
la BiHical boxM tmall 
iif iteel of di A^i«il diiiMii- 
aie lll«d oa a tod, like tbir 
at a DooiK A ejViadtt, 
axia U pftll"' to tluii rod, 
aad wlMManitee iaftndded wiib 
MmI l«nk, amnfrrd in a cerUin 
min, i» pUcnl aeat Um pUtaa. 

Bf una Hi of a rlockwoik motiaD tba CjlindtiT mlaU-t, arid ih« Ii'l-iL 
■trikinff tbe *l««l pUlM i^t tlmn ia Tibralion, pn^ducini.' a tiiuu, irbicli 
irfftubt iin till' UTWiuvaivDl of Uir trvtfa cm ifao pylimJcc. 

S41. VIbrKUmaa arplataa. — In ordnr tn mahe a plutv vibmlo It U 
Itrd in tb« cralni ill^. I'l). and a bow npidlv drawn ocroni iine cif tbe 
■inn ; or ebe it U fixed at aav point at itn lurTBco, and rRiiond to vibratn 
^ lapidlj drawing a itna^ envnrod wllb r««in t^inat tliv mlit«» of a 

pUft" contain nndal Hnn* (&10), whw4i vary in nunibrr and 
aocnrdiniT to ibo form of tiie f\nir^. t)i<^ir nlutiritv, tbtt tii'.ide nf 
■, and tiM) noiiibrr nf libntiooi. TIii-m: nndiJ Hiifs may bo 
vWble hj eovarinK tli« plate with fin« moiI Vforc it ia nindr to 
Xt maoa u tbe vitntiona «oinaiaD(^i>, tbe und \e».\m tbn 
fflnluur P*rtB, and accunniiaiM on tho nodal Unc«, a« wmi in fi(pi. 17J 

t'lji 114. 



The pollioa «* Ui« ocdAl lin** (nay be dMennii»rf fcy *<'"^^ 
peinu Hi vbick it i* dmirod to produce them. Tli^ nuBbtf 
with the number of tibrMioDS, that u, m ibe not« givM bj tb 
faigliDr. Tbo nodal line* elwi^ po uM W gTtai ejrmineliy orfonoi 
nine fonu UeJmjt pmdaced on tbeiuiapUU under the umBCoO' 
Tbcj wt-TB diMzuivrad bj' CbUilnL ..^ 

The TibmioaM of pUto* am ^oremed bv the foUowiog law : I* f^ 
af Ikt mm* kM mad t/U^, tmi giwmg Hkf tamt i^tttrn tf mJdm(^ , 

liwr^at y at tAtir ant^ 

Gonyr Ubl eymbaU an) eXBnipW of kOSltVBieBti in «hi(Jl •fondt V' 

^pc«dl■ct>d b}- the ribntion of metallio platM. The ghua batnocK* 
defend* on the * ibtauona of f^aM pUu»- 

R«. 174. 

FiB. 116. 

342. Vibratlona «r membraBee. — In conx^qufncaartbairllMnbili^, 
(n«mhmDt\« cumii^t I iUntt<- iiiiIfM tLt'j Arv 8ln<t('hMl,llki> tliiMikui ofadnOB- 
The aouud ihi.'r (^-iio ia man: lU-ute in prnporliun a* tlic; are eoudler Ml 
morn tightly »tn>icbud. To obtain ribntiag mentbranen, SaTaitbrtMtt 
gnldbeiiler'8-«ktn on wuodun framiui. 

Id thu drum, the linan ara 0tr<it<:h(>d on ihn end* of a cylJndrMal boi. 
When one end is glruch, it v«iuiuun>i?att<« it« vibrations to the ioUflUl 
culuruD of nir, and tho saiind i» tlmi conndcrabl; ■trongthaiMd. lAe 
fordi ■tnil^-.lir'd iigaiiini Ihv lower skin *trik« a^nst it wheu it tibnti^ 
a/LiI [irodui* tliu BDUud chnracleriatie of the dntm, 

MombraniH citlmr vihnt* bjr direct perciumon, se in the dnim, or the/ 
uajrboMt in vibratioubr thotibratiutuuf thuair, a«SavarthaaofaMtT«i 

vnunoKa or membramkv 205 

'W iflntieoa u« mfficicoitlj- ititnmo. Fi^. IM ab«m n 

■ tttntfaf and«r Ui« inflaencn of tlis ribntioni iu the air uuued 

r Ull. ^M anil ■Ueved on the mMnbwic ihnwx the for- 

'uTdoIiJ liiMi juct M upno plaUi*. 

'«"• in, lumrriMu iiuUnoM in wbkh solid bodies an set in Tibratiati 

'""ifesiimuof thenir. Tbc oondilkin meM fsroumbln fof the pro- 

lofkU) phmMni«w)a is, that tbe bodj to b» Mt in vibnitiun ia 

rnkoBoditioiDi that it eaa readilj produce libratioiu of tbo wuno 

I iboM tmumitted U> ithy tli« sir. Th« following btd some 

vJBffHMneos : 

• nsfaiHeUo rtringi tuned in unium urc ntivtchiHt on tbr umit 
> sooo M ooft of them in soiindei), tKn nlhnr in loi in vibn- 
Thii it also thn ratu if tho inturvnl of tho iitriapi ia an ouCave, or 
I dftb. A. riolin string mny also he mads to Tibnta, byMunding 

|T*o Utfe gUaves are taliMi of tbe same »bap«, and as nnarlj' as 

r of Um aainn dimensiMW tad migbl, nnd arc brought b uniauii 

ffotmag \Ma them piopw qntirtilisa of vntnr. If now onn ofthoni 

, tbe other b^giiH (o vibnito, «reii if it i« at some dislsiuie. but 

r bo added tn tbo ktl«r, it c^vm to vibrate. 

Breipirt round that If two clocb, wliose tiiuu w«* not vpry diffiront, 

««• tttd «D tlio Mine BotalUc sopport, they icon altftiaud eistctly tbo 

■Da linfl. 

M sill II ■11— am muaentiy fitUd for taking up tbe Tibmtions of thn 
.liraaaonMiat of tbeir small msM^ th^ir Uiy ■urfacc, and tho niidinom 
I wUck tbny subdividf .. With ■ pn-ltv Ftroiig irhjiiln, noiinl linn* 
' W DRalimd in ■ iwiinbraae tlreUhnd on a frnmu, ewo at tbe truit 


Tbe pbanoBstiaii so Moily produced in Muily moved bodies is slfo 
imai in laryi- aixt lesa elaslic maHora ; nil tiiit pillnn and wslbi of a 
tbmb ribrate'nMro or leas whito tbe belb aiv twing mng. 




— Th« uurl)i<,Hl uf 3L LUtuyuiu uxhibils tliv vibnitiHy motioD d '■ 
dUier diroRll; or by projwtim on a KK>en. Ii W aUa tfa- . 
iidvanUfR thai ihe ribntloij motions of two souiuling bodiM ti: 
cuiiipnrwl leifAuuf lif aid of th* tar, so as m obuiQ tb« txmO. t 
b'>m<^a ilicm. 

Thia inolli9d, which d«pnnil« on Ihe ponjiiteace of vlnial (Miwnwl 
on tho retina, conaiala ia fixing' » stnall mirror nn th? TibmliDi- 
ao as to vibrate with it, and import to n liuuiaoua ray a tibiatM; i < 
ainiilnr to it* own. 


Fig. 177. 

U. Liunjous uaea tuning: forks, and flxw to ona of t])o prongs a mmH 
tnetallic Dtirmr, m (fig. 177), and to tlI•^ othtT a O(iunt«rpoiae, n, which 
i* neocMnry to makir the tunine- fnrli rihtnto m^ilarlj for a loac 
time. At a few vanJa' <ii«lBnoe from tliy mirror thwe U a lamp 
Hurrouudeil by a dark eliimney, ia which there is n 4inall holo, pviog 

oumcu. McraaM of sniDTtNo viBRATonr vovemkkts. 207 

' iiiniMiu poJBt. The tuhlitg tatk Iteing kt leat, tlie ere u 
' H l&« lb* lummMM poaM is Mnn at a. The tunine Tork to 
r U ribnie, ami the Ima$« elmigiitiiB «> m to form u pnndrtrat 
> ^ *kidi diroinUliM in profiartion m th" nmptilad« of t)i» OKJtU- 
If, duriitii: iIm ot^llaliiitj of t!it> mirror, it U made U 
nWiiig the tamng forlt od ita Axi*, m linuoua line, ttir, U 
. isnnd itf tbs atniglit line oi. Tiie'f ditr^rent uSixU tn 

1 ly Ik* ■WCOBMIto dfaplaWimW of t\w lumiuuuii {leiiL-il, Buij 
dantiiM of tliMe iBBinotu impwiomn on the ry« nftcr thw 
I ha* wMei, • pb«aoBi«ian to wUck «« aball rt^vn Lii Irvutinff uf 

, inctMul of rivwinf ilinM vllnrtii dinwtlr ibrj are projactvd on tlic^ 
thir « t p wim »Dt ■» ananirrd ■« *h<>wii in tiff. ITi^. tb« pnndl 
fom tfae Tibntitig mirror U rrttectrd a Mcoud time from h 
1 ndnw, Ml, whkib Moda it iwwsHa an achromatic Ions, I, placed *» 
ftk pmjed tli» InM^M on tfaa aercan. 

M4. CvmbtDJiUMi ar two Ttkntwrr niMl«a* la tfe* BMaa 
, — .M. Liitwyouj tiiui rr*«U<wl tliu prriiilnm of th" optirnl coin- 
ItaMiai <if urn vibratory mntioaa — vibralini; at firat in t.)i>- aniiiv 
, anil tb«n at rigbt uglea to Mcb other. 



[•a- 1- 

Fig. 17d re]>rv»enta the eipt^riment u amn)];!^ for cosni 
parallel motiom. Two tuniii); forks providod with mincm 
•rr«ii|ifidl)iftt thcli^liiiwHticted fmraoDeoTlliein reschMlheotktt.i 
u klmuat pHratlol to it, niul is tiica KDt towanU a aciwn tilei I 
pMHieil ill rough ■ lona. 

If nuw tbp lint tuniug fork aluue vibntM, (he image oa the i 
thn Mmn lu in pxpnriitirnt 170 ; but if thny both vibtato, oappiiMJtl 
are in uuijiou, lht< t^ll>u^tiull iacrvuua or dimlnishsB acourdink.- a.' tin 
•imultiuicaui motiom iraparlnd to the iiiingc bf iho vilirntiuin <if tb- 
Dtirron do M do not crancide. 

Kg. 179. 

If (he tuning forka ]:iiuia th^ir positiou nf ui^tiilibriiim in tbe muim linn, 
And in the wuue direction, ihn imngw atiainn lU m&iimvnai and th( I 
imagn !» At it8 rolniinum whun iher p&M at the aui« time bu( in oppOMtti 
dinilioni BelwL-eo thwo two nxtrnmn cbm* Om ninplitiKd* of li» I 
tninKti vn-rii'i nrcnrdion' lo th« time irbick olapaa* Ix-twwiii tii« ntl I 
ttiDiiint At wbii^h thn tuning forka ppM tbmuKh thetr pnaitim <{ ntt i 
rt-spMtivi-W. Thr tmIk nf this (inio to the lime of & double tibraiiM it] 
enlind n difftrrne* ofphaiui nf tho vibmtion. 

If the luiiiug- f'lrka »tv t^xncttv ill iiniaon, the Inminniu appoanwaol 
the Ktven expLTit^ui-CB a {.Tniiiiiil diininuiiDu of k'n^'lh in ^portiea '■ 
tha amplitude of thn vlhrnlinn dinuni>ihi>ri j but if l})i> pitoh rt(on»iiiTMvl 
little altered, the lunpillude nf tlj» imH|:t> vunes periodloallj, UK],wlii1«] 
the beitU rrauUiu^ fnitn tbe imperfect hnnnDii; art) diatinctljr bcat4, tW] 
Vf« «e«s tho cunrouiitntit piiWlioru of lh<< imago. 

^i5, optical comhlDBtloB of two Tibmtory motloaa ax 
■asieB to oHcb othnr, — '\'\m •ipiioal ri:inibinnli'~>n of two twst 
vtliruluiy molii'ii" Ih flTtiL'tfd as «hovcn in Ibe figurw 180, (bat b| 
moana of two luuiii); forka, one of whic^h in horliontal and lh« 
««rtical, and both provided with mimin'. If tho horiionul fcd( 

aRAmicjti. Mcraon or trvarma veuutobt hrvxhzsts. 209 

I alct^ ■ korinwUl Umiaoui) outline u wmi on Ihe *en>«a, whilo 
Ibmioti of tbe oUier prdduco* * vortical inuffc. If b»th tuoing 
r dmvXXta»omij the two motiatM combiae, Md tti« t«flec(«d 
I m won or 1m* eonnptex curT«, the tarm of wlucb dopcoilj 

Kg. 180. 

' of ribnlidiw of tho two tuning fork* ia ■ gtTan timp. 
I gWoi ft vkliwble niMaa of comparing tho numbnr of vibrslaoM 
f»omiiiaa hoiiM. 

Fig. 181. 

181 iliinn tli« luminou* imotca on the •crmn wbon tbn tuntnit 
b uaiMMB, thftt id, wii«in iIih numb«r of TtbrAtiniM i* «qiiAl. 

Itcliau bolow wub eurre indiuate tbo diffuivni'UH i>f pbu^ 
tbtm. Tbe inilUil tarm of tho curve iii detvrrained b; tbu 


diffrnnee of jihtM. TliQ currv rDtain* bukU; t]i« Mun* totm wte A 
luslnf forki an Ib uabm, provided tlutt tko uupUtudft* of ifat IB 
ivcUcu^Ur riiintioM dMTMM in tli* Mne ntlo. 

If tiu) Uniag forks are mt quite b UKiaon, Ue initUl difffnowi 
pluM U not prBwrrod, nnd tbe curr« pUBM lkroii|{h all iu rariadM^ 

Fig. I9t 

Fig. 1^ reptes^nU tho ditTnrdit apfinitnuirft« nf tli« Imninow i 
whnn tha diffctvtif c bctwiWD the tiiuiu;; fuchii in an octnTo i that la, iriM 
ill- imiiiVr* of thiiir vibrnticin* are w I ; 3 ; n»d flfr. IS3 friTM ll 
■pric*3 of purTM wli"ii til" iiiiriiWrK of Iliw vitrnti'iiiB are a* .1 1 4. 

It will bo n-on that tlie curves aru raora complot wli«n tb« i 
tho number* [if viljrftlifmB «re lew cimplo. M. Lisdajoiu ha* ei 
thi)*» curves tlicor<*ttoa1W {Amtulrt lU Phfii/ue rt dt Ckimie, 
had cnlculal^d thi-ir ^uerol equation*. 

\Vli«n tbeae t^ipvriiuenU are madu with a Dubc«cq'* ptuMo-eL 



imtMil of im orditurr hmp, th» phMommB am TomvIrNbly 

\ •««»'■ VliaaKBtiicrKpti. — Tlii)< btwatifa) oppurntun p'U' 
I Iha ^TvM wliunUure u{ Irio^ iiUi' W rp^nit'^f not onlv lh« vjbrn- 
i yniducMl by solid todim, but aim thoM> priiiliiced by nrljid io- 
bj the Toice id (iiigiiis, ftnd «<m by nay noiw whtiUMVM', 
riMtaoee, tliat of tfautMkr, or tbo report of a cnnnmi. It goimmU of au 
rank, AB, about H fool u»J a half loDg ami a fo->t in il* 
tlMhal (Uaui»t«r. It in Biadeof pUatcrorl'«ri«, a (ubntiUKv which can 
M ^ti» ta ribtkte only vilk diflicHi^, aiid tii«7«>rori< tiaa liiil little teu- 

Pi|t. ISt. 

^pi^ to dmdm lliv vlbrntiom of the air within it. Th<* <mu1 A i* npnn, 
Wt the rad B U doaiKl by a vAii Wlom. to tlio niiddli' nf which io 
btoj a III WW tube n, b«ait at an «lh<iw and termiiiaicd by a rini; nn 

I lb U ftzad a Beiible membrane, either hinildcr, nr vi^ry thin indinn 
Itt A wermd ri»g, which i« fnreiHl more oi hn' vn tin.- fir«l by 
b of a tavtr, merrm to MnlHi lb» innmbnuin to th*- roquind nmciunt, 
law m can be tomed ao m to bv ineliued at dltf-rfnt annle* tn thn 
i—ahiaim. Nrar the ctntm of the mnmbmtin, fixed by «en1in^ wa«. i»n 
*wy Hfbt *»yle, which, of (wurae.fchare* the inoTomonlJ" of the mrmbnuip. 
b dtder that tli« atylo iiii(rht not b* at ■ nix/e, M. Scott fitted the 




■iMhiluif nag witk ■ tnovRMhlo pvcn i, wkiek lie call* s mlidiTUOT, 
which, belDf mitd» lo toiioh tht iaea\\irmait Snt At Odo point Uti Hm. 
mnotber, oakblmi tho nxporimeiitor U> ulUn tko •rxmagttavata of Ike 
IlDM U will. Ilv mean! of ibe aiibdirider the point ia mado to 
with » loop, Ihut is. > point where the ribMliiwii of tb» metnlmM 
nuximum. In coiULlrucUnn the phooaulogmph is vetr luutlagaiu 
OTgao of hewing, the «llipK>i<l convapraidin); to the •adilorj 
inenibnuiD to tho tjmpuiimi, ftod ibo nubdindM to t)>« dwia of 
boriM which touch the lympftiiiim. 

ThiJ beinf; the cunntrui'ttou, it foltowB that wlion * mittd ii ptojond 
nnv lh« nppariitun, thit nir in thn nllipiaiil, th* mitBibrBllB, asd tlffiljit 
wilt vibrate in uiiixun with il, nail it ooljr reuiainii to tncn ob k MoAin 
■urfoco the vibmtion:! of thn ityln, and to fix ihrni. For ihit palf** 
th^iu i» plaval ill ffint of th^ niotiiliraiiN ■ cupper cjlindiv C, tmmif 
muod a horiiuntal a^tis bv m<?iina of a hnndic »■. ()n ifas praliWIii 
axis of tUa Ff lindiT a rctow i« out which worlu in a But ; oanefDMIlii 
.when tho hiuidle is turned, the c^rlinder graduallv advanoM it tlw 
t^iraction of il« axii. Itound tbo cylinder in wmpp«d a AeH of ffu, 
eoTBrvd with a tliiii lajer of lampblack. Th« UinpbUck ia dapcMMJ 
bf unttin^ tho cvliadiu ia motion, and movia{[ b«aMtli it a ami'] 

The npparatua ii luttd hy hriniiing the preparvd popw lato OMtKl 
with tho pmnt of thr atyli, and thnn witting tho rrliitdar IB 
round tta axis. So long m nu Hound ii ht<atd the Myle rnmaina at iMt, 
and nicnily rcmuvM thu tunipblnck nlonj; n lioc whtcli i« a ImUx « ih* 
cylinder, but which bn;<oni<.i:; xtDvi^^ht when llie papw ia ■» 
But whun a Muud In huiird, thu sicnibrane and th« rtyla Hkrat* o 
unitoDi and tIiL> linu trni^nd out i* no longer atniight but itadiilatat 9tA 
undulHtiun corrospondiriK to a double vibration of the »Xy\», 0(b<v 
quMitlj the lif-unvi thua obt&innd faith full r denote th« nunibo-, Rnffi 
de, and iwu'hroniam of the vibmti^us. The figurva an larg* if the 
Mund ia loud, very amnll if the sound ia vpry WL-nk ; they m* filnUlktd 
out when the sound is low, iuju«eied togdtlitir when It is hif^h. WhM 
the Bound ia ulear the)* are frpi! tuid regular, fiwble and trre^lajr wtwn it 
i« confused. It would teom, however, tlinl the flgnna do not rrpnacM 
the whole ribrstioti of the membran^ but only the part of it 
takM place in a direction parallel to th<i axia of tho oylind«r. 

Fig. 185 aliona tlie trace produced when a simple noI« i« Mi^g; 
■trvngtht^Qud b_v meauH of its upper octave. The latter note b nj 
Mnt«d by thn curve of leMor amplitude- Fig. 180 r«pTMMil> tiwn 
I produced Join tl; by two pipes whose notes differ bjaa oet«Te. Fi([.lW 
til it* lower line n^presciits the rolling sound of th« lutter R wbw 


-nic raanACTOOKAm. 


I with « ririR ; >°<i 6g. 16H on tti lavret line nrjireaeDl* lh« 
I predated by * tin pl>tA irh«n »tn>ck wiili ihe Ongnr. 
I Tba vffOT UsM of fig*. 167 Aud 188 mv tbv Miinv. find r»pr««ent the 
brfboti; boe fcw nOM Tibrstiona of ■ lunic); fork ploofid dfbt ihu vllipioid. 
MM rmw WM« tnwcd b; ii Hik' point on out- braacli of thn fork, which 
Ml IliBt fond to in^ko exactly MO vibrntionn per «t^C(lIlc). In codwv- 
, Mch nndulAtion cf the upper lini^ oonvipondu to the ,J^ port of 
And thni tbt^sei lin«* ll«(^<lmt^ verj' vxoot Dieuix of mpMuring 

f^. 1»7. 

Kg. ISS. 

^pt latvtkl* of tiaw. For euunplc, in fig. 197, each of tLi- BCpant* 
IKtfa podndng the rolling lound of th« ktter R t^urreiipaDdii to about 
IB daabk Tlbnliniu o( the tuniug fork, uid coaxcquciitly lasts about 
Jb ar aliovt ^ of « Momd. 

IW OBTMa ODCe trM«d| it rcmftina to fix thi>m □□ the blorJienfid paper. 
fat tbia BnrT>OM!, M. Bcolt dipped tbem lint into a bath of pure alcohol ; 
■d when ibir? w«ro titj, b» tben dipped Uieui into a Bolulion of rcnn — 
I* InrtMifo, aawdanf *■ — Ln alcobuL B; tbii weaiu the lampblack ia 




ox BEAT 

ntsLnnFART mu*. TnGKimimxn. 

,^17. M«*l. HrF*»>«*U <u M Itanainr*. — Inordiiuiry Unfuapfta] 
Imll AmI )■ not ont; unod u> cxprnw n pAniciil«r wnMlioo, but iImI 
dncribv that pnMicular titAU or pondition of matter wbicb 
thin w^Mtion. ItMidM produong this (eiimticai, b«st mU varioiulT I 
budi«a ; it nirlta icv, bail* vat«r, makot m«ul« i«d-ba(, mai m Enrth. 

Twn ihcnriiNi u to t))E CAiuw of licnl arc curri-nt tt tko pteMiit twH 
thi.-iw iin- tlip Ihfory <f tmaiMOB, mid thti ihiairy nf iohAiUhk. 

On th« 6Mt tbiwry. bent u caiiscdbvBHubtlpiiiipoailctttblaflaU.wUckl 
, •uiT'.iiiiidH till.' itioti^riili't nf bodif*, nitd which ratn puM IVoai me bodr la] 
Hii(ilh>-r. Thciw heat atmotphrrr'. u'liich thiiHHurraiiud tl)c niali<ciiUtt < 
n repelling mtliionc« en vncbothur, in caoauquuicu of which !■«•[ wUik] 
»ppoiiitioD to the fon^uf cohMJon. The eotnuiGfi of thi« Mibntnctv into oar I 
bndim produces the Rosntion of wmth. its Offivw the iciMttioD of coU. 

On th<i second hj^tbens ih" hnat of r bndv is rAiwed by uii aadllKiq;! 
or fibmtor; raoUon of it!i muU-rial paTtirliw. imd ihu bott««t ^odlctl 
thow In which lh» Tibritlioii' h»T«i the grc-oteiit lei icity ond tli* i 
ftRlpliliide. Hc^nce on thin virn-. bvat is Uci[ H mhaanct. but > PUwAiCHMl 
o/ nuitUr, luid a cnndition which cnn be tmn^forred from one bcxlT to] 
another. It Ualio auunivd thut there is aii inipundembln «UMie < 
whifh pttrradn* all bodim nnd inlinite rpitri\ uid i* c^iabU of 
mittinfT > vibratory motion with great viilodly. A i»pid vibnMjl 
motion of this vtbnr producca bent, just m sound in ptodacvd bv 
ribnttoty motion uf atniogpheric lur, and the tranefet«i)c« of boM (rani 
onf body to wjotbcT i> pfltcti-d by ths interviuition of this tthet. 

This hypothesis is now ndnilttnd by th«i mogt disliiigiiished phpieiM; j 
it aRtirds n hvltcr exp1a:intion of the pheuouiuuB of heat than any rtW] 
theory, and it rnvrnls rm itititnalD coniitxTttoQ bvtwonn beat and light.] 
In acooi'dwict with it, beat is ttform ofmeti<m: and it wiU hneafltt li] 



ikat baat may Iw cooverlcd inla moUon, and mdprocalt; motion 
I c«B*«rt«4 iatn heat. 
Ib wimt rollowa, bai«r«T«r, tbe plienomeuii of hut will be oootmleMd, 
hr M poMUhle. tndvpMiiIiMitij of eitbcr b.vp«tbt<*i* i but w« ahall mib- 

Ir ntum lu thp nraAont fur th« Mkiptiou of tbi' Intti^r hvpotlieri*. 

41ft. a ■■■ 1 *1 '» * »B M of iMat. — The gTDiral nctioii i^ be«t upon 

i* lu ilei-elupp • i«piilMT«< (arw b«4vMD their mulKulcii which i» 

7 ■tniintluiiT vritb molvcnUr lUtTBctioi). l.'Ddor its iutlucnui 

'. bodir« t«nd to tijMmd — that it, to M*uin« a imator Toliinie ; 

tbu to ekmft iMnr Ad» ef HjyrqMi W — that ia, to pnM from the 

to tb* liquid, or hem tb» liq«ld to ^ gnMxiiis state. 

AH bodiM mxfmuA hj tb« nctMB of hmt. A« a gouenJ rul* gnsca aru 

miiabto, than liquidi^ and laatfy, aolidi. 
1b toUiU which hBT« dsflnita SgtUM, wa ran <'ilh»' rriitftidtrr ihc ex- 
■■OB IB aiQ ditMOMtoB, or UtDinMor expaauuD ; in two dini«Arion«, the 
lyU^tn'n/ expaarioo, Dt in thtw dimenrinuii, tli« enhtcal «xpMui«ti or thn 
JUpaawiM of rolainc, altltoiigrh oae of thuw tievvr talcta place without 
ft* ocliAr. Aa tiquida and gtw" have no definite fi^ima, th« espaiiBioiui 
tf nlraie hB*» In them aIon« to be oon«idcT«d. 

TW abow the linear expoDHon uf ■olidii, the appamitu r«)nv»rnl«d in 
fff. 160 Diaj be Med. A metallic rod, A, u Used at one eud b}- a aercw 

Fig- 189. 
' the othar end pt <i — 1 . » a^nvt the ihorl arm of an indci, K, 
Kkieh miTM ob a aeahk IMow tb« rod there ie a »ort of cylindrical 
liapiB wbieli aloolial k bimed. The uocdle, K, Li at fint at the ivro 
HiM, bat » tiw red beooBM* bMMd it upandu, and move* the neodle 


' TIm rubieaJ BXpuinMi dt aokid* u afaown bj a OrmiMaMda't nnf;. It 
nanto of a braM ball, a (Bg. 100), which at the ordinarj temperatiim 
|i^HB IViel; lhTwi|ifa a ring, m, almoat of the lame diameter. But 
Whm lb» tetl bu bwD liMled, it cxpattds ud no long«r pa«M tlirough 


ox BEAT. 

in ordBT to Aom tiM expaMioii of liquids, * Urge (tUm bulb p' 
bulb utd ■ put ct tbt iten conii^ 

colaured Hquid, u Mon m beat u i^PYj 
the liquid nipidlj riaM in tti* itom. >*^'\L 
•ipn/iiion lliiw pbwtved ti f*r giolriu'^ 
in UiB <aae of lolidA 

Tlic mmn •ppM>tm nu; bo OmI I 
plioiriofr Ui« ssjMBiioii of gu««. 
hilrd with ftir, ■ KioftU thi«*il «l 
in introdaoed into lh« tapUUrj tub*] 
wrvr as Uidnx. When tlie fclobc ia I 
in tli« tlighUSt d^ltM^ «*«*> by i 

1^8. I9U. 
the haad, tli« expMMion if ao gnaX that the Index I> drimi u> tb* i 
of the tubn, Mod ii GnaUy eipcUeit. Ilcoce <«vcn for a wty unall i 
of heat, gUM HV highly nxpaiunblr 

In theae diSatent experimeabi th» bodiea oontraet on ooolir;. rj£ 
'bto ihtj haT« attMDtxl thtnr fonnrr I^mparatiini thej Kauii>" tini 
original toIuuml Cerbtln ni«t<Js, howt<iTi, eopvciitlly tine, ficni u 
nseapdoB to thi* rule, and it appvan to be alio tho cbmi with lam* iumk 

URtaintHfGiiT or TRxpsiunrBM. isKiuioiiicTaT. 

M8. T«BBt**tatar«. — The (cmpcratw-' or botni^M of a body maj ' 
iatatA tm U'iu^f thv (iTVHtFr or Kwa extent to which it tetiAt lo iBpart ] 
Mnribic heat In other bodii^s. The t^impiratiini of imy (MUticular bedfj 
varied, by tulding to it or withiinwing from it a cvrtaia atDaunt of i 
kle hc&t. The lempiTature of n body must not bcocofoundad with Ihej 
quantity of boat it pos&eeaes ; a b<>dy may hare a high temperature . 
yet have a eery bui&U qiiandly of heat, and converwly a low t<anp 
itnd yet pOBsece a large ainount of heat. If a nip of wtXer be taken fHnl 
a biivketriil, both will indtoale the eame leuiperstui«, y«t tbequantiliM] 
they piMiK«f will be different. This subject of the quuitity of heat wQll 
be aTterwRrd* mor^ fully oxplnined in the chapter on Sperilic Ueat. 

'2^iO. Tbermomeiere. — TItrrmomeUrt are inBtrumcDla for ma 
twnporatuTi's. Owiug to the imperiWtinDs of our *eRM« we at« i 
to meaKuni kiiupumtutvB by the sensutiou^ 'if heat or cold which 
produce in ui, and for this purpose recouree must be had to the phjriellj 
adJOQ of heat OD bodies. These artiun^ are of various kindi^ bwtlhcf 
cipannon of bodies ha« been eelected u the easiest lo obacrvs. Bqt fcMt ! 
also produce* electrical phenomena in bodjea; and on Uieae the taml 



Mb nfnbarrtiaR tempucaitirei luTn bmn b<u>(id, m wv ahall 
•)«MrI cklpWr. 

• bnt (uilod for tliv coot rue lion of thtimoiiiaMn — the ex- 
tdi btiii^ loo Mitill, antl ihM of gtun* Iiv> gtvat. SUrcury 
» ikeoaljIiquUUuatd— ^e formvr liccnavH <»ily boil«nt 
mftrntrnttJiA tba btterbcMuw itdoMiiot«olidUy at the 

i*l Ummooivtcr in tbe nuwt cx!<aiMr*ly iwed. It <xin)ri«ta 
glkM tubi^ at th« nd of which i« blown tha Mb, • cvliu- 
neal rMcrvcnr. EInth ihu bulb nnd a ]iiui of th« >tem m 
Kwy. aad thp fipuiiion u in«iuiiiji<d by • sndn gradualttd 
lira itwU. or un a fmnu; to whkli it ia attached. 
I nHuTiKlut* of the bulb, the conotructtan of ihii thcf' 
fthot time openlMna ; th« enUroboti of the tube or it* 
part* of nqiuil <«jiadt]r, the iniTodaotioii of the nieioiiiy 
oir, aBil the ^TwInalinD. 

lM(«f tk* tKka iBt* p*fta ar «q>iKi opkcitjr. — A* the 
the tbsrmaiaotflrMi) only conrct 
Uoaa of the scali» coRwpond to 
Be ef the uercsij in the reaervdr, 
Be jrrailiieud m m l« inditnie 
S|Mcity in the tube. Jf ihtr tube 
iBdrical, anil nf ih« «ani« diamnior 
.■null) unly ho nMwnarr to divide 
qiwlUngih*. Biita»th4'diniiiotor 
WtwiutltT ^-n^lcr at uu««nd than 
. ttC equal cnpKaly in the tube ana 
r mw^ual kn^tba of the aeala. 
Uwftdara, to eelect a tube of 
m, a thwad of mercury about 
ja blfoduc«d into the capttlurr 
nd in diflVr^nt pimtiina in the 
b|r taktui to Ikcji it at the aaiuii 
If iho thMad u of th4> Mine 
rjr part of the tube, i( ehowa tliat 

• «f acywhere the aaiue ; but U 
^roite diflefeoit Jvoffths the tube 
d nothvr one eoufht. 
\gt^» ttieraiaiBeteir. — Id order 
tnmnetrr wiih inMTuiy, a unall 
, i:il ), U blown tiu it at ibo top, 

fmcreur; ; tho tube ii then 
eod the air in lh« bulb eipeotlcd by healin; it 

Kg. IBI. 

(Sf BUT. 

It spirii Inmp. T\w oxpMiM air putinllT Mn|>M . 
iM nMiliut*. tlic air wtiich n-miuiia iMOtrncts. nod * ]Kira 
nwn-iiry pa«va into tite bulb. !>. Tho bulb i* thcs »gA 
■ad nUow«(J to cool, a freab quanlllv of mi.-rcurv tnl^ra, andl 
tils bulb Knd port cf tbc tuba nrc full of mrrcurv. ThcuiMV 
iMattd to boilio^' ; ih« ni^rtDtial vapoiin in Mcaping canj 
tba kir aiul moisturF which mntUD in tbc tabc The !ut)«, I 
thn fipaniind in#K^ry nod of ni>»Kiiriiil vRpour, U hirnictica! 
one cad. When ihp thfrmnmctcr 14 cold ib« tuercuiy osgh 
bulb And n portion af tbn tl^tn. 

2->t. ormdnKtlan of tttq tbcravtneter.— Tbe Ui«fiilOI 
KUcd, it requirM (« b« gndaiitad, that ia, to bn pnmdcd «il 
which rkrifttioni of iMirpentiu* «ui b« nftsnd. And finU 
pointa must be 6xni which rvpitHiit ideotickl trupentun 
nlmys be «ii>ily produced. ] 

EipcrimMit Ima sbuitu ihnt ice iilwavM mfll» at the ) 
vhalcTW bo tbo iegno at bent, and thfti diatilM «'atcr ni 
pimauiv, uid in « rrnwl of tb« Mine kind, olwavi b«Us U 
ptnhm ('oDwqueuily, for tbe fint fixod jmihI, «r tvm, 
tun of melting' ifo ha* beMi lohea: and for * M<coDd fi 
lenipmturc of boiling irat«r in n metallic remd imdtc 
BUuoBiilietic pn'*tute uf "CO millimctp™. 

Thin iulvn-al of tumpnaton, 
T^tigf from loro lo the bnaliof ft 
as the unit for cnnipnriDjr t«mp4 
H • cvrlRin Icn^rih, it ^t or « 
ttuicn, i* iiM^d an n bant fop oompi 
SG4. S«temln«tl«a oTtb* I 
B v«eMl, ill th# bc>ltom of which i 
by which wnler ewspos {tig, 1991 
and ft pari of lh« »ti'm of the fl 
arc iuiuicncd in ibid for about a ol 
hour, and a mark made nt tbo 
ui^rciiry, which represcnW teiw. 

Till- M-'cond 6xvd puiot ia 
iiii'inn of th(i nppHnlui repi 
ti^-iirts tat uiiil lift, of whkfa 
p-i'\n» a vertical section. In 
letters ilc&ifruntv the iam« parts, 
of the appnrslua ia ofwppM. A 
A, open at both unda, in fixed ou ■ I'vliiidricAl veewl coo 
a, wuoud lubv. It, ccDMiiiric with the fint, and 


<a Ai MMa vaaMi, M. lo tliu Mcond fyli: 
ri boCh (sdi, tli«rp ani lLt«e lubulurm. a, K, D, J 
ttMOHartar, f, fiu in a. To E a iiUm lubo, contAJi 
', vbidi MTTHa M • maminiiier fur naeAttuing tbe 
b Lbo ippuatiu. IJ w wa cacapc tabe fat i 

■IfiiBtiw U plaood on * ftuBKU uid liTaled t 
ID H ifaM ID lb* tube A, wd pnAnnir tlirongh t 
of tka BiTWw* MCapea bjr thii ubulure D. T\ 
■imound<4 with vapmir, Uu mtmiry cxpui 
M«Uuii«7 Uio paiat U whkk U aitf)M is itiarlb 

lug lue 


M«(ht for. The object of Ibe Mcond com, ti, is to a 

saBinl tnbuliin) hj iu cmtaot with the air. 

4«toRnt)MAi<m at tb» foiai 100 (tee noxl uticl«^ 

ifaat tbe bEight of tii« buometer during tlie hx 

iiulliiB«l«n, for wImo th* buaoMtrie bd^ht in gre 

)[iiMiliij. wsUr boila eltW kLoTu or below 100 de 

it 10D tnar aIwkt* bo csadlv obtained, bjr mtking 

1 bj M. nioU llif fuuod tb»t, for »T<>rj- 27 miUii 

::i »f Uu: LarofUL-tur, tbum ma n dllFpreut.'e Id tbe 

If, for oxamplf, tbe bni}[ht of thu Iiaruiu<!it«r 

- ■ , T two-thinii of 27, above 700— wettr \ 

2S0 OS tttxT. [US- j 

■letrnt* nnil tvo-thtnl*. Contequrady 100| trould hnre to Iw dimM 
ftl ib0 point nt which thp awKWy fclopi. 

(iay-LiuMc ohsetvud tliitt wfit«r boiU rI b *amL>wh>t luftlKt 
pralUTv in n jiliuu thnn in n iiintfll vimwI : Hnd r* th<f boiling {Kiint ii 
eti by niiy mIih u-LIvh are diwolvfd. it han Uwn ftsBuined that it wii 
n-'iviMiT to iiac a metal vchpI nn.-l ill*till<til vntur in tixintr the Ixiiliac | 
iraiut. Tii, Hudberg bat, hov>>M'(-r,i>hi)wu ibnttJi'^^i^ )ati«r preotutia 
■upcrduouK. The nnturo of the vriacl. uid «ii!t« dtMiilTeil ia < 
water, iiifliinnc thp tnrnjwratuNi of builln^ water, but not IbM i 
vapour which ia formed. Tliat i* tn My. tbjit If the tan 
oilinfc walT fnim nny of tli«i above C»iiDt« i* hi^h^r than 100 4 
be ti^inpi^rnliirt' ••( the viiiioiU'doM Dot vxcefd 100, proridL-d thn 1 
i* rM nmrB thiui TitO millimntoriL ('nnnrqui'ittlT the hiirhn pntot I 
br deicruiiniKl in aiiv kind of a vwmI, providi.-d the tLpmo 
i|tiiti! tutToiiBcW by vnpiiiir, rmd dop* not dip in thi? Tvnt<;r. 

Eien witli disiiUml wator, the bulb of ibp thprmoraelt^r muBt nut Sfi 
in the liciiiid ; for il it only the uppt-r Inyt-r that really hn* the icjiipitm-] 
tin* of 100 di-prens, ninon ibe IPiiipemliirB inrrwi»*« from Uyec lu ] 
towBids thp bottom ill (.ftniieq induce uf tfau inrrenw^d prenniie. 

2S5. 0«nMr««U«i> or tb« aoal*. — Jii^t as the fnot-rule irhi>*h ' 
iidoptvd »* \hv unit of c>.<TiipHri>4i>ii fur length w divided ialu a num^rr </ ] 
pqiml diviiions callpd inchi-s fur tlic purpose of bntinp a muIlcT u=il J 
compariBon. so Uhnwiie tho unit of poiiiparisoji of titnipcrMuraA, ibt wnp J 
from Kto to the bulling* point, uiuet bp divided into n ni:raber of] 
fit ("liial capftcitT railed ili'^ittt. Tlirre aro three modmi in which 1 
AoTiv. On the coutiiivtil, nnd iitore i-Apecinlly In Fniuw, thU ' 
dividnl into 100 piirt». and this diririnn in called the On/^prailr or 1 
•rale 1 the latl»r bi'ins the name of the inventor. The Centigrade lhi^| 
iDometfT it altnoal ciHuiiively ndoptnl in fordgn «<?ifntili<^ work*, and I 
its uw in gradually extending in this country, it htM b^eo and wQl ! 
adopted iu this book. 

Th* depesB arn di>sigaftted by a nnnll riphcr placed a little b(m>tp> ic 
the ri^lit of the QUitiber wliit-b nitirks the tetiipenituni, and to biUtalt] 
tprnperatiirrs below xero the minua wiga b plnced befon; lluia. 
— Ifi" signifies Ifi di'pTees below KeM. 

In ncc^umle therniomeltirs tlis scale \% mflried on tho (twii it*elt 
rniinfit h>' ilioplnred, and its len^lb remains tixcd, a* i^lnm haa very lit 
ineipnnsibilily. This is efTecIftd by covering the *teiu with a tbb 1 
of wax, and then marking the divisions of the scale, as well a* the < 
spending nuinbir* with a «teel point. Tho thermnmotj^r ie then eipcM 
for about ton minutes to the vapoun of hydrofluoric acid, which attack 
til* glaw where thn wax has been rvmoved. T\\e imt of tlia wax is tbfl 1 
leinoA'ed, mid tlie ^tein is found to bo pcnuwiently etched. 



il&( Cmtfrode «t«l« two oth«Ts are freqiwmlljr usei—FaUrm- 

'iUuiun''>»cttle Uic tised p^Iata w thflanmi.' u on the Centjgmde 
Ikn lb* AiUnen betirntD Utou UdiiicM ilio 80 dcgreut limUiwl 
■HA Tbit U to M7, 80 A«str*» K<^iuuut uv «qu»l to lOO de- 
do; ont <Ii^n» Kt-ntiBiiir is nqual ti> '£^ qt -J of a iegtw 
k ul one d«gTe« Ceaiii(nd(» tnuaia ^ or J degree lUiiumur. 
tltlocoiiTiiirtmTitiuaberartUauiiiurdt^MMiDto Ccritigrad>>, 
i^lw aiuiipl«), it U nier^lv DeowM/; to multiply them by * 
I fbw U6). Situilurt}', Ccutignulo (li>2;i««« aiw tuuvitrtvtl tulo 
I hr multipljiiig: item br J. 
Ullt ni oinirtTic sculo iuvt^ti^ by FalirenlMat la 1714 i» slUl luucb 
I JJu;Unil. HJiil ulao in UaUand Mid Sottk Ainvriea. Tbe bi|!facr 
u like ilxM of ibe othfT acaIm, lh« U'lugteratuiv of boiling 
I lb* null fcaat or wru b iho tcmiiemtun obtained bv luixiuK 
Ivrijbl* of Hj-nnimooiac Biid «now, nnd lliir tnt^n'al boiwi^n tlw 
ppitobMdiTkilcdiulo^lSdi.-t'TtTni. Tin- wru ttn» wk-ctud U-i;uiim.' llw 
anin> n* tin; biriut tbou known, and wnt t)ioii);ht l» rvpmwnt 
Jiil« ciild. X^'licu Fabraubeit's lh«raioiuel«r U |ilucvd in lutltiu^* 
t aUad* at 32 lirgtr^i, md, xberrfotc, 100 degruM on tb» Ontigntilo 
'W7r nqiial ii> ]>iUde)CTwe* i-nihe Fatiiynhi'ii *cale,and tbiu 1 dt^g^'<^ 
u n|ual to t dcgne Faliruobeil, nod interaely 1 dvgn.-e 
: h equal h> { of a d«^iv« Cenii)trndp- 
r it hR i*(|iui>m] to coorwi a certniu nujuber of Falirpnheii dogreL-a (85 
■plo), intn ContifiTade d^^rooo, tbu nunibnr il'2 must firat bo sub- 
, in urdnt that tlw degree* maj count from ihti mok* ]i«n uf tb? 
Til* rc-niaitidcir in tb« ciampli: ia thu« OS, and ai I di'grro 
alHtit is t^oal to I ol a di>kTfo Uvntigrade, 03 dogiwM art^ «<[uul 
)( ! or 35 di^gnwH Ctvtigmdu. 

P be iba giira icinpnrMUM in Fabrcnhcit'a dngn^a and tb« 
aaidinf tempnatun in Ceiiti^mdL- ilegrete, tlie formur mav bo 
: iaio tha latter bj' nuaoi of tbc forunila 

Loonrnanlr, CeiitigTad«degtee(nwjr Iw convened iuto Fabn'ubeit Ijir 
I of liie f<tftUHla 

fC + 32 = F. 

foftntita^ an.* applicable to all tvmpcriitijiwft of the two itcAlca, 
Jail the *igti* are talKO into accouiii. Tliu», lo convort ihu tvoi- 
poataiv of 5 dvgrvea Fabraalwit into Cvoiigrade iegntm we have 

(a-a2)!=r^?-5= -15C. 




In like mumHT w* hare for couvurLiog It^umni'* into Fiiatatnifi ' 
At>gtttm the formuU 

SR + 32 = F^ 

■iid ci»iT-«nvl}-, for dinnging Fnlmnhdi'* into lUaiunnr's d«gn<4, &( | 

(F-82)i = R. 
SC6. BU|tlne«Bi*nt af a«ra. — Tbomiamctcri, tixva whtm CO* I 
iict»d witli llie irri'tilt'rt t-iir*. nw subject to a sdutch of error whiA 
Duat bo Uikvn into nnuaunt: tbis U, that in couno of tinin thn an] 
(ends to riw, the difplnrenipnt m^in«tiniM exi«ncljn^ to a« much mS 
dcgTMS ; so tliHt when the thermometec U unineTBed iti nioltiog ice ll | 

■0 lODgOT sinks to zeta. 

This is p'neratl.T altribut«d to a diini&utlon of the valumo of ft( I 
IWiervoir niid nl»> "f the ntntn, oOMnoned bv tho pmsure -if ill* J 
atmcMphcri!. It i« ubukI with verj- delteate thennooiebaw to fill tfcM | 
two fir thmo ynim" hefori" tiiny nfe KfiidllBtod. 

BiwidiM thin slow diF<[ilii(.'emL>nt, there are ottiio variatioiia m tkaj 
positian of the teni, wbi^n thf thi-nnomotrr hss been exp<Mc<l lo bigh 
tempentupiB, rRii"<~i(l by thrt fni't thnt iho biilh Had sii^m do iMt i 
on OooUng to their oriKi""! volume (24^), aud heao* it is DeoesMiy I 
TVTJfy thn porition of tntn when a thtmnninotor is nand for dsMwIt] 
del«rmi nations. 

lUtcnauIt has fouud that same raoKuiial ihennoroetnni, whicJi igtM'} 
at 0° and at 100°, Aifff^r bctireen Ihrae point*, nnd ihnt thMe diOI(raMI| 
fruquently HUiouut to ai-verai di'^Ti'M. Itet'iisiilt thiiika that this is i 
to the Jinpqiiftl ixpniision uf clifri-rciit Idiids of jjlnw. 

3G7. Umlts to tlia emplojmont of meroarlnl Uiernioiii* 
Of all thrrinciDK^Ic^r* in wliidi lir]uid« nro uaed, the one with dunn^l 
is the most usi-fii), bt<raiiw- this liquid o^ipnniU mott regularij, aali 
Mniy obtoinnd pufn, snd becBU»e its expBUBicm between —36° stid lO 
■ la nffuJar. that i>, propnrtionni to the degme of hoat. It aIm has thttl 
dvantago of having a rery low specille heal, But for IcmptntaMj 
elow — 9(t°C. the alcohol thermnnietiar mmt be used, for tnnmnri 
oUdillM at —40° C. Above 100 degh-es the ciieflieient of expaoMoal 
increaeas nnd the indicaliciis of the mercurial UietmomiTtcn an 
appronimute, the error arising (mniPtimfa lonnveral degraca. Me 
thermometers nlsn cnnnot he usml for t«mperalurw above SCO', for 
is the boiling point of mcrcirr. 

2oS. Aleotiol tliennometer. — The ahyiknl Ihrmiiimt^fr differs from I 
the nierpurinl thermometer in beinfr filled with coluured iileohol. ButltJ 
ibc? expaueiou of liquids \» luM reg-iilar in proportion tit they ar« near tk] 
boiling point, nlcohol, whic^h boils at "H° C, eipandi totj- irregutadf ■ | 
Hence, alcohol iheruinnieters are munlly graduRtnd 1^ placinx tbcB ( 
in baths at dillerent teinparatuies together with a »(audard immuill | 



■, Mxl marklnil oa tke •loohol ibermom^Ur tli» Icmprraturu 
bv tltp in«r\:urial Ibrnnoiiiater. In thin nminnr the alcoJiol 
tooompanbte with U>» oiMcurial ooe; thacixtuMir, iiiudi- 
Icnpaimttne* umUr lh« uue mmditiinia. The «|i:»hol 
it MpMiaUy Mcd for low IwnperatarM, for it dues not 
the gicNtvt knoim old. 

lUoBB of lb* d«llescr of > ilMrmoflMMr. — A Uipraio- 
ij \jc <lfllii?>ii« in Iwii wata. I. AVh"ii it indiMtt-a tpjt muall 
at umpwatnr*. i. Wbva it quicklj aiduiaes the umperiUurv 
Ronniing mediuni. 

M olgect U BttAiMil bj Itariny a ren' narrov cnpillnry lub« 
•J l«rgv bulb, Uic e-\[ian*ii>n of tb« m^rciirj <ai tbn iii«ni i* th^u 
(••null DumboTof dein««s, thclOLo^orrtOtoSOfuriuxtaDn!, 
^ d«^TM occnpMa ■ gTMl Iwigth on th* ttom, anii cnn be »ub- 
tloTorfsmall fraetiuiia. Tb« WMod kinil of ilelicaojr i« obtained 
ig Uie biitb voty naiiW, tor thon it npidlj' auumm tbn t('in|>v- 
ik« liquid in wliich it ia plarad. 
& nvmial UiMiiiainatar iJiould aiuir«r Id Ibn rollnwiDK t««ia : 
■ bulb aai eieat, to th* top of ih« column of mnrrury, ar* itn- 
Id inrllien ioe, tbn 10|t of llir nier^urr xhoulil exnctlr indiual* 
i when aiinpeiidod witb it* bu!b and ncalo immomd in tlii- *t«iim 
> iMiiUnK in a luetal raawl (a» id fig. 19!t), the barameter staiiitingf 
BL^lh*iii*9curjr«lM)uIilbe»tati<iiuu3rat lOO'C. Whnn lliainairu- 
ianrtedL ibi-mMcur; should Itll the lube.and fBll with a inntallic 
paalmwnijitlieiianiplctociclu.iiunofair. Tht raluuuf tbcdeirreve 
m vaSoTta ; lo iMi:«rl«a thiK. a Ultle criindi^T i)f inerciiijr mav bo 

■ front tho (oinutn bj a dtglit j»rk> aud ou 

■ the lube it niMT bo uada la pan* fmm one 
uf the bure to another. If th» wale bo 

gndu%t»i, tbo column will oocujir an 
tmber of iii-tcr««« in all parbt of itiM tube. 

■■■ ouaraBttAl tkmnaaaMtav. — -Sir 
mIw eofMlrwcW a lbi;nni>ni<'itf for ahow- 
of temparatare of two oalglibour- 
bom which it luu tnodTcd tb* name 
rtHmmiirfii It oMtHtM (if two iflaMi 
WlllillllHi air, and joiodd hy a hml glnu 
amaU diamutvr lix«d oa a (muf (iig. 1)*5|. 
ht affmnuu i* ipaUd. a coloured licjuid 
IhmI ia ■uffident fjiiitiiiiiy to Kll lli« hori- 
of tha lub<i, and about half tbo rcrtical 
.11 JKiportanl to »*• a liquid wbich dnn* 
if vapouN at ordinarj tvoiparaturra, iind dilute Milphiiric arid 

■ vilb lilinus ia gcurrallv prcfrrr^'d. Tb-- ajipaiutiut Wuig 

F>K. lUA- 


dotvd )h« 

ON nUT. 


■ir i.i paiuoj hom oat- bulb into ibu ntli*r hj liMtil^ 
unlil ib» 1eM<l i>r lhi> liquid i<> ibi- Mine in boUi bnwckaL A 
luro ia inarked nt Mch '■! d 
tli» liquid ooliuun. To gndant 
ih« agjiwinlun, ana of tlin buk 
i* rniai>d to a lemp^nlura W 
hi^bur thiui tb« other. Theilr 
nt' tbe tint iji rxpAnd*d uA 
caunt-a lUv o.<!u»iti of liquid t« W 
riw.- in ihv olbt^r k;r. Svbioi tbt 
«i>liinin in nncioRHr;, tbo auttbir 
10 in lunrkiHl on citcb Mf at tbt 
Uviil »f ihi) liiuid, lbs diiAuiM 
bvtwefrii iBtu and lObviiiirdinded 
into 10 *qiinl pKTu, bolli abow 
atid b<'ti)u' ii^rv. on each U;. 

^li~)<l, K«tU>leunn'a Btflar- 
«nttal Xlinnaompter. — I'p'- 
fumor .\Lillliir<ui>u liri< d-iiivj ■ 
form fif iiiflWiMiliiil ihnroniwMr 
wbiL-b (-HI) V u^vd for indiiatiUf 
lig. IWO. ii,„ tPtiipi-ratufn of liijuida, ind 

triiich ronstitiitvs n vnlunblc nddition to our mriiD? of illiMtnliDg tat 
Lecture [lurjiueei ninny iiiiiwilJUit export mtul" iii JieBt. Ita eaoMveAab 

Li evident from tb« umexed iffo^ 
(iM). TLt' bulbs are yeuieaUant 
it can tbcral'ore Iw rc«dil_T iiunvnnl 
ill u liquiil. In a iiilio wbii-li tno- 
ncctf tlie two UmVjj tUeK t> ■ »t«f- 
enck, which i» vnry luw'fnl m R 
tiii>n[i9 uf ft-Jj<i4lin^ th^ Ivirl of llW 
liquid*, » rnlhtT tmublcMimft talk- 
tt"ilh I>--li"'s imtruniiint. 

:>()1. ar«Kn«f> moUrillo Umt- 
mometer. — ltn');u»t ioTimliMl a 
thirnuarueter fuutided oa lk« ^ 
cqiinl nxpnn^ion of metak, aad 1»- 
iai\ I'knblti for its dnlicocy. Il MOuaHt 
of ihn-u (itri]t« of platinum. ^fMt 
aitd siU-cr, wbii'h are pajsod thioogb 
^'K' !"'■ a tv'ilinn mill so r« to f<imi a »(fy 

thin motallii; ribbon. This i» tbon poilwl in n spinil fonu, ai Bmn io fif- 
]!17, and one end beiuw fiwA to a inipport, a lig-lit noeille in llxod to tha 
athar, vhich ia frvo to mote ruund a graduattid acak. 


Silnr, wUdi u Hut voMt •spMnlblu of the mrial^, forms Uw InlenMl 
■ of the *{ium1, and plKtiDiitn tlic cxtcninl. WhriilhoinmporatnrvriiK*, 
( dt« expUMis taoK llixn jrulil nr pUiinuni, lli« 9]>lral uiiwiuds ilwlf, 
Itba biwiUb mores bnm Ivtt to right <if tiiu nboTc li{[urc. The contrari' 
^uproduood wlienlli«lMn|>w*luroMnk«. Thi< (Ml<li«p1iiced betw««n 
ft Mher two intrt«ls, iMctUae Ita es|)iuualiililT ii ioivmiviliuie Wtwecn 
ktof tb» nlcoT and tlu) plKttnunL Wnr tli<^« two m«tnU i^injiUiy^d 
■■, tlicu rapid uiw(|ua] cxpflniion migbi caum a fraclurv. IIt<uirii«a'» 
mwoMibir b grailiiBtvil in Cvuligtsdo <t(-fti^w, bv compttriug it witli h 
Oidtnt niFTeimnl tlicrraoiui^tfr. 

9li2. SvtItvrfOrd'* iB»itinngi *sd mlolmam ttienaomptetai. — It Im 
BHiAiy. ia niRtMiiiiliiglCiit ob«cr»«lton», t'j know llw hiehcit Miinpi-- 
tan of i)i« dar, aoil ibo low«i i(>mp<iniliir>' of llie night. Oidinu^ 
WIUuajBleiB uuuUl iMily ^vo ihuM iudtcnlioiHi br n continuoua ob 
■rwUcb wnuld )>■ impmclieabUr. $oT«mI liMtnimrni* havn ncconlitixlj^ 
«B umtulnl for this {Mrpow, lite rimplett of wliich is Rutherford's. On 
hrtanpilar pi««c of j>hil(? gUiu (ti^. IDS) two lhcnnoniot«rs nro IU<h1. 

f*iita» an brnt borizontnllv. The aav, A, is a mercurinl, oiiil thi^ 
I^ aa alcubul tbenmamettir. In A. tiier« in a smnll jiiiNv of Irua 


T-i — I 'iJi..Hi..ifrr.r^jTT;^Tj:n 

la iiR «D i> 

«o >• ao 

—J !■ ■ ■ 


1 ^. VJ~. 

iit. A, Btarinii' fK-i^l; in ihu tnbr, whicb hctvck n* «a indni. Tli« 
tMBonat«T brinif plni-nl bnrixontaltT, whrn the I-.-tui>('rHtun> riBcti lUti 
|Mbt pwlm the iodi'i Wfore it. Itut us noon bk thv iiktciitv cmi> 
■rt*, iliv iudi'I rriuain* in that ■part of thn tiilxr tn wliirh ii hn' ]>«(tn 
t>*M), for t^JT 1b im adhoMoa b«tw««ii the irou aud ihu mercun-. In 
lb «r*7 tbn indnx R|riMor> tbv bitibeiit Icupt-rntiiiv which linn btm 
bdan)*, iailiD ll|ror»iliUt«^1°. Ia tho minimuin tlit-ruiuiu#ti<riht>Ti-iii 
laD bonowirlaa* tubv whicb M-rrM na indrx. Whvn it is ni xhe pnd 
I IIm Mkmu oT liquid, and thm taoiprrauiM fnll!i, the column roiiinivia 
id MRMB tbi' tudj-jc vcitb it, ill cau^upiiM of ndh<wioii. itutil it hut 
»Aai tbn irmtott contnutioo. When ihn trmpcrnturi' rin^, ilio 


S20 ox ncAT. [as$- 

■loohdl expind*, anil psiwin^ lietween tlie sides of the tabe u4 A» 
index, io«* not dinplnm )i. Tbi! position of the index givM ihitnfeM I 
tke 1ove«t tqniporntinw wliioh hn« been n«chod : in tli« Agiot tU» i 

'2Ki. »Tr»mBWr».— Tli*' name pjnvDirtin i^ giren to instnmimti tel 
in«««uri[ifi uuipLTntitiwi nu hi^'li ibat iii«Kurial tb«tmo4net«n«o«ddMli 
bA annil. Thn older rontrivnunM for tbi« purpoM, WndgtwooAll 
DuiivII'n (wbii'h ill priui'i))1t' T««eR)bl^ tb« appunitiu in li^-. 18S), 
BroDgninrt'i, etP., nre gont- cntirply out of u»o. None of them (tivoi m 
exact mtfBHure of U'mperaluro. Thi- nrrBngi-mpQtii now unwil (at tlw ' 
pnrpciiiR nre either busi'd on lb* expanwuii of gaaen nnil vapour«,ot i»i 
the electrical pn>pertie» of budiei, and vrill bn *ab»iNiutint]y doMviixd. 

'i&i. mser«mt rcnwrkable tamparatarw— ^Tbo following t«U»| 
pv^n ■nnin of thn iminl («iiiar](nblp jiointH of temppratura. It mat !•] 
obwTvi>d tbat it is euier lo producv veiy eloratod t«[ap«ntuiu titan 1 
low ddtrrnu ot cold. 

Greatest arliflcinl i»1d producnd bj a bath of bixiilphido of 

carbon and liquid uitroiu acid — 14{P C. 

Omatnit oold pn)duc«] I>t nthnr and liquid carbonic acid . ~]10 C. 
Orea1e«t natural cold recorded b Arctic eipedltlona . - 40 

MiTPury fnieiM -SO-* 

Mixture of snow and »lt -M 

Ico niL'lta 

Greatest drniitr i>r wntPT ,,,,., +4 

Mfian teiu^rature of London M 

Blood heat 384 

Water boil* 100 

Mercury boila SM 

Re<ni-at (jiwtTiaible) (DanioU) .'i28 

Silvermelu tO(K 

('a?t iron melt* „ 1530 

HigbbstbMt of wind furnace „ \6(U 


EIPA5810K OF 90LID8. 

SB.^. Uooar expaniion an<i cnbie*! «xp«maioii. consHtiBU af j 

oxpanaloB.^Il ban Ihtii nlri-fl'lynnplninn] that iniKiUiI bull . ijan* 

Hirai may bt' att-ordiug lo ih^'e diiiienMiot)»i, liniar, *ii(iiir1iLi ' it 

The eofffieient of imrar apmuion u tha clou)^tion "t r 

exTANsios or solids. 

Inftii of a li- hIv wliea iu le-nperalttiw nMs from leio m 1 degree ; tho 
imjlrimit of miprrfCcM erptrnmam u tliit incrma nd' the mntaoe in being 
kwM tram *«ra to 1 ilegrM, uil tb« ««M|Kr*M( ^AvUnri <u|MnM>*iiii i* Uie 
bctiM* of tlw nnt of rnluntD nador tbc same ciicimiitaat^WL 
Tkoae eMOdema rmrr mib dilTvreni bodiiw, biil fnr ili* Mmc bodv- 

fc rv^fieimt tf cabiccl rj^nuiun ii lAnv linici fAnf v/" Mr linrtir 
■ifw'iin, Ml fat Mfn ftotn ibc followiag vonnidnnitiniM. SupiiDM b 
oW. the ]digth of whoM tide It I at teru, l#t Jt* )>« tlio eloii^llon 
r( tlib <dda in [«MBBg from Mm to 1 rlrf^rM, it* ti-ntfih nt I ilcgno 
viQ ba l+k, and tba roliuaa of the cube, whirh wm I at taro, 
«81 W (I-ril'. or l+!«i+3fc'+Jt». But lu tk- i-lou^ratioii k U 
•Iwaj* • TOTT (inall ftwtion (»i» tabk, art, 267), iU nquarp A*', niid it» 
I £*. ant so Boall Uiat thev maj be nvpWttfd, Aud tb« Tslii? at 1 
bfcooiM TTCj nvajrljr l^ 0>>n»Klii''ntly tho tncnwH) of 
! U SA, or lluico tliH coeflicieui of liuear i-x(iBU(dan. 
I llw MBW manner it mar be ■hoorn thnt tbi: cocfHdnnt of luperRciat 
I ia douUe tb« toeffirittDt of llnHtt ciLpaiisiuti. 

ift^; Kcaaarement or Uis coeflcleots of IlBaar «JtpaNBtOB> 

la*M*iar and x.*pla««*a mstbao. — TUi.' np}»trnl'ii; uwd bj' Liivuisirc 

mi Laflaee for dolcrniininft thr conffictoita of liiwar eiipanmou (li^. Ii)f0 
mMK* of a copper ItdiIj^, plswd on a fiiraaoe betwcon lam stone 
mffotlM. fjM the two RUppOTta oil tbo ripfht bund, there It a burizrmtal 
■n*, at tba pad of vfaieb i' a tclMcnp*); on th« niiddle tif ibin nxi*, and 
M right mfflf to it, b Ox«d a a\aM rod, tumin^ with it, nx d<w« also tb« 
latMCDM. TW otfaet two nupparti arn jninnd bv n ctou |i)eci^ uf iron, to 
wUdi anntfaer glaM rod w fixed, alw at ri^-lit uii^'W. Tht trmii^h, wbich 
Mrtaiiia M at wat«T, U bentod hj a fiim[iri> nnt ppprntniit^d M ihr- ti^-urr, 
md the liar wboa* dOatation it to bv dnlcriiiiue<) U plncud in it. 

fif. 'JOO tepmontn a *eeiioia of ibe nppHratiw: O i* llin t^Ieiiv<pf. 
Kll tbv bw, wIkud «n'U proa* again*! ih<* tvn Lrlna* fvlt F nti<l it. 
JU tiM nd F U &c(>d. ihi bar can rnilj expand in tlie direction KII, 

S38 ON HEAT. [m- 

and in nnilor to plimiaaW Ui«< effMU of fnctiun It iwfai on tnvi ^-Ub 
roUun. Lattl^, tbu l«l««cope bu a cioiu-wire in tba (iye|ii«c», wbick, 
wh«n tho toliweope move*, iiuiUcAtu tb« dqirMiioa bv a ourTe^uwUai 
DumbuT of diHriomi on a vertical H:d«, AR at n ilUttacc of 230 jaid). 

The trough in lim fiilrd w.ih ico, and tba bar bning U Mro, iIm | 
(IWifUoii oo tbe aciHv All, convi'jiondit])! lo Ui<r vin> of tlie telnc^R. b i 
mad OS. Tbu icv bavintr bouu Kinuvi-d, iho Uoui^b in fiUcd with oil <r 
wal^r, vhirh in lii>al<n.1 iti n fiyvn l(tiiip«ralut«>. Tii«i Imt tli«D wptalt, 1 
and wbrii ils IirmperHturu hae bi-oome Btulioiuirr, vibicb ia dctcrauBdj 
by mraiu of tbermnaiotcr*, the dtvinon of tb« acals, «tt>a t^iwugfc tbt 
t«l(«eop«, it KMd »ili 

Fig. 300. 

Fram ihuae data tho elongation of tbn bar ii detenninad ; for rfnel A^ 
has becomo Icngtir bv n quoiitiiv, C'lt, and lh# opdoai asi* if &> 
ti!lncap<- baa Wciuto iiielln-il in the diredion Oti. tJm Iwo lmajl'>v 
one and AIKI, nru similar, fur lUev bar* tli« aidoa at rigbt «aRlt« 

<w]iloDacb,vo tbat_ ' = -' . In the (ani« way, if UC 

another elongtttion, and AB' a corTespondiu? duviatiotu there 

still be "'■ = Vl!-. ff^" "■'^■'^li it folloim Uial tbn »lii> brtirwal 
All Alt 

elnng-alioii of the bar nnd ibi- dcDudion of tbe t«le6mpe ia cnutnti 

for it b bJtbp eqiinl In . A pnlimiRory iD(«»un»nient had ahows ' 

no Aft 

that thix ratio w -I,. Coaiwqut-ntly ^^ = ^ij, wfconco lIC = j^^; 

thai i*, Uie tAtal rlongalion of the bar i» obtained by dividini: 1^* 
lonjlth on the *n»lfi tmveiwpd by tlin crowwim by 744, Dindin); tliil 
eloogHlion by the l«Ti)rth of the bnr. siid tii^n by ihn leniporatUK of ih* 
bath, the ({iioiifnt is the dilatatinn for the unit of leugth and lor a angb 
iejtrw — in olJier word*, the eoeffieient of linoar dilnution. 

L'UT. SI07 and »unid»n'» matb*iL— Lavoi^j^rood Laplace'* mctM.] 
is fiiuiiiiril oil (111 ftHiii''e wlin-li i« fn'ijuently odoiitcd in pbyii«al i" 
mination*. nod wbi>-h dinxiau iii aiu)ilifyin|{ by a known tmxMt ' 
dim^iuionx which, in tiieiiiMlven. am too Huiail lo be «aidly mMnned. 
Unfurl II nati'ly this plan is oflt-ii more &llacioii4 iban pivljtable, Car U I* 


CXrAXIlOX or 8>L1I>«. 


to d«lemuie the ratio of th« motion nuMurad In ihM 
dapcnda. In tbu pcvaent Mao it U lucvMWjr [n koow tlm 
of Um mim of tlu> l«ra) in ttia uppAMUia. Uut thla pKUnibaTT 
gpaMwn naT bitiodiiCi! vmn at vach itiiporlMiice » panially to 
■■nwbftlanei: tliu adtistnjfv oT ftvat dclicnr,^. Th* following tiivtliocl, 
«Urii WW umJ bjr G«aoi»l itoy b 17«i, uid wblok wa« dcnwd bj 
JhawUn, depemU oo anotli«r pnndplu. It uomur* Ao flongatioiiB 
Anrtlj, uwl wtUuiui Bmplil^iiig ibeB, but it Diwsitrm them bv niouu 
rfft ■dcmnricr, whi^b iudint^u tcsj umU dUplHcemiuitJi. 

Tltn appaniiu (%. 301 ) coBiiata of tline |Htrsllvl mat&l trouf ha about 
flfevi I4DK- I>> tka Biiddteoiw Ibenbabikruf tli« bvlju-liow cxpu- 
■oai*lal>adMeTm)tioil.nDdull>o twu oIImt* ant nut inm ban orf cxkctlj 
A* MUM lan^ m ibia Ur. ttixlit ue fixt^l verticully ou butli tidea «f 

I tkm> bar*. Oti the rndi in tbe trou^hii A and I) tb«r« im ringa 
-w'ina Uka those or * lele«co[it-. On tlie rods in th« itou^U C 
l«nwll tcleaeope* bIm praridrd with ctiwi-wim. 

tna^hi btiftg NIM with 'k», and all tbrvn bnra at lem, ih«i 
I of iBtanBOtiaa of tbu wirva in lliv dlH.-, niid of lLi> wirua iu tlw 
e, arv nil in a tin" nt nach end of the bnr. Tho tcmprmturR tn 
I DBibUo tniu;rl> i* then raiM<l tt) 10(}' C. hy moau^ of tpirit lamp* 
)>la»d brnnuh tb* trnush ; tbu bar I'xpxndi, but an it i> iu Cdtilni^t with 
iW t»i of a WTvw. o, fixed on lli« Nde, nil itii' oUiii^aticii Inkivi plucc in 

2S0 Mr iiuT. [M- 

the diroctwo mir, and m t]i« croM-wiw h r«inu.iiM in pOMtton, t)i« cmc 
win m U DMired towrsKid B by s qimnlity equal to ttie elangalian. Bal 
•tnc* tbc aow a u atlaflicd ta Urn bar, br turning it iilinrljr bott n(h 
to left, til* bar in inoi'<id ID ibe ditvrtlou mn, and lli« hum illii ■ 
ngwnt ito oiiiriiiul puailton. Tu eftcct thU, tho an«w ha* been 
br a qilantitr aiACtlj nqiial to tlie elongation of th« bar, and at Ilk' 
advance of the scnw in n-adil_v dedumd from thu namber of tnMtf 
ita tirrad, tita total «x|iiiiinaii of t\w bar i« obtatii*d, whicb, dividfd bf 
Uut tempentura at the balb, and tUa quotimt bj the lea|rtli of tbt W 
at tcro, 0ir«« tb« (^ocflicicnt of linear ««}Mnnan. 

Corffieifnit a/luifor tapamaioii/ar 1" Mwrai 0* onJ ]00*> C 

White gloB . . . O-OOOOOWIS Copper .... O-00(»i:i>. 

Platiuura .... CH»OO0ftft4a nrwn»e OflOOOlSl-iT 

lTiit..-uip.^rcd atetsi . (HXWOIOTSS Bran CKWOOl^F^f 

Ca*l iron .... 0000011250 Wlvor OOOMIW": 

Wrought iruu . . 0'0<X)0122(>1 Tin OOWOSK i' 

Tflmpprad frteel . . 0-O0OO13396 Lead (MM0(HM7l 

Gold iH»(»149l» Tiae <M»0(B9»r 

From what hiu. b«cn aaid about tbe linear dU&latioo (30t»), the w 
«IIicient« of ciil)irRl expannon of iolida am obtained bj mttltipl jinf tkoM 
of linear vxpansiiia h_v thw*. 

Tbe coefHcinntii of the exponaion of the mttals rarr irilh tbeir phjadl 
condition, being diflereTit fur ihe luiini' mcinl orronling an it haaVencatt, 
IiamnifTcd naci rolled, hiirdmed oi auueali-d. A« a p?aeral rule, open- 
tiou4 wlitcli iiirn'asc it* doiuiily incrnnnrMiliri tbff ikic of nxpanfaoe. Sid 
even for lubatanoev in apjiarenlty the Mme condition, difTcreut ohsaraia 
bavK foiinil TfTj uniH(unl amoiintiiar <-Kpnnsiciin!i; thia mnv ariw in tbe 
case of ivinipiiund »iilwtanci>ii Hudi m gtaM, bnuw. or ntnel, rroni a want of 
unifnmiity in chemioat eompooition, and in aimpls bodtca froan aligbtdi^ 
fyrenceif of pliytii""! »tiiin. 

The expnneiiiit uf iiimirpliouB noli>.)«, hihI of thn«e wbich ciratalliMlfl 
the r^giilnr'rm, t> the ^iinif f'.>r all dimeai^icmi, uulns^ tbnv ai«*nb> 
jcct to a alraiii iii d^iiiii- pni'lii'iiUr direclii'in. A fragnivnl of such a aab- 
«lancr> rarim in hulk, but rtflniiis the uune sIiapH. Crystals not bolong* 
ing l<:i Ibe regular ny>l«'m i>xhibit whon iientad an unequal pxpauton in 
the direction uf their dilTi^reut axes, in couHeijueDce of whicb the magid- 
tilde of thnir itnglfs. and thercfnre their form, h altered. Id t]i« dimetne 
aynteiu the ex|iati«ion i« the sninq in tho dimction of the tiro equal um, 
bitt difhtrent in tlie third. In m-iiiali belonging to the beKagonnl KjMrm 
the expniiHion in the mnin in the dimi^tinn of tht> three (K^condnry ain; 
but difleivni from that aecordiug to the principal ono. In the irimetric 
ajHleiD it it difl^renl tn all threu dinctioiit. 


upaxsmx or souDS. 


3C8. Tk« ■B«apl»ntt or upanalvB ia«r»u* wttb tba umpe- 

■car*. — AiHMWidittj; to Ut. MatlhiniM'n, who t)»I«nuiii<^d tliv eipuuftcii 
r tlie BOMala and alloy* bj wtittbiag them tu wntn nt ditji'ti-ni Tcni> 
wtw g*, Iba cueffideob of exp)uiai«D Btv nm ijiiilc rrgiilnr Violwv<-n (P 
ii lOGP. lie foaad tbc foUoiriiig vaIum for Uiu liniw <iK]>aDtiiDn be* 
■MB (r> Mtal 1U4' : 

ffinc . . . L, = I^ (1 + 000002741 ( + 000000002.15 iT) 

ImA . . . U = I^ {1 + 000002730 t + 00(XW00074 C) 

Bflwr . . I* = ls,ri + O<)000ig00( + 0-O000000!38<«) 

Uoppr . . I^ = L, (1 +■ OOOoono.^ ( + Ofl000oon2ft4 /n 

OoU . . . L,= i^(i + ooo('Oi;)fiH( + o<Kxmoooiiaf') 

th» amvB aulhoritr hu found that al\oy» vxpuid rciir itfitrly ncra>rding 
• tk* foUnwiDg law : ' tbn ciH>IIicii>nU of fipAnnion of an »\Ki\ U equal 
Blbenwoa of ibu ooi^flicitnitituf uK|iaiii4ou of the Tolaincaof the mctnls 
^KpiainfT it.' 

3B0. Wvrvaalte ralatlTs to tlie »paaM«ii et aoltila. — L«t ' be 
b» lMf[ib of « boT (It icru, f iif U'ligth at ihe tcnipfrntiiti! t* C, and a 
tomeflhieiitof linnar pxponairin. Th-- tnlil-'s iiaiiRll) u:i*'e ibe <<xpAii8i>>ii 
iw r Wtweeo 0» and tOtf', «» iii article !!Li:. „r forlCW; in tbia kltcr 
■M a i> obtaiiMid by diiiding tbn ntimU'r hv liV>. 

Tbe nIatkiB a»iattng between Ibe aboT« qiumtttiea ih expressed by a 
kw limpJa fdraialm. 

TliK eloagatioa mcmpondin^ tafiial timet a, dr ol for a sliijfle uuit 
if Intjltll, or ail Uir I unita. Tbn length of tbo bar wbicb ii I at tcru i> 
-f sti at r, oooMqneutly — 

TU* fonanla kIvm lb* Irngtb of a body / at f, knivin^ ita leni^ at 
HV, and tbp coplBdcat of expnoMOD a ; and by <iiii)>1e alpibrnical ttana- 
!■ ■■Ill will, wa can obtain ft<im it fnrmiiliv for tha Itmgth at Kero, know- 
Bf tbe lanstl* ' *t f, and alao for liudiut; n the cuefficieot of linear 
npaMioBi Inowinf lbr> laogth* T and / at f° and r.ero nupectirely. 

Il k obvioua tbat ibe bmuln) for cubical ^ipaoaion aro eotirely 
wlnBiini to tbo pimodin^. 
Ua bUowin; an axamplaa nf the nppliratinn nf tbiun fbrmuln : — 
A MrtaMie bar bax a lei^tli f at r^, wbal will be ita l#Dgtli I tiff 
Vma tha aborv formnla we firit gpt ib« length of tlio (tiven bar at 

Mi\ wlieti ia . 

by meJOM of tbo aama formula we paM f^m 

Km to f Lo multiplyiDg ly 1 + at', which ^tw for tlie dMitvd length 

1 + di 





Tho iliwdty at n bndy b«ing d at aci«, it^uind Ua dwinty J" u f. 

If 1 III! thv Tuluiut' uf tbe body Ht tero. Hud D iu C(M;Jlint:iit ol tniaai 
rxpaanan, ihn voliime at t nil! hn I + IK. atid ns the tloiuitT of m hodf 
U in iiiirriw nitiu r^ tlit>}i-oluuiu wbicli tlw bodr AtMuueci ui uputdiag 
ire gvt tbu itiYnrw prv>pi)rtion 

d':ii=l : 1 + U(, 

CoiiMqupntly, nbpn b body ii hetilod from to (°, it* dmiriijr, iBi 
thvivfoK its wMgbl for 00 equal Tolumo, ant inT«re>^]y us Htm UaaBiiil 
rxpn'>aion, 1 + IH. 

2T0. Appll«aUa(u ot the eipanRloD of aotlda. — In thvi RTls we nuBl 
with nunii-ruui i-suiinik-* i.>f liia iiitimiiiw '•( espiiiniim, (Lj Tlw inM <A 
furanctv niii'-t n»t bu titled ti^'btly al tb«iiextreiuitii:9i, but inii*t,ailiwc, 
befrt-i? utouc tiKJ.iithurwiw, ill ex|innduig,tbo,T would «))lii ibe iiiaBMiiT> 
(ii.) In ninkiiiK' nuln'nya a auiull »[imi.-« !s luft belwctni thu*ucnn«iT<inili> 
for if l\wv toiii-lii'il, tiin force of cxpiuurinn would c-auw tli«i* 
orwmiUI btvuli tht< cli&ira. (iii.) Waior pipes 8ivfitlt<d toons aai 
luwiui of tolewopiu joints, which nUow room for cxjionMon. (!».) 
jtlOM in bcMited or c<>i>K'i] tun mpidly it cmclCM ; thiM ariacd from Iko fM 
ibnt fi\iaA hAiif! 1 biul cuiitlucioT of hcnt, ibu tidtn bucmne nneqiuQf 
bt'Hlf^d, axiA i-oriM' lUniilly iiin'ijiinUy cipuidoil, whicli causm n bnctiUb 

Whrti IkhIin \\a\v bi-vii bt^uleJ to a Iiij^b I«iii|wraIUK, tlin tone pm> 
ddced bj ibvir cotttniction (lu cooling ih very considurabla ; it is oijiial W 
the force wbich t» needed Iu coiiiprcuw or dxpniid the mntcrial to As 
utoM vxioex by mi'chniiiral ini.-ni». Accordinff to Biirloir « bar of lud' 
lenblc iron h riqimiv incli in section i* otrelch^d \s«si "^ >'' l«nKth by > 
nvlghl of It ton : the .-niiiu iricreaiws in opMieaMfl by abnul IP C A 
diifHreiiw of J'l' (Mwilween the cold of winter and the b«git of niBUDtf 
ia not uiifrvfiiiviilly viperi^iin^d iu ihin country. Jii Umt nuigoa wrnugU 
iniu bsr I-ii iiicbci long will vary iii kufrth by ^l^ of an inch, and vriU«x«it 
a strain. >i' its end? un> oecurely fti«tut)ed, of lifly toUB. It bnii bcoit Eslo 
culHleil from Joalo'f ilnin that tb« foi'cii cxrrtiid by beat in cxpabdlatr k 
pound of inui bi^lwi^L'ii \f and 100° during wbich it iucrvaai'i nlioul ^ 
of its bulk, IE oqual to 10,000 footpuuudij; that is, it could rai»e a w«ijfht 
of 7 tons tbrUMgh a height of one foot. 

(i.) An npplicntion of tliis contructili! force is aern in thn nindr of 
atcurin^ the tiros o» wbe'^ls. Tbe tire boii)g ninde red hot. and tlius 
cnii«idfrnbly eipiindod, is plm-ed on the cirouuiferruce of the whc"l and 
iheu cooled. Thi; tin*, whon cold, cmhmrm tlw wheel with such fotw 
a* not only to necure itself on the riiu, but also to preM hooM the joiott 
of tbe qioliit into the fuUuiK and nave (,ii.) Anothi^r int«nating a^pU- 
cntioQ wan made IU xh» cn«e of a gallery- at the CoQscmtmn d«> Art* 



in Pniit ^^ wlU of wbiek bud bopua tn bulge ntiiwiuds. 
n irrtf pwnw l acroa* tha baiUio^ Mid Mivwcd iulo platui uu 
LJe ur ibp wnlLs. Eacli nJluniHtv bar wks then beotnl bv nmUM 
I. lUiil wbcii thu bnr bad cxpondcd it vu •ci'ewod up. Tbu ban 
u>D «Uo<nd 14 oool ooDlnctMl, uid !u so doing drew tbu waUii 

Thr »Bnif> DpcrnltOTi w»* pcTforaiRd nn the otbnr bftw. 
BompaoaKUoD paadnlnaa. — An itupoTUut iip)ilicftt)'>B of tlie 
an u( DurUls lia« lK«a lawlli in Mr tompaualioit pendat^au This 
luluni ill vhich tbc olongntioD, wb«n th« tmipirrsliiiy hws, U tu 
Med tbu the dtaUnce bvtwei>ii \he ckuIk of au»]>r[iBian ociil 
n of (iMUIatiaa (70> TKmaiiu coiutaiiE, which, frnm ihf ln«-# of 
rfolom (Til, is nM«MW7 for 
piu iHolUtioiu, Mid in order 

IvrtMlulnm may b« ntud a* a 

:KIS. wbicfa fwpiMoBts tb« 

pendulum, KIM of ibe cnio- 

Pwm* of DouipDOMtioQ pen- 

thc ball, L, instil of Wiag 

I b^ a (ingle lud, ia Mpporlcd 

ime-norll. eoiuii'tiiig: of alur- 

fof afael Mid bnM. In tbi> 
iImiM mda rppmuct imdIj 
■ MiuU *l»i rod, b. vrlik-h 
ill* wbC'U of tb« appuattu, 
aix of tbeni. Tlie r«M of ib« 
nuinbo', an of bnM. Tbc 
anppoiti the ball, i* llxnd 
«ul to a faorixoaUd ciou- 
iia lomr «nd it \» ittt, and 
h tl«« two dlVtiUr botm in 
boriiontAl croai.pwieBa. 
ta ea^ hi M'(> from Ibo nino- 
tfan VMtiual roda irn lixoJ 
tbfti the floDgntiou 
■1 roda can only take pW« iu 
dirMttoB, and tlui at tli«< 
in an upward dltvctioa. Cud- 
In urdnr llial Uw produlum 
of llic MBW l«ngtli, It ia 
tbal lb« doRgmtiaa of the 


Ih-i. iu;:. 

akall tetui to make tl»« bnll riw by exaeilv ibe muiio qiinnlit^ 
of tbu HmI nd t«ndii to lowur it : a mutt which U 

S84 as HUT. [sn- 

nUaia»d when the sum of thi! Iratrtbi of Uie steel tods A i« to thu Nia 
rof the l«n^thiortbebraii8 rode n m ihn inrrrw rttio nf the PoefficieMitf 
igMinoii (if dUwI and hnaa. a and fr. tbftt i«. b the prnpnrtioa A : Dst ! *■ ! 
Tha alongMtion of thn rod may aUo bo c<iinptMuiat«l ftn by uauidCl 
eon^lmtatiitji atrip: Th«A« crnifiist of iwn blndd* of copper Miid iron mI^ | 
dM«d toftatlMv and Kied tu tbe pundiiluiii rud. ai rep««amied lu lig. M 
Tb6 copper bUde, wbicb i* mora oipantib!*, in b«low tbo iroin. Wkn. 

Fi(. 303. Pig. 204. V\g. 303. 

aj>)-ntttir<< *iuk». tbt> pi-nduliiiii njd becomtt aUortev, nad Uie Ul] 
lint al the inmn tinin thn cnnippnMtiiig strip* bnoom* mrttd, i 
in tig. 304, in r(ituiM|UL'ii<.'(> ut the coppar oontnii^tiag mare Uu 

^tbe iron, and two melultic bnlli nt their extremitiai boonm* Icmr. IT I 
the; bare the proper hIko id ^ef(^Klllce to ifae pendulum ball. th« ptrti 
which U-nd to approni-'b the ccntm of suspeiunon oompunnato Ibnw) wUA j 
lAnd to ronioTf frnni it, and the cenlrp of owillntlon i* not diapIaoHl. If I 
the teinpi^niturH t\.<»-i- 1b(^ pvuduliim ball duacenda, but at ihu aaiiH! Iloa 
the eiiinll balls bioend, as iihown in fig. 30S, ao thax th«n) jj. ilmp , 

One of the most atmple i^mponnatini; pendulums i* tbe mtrevry fm' | 
didum, invent'^d bj an Eu^livb natdintalii'r, GrAb.'kin. The ball of llw 
p(>udultim, iusli-rid of bring polid, consist* of a fflass oyliiider, cootaiiuBgj 
pure nipmirv, which is pl«wd in a eorl of slirnip, aiippnrMcl by a «l«el tod. [ 

['When thi* t^iiipcralure riscB lh« rod and Btirtup become loiij^r, and tbntj 
owcr tho rontrn of jrrnTity : but at th<^ unnin tiniii thn moKiiry expand*^ I 

fuui, riMni; in the oyljuder. priidiices an iiiv^r^ •'llvct, and as nierciU7 lag 

'flHih nion- expansible Ihnn steel, n c^iiniprnmtioa may be effiDCtpd vUfcrJ 
out nulling tbi> mniyurlAl v-.-mel '.'f uiu)ii>? diniensiooii. 

The aamo principk' i.» appliwi in thi- compuvuiting haiimecu of cfaniM>l 
rantnt*. Thn ninlion horn k ri-giilnlei) by n bolaiiet or wAiW, funttihad [ 
with a si'iral spriu);', mid l1i(> tinm of tlie clironumder d^pund* nn iktj 
forcn cif thn ipriofr. thn mnas of thr bnlanco, and on ita circMBifemeiyl 
Now when th<i to nipt' rat unr rtNes tbi! (-i^cumfe^l^nCt> Jnoreaoca, aad ll*'] 
obrouomi'tcT (ruct sluwvr : nnd tn prcvnnt tbU, part of tbo maaa Doutt tl 


Kxrixnox or Luti-tos. 


Bcanr ih<> axis. f>n tbn rirrnmfennMof th«ba]uiMeMnp«iwat- 
gtrip>U« fixrd, lit •nrbich tbu inori! cxpnniibk metal ii AD tlii^outmtU^ 
■1 Ui« «nd uf tkeae are sibkII aiaH>«8 of m^*] wbirh plnr llie «aiii« 
tMtki balU in tlia alforocnar. VTbcn tlic niiiiu* in tipnudod hj 
ikmuUinaaHM are brought ncnmr tli<iMiin«>iacotM«qu«iiooorth« 
of tb« atrip* : and at xhey can be Gxetl ia any pntltlon, thnj 
iMh amngvd ao a* to cooiprnMl* Tor th« ospatiflou of tbo bnJonct'. 

op.v5no5 or uqcnia. 

SL tppaiiiiiT khA raal eiranalaB. — If a linA of thin (rlaa>i pTO- 
lUalwitk acapilliirv iit^rii, th- iWli and part of lli« elviu bvin^ ftUad 
vUMnwiMlDaied liquitL, bo tmmvrml in hot wBti>r,thocolumn of liquid 
b 4» ftcm at flnt uukft, but tlipn im mediately nfYvr riM«, and coDttnuea 
ioamntO tli« liquid inniJe hailho mmioIfm|>rnitiiMianthi^hol water. 
lUifaMHokBitg "' ^' li'inid Hnot diw to llacontTnctian; U aiunfrom 
A* m— 4nn of lbi> k'"*) **bich becoraM h««trd bi!foci> thn hmt rnn 
J^ik tk* HqBKt ; but tbe «zpaiiAoii of tli« liquid hooii exOL't-da tliKt uf tbi- 
^M^ and UiM IWLuid oaeoidai 

Bhk* ia ibe caae ot tiqiiiib «r» tnttM dietin^il^k between tiio (Tipnrmf 
mi tba md nr M&MtJnto M|>a&*ioii. I'hit nppnn^nt cxpnnsirin in that 
■lib lb la acually ohwrrnd wb«« liquid* contaiiMi id t«mhU ure )ieat>^d ; 
4a dt«i»iftrf» DXpaMMi U itiBt Whicb would he obtcrvad if th« vmmiI did 
HI Kspanil ; or, a» thiii i> mtcc tho caw, is tli» a]>parvul expansion 
nnwlMl fiw ibe iininltaupnctl axpaailou of Ihe funtaiiiintr muol. 

A» lua bii«n aircadj Btatol, ihn cubical nipMiunti ot liquid* !!> alonn 
laaJtinl ; and as In lli* mm of M>Uda, tb« mrfficinU of rrpatmon ot n 
dpttd ia Uw iaataw of Uw nait of Toloma for a nttf\i- dnj^nw, but a din- 
UmiHimi b IiNe Bada betwem lL«i eorpieifM o/abmlidr erpami'm aiid tiie 
mtfkiad *f a ^ art m i nxpaiuiam, (>f th» many motliodii whirh bnvc boMi 
'IMfipjad fof dot^nniaing tbaw two «oeflici«Dt», we shall dMcribo thai of 
lliil'nir aad IVtiL 

0»aSet«Dt ar iba ahaolnta axpaaalaB of n^reurr- — In ordor 

■■^^"-nNiikr iLa mnlBdentaf abtKilulDRxpiuinonof mrn^iin-. ihr iulluonoe 

■nvbipe most b« «lliniDai«d. Dulonj^aod r«(jr*m-'tlir>ii ilopnnd* on 

li>i1ni«<alii al principfe that in twoconiiuunuAlinif tobwIh ilw b^hta 

rf twn jwtiHiwM of IJi^uid in rqiiilibnuni (tri- inTOnelj sa Iboir d«iMtif« 

■ Tirincipb uukipundcnt of the diam^tm et the vuseli and ther»- 

.uair luqauuinn*. 

Tkr Bii|Mmua oooniatoof two glau tubcm. A AndB(fig. SOO), j^ned by 

i% ox HZAT. [373- 

icapilUrr tubMUid kopt rnrtinftl hy ftn iionaup|ioil. Eoch of llwlnkct 
aurMuad«i by a m>Mal orr, of whicti thu nnnllvr, 1), w titled with 
, the (itlior cointsicintt ml, can bo hofttcd by tho tammee, wli'icli unp»- 1 
''KaU'd in t^ciinnoM in *liuw tlie caa. Mercury is pouml into die taknl 
A natt 1): U rcuuiun iit thenamn level in both an \ciag as ihny km M Alt 
MmelvnipcirHliin-, 1>iil rUt^ in It inpropnrtioii m it Isli^filird, u)At 

I*t A and J hv ilju lipij-bl Miil densitr of tlii; mercurr in tiin hg A, 1 
the t«mpnt«ta taro. and k' Mid if ihe eiunii qnanlitinti in llio If;; EL FbhI 
ihn hydrasiatiuki pnaci^ile previoiuly ciW wuhute luul kd^k'it, Now) 

&om thepmblem oniiHgoS33,«r=| ■ j^i D being Uiaood&iBOt of ■k-j 

wluto expuirion tif nHirvuiy; nubatitnling tlii« TnlnQ ofcT to tbe tfqa4liai [ 

we b»Tp ^"J =A^. frrnii which w« gel 1)= *-^. 

Thti coi'flidRnt of nbrnluU; cxpuniaon nf mi-reurr w obtninod fltm lUI 
funniik, kniiwiii^ ihi' bvighu A' and A, nnd ibe li-mperature ( of iliebtfkj 
in wbiub tbe^ lubu It u iiuineraHl. Iii itulung uid I'etit'B cxpocii 
tliii tenipomliirr win ii>(<iu>iin^ by n wrigiit tiifTmometer, V (Sift)) 
nwri'iiry uf wbleL •iwrDuwud 'uiu> iliv btLsio, C. Ttie lieigbb A' 
ore incaturcd by ncnihi^lomcUr, K (^ilj. 

- -); 


Fig. 2oa. 

SiilaBg Mid Petit found by thin method that the cwlficiont of ah 
•tpliuiot) of mercurj-. between 0° nnd 100° V.. is j^'^,. But tbifj I 
tbtit the eofiffident incriMjRL'ii witli tlip tenippmluw. Ilrtwwai 100^ i 
300° it is n'ji, una bi'twwn 200' luid MP it a ^-^. Tbe Mmu obM««| 
kTaticai liiiB Iwi-n iniide in reference t<i other liquids, shLiwing tbnt tlxirMt-l 
n«on i« nut Tpyuliir. It hodbceii found thntiliiiie^paiwiou U iMt iii|ulir1 
in proponiiMi m liquids are ncuirn cbnng't> in their »tnto uf HttjrrcK'itioiii. Ito 
)», »ppmirfi iht^ir freeing or boiling points. Etulnng and I'etil found , 
that thei expansion of niercnry between— 3(P nnd loo's* i»ieti«dly<i«iii! ^ 



irliO hii« dctiiniiiMd tbi« impoTtani pliysionl constfLDt. Iih 
tlu) mmn (v^flicipnl bi-twf«o (I' and lOU* u ^,\,-, hvin-ima 

ti-i PuoWcltinf »r tlia kpptuairt •ap«aalaD of moroarTi — The CO- 

Bf««i«« of appuvnt cxiunskiii uf ■ liquid VAries wiih tlx- niiturv of the 
imlopw. Tbal of mercury ia xUm vm downiua«<l by mvnii* r-l tht 
ffuntv* r«pm*ontvil in figim 2Cl7. It ooittUU of n glow cjUnder to 
MA is joined a Ixnit e>|Hl- 
h; ^MatubViCipcn nt the end. 
Tb» Bpparanu i« wciglMd 
ht eByn-, and th«n wlua 
B«d irili meKarj *1 I«ro; 
b diffotnce girw lb* w*inhl 
fill* mMcnry, I'. It >» thtn 

ifej to » known lempflwton!. Fig. 307. 

] 1^ mMTurj «xpu>d», a Mftjun qtumtity \M^<f» out. wliicli U n>ccirnd 
I ifc* opMlo Wid ffri|;h«d. If tlio wRiRlit of thix mercur)- be p, that 
f tke ntfCBTj' remftininK in thv &]ipajHtii» will bn 1* — p. 
bBMU tbn tMnpcvBtura )■ ugain uiro. ibi' mvivury In coollug pmlucM 
^KmtT ipiM in lli> rtiioe}, wbich n^prefpiiu the crnitmction of ihe 
^El «f niMruij P—^, from f to mru, or, what )« tho Mtm^ thinfc, tho 
l^^abv of tk» uunc wui^rhl tlOBt A to f , that in. the vn-i(:ht p repm- 
MIto tb* KxpatutoB of tix) weight P— p. for f- If thi^ Wdi^hi (Expands 
■ 1^^ 1)7 • quutitjr p for (°, a •t»gl« unit uf wMf-lit would expand 

LZ— torf mA P . for ■ doffk degree; consequently, for D*, 
lb* 0iaffideat of nppwrcnt expouidon of mnrcun: in ^lass, vo have 


ut cwrrary ia piMu to be ^^i,. 

■wrttsb* tli«T^toiD»t*r< — The appiLmtiis r^pruaixited in Bg. 

^ ealled ibi: ffighl IlirrmvmrUr, bccniiiw the tempiratum can be 

(rant the woijrht of niercuty wlilfb ovtJrti.iws. 

ai^rne aspertnunta have placed the cw-fllntinc of appnrcot nxpau- 

w* bare tliurefutQ ih* equation /i>_f li- =iAi» ffW" 

_ 0*^^ , formula which pT« the tonipertilum ( 

«fa« Uie wri^lf" r ami p am known, 

S74. CAvSotant «f tb* axpAnalan of claaa. — An tbi' abvilnle ex- 
^wea <if a Uiiuid Utho apparuiit expan«iou plus the expaiuaon due to 
tba Mrabipe, tbv coefficient of tho cubical expanriop of glaia has been 
1 bj taking the diffetvocd betw«i«n tho coi-fRciont of absolute u- 


DulooK aud Petit found the coefficient uf apparunt cspnn- 

238 OH IHAT. [»T- 

pUMkn of mweuiy in glAM, aad that of iu iiipMNiiit *xp«naion. Thuii, 
the oo«flieieiit ot c«bical expoii^u of glam Is 

Ragiwull luui found thnt thi? coefficictit of cipuiaUnt vmiie* wiUi fiAit J 
mt binije of gloM, anil further with ihe form of ihi> vorelcipM. Fqt j 
onlinary cIivoumI gins lubv!'. ilio i'iviScIl-iiI ia ()'0(.)U<)^51. 

-77. Oo«Bel«BM «f esjt&aalan af Tarloua llqnlil*. — The ■p|Mieit1 
cxponaiou of Uiiiiiijti may be di^ttirmiupd \>y ui(<Hn« of ili<' wrttflii liitniM* 
nUThr, iind tlic nbtolutc niqiBQUaa u obUincd b; Bddiugto thucoc&iat 
ibu eijiuiiaiun of Um glaM. 

Tetfd (iji/mnyil r^jmmiotii: of liyuiiU /writWRt (f and VKP C. 

Mwcnrjr OOlfiU Oil of turpvatiae . . . . Wt 

DlnUled water .... O-OlCil Kibvr MH 

\\\uit nntumtL-d wiUi salt 0-OC FUeil oiU iWS 

Sulphuric nrid .... Q-06 Nitric acid (Ml 

UvdrocLiloric acid . . . 0-00 Aloobol . IH 

Tha mnfficient of nppnrcnt vttxuiMon fnr 1° C, in obtMned tij dindiif ) 
Iheiie iiuiuben h,v 100 : but lht> aumbtT liiui obuiiied dotu not RjuiJCt 
tlio moan toviliFiriit of expulsion of liquids, for the rKpniuion of tbcW 
bodies increases ^rliinlly from t^Tfi, Th<.> enpaiiBiou uf mrrcunr ii jae- 
tk-nlU- fouslant betwferi — 3tf° nod IOC C, «bil« water cnolrarU tua 
xcro to 4°, and iben I'lpnnds. 

For muii;^ pliyMcal eiperiiuent^ n k[i.:iwlL>dp! of the cxni^t cxpaiMM 
of witter IB of gKat importniici;. This phyuco] constant ba« been itIUh 
Djiuvd witli ((ivHt earv by Dr. MattbleBseD, vrho baa fuuod that betveA 
4° and ^'^ it may bi- expretaud by the formula 

V(=l~0'000003o3 C(-4JO'0000008380(i-4)» + 

0'00000007173((— 1)» 
aad bctwwn .■«' and 100° by 

Vf=0'l>OOC9S+0'0000054724 ('+0«)00000n26 f 

Many liquids, with liiw boiliu^ poLnta, espeoially ODadcDiud paiM, ' 
have wr\ liigb cocflipiuila of expnnainn. Thilorier found tbat liquid i 
carbmiic acid expands four time* a« much na air. Drion ba» rMMitlj 
conllnued this ubaervntion, and baa obt<unt<d annlogoiu raaulla wltb | 
eUoride of ethylc, liquid aiilphiiroud acid, and liquid hypouitruni acid. 

373. correcUon er tb« bar«mMrto iMtBbt. — It ha* b«ra ilrMdlf 
explnineii undi-r tbc Itarmneter { Iti^ ), that, in order to iual{« ths iadie^ I 
Ltiona of this iiislnimeut rotiiparablu iu diffcreiil placBs and at diSmntl 
P'timMi they luust bu reduced to a uniform tcmpernturr, whlclt it Hut <l I 
melting ice. The correelion is made in tim following nuuuwr : 

-aaOj UaXUIVM DOtSITT OF WaTES. H be tine bantoiotric iMtght at f, ajail A iu bciitht nt un, d dkC 
• nmtf of Bwramy at i«tu, and tt iu ileufiity u f°. TIm< buiglito II and 

uv mrenelj •■ th« douiliM d tni d ; tltat is, A = . If wc 

tlM ToluBM of ntaaiaj tX *mo, it> votiuiM at ^wUl b« t+l», D, 
■-fmf tba eoeficMot of AbMiJub) exftiuioa of mcKUrj. Uut tbew 

■iMBMft, 1+IW undl, aiv invcnelya* tbc dsuitiw <f and if ; Uiat w, 
. _ I ^ ,_ * _ 1 _,. 1 _ II 


CooaMiiMntlj-, , = 

lt~ l+Dt' 


)<Wii^ O bjt iu ndtic |^,^ vri; hftvu A ^ 

In tkU i-xlruUticti, the cucJTicieiit of sbaolutc exjwiiHOii of niBtriiry i* 
uku. Mid not tlikt of appaivnt ospanMoa : for tli» valuo A U tlii> uius 
a* if Uh> trlaa did not cxpaad, Uw barometric bMjRht imox indi^i^ndvnt 
W tbc duuDutcr of tlia tiibn, and thfifi^foro if lU expauMoii. 

3TU. F«re« •X0rM4 br Uqoltfa In •ipMOdlBK- — 'ihn farce which 
Hfulits psert in oipAnding U vonr ([Teal, and o|unt u> ihat irliicli would 
la n^aired in urdur (o liriog the Kipaoded li<|iud buck to its urif^iual 
talame. Now we know what an eBonnuaa fom Ja rrquinid to comprcM 
Ur e«n • TMy •mail eitcnt. Thua btttwi>«u 0* uid W, niL-Kur; 
I b; (H»I7»0C ot iu voliuiK at 0°; 
emmjn^Mhty U (HWOO0e95 of it* 
t Ibr one otnoapliani hence a ptf»- 
1 9t man than flCiO ataMMfihona would 
tnqnistp Iu pnvcBt tupttmy axfo^ag 
hhM fn>m 0' t» lu°. 
^falifT^* a*mtHr or water. — 
Lil»ai II 1» thf! miiaikabli? plituoiue- 
ithal wliMi iu mnpuntuiB ninkii itc<in- 
'tndaap to 4"; but fruui that poiut, al- 
ftaa^h ill* cooling cooliiiDi!*, it itxpauda 
•p to liic breamg pctst, no that if rtfoaaNit 
tL* p-iint of gi«atcM oantnctioo of walw. 

Manr n>e(luMl« liava bi>«B uanl ta dotcr- 
OBar lb* raaxinrnm doiuit; of water. Hope 
mail I ihf- followiiiK i-x|icniii«<it. lie took 
■ itmf Ti— il. petfunl^d by two latctal 
H*WiM, u whkb be lii«d tLHmoiuetera 
{if. 9>!). and having fiU«l the Y«Mel 
irilh walef at 0^, he placnd it in a room 
it a Hmjiiiiiiiini uf 10". An th* lajan 
•f %aU at the Mm of tho v«Mal bacuM healed tliej tank to ^e 


m; iut. 

bottom, aoi ibe lower tfaprnioiBci^r m«rk*il 4', wbile tliai nf tlie 
nn« mil tlill nt miro. Ilnpc thrn mnd? Uit inveiw vxpi-riuiEiit -. Iw 
CIM the *e«ac1 with imUr m lfi°, hn plAC*d it in • nxnn tt 
Thi> Jiywrr Ihwinometw haviuii bhuIi t* 4^, ivmaluri auai 
Kimft Iini4<, nhili) tho upp«T onn cnalnl (lotni until il rrocbol 
Botli thc«« ciperiiiivnts prore lliat vnter is h«Avier at 4" lliAu at <P, 
in Villi citw* it rinka tn tfau Imrrr part of ibc tchfL 

Rallslniin maijc a il«l4<rmi nation of tlie maximam dnM>^ df 
in tko fntlonin^ innniir'T. He ti>r>k a |rUn )iulb, tondcd irith aand, 
tnjl^h^ it in vat«r of dtlTRninl trin[)i'Tatiirni. Allowing for t]M> 
ritm of nloM, he found llial 4'1° wua tbe t^nipvralure at irhicb 
moK ir«if ht, and c<in*i!iu«ntl; tbi* va* tlio tcmporataM of tho 
ilanaity uf water. 

Di^pwu: nrrirr^ at tli* t<-m]»r»tiire 4' by nnothfr mf^liod- He toA 
■ wnli-t lli<>niiOTin^l''r, Oint i» rn wiy, a biilb«l tiihn Minuininx wawr, uti 
placing it in n luitb. the temix^rntur^ofvliicb wa» inilicalfd by an unlinsj 
■u»)rrurv tliprmomtitcr, found that tlm water contnetfld tn th« gntalad 
eati'nt nt 4* and that tbiis is therefore (he point of gTeat««( ilniMtj. 

Thic phpnomMjon ii of urmt importanpe in the (^ranomT ofaitiue. b 
winirr tbi? ti'inperalurfl of lakrs anil river* falU, ftrnn himg ia ontKt 
with the c'dlil air. and from othtT cuiines. mch as radiattoa. ThttMn 
walortinkt t^ thn bntlnm, and a cnntinunl ii^rioa nf ciUTMt* paiiM 
uiilil lIiH vhcilt- baa ft tcuipvrnture of 4". Tli« cooling on tbe suite* 
nill conlinm-ii, but thr cooU'rt Inrrrs Iwing li^httr mnnin on tho lurfioiv 
■nd uhiniaicly ffi'eKe. Tliy ire formed tbas protect* the water h*!^*! 
which remains at a temperntore of 4°, evtn in tho raojl fvvrtv wintm, • 
lempemliLre at which fishes and olber inbabitanU of tli« wsitera art net 



S^). 0«r-Kaaaac'> mettioO.— Oiiix'a nre the moot «xpiui^bl(t bodJM^ 
and at Ui If ?Hiri>.' linie Oi<- uii>t rc^rnlar in tlieir o^naion. Thee 
denta of esjuumion. too, of the s^rcral gaao^ differ only by very 
quantitiea. Thn nibicnl cipannon of gaaea nned alone be <vini>idend. 

Oay-LuBHHi? Gr»t <1<-i-.'nijinpd ihe covffldeni uf tb« expansiuu of 
by mnan« of thi? oppnrnltis nrpri-jcnted in fig. '200, 

In a rectanirnlar iiitlnl bnth, nbout 1(! iurhes long, naa fitted an 
thermometer, which cooauftted of a capilkry tube, A}i, with a Iwlb, A, 

exPAxstinc or oases. 


Thre tabo wia diriclvd iutu parts of equal capncUj, nnd tli« 
* th> bulb ucitrt>iiied in tcniia of thnw [lArW. Thi« wnx ••ffocUiil 
hing tbt- hulh uid tube full of meKiirjr at i«n), and thai iuMting 
llj- tn Ripul a iraoU ifnoBtiljr of mcivuty, wbidi nu weitrhcd. I'ho 
felDa Uiiaff Maiu couled down lo aero, the vacaal space* iu tbo tiib« 
Ui the ircd^t of imircuiv nrbkh hul oveidowcd ; tbo 
i of merciaj Kiiuuatng in ib« agipAratiui. mid coiuwquently tha 
tha bnlbi was dntnnniiiiHl bf c»lBulatioru •Didogotui to tiimw 
t ikt piftunotM (88). 
' lu lill ibo tb(innuui«t«r with dry air it wns flr»t filled witb 
wkicfa wu boiM in tbo bulb itnirU'. A tubs, C, bllcd urith 
I uf caldoBi, WM ibeu tlx>^ '■» to iu I'liil lir mrnji* of n cnrk. A 
I wiie liMvtog tbcD bwn iutitKlucvU iulo Lbo atcni AB^ ibruugk 


i C, nd tb appwBttut beiiig allgbllT inclim^d aud agUatciI fmni 

Itbti^, Mr cntvivd, baling hcaa pmnouiily wxlt drlnd bv jiiLMin^ 

I tba eUnridi* of i-aldiuii IuIm. Tbo wbule of tbe mervury van 

, witb thr Mccption of a nuall tbrcad, vbicb rvimaJned m the 


ir IbanfUMnctBr wu thva ptncwl in tbc box filled witb mdUnn 
iimlejc Biovtd tOWBidi A, and tli<- point nsa doImI nt wliii^h it 
[MJtinauT. Thii )nvu (bu voluiui- uf iilr at isro: for the utpacltj 
* bulb waa hnuwii. Wat*^ «r oil wiui tbun RibuCitiittd for tb» ico, 
'kv balb Mia:M»iTelj b«nl«<l lo iliflVsn'nt Itimpi^nilurrq. Tbu air ei- 
ti Mill natod tli« imlvx ftOM A towcnU It. Thn poutios uf thu 
|;iB «Mtb rate wai nnt^d. and tb9 can««pnadiDg l^mperatiuv wu 
ptol by owttiia uf tbo tb>^mioni«l«n D and K. 

Mainit tfaat tbo attomphcric prnwuTu did not vnry duritif^ thH 
I ami aegl^cting \\ir ttftaAim of Ib■^ glus* an bviii^ ton urniLll 
witli tbal of Uhi ait, tbo total cxpoiiMou of tbe air w 


ubtaioed by BiiUraeliDp' from iU Toluine nt n givrtx tempentonf 
lU wroL IHeiilinji thi« liy thi» giv^n tmip-nil(in>, nad Uieii byl 
Wr L>r iiiiiu iMi(ilHi[ipJ in ibo vulumi? at ii'n>. tbti quotient wtbew 
of c'liHUinoi) fi<r n lititiln unit nf Toliinid nix! a aliiglo dagTM; thd 
ciwlfi^imt of •KpantioD. li will bi.- aftn. furt W an, itovt cocnct 
piVMUN and tcmjwmture maj bn inln.>iliic(><L 

Bv this metbod Oav-LuMRC fouud that the coeflident of Ktp< 
air wM 000375 ; tnd ho noiuidatod tbo two foUowiag Uw* ta ■ 
to tb« HipaiiMOD of fnse» : 

I. All gaift haiv ihe tame mrfficitnt o/rjpauKOH minr. 

II. TAm (wffiriml U tht nimii uitilrvrr bv lAt i/rraure ofipi 

Tlu-viimplnlnvniumnol, bovorar, rigMroiialy «xart (3M):tl 
ex|)rv«4 tbi> f x|)uuBiuii of ^usi.'s in uu nppruiiaialv miuincr. 

'JS2. Vrablama oa tbe •spanalen of fu«B,^]Llniiy nf t 
bUiDiM n^liitivp to thu i^xpautiluii of yaxtvi an! MiiiilnT to tboM 
expRiiaicm ofliqutdi. Witb obviona tniHlilic-iitiand thify*i«*ol< 
nmilnr ninnnor. In iii(i»it rA*e». tho pi«w)iii>i of th« aluioApber* i 
tnki'n iiiln fi».-oiiiit iu I'muiiltriu^ tli<> pxpniisloii of giui-m. Tlu & 
ii an cxnmpto of tin* mnnniT in wliic-b till* cirroctinn i» mRd«: 

i. Tbe voluiue nf h giu ut f*. niiil uiidur ibt? pnMiure tl, u V 
will be thu vnlumc V of tbii sainc gas at teta, nnd iiniler tlU 
preuuro 7iX) millimciurs ^ 

lluro then- nre two curnicticins to be mmli! ; oqr ivUtlTe lo I 
peraturv, and Htv olli>>r to lUe pi:v88iire. It w qiilt« iiiiinatBrfi 
]■ tftketi lint. If « hv tha co()ffic:ipnt of cubicsl cxjiRniiioii for 
digme. by rensnnin^ Hmilar to Ibnt in iho CMS of tine»r«X[>aMi( 
tJie vuluuiv uf the gas at xero, but atill uiidcr thi- prpwiini 11. 


I — .. This [irewure ia raduced to llie pre«uro 700, ia 

with Uoylo and Mariotte's btw (ISl), by pnttiflg 

1 + of 

IL A toliinitf of (fna weiffhs P' al f ; what will bo it" ' _ 

l^^t P bv the desired weight, a the cociKHent of (^xpaation i 

J" iu denHty at f, fitid tl ila dt-naity at turn. An iho nt 

oqual vnlnmea aiv proporUonal ta tlis denutiCB, wc bave 
If 1 b« the voliune of a gas at leio, its volunio at t wU] b« 1 -I- 

aa th« dvnutifs ar« iiiv«re«iy oa the volumes, -^ ^ , - — , ami i 

a I + tt 


, wbich glvcB tliK weight ftt ^ 

r ibo iroight Bt nro, md which fuitliLT ■bciwi tb>l rhn weight 

iFRM'lr (M tiw biaonial of npcMJon 1 +al. 

B>ult'» inetk««.— M. ItcfTiuull hae suLveseivel.v uh-'iI fniir 
bm mvtli'xU l'»r di^ii-Tiiiiiiiiig the nipansinn of gtur*. In ium>> uf 
IK, di? piBMiin: irvi coBitBllt kod tfat> lotuiui! TAriabl», h^ in Onv- 

I nelbnd ; in olbcn the Toliitnc rriiiiiini<(l tbi! (ninp wlitlr the 

I vnM. Tbo flnt laetbod will be dt-Kribed, Ii in tlie «auie «» 

Fig. 910. 

. br ItudbMjt and l>itlon([, but in distiDgutsbed bjr the t^ant wflh 
I wHiroM of frror an- nvnidi-d. 

IGoan>tcd iif a prultv lar|[e c^'lindricttt K«ervnir, B |f>i;. 
■ting in a bent rnpilUry tubr. In order to (ill tho rrsoiMiir 
■ir, it WM plaOMl In h bot irat>-r tinth, nnd ihn ritpilinn- lubu 
bj a c»oalcti<nii; tubo witb > Buriua of dryiug Iul>w>. Tliv«« 
I louH!d to a ainaU aJr puwp, P, hy wbicb a vacuiiiu I'ouM b«i 
I im tW rHnrvotr while at a i^iupi-mlure •.<{ 100°. I'bc rrHn-nLr 
1 oxhatutml, and air hfl»rward> adniiltiil hIdwIv ; tbi8 nperallon 
Jpd a (TH'-at niany tJniM, no that ihn tiir in tin- nM«-TVoir bvoauii; 
, tut Ibi- iiiiiUtiirw adhering to thi.' iqiIl-b ps«wl off in rnpciur at 
ke air whicfa entered bncamti dry In its pun^' tliri>iiH'i ^*" 

mr «•» ibwi kept (or half an hour at tie Icmpwatur- 


05 USAT. 


bcdliii^ watRf; tbo ftir pump bnviii;- Wm deUched, tbt? lirrikg tnk»i 
were thvu di^connechxl, luid tli4> nnd of ihn tulw linrmntiPiillT 
tbn height, II,uf th« bttrometet Wii)!' nolnL Wlitoi ibe rnervoir Bl 
c>f"l. It WA« [ilncnd in tbn nppanitus rvjffrwnted in li^. 211. It' 
thl■^(^ ijuitf surruuuiti^d with iw, and tli^ i^nd «f ibe lub« dipped la] 
niprcurv bnlh, (_'. After ilie air »a the msfTroir B luid BUiik to tt.'W,^ 
pi.iiut /> WH« hr(>h''n oil' Iit mrAii* of a forcept; ibe air in iKc int 
iinmnir iwodMiivd bv aliuu»pb«ria preOMitu, the nwrcury riauiK ' 
Iififlil oG. In ordrt (o mnMuni Ui« h^ifflit nf thi* column, Oa, 
will be cklUd A, K moTMbk- nid, $>u, ww lowered until it* point, a, ^ 

lluah niih thn mirAim of tli« m» 
tli« balb i tliv di8luiic« bFttrectD lli*| 
y o Biid the IcvdI of tbo ni«Kiiry f), '- 

tnrwurvft by in(<iui« «f th? callirt^H 
TliC' point b wan liiiiillir cloced witli ' 
moiuiri of thn tpoon a, and Um 111 
presnurv noted Hi tliis momcot. If ' 
prcuiln- be. W, Ihti prrwUM in lliel 
ie ir— A. 

The Traon'oir wu now wriglkp 
axcHrtain V, the weight of the lu 
which it cuDininvil. It wm tltoB 
p|i>tely fill«d with mercnry at iero,iai 
tobnTolhc welgbl Pof tbemeicaiy iail 
renervDlr nnd in the tubs. 

If 1 be th« e>iefllci(ini iif the cubioil ei'l 
pnnMon or fltutt, nnd I) tlie dnuity ofl 
mercury nt lero, tli» ^efficient ■ uf tha 
cubii^nl expnuMuQ of air it detnmiaaA ia I 
the fotlowin); manner. Thn voluitie uf tlM3 

Fig. 211. 

Ksen'oir aud of the tube nl mo ia 


from the rorraida V^ VD (116); coOMquc-iitty, ihiR volume ia 

5<i + «) a) 

At the tcnipertttiirt^ f, uAsumlij^', ft§ h tlie CA»e. Ibnt ibe marrroir and 

tube mpniid a* if they were wild gloMi. Hut from the fonniila P = VD^ 

the volume' of air in Iha rcMiroir at zero, and under the ptviiMtPB H'— J^ 

P' — I' 
-- At the Nune pn>Miire, but at P, it« toIiiqm would be 



and, by UuyU- and Muriuite'e Uw (iei>, ut the pivcsiire II, and« ^idl 

ibe tube mi!> ^Hicd, thia Tolunie must have b««n 


tXTAxttos or UAsxs. 245 

~mr~^ <*' 

Nfiw tba rnlatnea t«pf»ent»il by tlit^ roRDulM, (1) nod |2), arn each 
•qoal U> llM- n>)ain« ''t tha iraerroir «imI lh« tubu at I' ; xbaj uv ihi-rv- 
ioK nfiuL 1141110*109 the iaa^miiuiUxn, wu hmv 

p-d -t-sfjiissfi*-- P)(i + rf)(n'-A) . . . . (S) 

frnoi wiiicli U»F tolui? uf ■ is (leducocL 

Th« ikpajtu of a giT«t numUir of ^xperisient* IwtwMa Mm aad 100^, 
tod hr pmauim bctwvvn 30O millinurM-n und fiOO niJIIiniat^n, gnrc the 
frUowiof ■«»!>•«> for ih± o<MBieianU of nxpnnMon fur » <dugk- degmo. 

Ait 00036660 II^iMhlonc 4old . . 0(KK1«»13,.ff«n .... OOtMBWa CTMOgwn .... OflOlMMJl 

■■. .- „-"o (KI0M08S Carbonic Mid . . . OOOfkWSe 

SUfihanni* •*)•) . . OOOmOOQ 

ni^ nuinburB. mlfa which tbe itoulu obtainad hy Magniu cloarlj 
■p«F, tbiiw Ihal lliBcnrlBdcDUitf HipniuDODof UMpetmonciitg^aRf didi-r 
wnj^ihUr: h<it ihu iWi aratligfatlj^retiti-riii tbcrMnoftlieooiideiMaUe 
Mirb^ rariinaii^ Bad aulpbuToui ndd*. lEi'gnaiilt bui fiuthcr found, 
■1 tb« aanw lemiienUiir*, tlit- <M«'lliiri4-iit of i-xpniimon of mij gM 
wHfa tha pnaauro wbich it lupitoit*. Kinnlly be b»t (oiuid 
fttt Uh eoafieuHU of «xpaMi<iii of two diflHreiit ipuua difTw luom in 
yKfartioa •■ tfaoy am luider gmater prcwurM. 

Tbe Binal«r fbood bv liwgnault for tbe cmfBdent of tioaxpanrion of air, 

OOOSOOS, tt vqual to trl:» = it] D«artf ; and if w« take tbo rciHfidont of 

oiminon at lKXn066tt ... it nia; bv rrpiwiiiqd by tb» fracUon 

• ' '.is fvry coar«iiioiit for piirpoum of calculatiua. 

. Air th«nH«a*«Mr. — Tba «■> thrrmimittrr ia b»Md on tb* M- 

.. uf nir. Wbtin it b iMod t<i nipasuiv imnll HiD^r<'nw>* of teiiip«< 

Jt ha* tbe aame torn at tbe lubo UMd by Oay-Luwni^ in dctnr- 

tliv MCpaMMM of air (lig. SDH), that iii, n capillnry tub* with a 

■ : tbo iwiL Th« rowrvMr bMog: tilled with Aty air. on iiidpx of 

OBlntrpd raipbtiric add i* pasted Into the tub? : the njipnrntti.i i* Ihtiu 

eT*ri»4t«>l in OntiicTadB doKnm* bjr comparing th« poMiinod of th« index 

* . ilix indicalJoua of ani«minal tbeimometer. Of courwi the «nd of 

U>> lalw muH Tvtninn open; otberwiac, the air abovn tha indoK con- 

iiBiiiij^ III I ipandlnij: at th« aaine time a> that in th» bulb. [h>^ index 

wMdd mntitt (Uikwarf. A oorroctbn luuiit b» made ai tuufa oWrtation 

Ihr Iha atMioifiliarle pNMitra. 

Whvfl (owMtralile variation* of tempemttire at« to btt uipnouriHi, th« 
tab b«a tana lik» tliat Med in lUgnault'* experiment* llitii. 810 and 
111). Bj aiprriai'-iita made ai dMerib«>cl in patngraph 283, r, V. II. H', 
•ad A, na; be found, and tbe cwflieiDaU a iai i being known tl|>- ' 



Oil nuT. 

Inoipifnt r*d SSS'C. 

DhII r«l 700 

Chprrv wd flOO 

penlUTP t to wiilcU the tuW lias (xwn niivd w rnMlilj dadunnl ftao] 
equatioa (3). 

Ri>gnfliilt'» mwarcliM tiluiw tkiit th« air and Uie uermiinl tbe 
■IcruH up to 2&0', but abort? that jmint luenurj' ejcpAitd* raUtJvsljl 
tiiui air. 

In cuKvs whnm vorv l<ig!i teniperAlUTM am ta bo tnpajiuti>d th*i 
voir ia niadv of pintiuiiin. Thl^ uw or an air Uwnsotui^ter it 
LJlulong and IVtit'* rxprriiiK-nt iS'it) ; it wai by aufh an appnntttni 
l^ouiUet menmrrJ ili« tviiipi.-rHiuro curnifpoDding lo th«i i^oloun 
metals take wh«n hnati'd in a fin;, and found ibem to be ai MIowa:.] 

Dark orange II 

Wbite M 

Duiltu^ wLit* . . . , H 

Id tb<^ measurement of high tninprralutv* DRrtllu and Trooat ! 
Itwd, with Hdvnntnge. thn rapiiur of i<<diij» insteai) nf air. 

3Sfi. Baaalir »t t^aes. — The tvlniive dmiatij of n so*, or i(ji i 
grtreSy, U the ratio of tlio weight of a ctinain volum4> of lL« pw M] 
thrtt nf thp MDie volume of air : both tlie ga« aud tbe air being at i 
and At H pnuHiim nf 7iiO millimi.'ti>n>. 

In onli-r, ibfrefore. ft fmd tb"? Bpeclfi'.' gravity nf a |j;iw, it ia DC 
to il(it*^iiiiii the weinht of n rortnln voluint- of Ibis ga*. nt a prii— ni 
7l!1 riiiiliiitpliT^, Hiid A ti^mperatiirti nf mm, and then tlio wetsflit of I 
same voluinu uf air under tbe tawt cundilioiw. Fur ifaui porpotw a 1 
globn of about tiro gallons capacdly is uand, the ecrk of wbicb I* | 
vided with a Mi>|H'Dck, which chu bo sort'wed 1i> t.h« aJr pump. Ac| 
j(lcjb(T ia tirat WL'ij-htd empty, nnU Ihoii full of nir, and nfti-rwani* full 
. tta gas in qututiiiu. Thn wejglits of tin- gas and of lb" air aro ubb 
f\)y aublraclinf: tbr wdisht of tbu fxiiiiHBlt.d globe fmm th« wm^il i 
thn gliibi<s Hllfd. n'spi^ntjvi'ty, with nir and gas. Tbn ijuntii^tit, otitahMjl 
by dnidiufj the laltor by ihe fontier, pres tbe specific graTilr ofthi* i 
It is diltiRuit to ninhi' thee deterniiaalion^ nl tbf •nmt> l/'mperaliirv mJI 
ptvcisure. and tbvrt'forv all tbe weight* are rndiioed tu >era and th* i 
pnwiurc of 700 niillituetort. 

Thn gases arn dn>^d by causing thrni to pass throu);h dijinx tnli 
before they enter the ftlobe, and air must aliMi be paaaod over polash lai 
ftvD it from carlxinii? srid. And as fiv<in thii bn*i nir pumpt neverptodMal 
ft p«rf>>cc vncuuin, it i* titt'emury t" exhHU9t tbe [■lube until thn naB^I 
mct^r in each cn*r niarlis Ihp snmi' prr^urc. 

The globe having been ••liiHunted, dried air is allowed to imluv i 
tho proeeu !■ repenliKl seTiTal times until thn globe is perfcellji 
I( is then finally exlinit4t<>d until the residual tension. In miUimrtai^ lt< 
The weif)bt of tbe exliauaied globe is p. Air, which haa boeo drM'l 



(J PiexslTT OF GISES. ^^^IP 847 

1 purifii^d hy pftnain^ ihruu^li poUwh and cLIoride nf cnldum tubes, is 
I allovpil to poter slmtlv. I'he wi'lRht of ihfi glnlii. full of uir is P. 

IB ili« b«roiiii>iric b«iffat in nirllinit'ton, and t' the tPinpnmtuiv at 

I ihn* of weit;biinr, V—p u ttio weight of thti glnha fall of ur at tli« 

lUini /, mkI llif ]inv«itTi' II — f. 

flindno tbia w<>ight to llic prcMun 7(10 milliinetpn and thi? teinpnrn- 

I Mnt, l*t a ba t&a eo«Ccisat of tlla MpMurion of nlr, anA / Ui-^ i->)ef- 

,n( tWcubtMlalpMlriMorglAM. From Itii; If acid .Mnrii>tl<''i U*r 

ht, which U )'— J> at f, and n pritsaurc- of II — r, would he 

' utnlnr the [wouiiro 7ttO mil lime ton nud nl the mine tfliii- 

C, If lb» t«np«nLliiK i« (y, tlis cnpncity nf the ^lolte will 

in tltD isti» 1 -f- •( to I, whiltf tbr wi-ii,'ht uf iIil- gu uurnwH-a 

I niki 1 : I -f- a', aa fbllown from.tlio problenw in art. 2S2. Ocin«c- 

djr the wnifrht uf tbi.> air to tho globe at 0*, and at tbe prifaiiiTe 7UU 

will bn 

7110 (1 - f «0 

'(H-^XI + K) 

Fortiher, IM ■•' b«> ihe c<»et!ii.-ient uf <-xpaiirioii of th» gaa in quMliou, 

[ V b« lb* wrij-ht of tbc ttlobc full of the piK nl iho IcmporaturD I' and 

Mm ir, and Ivi p' Iw tli« weight of thi> ^]ob« wboo it in v\- 

t>i tho tcni<i')Ti r ; Ihu weight of tlic (pu iu tbii ghbe at iIm; 

T^Jflaiid tUn tMnpmiiufe of icro will be 


; til* I«Ut fomiula br the foriuBt wu oblahi the deiuitv 

(P —J. ) (ir— .) (I + «(> (i + •'*') 

rtW uniwnttini aiul the prvatun! do not Tory duriog the txpt-riiuenl 

•PBSBlt'a saathod «r a«t«rmlaliic tlia dvatlt^ ol «**•••— 
. Bfpukit ban ai) ittnditM tli-.' iibifvi.- niutliud Ibm [iiuiiy uf the cur- 
I oMj b* diMpcnaod with. 'I'bn Elob* in wbinh thi< tiu in wuishml 
ttaBpankd tttim one pan of a biiUuw, and h coiiiiterpni'U'd hy iiir-an> nf 
a fmad fHobt of the aanu) iliuiPiuionit, and hvriiir-lii'Hlly M'uled, «ii*i- 
pF^d fnuD the olfaM. Thww two globo* nipnnding nt thn tamo time 
•>nT> liifpUce ihu aoiiM qwuiUty of air, and cunsv^uently variation! in 
it* Umftttttmv sad proMurc of thn atniatphuru do nut inllueoct) the 
»iyhtny Thei gioho, too, ia fillt^l witli air or with llie gta, while 
flM^ la m omUIUc vm**! (illi^ with kk. Thu corrtTtiuu f'>r temp*' 
tan M lliiH iMilii»j ■■ f^^ f^* i« 't Uit- luiupi^ratiire uf inultina ii-ih 



up- I 

nclv corrM-tidM oeet B Mry i» to timIu«> iL<> w«i;{hli> of tin tvo 
«iuii<- {>r<M«urc 7nO niillimttcrr. for tbn wvjghta of tqim) voli 
[HirliiiaBl )i) tb" pr*«*iir*»i. 

2Sr. B«Mlir »f Kaaaa wKMtt attack nacial*,^ — For 
attack tliv oidiDMy ni^ttla, such aa cbluriiM^ » nauUl Mapoock Mi 
nard, and ihmiId witli Kround rIbm atoppera an antwiituimL Tli 
Introduced hv a liont glaM iub«, tli» vr*»«l Iwitmr li«M either upi 
inverted, acconlin^c an llin jra* U bparirr nr lifibt«« than air: w 
v«Miel [* tiDp|Mi»«d lo be full, ihn tnbo is Kntiidnwa, tlii> oltipper i) 
and the wcipbt uk«a. Tbi* irivps tlie wi-ipbt 6t tbo taa«l and i 
tha capadtT of the tmdk*! V> in(-ni<iir''d br nifiims of watrr, Ui« m 
th« air which it cuutaiiu is dnluwit, fur th«dMi»itTof air attf 
"W mill i mot*™ pivj»iiri>, in yJ, tliatof di*lill<>d nat^r undtr tbe ■ 
coDmiuii-'iu^ Tlitr ni-if-bt of the T«Mel full of air, Imb the Trcigli 
rontoinnil nir, givri tha woight i>f tbo t«um1 itMilf. From th«M ik 
— the ireig;ht i>f ih^ leMcl full of the gas, iha wietght uf lh(^ air i 
Rontninn, nnd the rniiffht of the vmcl aJoao— thn apprilic frT««lt] 
gu» in i>«iiily dprluosl, the necMWiy correctiutui bvinc made (or 
raturv and {iivtHiiie. 

Dmiatiet of gattt al stm and of a prnturt ejf TnO millimtltr; A 
hmig takm ai imuTy. 

Air i'OOOO 

llTdninn 00003 

Miir>h ]»> O-fiSOO 

AmuiouiHCjtl gtu , . . O'RSO' 

Carlwinic nxide .... 0M70 

Nitn-ven OWU 

Hinnxidc of uitrog»n . . I'OSrtO 

Onvjn-ii 1-1067 

Rcgnault hiw funiiehed thofullowinKdeteniiiiialiapauf Ui' 
Uti« <J thf mmt iinpnrtnnt kiul'ii nt (^ ('. and 7*10 mm. 

Air 12!».'tI87jrnii». Nitrofrpn . . . l-a06I( 

Ox7s«i. . . . W20803 Carbonic add . . 1-0774: 

Hydrogtin . . . 0-O8B57fl 

Siilphiin>1t«^ livdriig^n 
Hjdnichloric acid . 
Proioridn of mtn^cn 
Carbonic acid . 
Cjrano^ii . . 
Siilphiiroiw acid 
'.'hloriu* , , , 
Iljdriodic acid . 


cnASoRt OK cnnDiTiox. vAPormi. 

SAd. Tnaloa. Sta lawa. — Th« only phi^noniRna of h*«t wit 
wB hnvp liitbf'rto li">ri on^gnd hnvp b«*n thiun of i^xiiuulon- 
c*w of •'iliilx it is I'tuv lo fev Ibai thU FxpuiiIIou u liniitod. For 



I M • Mt a^Morb a laiffpi qunntitj- nf lipot, tbn l«piilnJT<> torn 
a Ik moltcula* ia iticj^««iil, ami (iltiniBt<?lj > point i> rvai-bed Rt 
tb» Meiwolw allractiou ii not ■uflicii'nt M r<iUiii tlip body m tb« 
M>. A ntw pbDMUenon in tlu-ii producvit. fusiuo IttkM plscc ; 
ttf bndf fiiiifi bem tli« mIuI bto the liijuid *tntc. 
I •nbtoiMi, boirtTar, nieh a* pnp«r, woixj, wnnl, nnd R»Ttitin mIU 
Au* •! ■ bi^ lNiip«ntnrv, but nni decumpdwtL Hanv bodinn 
If b(«« c«iNd«i«d Ttfractoiy ; thnt in, incHpahlR or fuaum : but, 
nioM H it liM been poMiiUe ht produce Ltgb^r h'lnpi'rHtiiTM, tlicir 
hai diminUittd. Ouulb bw ■uooo«d*d in fiuing rock crvxlftl by 
faluapfU britj^t Af oxTgm; ud man rer^ntly D'spmli. by 
if llneffi«ls uf tb« BUD, tbe Toliitic battery, nud ib<> ovy-hyilro- 
'•|Jp>V bu nK^ltnd ■luminn uui ningntuiiR, nnd Hftonvd cBrbon, 
b* flf>tibl«, whtcb U a eotiditioii iii^nr tbst of fiu>iin. 
I boen ciperimL'DUUy (bunid, tbat tho fuaianof bodi«a ia goTvmad 
■« bUoiring laws : 

wy laldamer htfiiu to fmt at a cwUim Itn ^i mraltm, whirA i* m> 
firtatA mittmr,' if tikt ffttmrt it eotutOHt. 

'imlntr &* tite mlauHy of the wwet <f iMt.fmm the mommtfimon 
M, (i« tfnt pa v l an of tkt body cmiM$ to rim, and remamt eoMltmt 
fiuiam u cDmpbU, 

^Fil*i^^g furnU ofctHaia mJiitanct*. 
-!!«-(*• Sodium W 
, . . . .-13'ft I[<wt'> furiblo mcta] . . M 
Sulpbur lU 
+38 Tin 23S 
44 Hismuth 204 
40 Cmlmium 331 
M L«*d 3S6 

Zioe i 493 

Aatimnnv ..... IfiO 

Stivur . ' 1000 

Gold ISW 

Iron 1000 

I falMi|»ac«> ]MM> from iIm aolid to thn liquid ■tato witbcmt abnw- 

iikfinitc melting pdjnt ; for miiiple. ^Ia*fl nnd imn bvcoiiie ^ra- 

\n^n and noftCT wbon hnt1i-d, nnd pSM by iiiiporc-plible stmres 

nltd to Ibe liquid cimditinn. Thin inlTrafdiatu enndilion ia 

aa lb* "Utc of tttrttmt futian. Such sulwlftini')' mny !»■ wiid to 

lowoM tomp'TOluro atwliirh poPPrptiWn siifletiinit occur*, and 

■dtod wben lh« furtlirr duvaiion of K'mperaturo ^ 

■Miv fioid; Irut no pT«ci» t«iiipi.Tatui«i caii bn gi« 




rw. . . . 

ftHibb m«tiU . 
idd. . . . 


. 44 

. 40 

. M 

. B7 

. tlO 

. 06 

. W* 

. 70 


mt BUT. 


Thn T«ri«tiiitn wliirli liikn plnnt in tho oMiin iif 

hav« III] p(■n'(^ptibk■ iiillu<.-ui.-(? on 1I14 mcltiu); y • ■ - la 

graatf-t vnrintions in prfM«>iiri« have it Tcry Apprreinhk rifrct. CruC W. 1 
TlioiiMijn fotinil lliat pre^suivi of 8-]° mid lU-9 atiu-vplin*!* lowrd 
incltitJif point of i« by (HMS* wd OUff C. rwpeotirrlr. Tb™o 1 
ju«Uff til" thi^owlio*! concluMon* of I'mf. J. Thomwjn, 
irkieh lui iiiciviue of pce»urc of n Uiiloapli«n» loiins the luelllDg] 
of iw by 1)0074 »" C. 

In tlip vtav 'jf MMiie (ubalanrosL however, the luelljtig point \» I 
b,v pTPwiin'. TU<i>, Kopkinii hiw fnuod that th« mdliuir paint of ' 
wliirh at IIj" (irJiuKry pwwtui* U IHT', i« 74'r'' under n p(v»*ur* of I 
uul H0 2' iindiT n pmuiira of TBA Mmmphnra* ; tho meltinjr 
spf rriiftc^li in raiwil Ltl)" hr & pKMiire of 7PS atmOMpherM. The«# 1 
hdvp Wn i-onfiriii«l by >tuiin.-ii for lower pTMiurM; 

la ^>nentl all tlio»» iiub^Inncm which fjqumd on Sqmftiitii, such k 
sulphur, I'tc., hBTe tbt^irmrltiiig puinl rnuf 1/ by iuctviuvil preoaiiret 
Ml thn mntrUT, whirh amtract rm Uquefyinff, boTO their nwlltnp 
lotcrrrHhy jnoiwed preasuiv. 

Sf'O. AUoj*. noxea.— Alloys nin ^ncrallymom fii^ibla thtn Mil 
of ih" iticlnU of wbii'h tlipy at* compoM«1 ; for tiistJiiui-. un ii]ti>y of fyt 
p«ria of tiu and oiip of Wd funua tt 11)4'. Thft »lloy known •* Rem'* 
fuMihli! mftiil, Trbirh pnn>i«Iit r>f 4 part* of bixniulh, 1 pari vf leuil, tati I 
of [iu, iiiellx at ti4°. and an allny of 1 or 2 pnrta of cadDiium with 2 pnH 
of liu, 4 piirtii of Ifn^l, and 7 at ^ parts of biimuth, knovn *s IToaA 
/ionWff nirtal, m-\t* Vlwi-tMi ISO" and 71" C Fu(dbl« olloyaarcof <fvt*ml«l. 
UM in autdurinK niid in tnktnt; enntn. 

Mixtumt of tli^ fntiy ni^id>t Mi<>!t at lower temperstutBe than tho pan 

' KCida. A oitxture of tbc rhlaridr* of potA^iiim and of aodium foMsMI 

lower tcmprrntiim thnn «)tbi>r nf iM oitiKlitii^iil4 ; tlie eame is tbe cM 

I with » nilitiire of the onrbonAtcn of potn»> and $"dii. iwpocMlty wbn 

'Ihtiy are mixed in thn proportion of tlmir clieoiical equiralent*. 

An Applirnliiin of lliis property 'ut met with in Uiu caac of, 
which are much nmii in nielnlintBionl oprotiotn. They constet of Mlb 
■tnnres which, wlii>n adiiiKl tu ail ore, partly by their ebomiral Mlioa, 
help liie redoetioii ■■>{ lb" siibatiwci' to the tni-tnllic ntntn, aod, paillr h* 
pjeaeiilin^ n rtindily fnsibb' ni»dinra, promote the fonnation of a re^Ia 

390. ZiKtoBt lie>t.^Siiiei>, diiriiij; thir pnwuijre of a body front the aoUd 
I the liijuid atatn, the tempernlnre renininB romitAiiI iinttl the fuMnn il 
OOniplel/', whntovRr be the intensity of tin- source of h*M, it niHt It 
eoncludnl thai, in chunfrinif thrir cnnditinn. bodi™ nb«nrb a eooaiiklabb 
amount of beat, thi- only "■ff'wl of which i» t-t iDBinlalu thoni in tlte Iif aid 
alate. 'I'bin bi'nr^ which i» oot indientnl bv the thcrniomeler. iacalM 
htmt Seat, or latml halt by fu*%<m, an eiqireaslon wbieli, though not ia 


:i'--conlMicp inlli inodMii ichuu, u mnrenlent bam the Curt of iu 
-»i Tvi-nnniti'^n and enpUijaaenl. 

.']b> nf wlut it inr^nnt br UUnl hot may be ribtained from Ihu 

Li|t vipfriinmt. If H {WLind of watrr at W u iiiuvitd witli ■ 

if waierU lore^ die l«nipemtufi! of thn mixditv h id". Itui ifii 

' <r pouadad Mr at mm M mixed wllh r pound uf vnXfr at >W. tbo 

I npli#, «iid two povaib of wator at c«r> are obtained, ('onuiiiii-ntly, 

I mm cba*f^ nf a pound of io« to a pound of wat«r at tb« Miue tmn- 

ir» nqutrnt aa nach h«iil aa ftilt raiM a pouud of irutvr ihrnugh 

Thla qouitit* uf h»t tvpmctit' tbo latt-iit bi-nt of th^ fiinion i>r 

, or tlia Umnt l>f«I of wat«r. 

' liquid has its owu lataut boni, and in the cbaptcr on Calm* 
' w> aWtl idu>ir boir ibi* i* dniRrminrd. 

-A body ia aaid to diMolvr when it b«uoniM iiijuid in 
ot an affinitT botwivo it* moInruW ami tbow of a liquid. 
I afaUc, aufiar, and mtm miiXe dii«i>lve !□ WBl«r. 

■olstina. as well as diirinff fusion, a eortaiii quantity of heat 
brcoBW latent, and hwiLv It U iW lli« aoluljon of a ^ubitanc* 
' prodnm* a diwinutiuo of tompemtuiv. In cvrtuin canw, bow- 
, pwIi'mI of l)in t#nipi>ralur« be iuft ]»wi<ri>d, it aotiinlly risi-i, as wbun 
polaai b diaaolved iu wat<-r. This dcppiids iip-iu ibe fai-t that 
tiaaltWNMM and cnnltnry pbnnomrnn am pmdiK^cd. 'I'hi.- lint is 
fmmgn tfnia Out aolid I« Ib« liquid ci>iidiliuii, wbiirb alwayn lownn 
fctttpiiralurg. Tba leoand ti tbv cArmieal i-otiibiontion of the body 
. w-Jlh ibo HquJd, and which, as tii the ca>« of all rboiiiirnl c»n>' 
pftaliirca an incrcasp of tvmpvraturr. Cutismgui^utlv, n» tbc^ 
tl>F otbtrvf tliMe aiTMt* pr«driininatni>, or na tbcy are equal, tb« 
Btun- pilktrr riwa, or sinks, or reaiain* couslaul. 
■olKIIBeaitloa. — SaliJi/lFaluin or wmg^alMm )■ the paasafn- of a 
bnoi thp liquid to th« Solid Hnle. Thi* pheDomeoon is ri-i;iilnlrd 
^iLa Iwn r^illowiofr lawa; — 
'1. Kiriy ii0df, mJrr llif wnip piftturt, tolidj/lm at ajiird tcmiieraturr, 
■ioA ■< tJtt amar tu that offiuion. 

M. Frrmt Ihr niimnninniufTrf fii tlui md of thti golidtfication. thr trropiT/t- 
lar* nf a Uifmtl rrmmm* eonArnl. 

CBTtsin bodi«», mnni nppcially somn of the fuln. pivwut nil vxcivplion 
I* tb- Snt law, ia so far that bv rrpeat«d fiiition;! lh«r sutMn u> und»rf!0 
a ninlrwwlar rJiaiigv wfalrb aJtnni ihnir mutlinK point. 

Tb* MwnDd law ia a coIwelquv■lCl^ of tb' fact that the latent 1i>>at ah- 
«iint imiiv Ai'iuo b<>«Daii«a fn>p at the naonieiit of toHdificut^on. 

Haaj liquid*, «ich aa aUuho], eth«r, and bisulphide of carbon, do not 
•Adily (Taa at (lie lowi-it known lemperatuie. But M. 1)«ipr<-Li,bY ibo 
ttM {avJorrd by ■ Biizlun of hqnid protoxide of nitrogen, solid carhuDic 


cat BUT. 


ftcid, «nd Rthnr, Iim rrducnd alMihol to mch n coniut^qicci tfaat ii< 
iXHiUuutii^' it oixild N? inr»rt»d oritliout loaiiig tbe liquid. 

•JiKi. Ctr»tmm»»ti4>a.-~OraKTtA\y ■pcaldnfr, bodiw whkli jui 
froni tlx- liquid to ihn lolid ■tnt" HMiime ragiilM 8«a«MriiM.l 
auL'h as tli(> cubt^, |>riMiu', tlKimbobudroDA, hic. ; ihette ue cbII«1 
If thn cryitiUi ora formiKl fmtn « body in tiuioa, mrh m aiilphi 
bixuiiitli. (be rry«Ullitnti<iii in «ud to taliu place bv tli« dry miy. But Ij 
thv rryslaliiMtion t«kiM plaM fion the ^ow evnporation of n wihittaa 
A antt. it is Hud to Iw bf th* motU looy. Snnw, ino, and ttiaity win 
HPiit rxntii|]le« of trrTsUlli»atii.m. 

■204. m«iardaUeB of tn* point of ooUdlSeatlon. — Th^ 
point i>f put* wiiti>r can b" diiriiiiiBln-d by ».-i«ir«l de^rrv^o, if tbe 
ill! prpviinuly fnwcl froin air by Liiilinif and then krpt in n pctfncUj'' 
plso. Ill fad, it may bn cnnli'd lo - 16" C, and even bnlotr, 
frcejinir. Uut when it is uligblly nf^lntMl, the liquid »oon 
Tb« Aninller qiinntit]' of liquid Ui« lower the tnnip«ratiiTo to 
It can bo coolwl, aud tbe gnaltfr the mncbanical dUtiirbancei it eU| 
without fniMinR. Koumct baa obaervrd tho firoquMit o>x:arTQnc« of 
fonued of parli(-1i>* .it liquid matter aiiapended la an atmoaplien wbdH 
tnmpemluni in 10° or ■■vpu 10* bulow »ero. 

A vnry rnpid ngitntion nljio prnvnnta thn fonnntion of !<«. The lUM 
ill the caiv with hU uclions wliicb. hindirrinf; tli<> mulcfulca in tbar 
movnmenld, do not permit them fi niTRiifiR thnrnwlvra lu the cosKliliiMB 
neC(>»»iry for tiiv «oIid ^tale. M. UespreU was able to lower tbe tHD> 
ppmture of vnter contained in Unr- capillary tnbu to —30° witliout iMr 
aolidifyiog. Thie «iqN>rimi>nt nbown how it ia that plants b niony 
do not beconis froico, aa tbe s&p is coutalued in vvn line capUlMJ 
ve««el8. Finally M. Moutenn has fonnd that a powerful pwawiw Mt 
only mlnrds the fri^ezin); of watfr, but prevt^u1« its ctimplnta MUdiflo^ 
tion. Id this raae the pleasure opposes thu ti^dcncy of ib^ watot N 
exjinud on ErfeiSn^'. and tliiM Tirtiially liiw^r^ the point of anlidificatiM. 

If watfr contains 8nlt« or other fori^ipfn bodies ita freeitnif pofalt I 
lowprwi. Sea water freeiM al - 3'6° In — 8° C. ; lb* ice which fatmt !l 
qailit purf, and a sniumted solution reiiiains, In Finland adikiiti>|R' it 
l«k*n of thi» ptviperty to ronccnti'ale saa water for the purpoM of 
cxtrBcliug Hilt from it. If water cunlaiuM atoobo), preciaely uakiiOBt 
phenomimn om obi>erved : tbe ice formed U pure, and nil tbe klcobol b 
contuioed in thu residue. 

Dufour has obser^iil aome vl^^y purious dun's of lifitiida «M>l«d «irt tl 
cimlHcl with Mild bodins. His mode of eiperiim^ntiiig ww to pWf &• 
lirjnid in nnotlier of tbe Banie s])eciHc (gravity but of lowrr melting pctot 
and ill whirh it was insoluble. Spheres of watir. for itist&uoc, •uapawM 
in m mixtuie of cblorofurm and oil, usually M>Udili«d bctwMn -fmt 


r. whnBaomt-iBiallnrfrlolMitc* cooled down tn —18° or —90°. Cod< 
. wilii a fragnml of im imineiliMett fol up MmgeUliuD. Olobiild* of 
r (whicb ■oUdiSea nt Ilo''| Tcm«incil liquid at 40°; and globules of 
(nliilifrinft point 4^) at SO'. 
fhm a iiqaid aolidifioa after beiii); nxilpd Iwlow iti nnmift] frowxing 
, tha >olidtficMtion UIhu placn rrn- rapidly, and i* ncci>iii|iaui«d hy 
uFtii of heat, otlea sufiicivDt to raise iis teiiipvmtura ftoai 
I feint at wbicfa aolidilicatioii bvgina up tu it» ordinnry (rr^xing poiol. 
I fa well (MB in ihn Crm> of hypiuiilphiii! of *ndn. which lu'.'lbi in iu 
' of cntstaltiMitiva at Vi", and wlivu curvdillv cootixl will remaia 
1 at ili» onlinarr trmprnttiiN of th« aunoaphcie. If it thi>n b^ niad^ 
ifj bj agitaiicu or bv uddiog a SEiiall fragment of the sultd salt, tha 
r Hmpermttm ia diatinctlr fdt bj- Ihv hand. In thia ea» thii heat 
I kail bnynnn lat^^t in ifapprocnu of liqu(>lnclion agnin hi.icotiiM frM. 
I. Cttmac* M voiame «n aMMiOoatto* and UqtMiMtlott.— The 
i txpanuoc of bnttiva iretinntlly increases as thej apprnitch their 
pciinlM. and in in inmt M»eg followed bv a furlhi-r uxpaiuuciu at 
> ■WIMM at liqitcAtcttuD. M that tbo liquid i>c(.'up:o5 n KTeater roluio* 
I tli»Mlid(raau which it i* formed, rhnsphonis, f.>r in»t«nce, IDQieaflM 
1 3-4 par ccnL on Uqucfactlou : tbat in, 10l> vulumi-s of solid phoa- 
I at ♦I" (iJia auJliBir pmnt) bccamo ITO-4 at thn miao fmperature 
neltnl. i>ul]ibur cxpsoda about 6 per cent, ou liquefjiug, and 
■uarv add aboul 1 1 per cent. 

'•'' iIt« pnwnts a remarkable eioeption ; it expands on the mcoiimt ot 
nttid living, or CoBttarta on nieltin;;, br about 10 per cent. Unorolumaof 
ioi at O' givea fr808 of water at (f, or 1 Tnliime of water at 0° givM 
rin-,* irf ten at the tuae t«inp«miu«. lu coiiacHiui>iic« of ihia oxpamdoo, 
ha disla gn tbe *MrfM» of water. 

Tfca mrrvaiw of tulame in tli>! fonnnlioD of ice U nccumpauit^d by an 
npMHJTF force whicli •omctimiMi produtes powi^rful nii^chnnicnl ■'D<>cti>, 
id whii-h tbfl biinttiiig of water pipe* and the brpakiii^ of ju^i* ci>uU(iiiiug 
wato' Bn> fMniliar examplea. Tlie Bplittia;^ of vtourii, rooks, and tho 
*«*!liug np of idoIm gronnd during It<u>i, arv miurd hy the fact 1bs( 
«ai«r |>Mie4iM«M into (lie pociw and UiiTe bwoiuev fr<»i-ii. 

TbM expHBiivB force of ire waa iitrikitiglr nhown by name expnrimMita 
if Major WUKanw tat'anada. Having quite tilled a 13-tiu.'b ironbainb- 
tbali witli walBT, b* firmly eloard the touch-hole with ui inn fltifc 
vtigking 3 pnonda. and eipMed it to tbi* Mate to the frohL .Afu^riome 
tlmi> lb* iroa plug waa forced out with a loud expIosiuD, and thrnwu to a 
Anna of 4lfi font, and a rylindor of ieo S iochw long iasuc^l from the 
gpuD^. In another (a*e tlu- tlicll bunt before the plug wag driven mit. 
nd b tbi* CM!¥> a lUieot of In (ptvad nut all rounil thu criu'k. It is f.<»- 
iibU that araJer tli« great ptmuK w>nu» of tlie wnler »uU rctnaincd. 

S54 0« HKAT. [1 

tiquid up (o the lime aI vfhicii the mtUlutMi v!M ttvfxwan* ; tluil il( 
lMn«d ^ra tlie ili^U in a liquid tUlr, but nt a [riup<rraliiri> Mn*S 
Mint thi'ri'faTir innUvully brmui ti> sulidify «'b^ lh« pMntuiv n-u i 
unit llinti rnlsini'ii ihn •hdpi' of thn orifiire wbMico it iniicJ. 

Cul-iMii, blFULulb, Hiid tuitimonj «x]i«ni] on mlidifyinii lilcei 
Hiidrftnihiia V ihpiI for oaatiny : bul^•otd,!^ilTM. midcoppi-rojotRtt,! 
heuui^coitisof tlifsri iiiptnl" oaniiiil ti* fAit, l)ut iiiiutbe ctoinpn) nitbal 

Wti. rr«*BlBc OBlxtoraft. — 'thv absuqiliuu of li«st ID ■!)(> piUMfBl 
bodim fitiid the ■'>lid to tli« liquid Klate hu bei-a laeA ht pnidiK* aniH 
cold. Tlii> ii Plt'e-c'tts] bv uixinfr tu!,-pllivr badie* wliirh liavd i 
fiw «<ach oltier, And of wliich nni> nt Irjiat is «>1id, tuch m «kt«V I 
lutt, icv niid A suit, or ti[i Hi'id mid a salt. Ctimiiml alGnitv i 
tlip fiwioii, th"- jinrtitrii wliiidi nicltn mWtlie rert of tin* niiitureof ftl 
quantity of lH.■Ilsil]tt^ lit>at, wMcb ihti* bocomu Intitit. In muij i 
tniy rgnsidcmbln diniiniition of triiipvniluiv is pn)iiui»<l. 

Tlii< Ml»H'iii^ tnbl^ give* ili» nitini-i af the snbatnncei mixMl,! 
propiM'tianti, nud tiii- comsponding diiuiuulion* of i«rapotatu»». 

Pan* lUduetioii < 

SubnUoma. bj ntghl. IciujiaialDn.^ 

SulpbfttA of Bodium .... 81 j-iftstn il 

Hydrochloric acid .... 8J ' " " 

Pouudpd icp or snow .... 21 . ._ 

r. .. . I ■ - ■ +10"tO — H 

Siilphiite of sodium .... 31 j-io»to IC 

Dilnlfi Tiilrip ftPld 2l'"* ~ 

SulpliKlv of 8'jdiUIU .... Ot 

Nilratp of ninmoniiim ... fil . . . -f-lO'Ki -! 

Diliitt- nitric acid 4 ) 

I'hooplinin of godiiim . . . . 91 j.lrtOt < 

Diliil* nitric acid 4/ ' ' '^**^*^-- 

If till! Bukjlunccs InltPD bo themwlvrs timt prnvioiislj eot^ed 

Rtill mori> cnnsidiTnbln of tetiiperntun.- is occHMonod. 

Frepeiii^ riii»luri's are ftvqiiMilly used in chemistry, in phTsi<«, i 
(ttmintic ecoiiom)'. Thi> portable ice-iii«T(iiij(; inai-Liiipa which havn coo 
in nun diirinjr tlie Iiwt frw years, consist of n cvliiidrical mntallic rcH 
divided into four cj nice n trie com pnrtui cuts. In tlie ci-ntral one i* plan 
the water to he frozim ; in th" iit-xl there is tlio frecMUB miiliin^ whii 
iieiially coii»i"t" of "ulphate of sodium and hydrochloric iicid : tf poawb 
the t'ciriiH.T and (j of tin- Intti-r will ninlie 5 t« pouuda of iw in an hm 
Tlie tliinl roni part ([lent aha coutaini* water, and tbn <iul«id» onn contai 
BUinu badly couducliu); riulHrtanci>, aiich m cutt-oD, to pntvvtil lh« infloM 
of tb« cxl''Tiinl iPiitp^mliLn^. The t>i!9t eflvct i^ nbtnined irbea pnl 

•J rAraviLi. $35 

Hiwilritiw, ? <ir .1 prtiindit. t>( lh<' luinturv uv nam], and wWa th*y 

Faafolj nilxi-d. It i> alno adtviUKPOUi' to ute ili« miwliiiiM for 
of MomaiTR Ap(T«tMin«. 
rtpnriw. iiusintEiiEXT op thetb lESsioir. 
•T Vap«ara. — We liAve alivfldv swii (]3r.l that vaponn are tli« 
ana Ihiids iutu which rolaUlc (ufaotAiirc*, >ueh an rthcr, nlcohol. 
(T, Bnd oHTcurr, an- oliftn^ed by the aliMrplion of hvM. V'lt/itUf 
ih *re thmr whLrh thou pumnu thci property "f pruuing into tht\ 
iom ilAtP, imA^itd H^mdi, ibow wiiirh (in not form vnp.iiir» «I »iiy 
MiaUfw vithi'Ut undnyoiup clii^uiionl dvcuuiporatioii, hiicIi rh llie 
■ oDb, Tbon niv nuiw •oUds, aiich an ico, Munic, comphar. and in 
ml all odorifarniu loliij oiihtUnrMi, whk-li run directlr form lapoum 
. UiM bKvmiag liquid. 

' tnnifuircni lik« pweA, aud generally nilciurlMS : tbe«« an 
EfiFw o>li->iir>>d liqiiidii, ulikh aln f(irr colourvd Tajiour*- 
▼«»«rla«U«B. — 'rhi! panujir of a tii^uid into the paseoui atatt- 
by lh« fTPiw^al t^fin miporuufion ; ihe li-nii feojtoratian 
eUIy nfera t« the «low pr>durti<>n of vapour at the ffpc suriiHt- ol' a 
d, mmI hpSiag t'l iia rspiil prodii«iii}Q in tL(< iiimk •>( thn liquid itwlf. 
■li*ll pfMeolly KW (;{1 1 ) tlut at thi- oniiimrj alnKMphvric preasuiv, 
litMa, liko fiuion, tnkiu plarq al n dotlnitc 
Ktiir«- Thi« M sot tL« cajK with uMipuni- 
ciiitli \aknt pUc« evna wilb thr mnip liquid 
' liiflirmnt tiNnp«raiimi^ aJlhougli ihu fur- 
I of » rapaur ttm» to moae below a curtain 
Hwmity, for pxanplo, (rivM no vapour 
[— 10^, ttor lulpfaurii- »rid hrlow SC. 

Mttm» tmr** 9t vapotin. — Lllip puMt, 
lure a Mitain cta'tii? r>rcp, in rirtun of 
i)ir'T rxrrt {imHiiri!! na the MdM of tmmIs 
|bich lliejr are Duatained. 1'bo tennon of 
■t nay b) d«!iuoni4niti<d by tb« following 
IRnnit. A qoantity of ni^nitry if ploL-ud in 
•nt ^tmm tablr (%. 312), tbn abortiir l.t; of 
lb i» tiemtii a fitiir drop* of ether an* Iht-ii 
ti ima thn dotti l»g and the tubr immpnind .11' 

, witter huh at a Iom p«rat lire of about Vi". 
mnrary tlitoi ninkw dlowly iu lh» short 
rb, mkI the «paoi «( i> filled with n koji 
tb La* all tli« nppt^nuice of air, aiid w)i(I4f 
:Jr fofm (v><int«r)jahumw tbn prnaniir* of the 
tafiurTmrv (W.aDd tli«<aliiiMpb«Tic pivMurv 

gaa'ia tb> vapour of otbvr. If tlic ^t- 3IX. 



ox HKAT. 

water hn tooUd, or if tbr tuW b* nnoivd from lh« 1»tb, 
«rli>i:li litis tli« space ah dUappc^us, uul tbc drop of t4h«rli 
If, on tile coDtrarj-, tlto bnlh bit honied ttill ki^er, thn le 
ntmUTJ deocands bslov t, indii.'Sliu^ an incraa*ut tvciiioii. 

300. VorBittUMi »r mpeors In > TlMin«iB.~Io ihi* ptc' 
tbnMiI tile liquid ehAiiK^il \vt\ tlowU tutu tlic vnpuroiu cuod 
Mine u the case wlieu • liquid in fr(wlr«xpo«ed Inthe ftir. In 
the klmraphcm is iin obsIiu-lF ti> the vuikiriiuitioi). lo a vaeuum 
ntastuio-, Bud tlip funtintiou of ntpoiin it inatantannniu, m in ' 

following «ip«tiiaeBl. Fn«r 
tubes. Oiled witli inercurT, UN 
in the Mimn trmiKk (f'f- S13). 
Ibeiii, A. ivrves na t, l>«n>ni«I«t 
fow drnp* .if wntor, alriihi>l. nil 
are KWpecltveli' tRtrndiict^d ii 
tiibo, B, C.. D. ' WliMi Ihp liqali 
tli« Tscuiim a dt'prcAiion cf tbi 
IB at OSM produced. And 
|)t«Ma«n cnnnol hn prndui 
wri)flil of thv liquid, (cliicli 
finiti"ly mini! frBclinn of tlio 
the disjiliM-'ed uienrurif. il mitlt 
Oie fominliiin of Homo vri' 
eWtJc force La« deprea»«id tba 
cot limn. 


pn'nrion !■ not the Mme in all 

it in ifrvAter in thn can* of nlc 

of wnti-r. nnd (fiwitpr witti ell 

with ftlcnhol. Wn coiiM-ciuentl 

ihi! two ruUowiiLg laws for the b 

(if vfipiiiir«. J 

I. In a vinium all iiotatib j^ 

Fi«- -13. uirlimliaii-onilii rmivrrled into Mg 

It. At Ihe tame tempemlurf thi: vap<im-t of Aignrnt \i^n^ 

rmt tlattic foreM. 

For exnmple, at SfC. the t<>nidon of ether vaiKHir i* M tiawa 
that of ni^iieoud vnpour. 

901. Botaratvii *«ponr*. Mudmoni of t*nal«n.— Whi 
qiiautitv ,>f n vnliitile liquid, >-\k\\ us ellit-r. ip iiitn-liioed into a I* 
tiiW il in nt once rnmplpti-ly va|M>riM^, nml th« mereuriid iviluiii 
depro-'etl (.i ii» full eiU'iit, for if some more ether be introdi 
dnpirwinn incrcMMM. By conlinuiuglliendditionof ctliw, " " " 

ifot)i«T, itfiid 



rMnain* in th« Uquid «taln. Th«i» !:«, (hnrrroni, for > 
niptnture m limit U> ibe qnaDlUy of Ta|>oaii which cna bo 
M pirn (paca^ Tbia ■[•£« i* Mvnrdinplir Mid to Iw ntfurutrdL 
rbrn ib« raporiMOOD of tbo «ther cewrsi, tfai- <l«^TMai«a «r th« 
Mlwna ftopi. Acd Li-iroe tketv ia a limit to the Cl^t1siall of the 
iUmuI wkldi, »# vft »Uitll ptcaDiitly n^o (901), Tuiw with th» 
re, hat which for a piveD teiupi-mtuiv !■ indtpmilmt of Urn 

w tfatl, in a elceed apace, «itimi«d with raponr and conlMB- 
I M *icf*, ill* t«up«retiiic rcmatniDft' caoitant, there is a 
■«f UmMOH whiA lbs vafwiur cannot excHvd, ft baromeirir tiitx- 
ppin^io adi-epbalb (lit.M'M). Thi* 
Hi with Bipn-ury, and ihi^n wi murh 
|dad aa to be in ex«M afturlheT-yr- 
MBitm U (•taratod. Thn bright «( 
jial colanui Ia hvxI Dutvd bv tueaiu 
P imuJuatod Ml tbo tube ilwir. Now. 
be lube be dDp re wtd, which l^nds to 
Um TBpoor, or whether it be mued, 
|da M expand il, lh« bright of the 
colwnn ia coariant. The taunon of 
r reiaafaia cotuiant in iho two cnata, 
IBW—ion neilhTT invn-nimi niir di- 
L UuBce il ia condudtd that wbtin 
Itol VBjKHir it c-^iupreoaed, a portion 
tbe liquid atnle ; that when, on the 
d. tba pneMu* b diiiuaiah«d, a por- 
e «xn«« ot tiqnkl raporiiHM, and ibt> 
fM hj the vapottr U again •aluraled : 
Ik caaei ilie tennon and the denuty 
K«r KioatD ociiwtant 
— — ttiiMad vKpvnra. — Fmm 
^Mi Mid, Tapoura pretutit two rery 
(kIm, aeeonUng m thej ar« Mturatod 
[b tha fint CMC, where they are 
and in contact with lli« liquid, they 
fletaly friira gatea, tinoa for a giien 
tn they can naidwr ba eompnwHl 
tdcd: their vimttie force aud llx^ir 
tnam couatanl. 
lacoad caae.on iho rontmn'. whnrp thi'r nri- not naturated, they 

EmUe pi*». t'lir if tJn> pxperiniMiti id^;. 214) b« repeated 
qnantityofrtlwTbelny lntr«diiCBd, »o that the Tapouria tint 

Fin. 214. 

ox BEAT. 

MtiiMtfid, Uld if thf tahc hp ihnn *1i([bllT mind, tfan IrTt] at 
Gurv U *w-ii lu riw), wbicli aliow? tlml tht^ t^lvlic rt>n.'<! i>f lh# t^ 
dicniDitliPcL Similarly, by imniTiing tin- fuh-- *li!l rowp, ll 
lf»* iij*r«iirr aiiik*. Thi> THjuiir tvmBiMiut^ally bsliiivM jinl 
would dn, it* li-fiiion dtminiihci irlicn ihn voluino incrrud 
v«nt ; and ■• in both rnu-t th« volume i>f th'^ vapour i« invsn 
I p««uure, it U <y<llt'ludvd llmt ttoo-iatiiralfd rapourt ohry 
Mariottr'i law. 

Wh^n It nun-MluraWd Tapuur w hnattd, it* rolume hi 
that of ■ gad : mid ibu numbf r O0(Mtl)1, wliich i" th(> coelGi 
«xp«nri<ni or arr, may be uI[«q I 


II<*u(» w »v*> tliat the pbysiod 
of imMbirnii'd vopourn arc conpl 
thow nf iH>rniati<.-nt gaws aait tl 
malar for tht pompnwjibiUtT aad ffl 
of)n>'«'0'" andSftl) also apply toi 
vapours. But it mit»t nut be foi; 
(hum in alwnyii a limit of prwurW 
iiijT atwbirh iiniiamrAWd vapoan- 
ntate of Mituralion. auil (bat they 1 
nia\initim nf t<^nf<n and di-luity 
only be ncewled wlj>-u lli« IviiijiC 
while thi'y arc in ooiitnrt with th« 

aOA, TenalttD of aqaasaa TmpI 
••p«.^For the aaki' of m<faAanagl 
foTVtr of nq)i«oiu vapour bnlmr J 
l.ii(i»an used two baDiii«ter inbott 
tiiF'rciiry, and placnd in th« Muna 
Slul, The otrnigbt itibc, A, li 
banmiBter : tbr- olh<T, U. in lx?nt, i 
of the Torricellian vnruum can b«J 
In n freeriiifr mi\tiin> (SlHI). Wj 
water \i- ndiniiti'd into thti bent ta 
of the mortiiry HtultN Iwloir tlial 
A, to an extent whith varios wil 
perature of the fk««izing niittiit*. 

, . 4 f)0 inlUIl 
. . IlM 

. . 0-At 

. . 0S6 

^. 21A. 

At 0" the depression i* 

ThaM d^pTBMXons. 



miiAl hf dun to the tonnnB 


Be, *liow that et*D 8t Irtw t^inppratiirm there in 
! jitraoHpIieiT'. 

I iJk!' aboTci pxpHrinK'nt iho part It nnr) th« pnrl (' ore nol 
1 tu the freetLDg niixturr. wu siiull piv^cuTl^ si-c thnt wlii-n 
Oriill^ VMWvb atn at <lifli>rr<tiit (■■in|)>imlurT'ii. thn innsinn 
b 111* Mua« in bolli, nud iilwajs c-jm-^pouiLt tu tbe lowcai 

■raporates rrea below lero follow* from tli? fact, lliat w»t 

Id Um air dniinK fivst lint 
•mi tfaen irj, tliowing ilial 
iT water evaporate tnvn sftuc 
bWM convrrtmi inln itv. 
•■ Af u|ne«Ba ««p*Br 
« MaA OB* IitiBdr«il de- 
■<<■•'' iNrfAMf.— Lialtuu mva- 
rtie fcrtre oS ai|Ucoiu vnpour 
nd lOO', % iii«Mis of Ihe 
fwulvd in &x. '.US. Two 
M, A and B. UN Ullvd with 
uiT«irtc<l in an iron bath full 
tad ylacad oa a fiimoi^n. 
■onl^H ft naall quauiitv of 
tub«* UK luppnrlod in a 
wel full of natt-r, lb» Ivui- 
irlricli in indicBii^d by tin* 

Th^ b«lh bring ^;t^unlly 
Iter in the cyUmtt^r bvcoiuM 
M watHT wbsoh in in tho tubu 
KBi in pn>i>orti')ii a« t)io 
•tfomr incw—n*, lh« tncroun* C 
ibpcMNoiM of (be oivTcnrv 

to raffa deKTFc of ibn thcr- 

adieaW on thn »r*\^ 1'., nnil 
! ■ tabln of ifae vlu^c fcircmi 
ud IO(y ba*breiicon«trui:l«d. 
'f mtiAod. — lUlon'a method in wanlinf.- in prvcision, fi>r 
bs vtlinder hat not every whoru the ■nmn temperature, and 
■ exaL-t tnofwanm of tbnaqueoiuTapoijri? not indicnl<^d. 
Staiiia ia a modillcntion of thai ut J>iihun. The oyliudriuAl 
nd bj a ltug« cirliiulrical lino drum, MM (fin. 217), in thr 
ob aw two lobulam. Tb<i tubo* A utid It jinm tbrniigh 
i^afttl Mv Sited by uioulcbuuu culltLn. Tbo tiiht; I'uiittLining 
joneeled wilb a iiuk, a, by tncnoH of a coppm thtcc-way 

i~g. me, 

mt ffCAT. 

(uba, 0. Th^ ibird limb of llii* tube U tvttntettd «i' 
I), f nutninitif.' ]>uiiii» itupiT-;,'TUit>»l with airljiliutic acid, wliich U col 
with till' nir piinip. > 

Wlieu llii- lladk « raiil&lns »oxar VAVn, a mall portioa i* dilliO 
B bj goBll.v bmiiiiK the fi*>k. Exhautiinf ilu^n br mnuu of I 

pump, the wa(M dulil 
K (inuoiuly fmni tbe fa 

1, i- frxu lli(< larooMtric 
lownrHs ]), vrhidi ool 
the Tapoiir*. Aflw 
vapi>riM'd Mine quu 
wnli>r, and it i> Ihou^ 
till- nir in tltii tub« ii 
drawn, tba capQa] 
which «snn*rts B wl 
thritoWBr tub* i* 
Tht' iiibi* B bninelhM 
il i* cxprrimociinl wid 
Ilnltou'a method. 

Th(i drum MN brini 
will) wAt«r )« iptatij 
by a spirit lainpv vl 
trtpnnitcd friiini the till 
woinlf II MTvi'ii. By DM 
■tinrr K nil portii of th 
are ke))( at (he m&h< t< 
turn. InthrndcoTtlMi 
th« bright or th4> nuu 
Uie tuhM ran Iw read 
mmuiH ol'a ratbcUmeb 
the ditTt'rniif? inlliaM) 
ivduri^d to lera, tbe 
^'K -i'- (rf rapmr i« deduM 

moruii of thia apparaliiii. t)i>> nliulic form of vapour bt-lwcen < 
h^ heea ilHcrmiuL-d with accuracy, 

305. TanaloD of aqnaona vaponr ttb6V* one trandTed i 
Two in«tlii"U lijiii' li-tTi •'iiipli'ii'il riir.1'''"i'iiiiniiiE ilm nf i 
vapour nl teiiiperntiirca nhnrn 100", tin.- one by Diilong: aad A 
18.10, nmt Ihn oilier by Rngnanli. in ]tm. 

Fip, 'Ji>* rcpn^9i)Qts a Ti-rticBi m-clion of lh« appnrntiw iiied hp 
and Arn^n, It rmisisled of acnppnr boilnr, k, with vury Lhickm 
of about UO (Eulloiis capacity. Two (tun barrels, a, of which oalj 



nmos or vafooxs. 


Rwing, irrm fitnljT tixnl ia the liden of tiii! botlpr, anil 
I yrnier. Tba f^u bnmrl* w«tc HomiI below, uid cooUiiled 
vhicli wi^rr plictd lbormami!ten f, iii(Jicnliiig Uio t«ni- 
) wa(«c Buil of tlw Tkpour. Thn t«DHoD oi ihf vHpoiu WHS 
naan* of a tnmioinetvr willi cumpreeMid air. xi. [ircviaiuly 
l>aiid flti«^ iaiou iroDTCHwl, J, fillvd with nirrnirr. 
thp heigtit of Ihc mercury in th» Te«««l, il wm coDueetwt 
iw witli > gUM tub«, n, in wbicli ihe lev*d was ftlwny* tho 
bmth. A mppci toW, ^ oonnwMl tb« Mpp^r pan of iIip 

^^ FiK.2lfl. 

ITCrom] lube, c. UlU'd Ja ihv boiler. Tha rube i, ncid the 
h» Imtll i', trorc l>Ui.'d with watvr, which u-m k<-pl rnot by 
mit of cold wfiier flowinir from a marvii tuid circulntin); 

which WM ttiiontrn^ml ^Kim Ihe tube c. exnvistd a preo- 
■tcr of the lube (': this pmsiir« wiu tnuumiltcd to the 
tb9 mercnry in the hath d, anil th« mniviin' t<wf> !n the 
ly Qottn); on th« DUinomvt«>r the prvMurM co^Tt^«poudillg' to 

lli« ihMmitnctrr, Uuloog tnd Antgo wotc nbU to make a 
B>nit '>f tb» icoaloB up to '24 «tinn«phi<Tej>, and the uoiMOti 

60 aimivphnra wan dDtcniiini>d by (.-nlculatiou. 
■ ar TBponr below nott *'bw9 one hundred docreea. — 
1^91x1 n Di'Ttbwi by wliivb ib« tt-ii-inu ■'( i>i|intir luiLy bo 
aponuuiw either below or abovo 100". It depuuda ou the 



piineiple that when k liquid boiU, lh« t«nrioB of the vii|Knir tt 
tt)« prewiin) it •iipptirla {.lU). If, thnttiem, th« tnafttMtat 
comnpundiii^ prra»nn arc known, tin- qiiwitiixn U tolvnd, uiil the 
meivlj iHinMita in caiiaiti); water to boil iu ■ veatel lUikv • p^M 
and iu--a<'iiring tlm r-nrrraponding t^nipcnUurs. 

The sppitrntMs ci)UU«U uf a cDp)>«T wtott, C (6g. 2II>) 
»eaW, «nii almut two-thinis full of wntor. la the oirsr thi« 
ihoruiomi^IciB, Twu of wJiich juM tJip blo tlte wttt«T, aad tiro 

ftlnioel l-i the hottoui. Itv tiieaus of a tub«. AB, the nu<rtClacoiu>>'<t«l , 
with n gliL98 globe, M, of abnul ti gnllniw i;apiicit}r, aod full of aic Ttel 
tub«i AB pfuwei" through a uieUllit tyliiider, D, Ifaroiitifa which a mrrml 
iif told wivlot ii coii*tnntly Ho»-in(f froai tbo n-aorvoir. E. To An hiu'T 
part t\( the ^lube H. Iiil>.* with two brancheti i> allAchi'd, onn of wLirJ) if , 
cuiuii'fted nith n miuioiiiftur, O: tho othfer tube, lUl', which !■ of l*ad,j 
can b« Btiaciied vMivr lo an eshauBliiig; or a coiidiWiug air pump, fc.-'' ff- 
injj UB tile air in the globe it to be mrelieU or condenaed. The rv»'T> -ir. 
K, in nhirli i* the globe, cnntnins wslor of tti« tvmpN'Muf* of the mt- 
louudiu]; ail. 

tiWJKni w WAtottn. 

I of •quaou* vajiour bi'low 100° it f> be mcMurMl, 
H'oi tbs toadiiii pipe is eoDnn;l«l with Ibv plate of Ibn urpump, 
ft bong gMtdj liiMtftt, Uiv wat«T bvginii tu boil at a tvmprrniura 
Vf, in nOMqwocp of the diminlshi^il pn-«»iirr. Ami nu\i-v tbe 
feaadaatoA ia the tube AB, which ■■ oIwutii coul, thu pntuura 

tbdinlad bj^ tlw taaaatiurUz iloea nal incrciuo, and tht-nfan 
I oT Uut ntpo«r diuing ebuUiciou roniainfe «i}ual to ihH pre«ure 

(» air IB then ftllow«d to ootM ; thin nltrr* the pn>Miire, and Uie 

nb at a Miw Icinptimture : butli thi-w are rvnd olf, Btid ibo ox- 

I leptaMd a* nftno a* dctitwl up to 100°. 

lar to ■iiiMiin tlu- uwMdn above KHj", tbv lub« H' ia raunci-tvil 
r punifs bjr meaoa of which tha air iu tbn globn M, and 
I C, an expoasd f> mrcm^re piVMur««i, higbvr tliiui lh« 

an. Thii>«dml£ti0Diar«BRl«il4:(Ill, uidit id uuly ncriwarylo 

tk* *DflW*tkra in tbs haight of thn mertury in the two tubuA <iif 

lNiw>l4ir, O, and the conMpoudUig temprnturv, in anjcr to obtain 

loo fiir a givm ttnpcnitun:. 

Ibltm-int; lablM by M. Ii«gnaull ^te ihc> teaitiou of iU|Ucoui 

hnn - 10* M lOr. 

rftifutmrntapMirfrmH - lO" to 101° C 








17 801 































1 101-0 




787 83 




lo th« Mcond Mbla th» dunib«n wtm obtaiasd by dtnet oUcmiMB J 
up to'H iitiiuiap)i*t«a; tbo otb«raw«fo<al«il*ted bj tbe ^ ofBftmlkl 
of intvqKiUtion. 

Tmuiim m atmotftitrm/rvm 100> to 330'9*. 















i 3 

» 3 


















Thei^ laliln ^biiir Ihnt thn nlaotic fDrei' inftvAWM much niace 
than tbo triiiporaliin'. Thu law wliicli rrgnUlva thia incrMM i* Btlj 
■countEi'ly known. 

SO'. TeMal«« «f (b* Tspsarm at «lStoT*ni UqaUl*.— Rpgnmll h«1 
dHtvrniinml ih» HUstic fi>rct.> nl varioiu teiupvratiirn uf u cuttatii nuntxt | 
of Uquida wbidi an> giTen in tho fcJiQwing table: — 


TmwonB in 




Mercury . i 

Altohol . 







Etlior . . 










47: 1 









, of cnrb'-'ii 











80$. T«aUo» or the **9«n>« vr mx«a UqMM*.— R«guMlt'« aip«- 
rimonta on tht; ii'n>.i.>u uf ibf rapoui of niixod tiquida ftovt th«t (L) whfll 
two liijultU tsvrt iiu solvent Action on each other — iiich u water uiil 



htftmiamtOfmtat moAitatal^—tha tiin*Uin of Ui« rnpoiir whicfa 
B tkaniiaiHMl}r«^iial tolhasiunoftiiL- ti^naimuof tho ta-Diiciw- 
■iib at tfaa waw IMupcnttiie : (ii.) with ttatnr luid rt/irr, irhkh 
^tfinolveMteb ()tli»r, Ui« tcarion of tht^ mixtutw it miioh Imstlias 
^ <tf the tMudana uT tliv MpuHle liquid*, bang •eaimlv wjual to 
iiaMlMTkloM!; (iiL) wbon t«<i liqiiiiUdlMolniUi r11 ]iro|iorlion8, 
■mi buulplilde of CMbou, or«a>ler mid alcuho), the tMukin of Uw 
f tbo muted liquid ia inlennnliBte bntwoao Uie t«n»aD«af th« 

MX km ihoirn that the tensiou of iu|ucom vnpaui emitted from k 
hitiini, » compariMl vith timl nf purr wnfr, ia diminiahid br an 
fK^rtJutia] to the quantity of unliyilruiiB mill dmaulvcd, when 
pyitolH— without wnti<r or yield* I'tHoivsix'Eit cryntHbi ; nhrii thi* 
jll^iw wart, or bu a powerful attriu-tiuu for wiitvr. the ndui'liou 
■ ii proportiowd U> the qiuuititv of crTiiMJlin^i toll. 

Vig. ::zo. 

In nv« onniinBnUjktlDi vowmIb >t dUToreDl tam- 

Wh«*i t«o vr*wl« couluuiDf.' thv Rami- liciiiid, liiil at dif- 
:, mil Mniivcl«d Willi i^a>'U othvi; tlii.- t>lH»ti<r fotm ia 
MiimpoiMling to the mun of iha tvo tiriiipi.-riiiurfi>, im would 
hf RippMMl. llitui, if lh*m am two globes, tig. 2iO, our. A, 
qt vaUtc kept at teta bv tuvaim of luvilin^ ice, the utlier, Jl, Min- 
|nt«T al 100°, IIm t«n«ioD, a« lon|[ n* thu Kloboa nm not i:onn«clJtd, 
inllinwlvn in th« lint, uid 7tKl millimeter* iii lb« nucoiid. But 
n an nonupcted b}' ofH-iUBir tlii- •Iiipcuck. (', the vnpi^ur in t)i<! 
fan it* gtr»U:T tensioii, pAMM* inlo tbo othnr fMi^, and i* ihem 
11, to tti^t ti>« vapour in B can n«v«r rvtwli a higher temperature 

•tee cot HUT. [3M- 

(bnn that in th« ftiahn ,\. The lipoid limplj dldib Cram 8 lowtMt k \ 
witboutimv iacrviue ot t^iiaidii. 
Ftnm Ihi* cspTinii'nt tlic KcnRml |»ttidpli> maj tw dnluwd thai n^ { 

two rraet) eonlainiir_^ tJlf tnnie ligniil, bat lU diffrrmt irmprrabmt, art \ 
HKil't. Ikti trution ti idrn/Jail in hafh iv(m6, eitd it thr iMiMf at lAct i 
tfHaiilmff lo thf /"Nyr UmpivaSuTr, An ap^licHlinu of ihUprindplthW'l 
bm-n mitdr br Watt in ihr cnrtAvnMT of tli" >I>-iiiti cn;riiM'- 

310. MTrnpormtlm. <9«tii>»a wMeb Keeatarat* It* — rrmynirfii, I 
hM bi'Pii nln-ndy itiitriJ ( W^l. is the slo* pruifurtion of TapOUT M dwl 
»urt'fii:« of a liqiiicl. It ii in cnnxiqiipiice of this «T«pOMtiuii tbu 
clolhm dry vrlieii cxpiwed la iho air, and that nppn tcivbI* i lailaillJM I 
walor b«(^ome emptied. The rnpciut* wbicrh, -nang in the MiOOifhi^l 
t-nni)i-i)se, aod b^ciiming clouds fall an raii:. nre dii« ti> tba craponlkkl 
from ibn wais laki-*, rivi-ta. and tbv unil. 

Four OAiiae* Lnfiiii-nre ib>!i ra{ii(litT of Iho fvapontkm of aUiiiiidti 
thf tcnippniturc ; ii. thi? qunntity of the Niini: vnjvour in iha fvr 
in;; ntuius|)h(:>r» ; tii. llie Ktievnl of tliis itlBKis[ib*vii ; i*. tlto est«al i 
the Biirfnpe of tfrnpciriition. 

liK-reiuH' 'if fiiiiixTntimi occoleratea the evaporation hv iucrvMuig ' 
eliwtiv force of thv vapoim. 

Tn ordrr t<i tinileniiuid llM . 
flui-ncp of the wcoad catue, itiaUl 
brt obvrvnif that no «Ta|<onlida [ 
couM Uk9 place in * vpaco alm^fl 
Kniiirninl with vtpour of iht 
\\'\tM, and tbal it would rrach 
mniiinucn in air (^oaiplnt*lr ftwSj 
from this Tnpniir. It therpftm Mr] 
Inn-s ibflt iHTtwM'U thi«e two 
irenifa this rapidity of eva 
variM acrnniiiiir a« tb« 
nlDio^licrv ii alratdj more or If 
chaivwd with ihoMRiei vapour. 

Thp rflVct t>f tb« rrncwKl of tloal 
nimaaphora ia nmiiaily «Ep)alned;i 
for if die air or paii. irhi«b no 
thn Itqiiiii, in not rvnewed, lit 
Woiiiea tntur&ted, and 

Tli« i&Duence of fim | 
ia fclf'OvidcBt 

■'^11. %*«a of ebniUHon. — EhUlifion, or W/inj7.iath(r*pidpruilunia>j 
of elaatjc biiUilee of lapourin (he iiiam of n liijiiid itM'lC 

Kig, -ni. 

TEStunr or vapoou. 


\A, itiitBT for nxamplp, u hetXid U tlw lowur purl uf n 
i i>ili)il(!8 u» dii« to ihe iliseog«|rttn«Iit of &ir which hud 
prnuafly bvrn BUnrbnt Small bubklM of npour tbon bwfin to 
iW from ihe hMIMl parts of the Mm, but M th*y pwu tLroo^b tlio 
t^Jmt UIII4B, tfae Ijutipciniliim of whieb i* Uivrft, xhrj roniletue before 
Mchituc ibir Burfaoo. The fontiiUlaa tad siicu«iiht« condcnMtlou eS 
AwH fifwt bubbl«a oeouam lite Mifun^ noiicwi in liquids befura thoy 
l«fiB I" bitiL Ijwtl.F, Urftn bubbln ri*# kimI bunt on the aut(«otv *ii<l 
'ttit muUlutM ili« jibeDoniMion oTebuUUiau (tiir. 221). 

Tbn Um of ebollillan luTv bora dtttonuinnd oxpori mentally, and ar« 

L TV Ui Kp im lmv o^ (WUion, or f^ botHuff point, utcrauM inUt ^ 

i^ of rthrlc . 


Im . . - . 

Ill ... . 

«t water . . 

•rid . . . 

U. For a ifirm frwmrt rtnltitttm eommtna* at « ctHim lairftrraturr, 
Kbci mnr» m iiftr€mt iijHid*, but itMiA,/or tftal pramirn, u aluayt 
At MMv m Mr «raM ACfwdl 

m. It'kiarrrr be the Mnmly <f (*r touret efbtal, at —en lu oiuJK- 
ihi rio<iam«i»rf«, lit (uMptmturr of lAt li^d rtmamt Halimary. 

BtnUug poinU unAr ihr prf»*nr« TOO miUimfftrt. 

-Iff" Turpentiue ieO« 

+11 Ilotyrii: Mid 11)7 

87 Pho«pliorua 390 

48 Stiocifc Mulphuric acid . . . S25 

63 Uotcur; 330 

H Sulphur M7 

100 Cadmium 6U0 

117 Zinc 1040 

r >nt mnay mwe> wbkh indoeiir? ttio boJliug point of a liquid, 
%m1i m tb* mWtiuice* imdittA, tbo nutum of tb« ycxwI, and i)itf prw 
mn. W* tball illiMliW ibo «flucu of tbeae dilTKreut cuumm, more pw- 
liixUri; on wai^r. 

Kuff iu« pointed oni tbu in ■Dtlefpu* cbamical mmpouDda ilw tame 
tMmtit^ In rhvnucal oain{Ki(itien bequeutij involm thu wnic diil«ifiiic« 
rf b^SsfT poJDta ; and bo ban radcikvouiiid to tfaow tlini in a tmj ex- 
terna aMiM of ecMUpouiidi lh« ditTvn:-Dce of CU' i« attciiJeJ by a dif- 
kran i>r \V C. in ih.- boilbfr jmiul. 

XIS. la>B*ne« sf BtiltsUBo«* In tatntioB on tb« boiling point. — 

Tk abuliititm of a liquid i* tbo more ft'turlrJ, xhy j.Ti'Ul<.'r ll»? r^untiUtv 

•I tai HibataDCO H may contain in Mlution,i>ro\Klt'f! thnt tbt- lutintani'^ be 

.ii]r,ui, at all pvpQii.beleMrolatilc than th# liquid itwif. Water 

...... uub >i 100° wbcD pttra boil* at tli« folluwing tvuipeiMtUTM when 

i with <lifr«i«nt olta : 

OK StEAT. [3U- 

Wkter «ttirat(!il Tritb common mH . . boila M lOfP 
„ „ nitnto of potaMamn „ 110 

M „ rarburiAte of poUtMUm „ 1^% 

„ ,, dilarido <if ealduin ,, 170 

Acids in »nliil.iiin prwent analoftiiiis naiilw; but mhstUMv^ — :— ?- 
ntPchiuuMUy sinpi-nJed, nuch n* wifthv malttra, brnB, wooden ■ 
vlQ., do not »Kwt till) boiling pnint. 

Di»ulv«l air vxci'lii n wry nmrkpd InflupBce on tlie boIUn); point tf 
wntpr. n«!iic first ohmTTi-d ihnt ystttet fmid from nir lir ebuUiliiai 
nnd plHC'c'd iu n lla^k ivitli h lunji neck, coiiid ti' rnia-tl to Wi^ iril&oqt 
boiling. M. Dnonv found thnt wiilor deprived of air Bad KAled up it* 
Ions (il«»» tulje iii«j be l]pat''d at (ititi end as hifrh m 138" without l«iiliaft 
and is then vuddnnly uid vioU-nlly thrown to tkc utlior by abiinti of vipoi. 

Wbrn a liquid is »ii"pend«ii in anoilinr of th» soma oprcific giwttJr 
but bigbtT boilint: pmnl, it mny he misod far btjyood lt« boiling ptlst 
witboiit Uii^ forniRtlrm of ■ tracn of rmpniir. Dufnur bu raadn a aonbtf 
of vnlunbk- FX|H-riin(-utii uii tbia flubjtol : be u«ed in the mm oj mm 
a mixtuK of nil of clom und linsevd ul, and pluvd in it ftlobulstf 
Trat«r, and IIk'h imuliinlly bt«led tb« oil ; in Ibis iraj cbultilion IMI^ 
act in below 1 111" or ll'i", very commonly glubulea of lU utUinMMl 
diaiHxtitr rrnriieil n t<<iiippmtiin> nf 120° or 190°, whil« very mJH 
globulM tif I to :t III 11 time ten reni.*hed tbe lemiH^ntlurn ol I'IV.aUS* 
ptratUTc M whicli the tennon of vnpnur on a tree miifibra »8nS 

At theto hitfli teinpprBturiW the ponlnct of a aolid body, or tli« pvdaO*. 
tion of grw biiliblpi' in tbe li'iuid, occs>>icti«d a »udden vnporisalioB of lit 
ftlobule, nei^oinpHiiied by a lound like tbo biuing of a hot iron in ittUt. 

Sntuml^'d nqiif otiA imliitinna of aiilphittn of copper, cbloride of H^dinm, 
etc., rt^ijntticfd tiffiiid iit a teiu peril turt^ far beyond tbeir V'iling point, wlm 
iu>incr«>d in nie1lt<d ttoHric iirid. In liliR mnnnnr, jilobula* of i:bloroft(H 
(wliivb lioil!< Hi <ll°l su«]>t'tid>.'d in n aululion of cbIorid«i of Httc cauUb* 
hcatod to 97" or i'K' without boiling. 

It 18 n digpiilixl qiicstioi) n> (o vbat is th? t«m|ieTatiiT^ of tb^ Tt|oar 
from boiliu),' aiiluruled saline solutions. It lias Wen atKtnl by Itadbc^ 
to be tbat of piini nnter bailinijc iindr^r tbc ssiue prueuri! ; the inm4 rfM 
«X|ierin]eoU of Ma^iiuj Heeoi to abuw. bowever, tbat tbLa la not tba ca 
but tbnt tbu vapour of boiling snbitinna i? holler than tbu of fiare 
«a(«r; and llint the leiupemtMre rises ns the aoliitioua becMne nu 
cunccntraled. and iben-fure boil at higher tempenilurci^ Navattboteliy 
the vapour wns nln-ajs round somewbat cuoler ihiin the himi of At 
bmliDg KilutioD, and tbu difTvrcnce was grcaler at liigh than at lev 




SIX ZnSBane* af Ui* D«lnr« of Uto v*s»el oa Um b«IUnf 
tMM,— tiiji-LaHK obsnrriHl ttini wni.r in a ^\ti» roiwl requiwid * 
h^rr tnuprntute for ebuUiliiii tliiui in a WHtikl oiw. Taking thv t<>iu- 

I fwuKiv iif biiltng w»t4r in * coppr vwiid nl l<xy, ju b<iitiii)i: pxjnt 
li • t^m voMel wu found l« b« 101" ; ubl if ihe jihun vifue] hud 
bca prvvioactj e1««ii«d br nrnaiM of wilphuric mcid nnil of fntAat tho 
••■ytntun would iW to 1ilA°.ir ntm lo IO(r'l>«rciiv rbuUltion cum- 
■■nerd. \ pMcar of OKtal placed io Uie bottom of the Twnl ira* 
tirawii •ulBi'ieiii ui Imrw iIib taoipontutQ to UXf, luuj rI ilio Miue time 

III jH^Trnt tbp vii^lent uimuaiiHw wbkli uconipiui.v Uio nbuUiiinii of 
-' ' -r H->-l Ktluiioiw in glawruwU. M'hnlever b» lb« boiling point 
. " ii'-^. (lie (--iiijwrstara of it* vapour in iiciinlliUMloed by ttw NibitlancB 

AIL iMTMTriTT *t pr««aaf« on tba bolltaf point. — We me froni 
tiw tabln at baudDoa (^t) IhM at l(W, ihu tamiiumtuio U which 
vklar b«U* aad«r • prowiu* of 
7'10 BttDinwtan, aqiwoiu rapattr 
ha* • kNwIoa exantv r^ual ta 
lU* pM^nne. llii* princitile i< 
', wkI DMT L« thiin enun- 
^ AfwW ioi'b irhN, titt 

tit m p/i ar U . Cotupqumtljr 
■r tbe pmsMUI* incNMA* or dinii- ' 
ni4iM, tb* leMon of tbe Yapour, 
wmI lli«<i»fot)> tlw In-Ill p<ir«tun> 
for dbuUition, utut 
' or (Ifmiouh. 
Id soia to aluiir that tbe buil- 
ln|t {aiinl u lowvr undor dimi- 
mabMl pw MilTB. a tiiMl) diali 
eoaUiniftit watrvr at 30^ la Jilaccd 
iiwlii ikenM:wiT<»r'>f aBdirpuiu]), 
-wUcb ia tlMU cxbaiMtnl. Tbn 
Iqiafil aorm bf^rtna to bnil, tbs 
^■pDHT f-mnol Mag pwnprd Mt 
M mfidlj a* it ia genntMcd. 

A pandoiiL-a) but T«y aimplc t^poriaieiil alw w*ll illiutnto* ttin 
itfrnd-arm otthr boilin; poqnl oii tli(> prmurr. In a glnia flwik wnt«T 

II biBad far ttatui limv, an<) wlw^ all air tin* b<ien vxpnll^d by th« ateam 
thaflaili 1* dnand br a cork and ioivrted iw rLowii iu li|;. S'H. If the 

ia tbcn c™>l«l '>?' a MrFiin of I'old wnli>r ftoiii a 'pong;*, tli« 
hffin* to bctl tig*ta. Tlii* mtim from tliu coudeuwlion nt th<> 


r^. 333: 


ox BEAT. 

Nioam ftlMTe lli«< lurfitM of the mtett b; whi<;h • i>utial 

It U in r<-n*tq«Miea of thu dimmiiliim at pmunm- ibn lif 
bigh tnouQtsiiu at lower tetiipHratuiv«. Oe Moat Blwie, ( 
mt«T boil* lit M^ and nl Quito *t W. 

On till) morv npid er»|><)ratii>ii of water nndn fvobln 
1mm4 the iwo of the ail pump ia coucuntraliiitr tboM wilt 
tiUher c«imot bear a high dc^iw of hfiat, or which <ai 
c&Mply t>ra)>i>rBtiHl ui an exliaualad space. Mr. Hovi 
Bioit imiiortjuit and iiwful appliealion of thi> priiMi| 
tniuiufac.tiir« of au^t. Tbn trrrup, in hi« ntiethod, io mrbsai 
tjgbl vMsvl, whii^h in cxkaiulcd bjr a ateam engiiiL-. Tbe 
eoaaoquBiitlr giw* (iii al a tnwer temperature, which mmum 
frORi injury, '['hn Mma plau ii adnpli-d in evaponUi^ 
certain plnnta iiavd in praparing' moilicinai nxtrnetji. 

On till) DlhiT hand, cbullitian ia retnnJnl b;r iucrcating it 
under a preuute of two atninRphen<«, for Mamplo, wator 

3IK. rraBkllA*a *xr«rlaMnt.— Tbo inlltuiiMi nf pwwM 
llliou uiay fiirllior bi< ilhi^lrHtinl by int<aD4 of aa aX 
FnuikliD**. I'liu uppnnitu^ comiata of a bulb, a, ud 
joitiHd bv a tube of wuallui' diiDeiui'mii (fig. 338). Tb 

drawn oiii. and t 
lillnd with wai 
theu in ^-Tcat 
away by miHtiu 
lamp. \Vh<-u 
budl^d aiilKdoo 
expol all th«< al 
i ia amlcd. It 
a vamum in Um 
or raibcr th«T« 
aiitn due to ihe^ 
(U]uec>iu Yajwiir, which M oniindrv lempi'mturM i' very m 
acquMitlj-. if the bulb a he jilnci-ci in the linnd th« hnat ia i 
piodiico n t^'iisino which drircs th« wnt«r into the tube h, ■ 
brink ebuIliiii>D. 

St6. Maaaurement of b«lt;hta hy ttM kolUoc pal 
lb« oonnwlion lo'tw-^-m iho br-iling pf>irjt of wat'*r aiid the ^ 
hfli|tht« of niouutaius in«_v bt- mi-iuuri'ii bv the thennomi-lct 
by the haroniAttT. Suppoio, for mainple, il i« fmiiiii Ih»i <vai 
tbn ■iiiiiniit of a niountatu -at JK>'. und at iL) haie hi ~ ~ 
Itimporatiiroii the olaitic force or leniion of Uia vapour ix «<)i 

Tig. m. 




~ ^'k- lacwuK (HI Um liquid, tbn i», to lh« preuare oT tba WMUBplietA 

•r.i [lUws rMpectir«lf. Nov the t«iiin««u nf •qii^mg tapour for 

imilwratUK* hftv« b*«ii dcloraiinwl, uid B00onlui).'lv tbu temionii 

laiiiag b> Ibe ftbore [(^inporslufn tav Katiiclil in ihc mUm- 

I -:tih>'n niirtiH>iil the ntnuMphrrit; prMourm k the two placea: in 

■ ' 7^1% tkejr fpre the LiiPiiui^trlc liejglitJS BUtl &uin thno tlir 

'i[ tliA nuiuntaia ia»y bo caleulktcd bj' Ihs mi'lbod nlrMtdv 

(ll)0). All MWi-ot of flbout 1080 feet products a dimuiutiuu i^f 

ID tb« boUiti^ point, 

bvAntinenla M««d for thi* purpoin sm ttll«d Ikmua-hnntm^tm, 

Ifftfmita^ nnd vrcni first nppliMj bv WuUaatoii- Tbvy cuniUt 

Ijr of s ainall niRUdlic Tr<wl for binliog irRti^r, bltoil with 

d^ota UvenDonMei*, wbicb tir« only p»dual«d ftom 60° to 

that, each dt^pM oetufy-ing « cfauddcmUc «[Mee ooi Iho •oal*, 

■mI «iv«ii the loot))* of a d(>;nv« nwi^ be Mtiniau>d, and Uiiu U 

ta dotcrmuie tbo beight of a pUco by uiMua of tbo bojliae 

to wttUn abuut 10 tent. 

', yarwM^a of VKpotir In ft clased tolM. — Wc bavi- liiihcrtu 

rapuun um b>iin^ prulucnd in ui ioiUltiiili) himc. or wbrrv 

orwld ospand fnwiy. Biid it ia eailj iiuiJiir tliia <^inidiliuu tliiit 

can talis piUcn. In ■ cIiuliI vnwl the vnpouni prculuc'l 

Ml Umw, tlwir tMuion tlinr di^n-ily iricraaM «iiL iL~ - 

:t«, but tli« rapid duoagagnmont of vapour which miullliitin 

is ImpoMiblo. Ucaoa while tbo tvnijifi'aiiiri; of a liiuid 

opan «c«ol can never exce«d (bat of ebullition, iu a cloaed Touoi 

ba mudi btgflur. Tha liquid ftaio biw, ocvtirihalM^ a limit ; for, 

tu expwimmta ly Capiiairl-Latour, if eitbtir wntur. ulcohoi, 

be placed in 'tron^ ^lu* lube*, wliic^h nre barmcticAll;' ncaled 

thm air ba« betm cjtpelleit by boiling, wh^a tliw« tahvt nre 

td a aufiicieDt degree oT heat, a raomeot )■ mchni aI nhicb 

' Bqnid laihlnilj diMpptara, tnd ia cO[iv«rt«d into vepuur Ht -'00', 

fjitg > apaca kaa tiiao double ita volume in the liquid utatc, and 

'Aai tbn temiioo waa ibno 34 atoioipbOTva. 

t' <.b>4 wbicfa kiilf tiUi a tabe i» oonverlod into rapour at SOT'C 
< im mbo about half liU«d wilh waUT, in which aolUH cait>onet« of 
.^bvndtMulved.todiniiuiiibtliv action of the wali-tin the|flaM,ba 
UiaeMBplrtely nporiwd nt almut tbelitinpiTaliircDf mnlttt^iinC. 
mun ehtoiidit of Mbyle wm bi^alril iu a wry thicli »ea]»d tiilw. the 
lypar mutux e>awd to bo <ii>liiirt at I'O", and wm itpUcnl by hq 
SMofrnnl nnbulou* >on«. A* tbotvuip«niIiir« row thlx raw hu-r-'H-i'd in 
mdib la bi)lh dirncdana, bevoDitng al th« Mnu- time more InuLBpuivnl i 
■ftct a t(tim the liquid waa coinpb>1--ly i np^riM'il, anil tlic tubo li<->'nine 
lUMfiniH and aeeuinftly einply. On cooling, tho pboiiumena wuio - 





ox KIAT. 

reprr>d<iiyvl in tlie cippnail«i niiii<>T. KniJIar uppeiiniiKM w«t^ 
hPKlii]K<-)li'rr in a wnlfl lube al tlKT*. 

AimItpwh hiw otwrnet] th»t wlii<ii tiinid citr1)onii' acid whI 
31^ C. l)i<? I■lI^^a('l^ of dt'inan-Hlion IwIwm^u tlit> 1>quKl anil tWgiMli 
fainlrr, Iiul iu curvatiitp, nnd grntluiiUy duap{Hi*ind. TIm>({wm>wi 
oci'ii|>ieil by ft hoinogwiiHiiio Hiiiii, whicb.wliMilhepraMiiM waasd 
diuiitiiiibi'il, or ihe tMiipuraluru nURlilly lawerrd, (^xhibilnl a fi 
appvArftiirn <if ninring or flirJienn^ •lrii« t.bri>uglx>iit lu wholil 
Abuvtf ■fif' uii ufiparvnt Uqiidaelioii or carbuuic anliydridc, or wfl 
into two diatiiielfonnii of matbir. could tHBoRivtKd,eT«D wb«ii tfc«pi 
uf 400 Atmoephnea waa appli^. It would thiu aMOt tliM then 
ha «very liquid a triiipuraluiw nt whicli no luuoiuit of pmuun ■ b 
nf retninin^ it in thi* liquid foim. It in nnl aurpri«in^, tlianlbn 
tiK-rp {inwiuru, huwi-irr iiiteiiae, should fail to liquefy nianyof tlie 
nbirh tisiinllr ux'M aa plica. 

■11i4. Vkpla*B dlc«at«r. — Pnpiii, a Fn*iicb pliVMi^i&n, appMin W 
b™n tlip tint lu iitinly tbe plVcctn of (bu prodtictinn i>f vapour ia 
ve«a»la. The appikn4tii« whirh bcinni bis nani«i cousials uf a qrlia 
iron vciacl (6g.22i) proviilrd with a cnvi-r, which t« fitvlj h 
dnwn by tli« wmw H. In cird^r to dtwe tli* vommI hermH^atUyi 

Ivmi i* pUrcd betweafl A» ii 
the cnver nnit th« TetatL i 
tmreraca tho cj-l)iid«r, 8, all 
tiibiiluiv. ». ili« wiv«T in fHt 
by u imnll oriHtNt in wbicb U 
A rod, n. Tbis rod preaaea I 
a IvVL'f, A, tnoveiibla al * 
the pn^mnrn may be RguU 
nipfUH uf a wcijflit inoraaUal 
Invi>r. Tbr Icvnr ia ao wa 
tbal wb>'n the (•■a>ii>n in t' 
ti^rior i>t i^qual to (I ntiQ<Mph«i 
example, the valve riaea ai 
THpour PBCHpen. The deatnia 
the nppatntun is tlitm avucdc 
the imrabfljii^iii bu bvnnn n 
the nnnic i>f w/Vfy iWnr. T 
^■titt^r ii aWvA about twiti< 
with watnr, and is h<>ated on 
liat'e. The wHlcr may tb 
nlMMl to a ic'iiipi'inluro far 
npniir inciviised to sevi-rel aluiuspher 

— -3I»] LATtST HEAT Of VArO[t|t. 27$ 

Wn bare Mfa that waXer boiU at nucli Ii>wer temp^rntuns od higb 

Vb.Lir.iaink (HUt; th* tempMWtun of w«i«r boiling tii oppn T'-unU in 

lucalitiea U nui niflleitnt lo aoAcn Animal librn c^ompUuly aod 

th* DVtrinnt, and bnnc* Pafiio'e itigMWr ia uml tn tbc nr«>> 


'• iifttttr u tun) in extncdnt; ^1tttin». Wb«n boaea am 
in llil* appaMtus t}»j are tofuued m thftt the geUUiM wfaidi 
■7 cootwrn i> diBKiWwL 

mo, Xamm ba*t of ««p«tw. — A» tli«i tmipemluiw nf a liquid 
danaiii* c<in*i«at duHitji ebullilifm whaterpT be the Koumt «f haat (311), 
% 6>IUnra that a eaiMid«a«b1a quantit}^ cf boat bncoiiiM atMorhed in 
%b<ttIitloa. Uio <talj «S«ct of whick ia lo tnncfonn the budj from thti 
ft^iil to the pwcous cDoditiim. And cotiTcnclj when a Mturat«d 
^"- <!r pMMiM into tiM MaW or liquid, it give* out an aiuount of heat. 

•A pJieaaniPiia wen flrrt obaerr«d by liltck, and bn dmrribed 
__ tnem by Mjiav t^al during Taporinntinn r quanlily of wtmlblH heat 
^■anne laical, and that tint \»Mat bvu sgTiiii bi-oiuiie free during rondna* 
Tba qosntttj of beat which a liquid mud abiinrb in ptuwia^ 
tlH UfttU to th« gaMcnw kUU, and wliich it givii* out in piuwin^ 
til* Maifl of Tapoar to that of liijuid, u apalceo of a* tho lotmt k^al 
^ fafaraHam. 

Tho analoBT ^ '''**^ pIwWMKDft lo thoM of funion sit) bu at aatn 
Man; tba Bondna of detonntmog them will be doiu^ibnd Jn tho chapter on 
^Vtonimelrr; bat lh« following TMult* which have been obtained for tbu 
llli II T baaU of MTapocatioo of a few UquiiU mar be hom girto : — 

Vatrt . &% Bioulphide of carbon . . . . H7 

jJUouhril 30ft Turpentins ?4 

Iktw^ae acid . lOS Bnimine «( 

B)Mr 90 Iodine 34 

Tha BMnili; of tlww DDisbar* \«, in ihe rv» of water, for inatauor. 

Ikal it mtni'M ■<■ mtKh Iwat to convert a pound of wntor frnni thn utaW 

fiqwd at the 1>04ling point t^ that of Tapiur at the aaa)i<i I<<ni|>erHture', 

raimi a putuid of wairr ihrou^h &I0 dejjmeii or filO poundji of 

onodagtaa; or that the cnnviTnion of ont poiind iif vapour 

■t 78* into liqvid aloobol of tbo nune tuuponture would lipat 

SDH pnuul* of wat«r through ««k doKTon. 

Wall, who DMde aoue im'nligalioaa on th<i tubjecl, found that 'A# 
■Ab^ )|waa"i'Qi ^ Antf nwnMry to rowr a gitt* nxii/M of watrr from zrr'i 
taamjf hw^arnfiirr, mtJ lim lo najiorotr- it tntirrlt/, ■■ a fmtfiiuf 'pumlAy. 
Bia axfu^nMita ibowMl that tbia quantity ia (MO. llonm the lim-i>r tho 
tMBMntm. the grmter the latent hrat, and, nn thi olhnr liaiiil, ihn 
tjglM Ifca tempamlure llie I«a« the l&lvul huai. The liifeut livnt of ibo 




Tipoiu' of mler ovaportted nt 100'' wnuld bd S40, while ktSQ^il 
l» WO. At liifrher toiup^nitur^ the laUnt beM al BqBMU 
I wonld ga on diminUbinif. Wnli-r oritporntnl imdRr a prsua 
naaphorm at a tvmpentim of 300°, would luivi' ■ klMiI kot 
'^aod iril Criiilil br rTR)Kinitrd Bt (UO^ it would have tlO lUcQt hcMit 
Hxpt^TimvuIn hr Southern and Ctvi^hlou in 1803 led in ft 
coneliukm : iinmoljr, that lir latarlhtai <^ 4t>^>0Ttdiem h« nMrfxt 
/or all Umpmilit/vt, and Ikat Ikt tolat quamtUf <^ lual tMVMMry (• "^"^ 
tealtr, it the MnM&Jr Am( pliu thit eombmt, wLicb tbi^r found b 
namben to b* fi4Q i r»nuyiuratlv, to «ra;pi>nit« vatnr at Vff, 
Uuvmal unita (^Vi) irouM b« n««dwl, while il wvuld requite VXi^ 
= 740 tbnnnal uniia to vrapanitc it at 300°, 

llegiuulc, who Hiftiuiued tliia quMtion witli great ouy, »m 
FMiilta which difTorwl from both theie lnw& He found that th* 
fiMobVy if Ami luiMMajy for Ihr tvoportaioit of imltr ■mmovj nU 
Umprmturt, and U not conittant, aa Watt bad auppoaed. It U 
Milled hv thv fomiiilA 

Q=<KWJ + 030«T 
In which Q if the total quniititv uf heat, and T the tempMalun 
valor diirintc L-vnjiomlioii. while thn nombnn nra oonataol q 
The total (|tinnliiy of Ijeat tii^c^MKrv to evaporate water at lOCTil 
f aWWi -f (0305 X 100) = USr, at 130° it ia M3, at IW it b l»l, ail 
180° il is m\- 

320. 0*M 4s« t* eTBporatioD. MerciUT firosea, — Whale' 
the ttuiiponitiicv nt nhich it Tnpr>iir ia proiliiced, no alieorptiilB nf 
alwBVi tuhr-i plai'e. If. tbervfure. h liquid eraporatM, aind dot* 
loCMVR froni without n qunntit^r of hrat pqiinl to that which i« cipdilrf 

ill pruilucinif ihu vapour, iis tetu|«nUn 
■inlra, and tli« cdoUhk i* giMitef in pop*- 
lion H» the ovftpomtioii i* inof« rapid. 

(.pslin siiccomled ill frw;;unj w»t«f ly 
means of mpid evaporation. Und<r " 
m-civcr uf the air punip la plKwd a fewll 
ronfnining' airontc (ulphuricnrid, and alM*l 
it nthiu metallic capmi]eCflf.:22'>j<yiBUi»> 
mil H loiinll quantity of wntnr. B; <0(- 
liiiii-Hiiip :h^ receiver the water beglH b( 

^ M biiil (M14), Mid idnc* the rnpouri are •!»- 

K!!^^^^?^S^ ii(irWd bv tlie gulphiiric ectd ae bK 

^ itinj- nrr> fomipci, n rnpid i>rn]Hwiaat)aa 

'''P-'" prodiiced,*iiiehqiiiciiIyeflrecl»theft«winf 

of thp watnr. 

Thte eipdrim-'nt ia best perfocuieJ Ijy Uf>iDg, inatead of the tlin 



TOMd, ■ w«h!bi{U», cMtod irith laniplilack ud reMiOi; cn^ 

The adraniag* of iki« u iwo(.M -. fimtiv, the UnipbUck 

' U ocndiMtar. aad aeooiKllj, it ia not maUtrniml by the liquid, 

in (1m Com of b griobuhg uot iu oouUiCt with Um 

Sbwcontttuclad ta» apfwratu* which i* W^il upon L^rIIp's «2- 

bj* wbid) coondurabtH quantitiva uf wntrr mny bt^ froum 

I than lin»> It cmuutx of a horimntnl bnuu crljiidw, nboui 

laebn in liMi^th uid lour Lii diftuivler, litie-1 ou the budde *ilb an 

F utiMMiy and Inod, m m to rsist the actinn of strnnjc mlphurit! 

iwhtch it i» Hbouc bnlf flllp^l. tti ihv top or tlii^ cvlind^T, awl 

, i> 6tt«I a Imn lube, licnl Iwici: at riKbt anitloii, and cun> 

a Mirh » nuumrr thai a fliiiik nontaining wat^ir mil b«i rafitir 

air-ti){liL At the otbvr md of the ptIuuIit. alwi at ilie top, 

tBKinHwfaat wido uptiftbt tubp ft. Thiaiaeonm^lnd with a Mmple 

, apcaallr dnriatd for IIm> parpote, and Uiera Is an amin^uiHDt 

■nolifiD which wofka the pump wofk* olui a itinvr. which 

. in cuniiniwl a(riution- A frp«h xurfitcyi in thiw continually 

r MpiMiiu vapodT ; and as th«' apacu lo be u.\1inubIi.h1 Id suihII, 

^Tvrj'elEcctiTc, Knti iktteT ita workiiii; minni<>nc<*a ibn wntor 

i tbra ttiMtM. Tlivt* app&rndi* hav« b«uii inlraducird for 

and whtrm tbi'ti: i* n conliiiual dc^ninnd nnd uxt fur 

ijc acid, lltera Mema do naion whjr thie thould ni>t bi! ikii 

I vmin of making in. 

Of liquids mom voUlile than wai«r, more parliiriikrly tiiguiit 

I add, which boiU at — lO", a de|^rr<? of cold U olitainod luDi- 

' UrteiiM! iit fn9M mercury. Thn experiment may V mad* by 

: thn bulb of a tbi-nnonii-rvr nith cottcu wool, and after having 

. It with liquid *ulphuroui nrid, placiagt it nnd*r tfa* ncciver of 

ponrp. Wbra a vacuuiu ia produced the mertury ia quickly 

r, by dftiwting a j»t of liquid carbonic acid on lh« bulb of aii 
hnl tbcTiBnaieter. obtained a cold of -lOO' without frci^uoi; tho 
huL W.- h«i«i alri«iiy »»»o, hnwp»M(i!n'JJ, ilial. with a iiiiMure <>f 
t tvbnaic arid. Liquid proioxido of nitroficni. and ether, H. l>i.-spr«t« 
isad a attlBci«ni drim'o of cold to reduce alcohol lo Ibe TJwon* atatc. 

of the evapuration of biiulphtdc' of cutbuD thu formation of 
bv IUiiatr>tiMl without the aid of an iiir piimji. A liT.lIo n-ninr in 
a aaull jii^CM of wood, and n ckpaule of ihiu c<i])[>t<r fuil, cou- 
hMdpludo of carboo, b ptaciHl on tlitt water. The waporntion of 
y ftCMlvralnd by nimns of a pnir iif Vllowi, nnd nfttrr a 
iha wat«c tnotm round ilie oapaule, au thai the Inticr ail- 
Qu wood. 

276 ON HEAT. [310*-' 

The L-old produced br evt^wnUioa u oicd in tuA cItnutM to oxi *iMj 
li? mriinii of ai'/oriaat. TheM are porniu euthen VMn^k, Uiraogh 
HAliT pecvilntea. su thai un tbo uutniile ihuro U n ctintitiiwl enponlMi 
which ii ii««)lcnil'id whnn lh« vcweU arc placod in n curmit of ur. Fw. 
thi* HkiiiK tVAAUi viae It (.iiulod by rmppioj^ the botllai in wet dulb 
pliuriiift them in ■ draught. 

In ilHniwti'a niRthod of oMtkiiif io» ftrtilicially, a stMin Mgim i« 
Ui work an air {luiiip, which pnvluoNi a npid cvnpunltOB of « 
in which ii iniiiinnk>>l tho TiutM'l onnlaining the watur to \tf bxanti. Xit 
appaniliiB is bo t'uuMTU(;t«d tiial tite vapaiuHd ethor am be ooailtnanl 
uand ajfain. 

Tbe exiling efTccl pniducod \>y a wind ur draught doM not DKMau)^| 
Bri«n fhim tbr wind Ix^inf; cooler, for it tnay, as thown by ihn 
uii-ler, V lU'lnally warinnrj hut nrina* frutii tlio rapid evaporalioo It 
from the luriWe of tho skiu. Wo hmis the fcolinft of oppmrnan, «wo 
•t modi>r«t'' t(imp9ratii««, whim we ant in an aunoqibetc Mturaud b] 
uioiglun in whidi iiu i^vaporalirjii tak^ plAW. 

:i:!Oa. Curi'a apparaioa for ftesalas water. — V>> faaTia ilmdt 
H^en thai whnn any lii^iii<i In cnnv>>rU>d into vapour it afaaorbii a cuuiiltf- 
ablu qunutily of Bciiiiblc bral ^ this fumialim a source of cold which iitb 
mnrv abundant thu mar« volatile tha liquid nnd tli* gt«&ter iu VaUtt 

'I'hiH propi^rly of liquids hiu bet^n ittiliml bv if. Curri, in Itmaat 
wal>>r hy lhi> diolillntinn of ammonia. The 8]i|>aMtii<icuiuiaUor»<7li>- 
drical boilnr C ( ligv. TUf, 227) and of a uliKhtly cnnical ntmiH A, wUeh 
in tlw /lYfier. I'hesc two vcmkIs are cnnnwlnd by a tube m. and ■ laac* 
n bitids tliL'iu Snuly. They are m»de of atrunfr gnlvntii«od plata, and can 
r«ili"t a pleasure »f uvnn aTmnophfinu. 

The boiler C. which liuldn about two )^lonii, is three parti filial *ill> 
Atri)ng solution nf nninionin. In n tiibuhire tn lh« upper pan of the 
boiler Houi-< oil is pla<?t<d. nud in Ihiit a th(^r1Uotn(^tl^T ' indiraling toui- 
jmmturss from 100" to UA)". Tiip fnicier A ennnirta of two canOMltne 
L'uvi.'lop««, in iiuch a niaiin<>r that ic« ct^ntre being boUow, a Meb) 
vniuel O. fuulaiuiu(f ibe wsIl-i to be froMO, ran b4 pWi>d in iM" 
Hpace. HnncR inly llie annular i-paci> b«lw><ea lliv ridtM of tbe frceier It 
in Domiuuuii'nlioii with tlll^ boiler by means of the tube m. In llw 
upper part of thci free;;er there in a aniall tnbulurn, whjcb can be ckwd 
fay a nielal atuppi-r, and by which the Kolution of auinionia U intiodaeal. 

The fononttoQ of ico comprehends two dintinct operatioui. ti tb« 
Tint, th<> l»iil<'r IB placed in a fiLmiu.'t> F, aiid ihu freecer in a balk el 
cold water ol' about 12°. The boiler U'iug heated io 180° iIm Ml- 
moniacal gne dissolved in the wslcr of the boiler ia diaengBgvd, and, 
in virtue of its own preasurv, ia liqueliml iu the froCHrr, along «ilb 

-SIOi} CAMtt'n AFriRATCs ros rsEEZtita wateb. S77 

Anal a laiUi of lu vM^hl of wMer. This dtnliltntion of C lowaida 
|k.laMit klmut >D liour wid a ijuartcr, and wb^ri it is fioMbed ibu 
■mmI opnukia commracM ; Uit» ooiuwu iu [iWiui^ tbc boiler in tJi« 
Wd-vatM IbUb (lifC. ^7), nod llie freeser outnldo, rnro being taki'ii 14> 
iRMund it with Jtrj dr; flannnl. Tb* TCMel G, Hboiit l\in» (fintrtrn 
U of wlrr. U l>lac«l in lh« bveter- Aa tbe boUiT cuoLi, thu nmnioiiia. 
1(1 ^a villi wbicii it i* fiDod i* ngiiin diuiilTnd ; tbo pi^uuurc ihiiMbein^ 
lUmlied tbe uBouinia whtcb biMb«>^n ti<)ii«lit?d iii it i* coUTPitfd iato 
ptgMnnnn Grid, umI now dinlili fram A tovratdi ('., to nniiiiMitve in tfan 
HUvwluck hM mnaliMd in tbe boU«r. During tliia di«tUUliun tbu 
t^andia which i> raRded nbtosb* a pnut quantity of beat, whirb in 
nUnwB from tbfl v«««»lGaDd the vrau^r it conlainn, Ilinoi' it i« 
IMI tkit •raler frwMd. In order la liave bi;ti«r contact betwi>vu the 

Fig. W6. 

Fig. aar. 

W§*i llw v«M#l n and ihf tnnatt. nlmbol is pouted belwoen thnni. 
Pklnut ui huur «nii n qnRTt4tr n p<^rfcctl,v rnnipact cflindricoi block of 
N can ba ttkm from the tmwl O. 

ThU app^nttia i^Tfts atKHit (our pounds nf ic« in an hour, at a ]iri>->> ft 
b«I ■ farthinit a ptiund ■■ iar^ <fMitinuou«l}' working apparalUH bavi-, 
nwrw, biHdi cMfMtru«lod, vlticb produce U luuob as WO |><>und> of 
la in «D bi>ur. 

OS- Kt\T. 


LiarBFACTiO)' OF TAronu un> OASBt. 

3^1. LIqaanielloa of v*p««r*>— Till* ^'^ur^ur/iiM or tuuAimalmt 
VBiKiim is tlivir piuunuw ^r^ni iIir iu.-[if(irtii tu thu licjuid dlfltc Co 
mti<ni ninr lii- due to tfaivi! oa't«t>«>— coolinf, ooniptvuHoti, or 
afliiiilj. i'ur iLiu lint twi^ cnuwa the vapoun must be ntunt«d iSlJiq 
while tlie lattra' prodiiCM Hi<e HqiinfitRtioii of thn most nm6:td ta 
Tbus, u Uiv« iiusilwr of stllfl atuurb and ooiuleiUD the wjuiwiu rtjoorift 
thn ntniofplK'm. howovpr mi*U iw qiinntitr. 

Wlit'ii rapoimani oundunscd, tbrit Uunt heat beoo«n«»fr<o,iluiisll| 
nfTi^cIs th« thermometer. Thia is mndily seen when a cunriil of ' 
at 100° it pBwod into a tmmI of w<kl«r ni tbn ordinary trnprnliavl 
Thu liquid Iwconuw rapidlv boated, imd boud n-Hvliea 100^. Th? iiuMi? | 
of lioat ^Tcn up io liqurfnctiou is eqiuJ to tho quimtitT ahmiiicd in {M- 
dndug the vRjKiur. 

32:!. BUtlllaUan. Btllla,— />ufi1iEa/ioH U aa operatiou bv wUd ( 
volatilu liquiil luitv W MiparalCid from aubttonco* vhieh it hold) b 

or liy whioli two liquida of ditTi^r<?nT voUtilitJM siaf b* 
amtwl. Tilt? uprrulion di-pi-nda on tht' trniMfcinnntion of IvjuitbinM 
vapoun hr tho ru-tinn of hnat. Rod oq llie condimMlion of lh«M vapanr* 
' fooling. 



»f»ratm HMd in dwtilUiioii it caIImI * itU. lu fonn may TAry 
Imi MnaiMs wMntialtr of Uitiw ptuta: ltt,timboilf,A(6^-TiSt, 
TfNaal containinff ibo liquid, l]i« Iowm pun of whirh At* in ibn 
bull ifae Ann/, K wliicJi lite no the bodv, ood froDi which a 
lk,C, fekda to, CM, llK:ir»nui,.S,atoag*liinItinorca]ipcTtube, 
« dtuni l(e|it ivHuinatlr fuU ot cold water. T1i« obJT<1 of tb« 
to cMMaoaa tbe tajiour, by «ipo«iiipr n ftnntft <Mt«ut of colJ 

I ofdinaiT woll water from t]iain*nTimpunli<niwbicli itcoiilaiaa^ 
id in a 'til) Hnd liMlFd, Tlie rapMin diMog«g»d are eondmaed 
mn. anil the aldiilM valcr ariiinf; from tbe ecatdenaatlon !• col- 
Uia racMrar, U. ThiT vafoura in raidaMiogr mpitilt' h<Hil tlio 
I, whkh mnit, llienJiHc, be conaUntly Kncwml. Kor 

' a conUaiial supply ot r-M inter paaMi into tb« bolioni nf 
, mhUe thm Vifihivi bicntnl waUr ri*ca to the surfaLfi atd ciK'apM 
k b tlii^ li>p nf tlic cidpm. 

UaklB** eandena«r> — In diMillin)! nnnllRr quniilitieft i>f liquid, 
Jma tile l^^iliiif,' pinat «f a liquid, »o as uol Ui Iuhi nny nf it, tlia 
■ bnnwa na T,irbig'» cmutmir b Mtrvrael; lUKiful. It consiKta of 
toba, ff, ft)i. S^r nbont 30 incboa loof, Sltad in a coppor or tin 
ifmtua of pvrfnratiHl corlu. AooaataDt mipplyof cold antnr from 
fl ■ pMaoa into tba apaen bctarmui Uic two tnb«a, b«it)^ conveved 



ox HEAT. 

to the toirer purt of the condeoMr b^ s runiwl and Uibe/, ■&! ftiraf 
out front the upper part bv tbe tube jr. Tbe Uquid la be dt*tiUf<i u r«- 
iMaed 111 a retort, tha unck oTwhirh U placed in thn tubn; the tattUud 
liquid drop* quite cold into a veaMl pUivd to receUe il M tW Mb*i 
tmmilv of ibo condi'iiainff tube. 

SSSa. ApparsMs fbr 4et*niilalD| tlie alootiolle vmlne of vUm- 
— Odo of the foniu of tliu nppAmtu* conu-itu of n gl*>s dulc rcF^i - 



Fig. 230. 

n tripod, and 1iPftt«d by II opirii ]Miip ftl^. 3^). By nientui of n ':ii- 
cliniir liibii this i* ooiiiiected witli ii Berpt^uline pUced in n rupp-'i 
tilled wilU i'«ld wnt^r. and belnw which is a t«st-glnwi for t-olicctir .- 
di"lillntn. ()u tliia an! three diviaioiiit, oiiu i>, which meiuiirr* th- ■■["■'-■i- 
tilv uf wiiie tiUicn; tlie two others itidicaling nne-hnlf and oiu~thini I'J' 
thin volume. 

The lest-gliis* 'i Sllrd with the wine up to n, this ii th«n pouivd IDIa 
tbn Husk, wbicli, Uftvinj; I)a«ii cnnuiictt^d with tlie Heqientiiic, the Ji*- 
tillstion is conini<^ced. The li']uid which diMil* ovn- in a. mlxtuw el 
alcohol nnd waliT: fnr nrdinnry n'ino, eiirh m darvtn aiiJ bi-.«lu, kbMil 
one-third is distilled over, and for wiiies richer iu spirit, mii-h as sliMrit* 
and p-jrla, oiio-lifllf must be distilled : experiment hiw iihuwn tiut aniln 
theH> cifpuinslancii^ all tlie fth'i>hol pawea over in thf diuilUl«t Tlw 
measure in ihrn tillnd up with ilitttillcd WRt«r tn a ; this given n niixlvN 
of alnohol ni)d wnter of th<< iwnin Tolnnie Ha the wine taken, fn^ frnm alt 
solid luattem, rnich m su^iar. fuKuiriiig mattiM. and nrid, but crataiiiiaf 
all tho alcohol. The specific gravity of thi» di>tillat« is then Ukni by 


LiqverAtnnK or vxrovtfi 


>of ui kln>lK>1on>nt*r I III)) uid the iiiimW lliiia «l>t«iiHid Min»- 

1 10 k rvnain ■trKOgtli of iilcohul ts indk-iitcd tiT th« Uhlcx. 

•■fMr tBk«. — In pivjaring g»»« Mni polWtina tlii'tn orcf 

r or water, '* ocoaekiuUj Iibjiikhb tliat tljw liquids ruiiLi back 

[ pOMfMUig TH—tl. and dntny tbo opRMtion. This ariwu from 

I of kliBoa]dwric pKKtniv ov«r the Icnnoa tn tlif rnovl. If a gM, 

rid, far rxcmpte, bo twnpnitad in Uw Hank m (B^. :i:il). tad 

I iauo wat«r in ibe t««mI A, m lon^ m 

I ii ffiren off trvd^, iU temiiiMi Mcnnls 

[MBHi}ilMaMt proHure and Ihn w«ititit 

cahmn ol water », m> ilini ttiv 

r ia ilia tmmJ CMOOt fwa in ihn tubr, 

I tbMrption ia hupoaaiblci. But if tbv 

ilrrrrmsM Mtli»r tbroiipli tlin fivk 

eooled, or Ibo gM beln;; diien- 

|do alnwly, Uin Mlomd [>rflUTim 

. and yrhru tt cjtnnla thu intcroal 

hj tHOtu lliaii ibn wi'ifrlil of lhf> 

I of watar fo, the water rixM iota tb« 

I iha opemiion i* tpotlvd. This acciil^nt U jiKieinIrd bjr tucanii 

I Are tub«» whtcb pTdTont alMurption b; allowing: air to Mit«r in 
I Uk) intetnal tMuioo dM'iv*iiM:<^ Tbo oliupleit U a tube Cu 


_. , ain? tliiougli thn cork wlilcli cloaea the Ba*1c M, in which 

iJu f* i* grmi-nle'i and dippio); in thi- liquid. VVhru thi- tiiuion nf the- 
at Aninkkca ia M, Ibe atmocipberic praaturs on thu wAtur iu iba balli 


R f*iM!> it to m* to ■ otTtatn haxbt in the take D.\ : but tliU | 
BCtlug «bo 00 ifau liiiiiit in ih* tube Co, d«prraw« it to lii>> omd* i 
■Miimui|T that tlii* liquid bu Um MiiMdcaHitT u the wnlcr b C 
M tbe diManoe «>■ ift leM thui tli* hm^ht ])II, Mr ani«rs bj Ui« apam^ 
Ay bufoK th« mtei in tb« bath c»a riae to A, jmd no abaucplica tiia 

Piir. :!33 iv|inM»3t« another Uni oS Mf«tir tabe. It has a bulb ii^ 0:1 
MMnin^ a cvrtain quaatilT of UqoiJ, a> iota also id. WboD tbt 
af tbo ifw in lli« rvt-vt M «xcse(U tbe aaiMMipbMie preHura, tk la 

ilagirf ri*o hitrbcc tbAo in tbe bulb, a: if ibi- jtm ha« tlio 1 

I MiBO«pfa«iv, tbi! Uvel is tbe Miti* in ihn tubA a* in llm btdli. l*t:;.. 
' tba tciudnn nf lb« tta* ■■ Ibm tbui tlii.' aliutwpbcnc pnuBim the ! 
I In tii« It-^- iJi'; and, aa can \» tAiipn thai tl>« luifAit ia it \em I 
M. an lUKin w liin air which eatvra ifarougb « raacbea tbo currcd pari i 
nl-«a tliu olutuii Ml, and pu«M into tba nwtt b«for# tb^ waU* ia 
«^lind«r cnn rcndi & : the tcDtioii ta tbe intcriiM' ia th«a «<)aal la 1 
CXt«rior, au'! iii> «li«iirptinn takM placo. 

aaS. UqudfBellQB or (uea, — Wc faave uliMiiy w«ai tbal a lalmMJ 
)PapoiiT, tbe ustnpcraiuTe of which in c<m*tiuit, i> liiiiinlifld by tnmMOi 

I prowuK, and that, tbe pn<Miire n>niHlniii>; cnuttmit, it u bm(%-)il iiM 
the liqiiiil ■tnli' hj dimintthinii tbe tfinprmt (■(>■. 

UiiMiturat'^it THiHAiralK'hHieiD all ttMjiecu likegaM>a. And it Uaalinl) ' 
to aiippruv thnc what nir oriiinariiv ckllod fwrmoHmf s/tuf» an : 
Mlunled vapimr*. Vi^r the gu»eoas form la accide<iital, and ia doI . 
in tbo nntuTfl nt th» (uhsianci!. At uTdinnrv l«iupcml<ima 
acid U a km, while in couninoa nwr \h<^ p»)m it i» a liquid : in 1 
dimntca cth«r ia a iiqutd, at a trapicnl heat it ii a ^ai. Anil jual 1 
Mttiruteil lajitiurs may be brought ti) llie otain of tatoiatioa and 
liquoiiM by nuitabijr dimioiiJunft the tviDperaturv or iac 
prcMure, (O b_v llie fame meniiB gaf™ innr be liijiietied. Bat 
are mtutlr vc-rr fnr removi'il fruin liiia stale of soturatina giMt 
and pr***iw' an' re")uired. Some of thnm mny indeed b« 
either by told cir by pnwaiure: for Ih* minority, howorw, brtfc 
iQiiDt be tinmltniK^niialy oniplavrd. Vwr gSMV can nt«i*t tbeiw o«W- 
billed ucliuii». and [irobablv thoae which have dmI ^-el bc«Jt li^uafttd) 
hydMjtnn. oxygcti, nitru^CHti, biuoxid« uf nitro(.vQ- *i>d narbonk anit, 
wuuld becDiiie so if submitii'd to a nilHciniil degree ot oohl aai' 


Farnilay wa* the Rrtt tn liquc-fy aoma of the fraaea. 1IU ntthtA 
cunaista iu 'euclo»iti^ in a bent v'Iom iiibe (Bg. 2^1) ■iib'taKte tf 
wbrtM cbomical nclion the fa» to far li(]ticlk-d ia jirndnt^l, and ihM 
ataling lliu ah'>r|,>r i-g. In pntpurlion ni- the ^h* i» di«Mi|fai.i^ itt 
pnuauTT inci'Mkirw. and it iiltiuialely Uquclica and coUoci* in thv sbedmr 

LiqCtKACriOX OF OliSZi. 


Fifr -23*. 

mar o«prci«llj- If h* condpiiMtion h nmstoil bv plBoiuc th« 

FT l(gr ill ■ frmiutc nuiturr. A mami] ni*u>Miv<n ma; bn plnocd iu 

' t^' .'puBtn* to indimio tbo Uiuicoi. 

iHigvii gM U nodily li<|i>efttd by 

i^r cranul* of nxwurjr in n twnt lubo 

tUf (Imiipll-rn; timl r&rtK>iuL- hl-UI by 

bicwbtMuUc of Mdn ; otli«r yMra 

been ooadooMd ^ Uking ulTaalaf« 

r— aioo^ tbo eaiM4vtMitm of 

hAaoga nuker to ckvinUtry tbon lo 

I. Fat rxtaujABf cblorictv oT (ilver 

aliuut IfOO tinxa iU rolumti ot »m- 

pu; wben lh« coiiipouatl thua 
U plkcn) in B cxindrniin^ tubn anil (T'^'^y bvAtod, wliil? thv 
le|r u imineni^l iu h frvuiin^ mixtiiiv, a qunotily of liquid 
jPM iqiBtfdily rollscW in llw »horlfr leg. 

i|ip«i«uii M Uqaefy uid ■Dlldlfr («•«•• — Tbilnrivr firrt 

kn appnntua bv vhirh cnntiiilcmhl-' <^itiiiiliti-'a of mrbuuii.' 

emld (m liquefied. Iu principle b lliv mini' ;u tbiil UBuUbyKiundnj 

vuricintt villi kIui tubu: the ^a* i* ffrnemU'd in an imn cytioder, 

ihrotifTb a lauullic liib« Into anolb^r «JiiiilHrcvliridTT. wbvTu it 

Tbrr ttv of thia BppnntUB i< nnt frrc fniiii diui^nr ; muay 

faBT« bImmIj bnpp«n^ vitL it, and it hiw brvu Kupvraodvd by 

■ppaovtoi oanitructiMl by Nallenr, of Vienna, which in both conrcniuot 

I trnln. 

A TRrlJ<r«l iertim of tlx) ■ppamttu, as mndiJied by M. Qiuicbl, Li re- 
bW in Ag. 33ft, and on a largnr krI" in fig. £KX It coum^is of a 
^inMifflit-irDi) iMerroir Af ofaoiUHthiii'; t««i tban a quart oipaL-ily. wbirU 
no (vaid a prvMim of ntotr. than OOO ntmophi^m. A xmall fore yiiiirip 
it aocwHl oo the lowKt part of lliin Kw-n'oir. Tli« pi^tou nid f in moird 
iff tb» cnuik rod E, wbitrh i« woriMd by tba handiii M. j\a iho ciiiii- 
inalun uf tlw> m* and the friction of lli« pictoo produoe a cou-iiiii^ntblo 
£«ci]rafieiiiriit uf Ileal, the merroir A in ■uiroundul by a erjppnr Yi-iam\ 
h wUrJi ic* nf a (riitaug miKluro i> plnct^d. Tli« wat«r ariaiu^ Ctom the 
ihiii|r or tJie ire paaMtr by a lube, ■>, Into a cyUudric«l copper caso, C, 
vfckh MuriMMb lbs force pump, from irbeneo il rocflpR* ihmugh the 
lib* m. Hid 11m ttopcock «. The whuk artaugviiKriit r«U ui) an iran 
&>»•. PQ. 
Tbe fH to be Uqu<rfl''t J* previously collected in air-ti^lit bii^, R, from 
I h [wimn iuto a bolile, V, oeataiaing aami! Huitablc drying »ub- 
I] it Un-n paoMs into the ooodMLRing pump tJiroiigh ibe valcnniwd 
indianilibtf labr II. Atl'-r the apparatun luat hvvn •Kotked fomutm-liuwy 
liiB II Ml 1 1 III A can be onKXi-vod from ibo pump without any uacapo of 


tat atxT. 

Uie liqniil, (br it in cUmmI ImIdw hj ■ ratre. S (fig. Sffi). In 
colltct Mine of tliH Hquiil )|;m ^e iM wrrar t» Inverted, uid on ' 
Um ■lapeock r, ibe liquid «MapM )^ « Mn«U tubalure j*. 

WbMicHbonic acid bM bwm Uqueted, nd i« oIIovimI la Mcaptl 
air, • portino only of the liijuid rolaltluea. in oaaaequeam uf i 

Fig. aaa. 

«bflorb#i) br iliis eTii[Hiriilinn, the reM i> m mucli moled u to aotiffy i 
whitp flnkejt lihn piiow or luihydnMH phonphorie acid. 

Solid cnrlmnic nrid «vf»pcir«t<* my iilowlf . Dv meiuia «f an akob 
thcrmoiueter its tiMii|M.TMtiirp lias been fuund to lie about -00^. A • 


il; pUcMl OB lli« Unnd doM not produce the ««imtian of audi gn»t 

I ■* miirhl be pxppotod. This nri*'* from thn ini|itiriWt contact. But 

'totii h^ niiswl wUli ctli^ ihxcoli] proJucciiissotnU-tui! thntwbnn 

I b plaocd OB lilt iikin nil lii« i-l&cU of n wivro burn arc p^>dul»(l• 

I of l]i«M> two •iibatiinoM M>lidiflM fuur timi?* ila wri^bt uf mer> 

I ■ frw mitiiilvs. Wb«i a IdIm coalaioioe liquid cnrboniir aoiij ia 

I in this nriiUire Ute U<i<u>l bMOBKi Mild, and look* like a tntuspn- 

I pt* of in;. 

Mt remMrtnUn liquefaction obtaiDml by thl* nppnratii* i* thai of 

: ottAtrogeA. Tile rh ouce Ui)u«lt«d unljr vvnpuriilta tlnvlv, and 

I a (i-mpRraiiirc of 88* below tcm. Mrrrury plncrd in it in uniflll 

litks in*iantl/ mlidiSM. Tli« tame iit the cnxi with water : it 

; h* adcUNl dmp br drop, othervrjw ita 1nti-ul hf^ut U'lni; much (.fmlct 

I tbu ot tatttairy, i)i« hrat^vpn up bj the w*i«r in MilidifTiiig would 

Bt to c*iiM an pxpIiMdou of ih« prouixfd*^ of utlrifren. 

I t)t vaoogim in rudily il<icninpoH'[l by hrnt, and ha* the. pro- 
nppurtEng' lli« rorabiiMioD of bodit°i with almcat m much bril- 
rr a« niTKcn : and crm at low tenipcratUKa it ■pivtnrrct llii* prnpiMty. 
I ITlica a piwe of iDcWkdawMit chMCMl ia thrnwn on liquid pr<Mii\i<Je of 
jMtriMwn >> OOOtiniiM to bum with a brilliant li(.'ht. 

The oM prodncMl by ihr nTaponttioii of rthir hn* brain uaed by MM. 
bdr and Drinu to tht ItquHtaatian of gnaM. Tty pimiing a Olttrvnt of air 
ban • Uowpip* b^Uowa throu|tli aovMal tubes btna fuwmincMof pther, 
ilMn]MtMbire of -31°C. can Iw ivach(<il in fi\t or Mt niinmeti. and may 
r V hrfU np tot fifliwa or Iwroty miautM. ity ctapomting liquid >uU 
I add in ilicMtne ni*nti«r a (rront^r [lpgn>e of rnld, ~!Vf C; ia 
At lliia Icmprralun.- amnianinciil fnia may hi- liquefied. lij 
' (•tapocaliii^ liquid Hminonia iindi-r th* air-pump, in llip preiMQce 
wlplinric add, a tcinpi-T»turo of —XT' ia attained, which is found 
nt to liquefy carbi'iuc add uudcr thn onlinary pmuuri> of ihe 
WM wphaw. 

fir iHiau fif a faaih oJ ctbor and of tolid cnrbfmip odd, aud by u*ing 
|«]ibi^ pnaautea. Andrews KKC^ralt^ in r^dnciuK iiir to ^ of it« bulk, 
M^gCB to f^, bt-diKtrno to iliVT carbonic o;tidu tu ^j,. and nitric oxide 
In ^ of ita original Tolumit, but wilhinit prodiidn^ liqunfnrtioD. Hy- 
'j^r^t"" ^^ narbonic oxide depatWd 1cm from Boyl« and Mariottc'a law 
Ifbisosj^Mi and nitric oxide. 

xtxTL'sn or txsta xvo tapofm. 

m. ^w* *f *>>• intxtnrB of (aaea and vaponra. — Ei'piy mixture 
of a ^ and a Tapo'ir obey* the following two law* :— 



ox HEAT. 

I. 71b ttntioa, 4Hid, e<mu^Hfnlfy, tli« qtumlilg vf r^aw MA 
a giw» t/Mta on thr nuntfm' thr name trmprratmrr, wiudttr Om 

tain* « sftu 'IT it a tiantmn. 

II. The tauiM vf the nuiwr* 
wiirh ttui hismM post** if H 
mmr tjxirr ahnr, 

Tlinw nrr known MiWiM'* 
their dUeoT<-rtr, and UN dani 
Ihr. following appiiratu.i.vrliifh 
bt OtiT-LuMac. It lyiwUtt of* 
A (fiK- -■*~ h tn n-hid) two atopcn 
tl, an ceiurtilvd. Th» lower ato^ 
vtdn) witJi a tubiilurR, ffhirli 
tube A wttb a lub? B of Mnall«r 
A icaie lwtw*cn lh« two tube* 
mcHQrv the bri^rbta of tlw 
coluniiH in them tubciL 

The tube A is fill«l witli ma 
lli« f>t(i{vi>rk« b and d luc rlngnL 
lilobv, M, filled with drv nir on 
^■t*, i> ttrirvcA on by nH«nn of 
iu the place of tbe ttmnni C. 
atopiM>cl(« are iben opruvd, aa 
nierciin- u nllowed lo ctrnpv, wl 
plotml br the dry air of tko |^ 
etopcoch« are then clowd, Mid ai 
the tuW expand* on Imi In^ tba 
prec«ur« cm it U loia tbim tbainf 
■pberv. McK'urris acrordiagfyg 
tbo tubi! n uulil it U at tbe I 
is both tube«. The ylobe i« then rcinnvBd, und n-plsced b*« 
jttoridvd with B rtA])Cock o, of a peculiar constrLiction. It ia 
rated, but ba« a «mnll cnvily. lU n>pn<«cntrd in n, on the IcA of 
Some of the liquid to be va]ii)rii!ed Ih (ii.>ured tntoC, and th^bs 
ntcriTury, k, hnving bivn noted, Ihf^ ntn^tFadc b 'u opened, and « 
thai ils cavity hcccnmii filW with I'liniid ; being airain tiiruMi, 
cntorn tho ipuoi.' A and vnpiii'iiH'*. Tlie li<[ui<l i.i allowed to & 
drop nntjl the nir in tho liib>> i> aalurtiti'il, which i» tho CMO 
Icvul k of tbe iiitTcurv censi^ii w aitik (-iOI). 

As lb>' leni-irin of the vapour prixJuepd in tho •pare A i* tdi 
nf thv atr already present, the total vuluuie of gM in iiicreaond 
eMily be restored to its original volume by pouring tnaraui 

Fig. 237 

HiSTCiiu or oxsats «xi> Tjipooiu. 


■ merrurjr in %hf Unrv tube bax hma niurd lo (br l«vel Jt, tbnm 
branns Bo, in tlie IctcI of %be mnvnir in tb« tvm tub««i, vbicb 
1^ rcffumts tli» Mnsinn of tb* vapflnir ; for m Ibe air ho* n* 
b original volnmv, iu Icmaoii baa nut cbiuiircd. Now if a few 
I ihfl MOM H<|tiU be p«Mwl into lb* vatulud of k bamoii^tiic lube 
^bm fixBnlv i<qu«l to Bo i« prodiimd. whti^b prort* thnt, for tbn 
(■janmiun-. the unmiMi of * MluMUd vapour is tlia mmt ia a fru 
krumii; from wbich it la nnelnded Utat at Uic mii* lemptrralurp 
Itll} iif lapoar ti alM tlw um). 
^eond Uw i> lik«wUA proved bv lhii>i csqwriincnt, for wb^n tb« 

QtMMgMtwdiuIeirc], ibe mixture sitppoit* tlie atntOapbMIC prM>- 
9m loji of th« coJumn li, in Rildition to ibc irriirbf of ihc rolunm 
jr; Bo. But ot tbcop IWL> prveBUTM, onv npTMvnu tUc IfimIud cf 
jjii, and tba otb«r lbs Utmnon of tfao raponi'. Tbe accorul tnw ic, 
k ■ McwMiy coaMiqnenM of tb« fiTtt. 

■BHitt can only b* nuido witb tbi> appnmtiu ■! ordinary- ijimp«- 
jlmt V. Ibiifiiaiilt. bj mvans iif au ■pparalus wbicb run be uavd 
kit te mp w a uiw«, hiu> invtuiigmnj ihc trnaions of the Tapoiin^ of 
Bmv, biinilpbid« of caibon, ntid bi^m.olc, liotb in (uruokiid In air. 
pnad tbat ili« i«mioa in nir in l«u ihnn ii U ia vnnio, but the 
^ arv >o *»all M not lo ioTiilidaW Dalioo'e Law. M. Itegnanlt 

EcUurrl lo amHdcr tbb Uw m ^Miorcticnllir tru«, attributing the 
I wbkb be obermMl to tbe liygrMCopic properttea of tbe wdcn 

h«kl*aH on Billtnrva of smac-a anil T«po««.— I, A volume 
^ V, al tbe j.i>>«*nrB 11. bcinjc KITMi, wbst wil! be it« volume V, 
b aannted witb vapour, Um t«ntpmiur« and tlie pr^saure te- 

t the fiutic fome of tbe rapnur wbic-b mtumt«f the air. tbe 
Itbtt niixlurr. tmlr supporln a ph->BiiTB equal lo H — F (327;. 
^W mmI .Uanoitn'n Uw tli« voiiimc* V and V are inversel; m 
, oonwqDently 


, whence V = 

.-^ ™ 

V- n- F* "■"" ' " n - F 

'im a pren Tnlnme of mlnrsted air at tl)» prcuiirr T[, mid 
/, what will be iia vulume V', nUu ntumii'd, at thn 
[', and the umpetMiue t f 
fllie maximuta tmmon of aqiMoiu vapour at f, nod/* itx niul- 
■ion at P^, ibe air akme in rach nf the ini;iturM V and V will 
ralv iiodnr lite pt>w«urw H— / aud H'—J'i eoDa«(u«niIy, 
. that tfa« tampcnttiire i* ofinitnnt, wv obtun 
V _ II - Z' 


ox HEAT. 


But M th« noluNies V and V «f nii, M the leiDpenliuM r* uri f. • 
the niio of 1 + •<' to 1 -f of, ■ lieing the co«lfideGt of tbe e).f 
air, liiH Hjiifttinn bfcomp* 

V _ 11 -/ „ I+rf' 

III, Wh« in ihewMfrlill'ofavoluiiieof HirV, »alutBt«J«ilhi 
vapniir At 111^ fnippnituro (, anil pnfouiv Tl f 

If wc rail y the inajthnuiii b-ivsion of llie Tspnur aI f, ibe tmwil 
tliH lUr t.\'mf will be II — !■'. and tb* proMnm nducM ilccif to1 
lit, the vci^ht of V cubic inrliM of drv air at I, anil iiiiiiT tiiv p:i 
H — F; and 2nd, thn weight of V cubic incbn of mturntfct npouti 
under the )>r(Murv. 

To «f>Iv)i tlji- first part of llw prablein we know that a euhie iiwk o 
dry air at (y and lh« pn««iirr7i)0 iniilimclAri weighs 0'31 ^raiiuLvidl 

at t^. and iho pn-wire H— F, it weighs^'"*' ' J~^ (^a), c-.a*'} 

qiirjitlr V cuUc inclisa of dfj air w«ig|li 

0-.11 fH-F ) V «J 

(1 + ^) tm' " 

To obtain the woiRht of thn THpciur. th« w«iif hi of th^ mia" toIiuof *( 
dry nir Hi lb-.- «a[iK' l-t'mpnrniuiv and pmtun* intuil bt^ aoughi, and ihii 
is to bfi multiplied by Iho nrlatiri; donaity of thp Tnpour. Xo« «* V 

cnUe inches of dry air at (*, and the prwure F, woijtti -j-^ — - , -.^ 

V eiibic inchna of aqunou* TapolUi vhoee density ia | o( that at lit 
(338), ureigh 

0-81 X VF fi 

(I -t-a()760 8 

and 03 thu weight P la equal to the sum of the wei^ta (l^ and (S) ^ 


p = 0-Sl X V fll— F) 

(I + a(j ;uo 



>< VP„S 


0-31 X V 
(1 i-at) 700 


SrHEROIDAI. <'O!illlTI0Il, 

ass*. li»laeatrott't pb« name nan. BontlKnr*a •ap«trliatBU> — 
When liqiiiJe urp llirown upon incimdf»e«nt nielalljc eiu&o>-- ■' 
|mw*Dt n-mnrkablc phrnomend, vcbioli were firet obnmvcd by 1. 
(tMt a cciiliiry ago, and bai c been nnraeiJ nftcr thnir diecoveter. 
bavi- since then been •tudicd bj' olb<>r phvaieixb), and morr c* 
by M. It>:iuti{rny, u> whom our pr«>i*ent lcno«ledg« of the aubjwH it 
nukinly due. 



II ■ kJenbly Uiick mtnr or pliittniim di«ih U bnntMl U> nAotn, 

itla wmUf , prefiossly wvtoci]. dri>pp«d iuU> lh« <li«h by meona oT 

.^D, UiM Uqa»d ilorai twt ipiFtKl itwlf out on Ibv diah, «ad doc* not 

PD it, M it wonld at tiha wduiajr i^itipernturu, but aamunw tiie 

' * flktlf<n>d fclotiole, wUcli fHct M. tiouiifruy Fipmwj bj Mjring 

iiai puaird iDto ibn ipktroiAd Uatr, tt cotatna mpiiily round un 

DM of tho dub, Ukbg touKtiinea tbe form of ■ wUr, and not only 

. aot boA, but it* svipcmtioii i* only about oncGflk w njud a* 

A> the ditb cools, k point U readied at wbicb it in not hut 

keep tfa* vrat«r in ib« ipberoidal atiLl«; it U accordingly 

1 bj the liquU, aad a violtoit ebullition nidddnly eCDniftn, 

I ««lalil« fiqoida can aamme the spbetuidal condili-iu ; tlie lowut 

I at which il cjui bo producvd rariiv with Roch liquid, and ia 

t fUratad tb* luKbi^r the boiling puinl of th« liquid. Fur wabir, the 

I tiwt barr al |pa«l a t(>ii){>«<raturc of 'MXf; for alcohol, IfU" ; and for 

TL- tiBfeialure of ■ liquid in the (phL-roidal utitto ii alwan br-inw ita 

; potnL Thin tempMature bm bMn roeaaiirrd by M. Boutigny by 

I of a rtrj delicat« thennomcUtr ; but biH uietbod is not Ireo from 

>, mi it !■ prohabli) ihnt thn ti-mpimturps bf^ obtninod vvns too 

n» foand tliat of walvr to bt> (I5'' ; alcohol, 7.V ; uthiT, .H4" ; and 

1 M^nrmu acid, — 1 1" But tbi; li-'iiipiirBlurv of thn vapnur which 

i ^pcan tu be an high tut lluit of thn iohmiI iUt'tf. 
I propBTty (J liquid* b Urn •phcniirlul stAlu mnaiiiiiiK hfllow thvir 
< "'.I ba* bMi applied by .M. Itoutifrny iu a rfrimu-kablv vxprri- 
I rr»«nn|t water in a riMl-hot crucible. He hc^atod a platinum 
gfth u br^^ht redumt, anil placed a nnall quantity of liquid *ulphurou* 
in iu It iumodialcly aaaumcd the sph^ruiilal cundiii.'-n, and ita 
, laiainliuii waa rvniarfcably ilnw. Itji tcmprraturc, oi ho* Uk'ii kIaImI, 
<«M aboBt —11", and wbi^R a small quantity of wattir vwi ndded it 
^■■ilMlelj aoUdi&ad, Rn<l n ■mull pi(H.'i- uf ice cuulil he thrown out of 
IW raii-bot cradUfc In a nioilar monnrr I'Aradny, by larauH ufa mix- 
ta* of aolid carbonic acid and «thcT, auct^eedtfil in rn%iiiii)|r mercury- in 
■ nd-hiit crucible. 

Ia iJta ifiienudal itate tliv liquid in not In contact with the rmaol. 
H. Bootiftny pr«*ed thit by h^Minit b nivrr plain plnnid in a boHtoB- 
^ [MTriiitT. and droppittir on it a little dark coltjunHl waitr. The 
■nud amatuli the apbrroidal condition, and the Hamit of a cnndln pixeed 
It Moar di«taaM mnld be dlatinctly aeen betweion thv drop and the plate. 
If a pWte petforated by wvcrml fine boloa be bcated, a liquid will ajaumn 
tha iphaiuldal eUte when projectod upon it. Thin ia alu the ciu^ with 
a Aat Mis of platintim wire prveacd iuto a tlightly coiifave Hliapc. An 
Ktfmmmt vf aaolbw tiim, dm to Mr. A. I]. Chuicb, alao illuiitrato* 




tbe auie bet A poliafced rilm dish Is rnkde r«<l liot. ml 
(if ■ tolatwn of mlphiilv of Mdium uv pn^nctcd tm it 
)HUaM inlo ihe sphproidal condittnn, bdi) tfae silvvr nt 
■Uantioa. itut if Uie dbh la bIIuwhI to onnl, the liqot 
moiateiiB it, fimdurinit * du-k ■pol, dan to iho foTmnticin of 
■ilrvr. In like manDer nitric acid ttMiuuM the epbenudid 
projected on a boated mlrer plate, and do«a not nttnck the lOi 
•a the plat* remaiiw hot. 

Similarly liquids may be made to roll upon liquids, and 
vlucJi vaporiw irithout boeoming liquid bIho amiinit^ a coi 
goua 1(1 tlie Rplit^roidal state of llquidn when thi-y am plomd 
whoMO tcinpcnturt' \a Milfidcatly bifh to rnporite tliera rn^ 
i* eeen when h piece «f cubonU* oi aatimoiiium is placed I 
pintiaiim cruriblc. 

The plit^nnniena of tbn «[>h«oidal utala SMin to pnire llii 
Klobiile rvula ii]>i.>ii a t".>rt of cushion of ila own vapour, prad 
heat rA>liRte<l from the bot mirfacc againn ite under ^de. 
thia Tapuur iMcupci from iinrler the globule, its place ip 
honb quantity fotniod in the aanw nnr, » Ihnl thf globule i 
buoyed up by it, and does not come in aciunl cuntnct with 
■urfncc. Wliuu, huwever, iLo temperaluni uf Ibi* latter tt 
malinn of rapour at thn under luriacn becninri Ipm and li 
at li>u(^h it i» not ituAifieut to pwveiit l)ie (ilobule tondi 
metal or liquid on wbii^h it mta. AnaannnncoDtnrinocurehi 
inijutrted to the globule, it «aiten into ebullition. Had quicklj 

Thesa oxporimrata cm thn cphenHdal ntnlc rxplain 
kand may be dipped into melted lead, or even mvlted 
jury. It in nwi'MBry thai thu liquid motDJ be iintlpd gntti 
aoilidif)')!)^ point. U'linlly th«i nntitml inoi»<tiin> nf ili« hand 
but it is bi-tter ta ivi]K< il with n ditiiip ifliith. In conaoq 
l^eat b«Rt, thn hand brc-onicii covpnil witii n layer of aplM 
which preieiitp the ci'iulact <S the metal witi ibe hacd. 
alone opotatcs, and tins ii* print'ipally rspttudni in fbrail 
vapour on the surface of the linnil. If ihn hand ie imiue: 
watiT, tho water lulbt'Toa to the Beiih, imd cometiuaitly k i 

Tliv tali-G of ordeals by lire diiriug Ilic uiiddle a^-ea, of mi 
riHi luirefooted over red-hot inrni without being injured, 
true in aonia canes, and would And a roady eiph^ation is tl 

DccsnT or vakdv. 

pr.tKiiT or vtrui^iu. 


Betk«4.— The dauUi/ vf a xnpuar in the nlfttioii 
I veigbi iA a gictoi roloniv aT thU vapour and of liwt of the 
e nf kir at the nme tem[m«turu sntl [>r«H(iir«. 
tbocU |>iiDHpallT aK uiii>d in ilcU-nninUiiC the dnnrilr of 
kf-LusM's. wliicli wrvM for liquids wbicfa boil at about 100^, 
', which can ho noed np to 3fiO*. 

Ift VPpnMiito lh« a{ipantu« uwd b;r (.•av^I.iuiMe. It cflHiat* 
aael eaataiiitn([ nwmir}^, in 
U ■ gLm <7liiiilcr, M. llila 
lib wau-r ur oil, and th« tHis- 
JH*'™*— * br the thcniKimetcr, 
iaunoi of tho cjrtisdcr U a 
^^ jar, C, whioli, M Stit, ia 

Id wliflM rapou dsmtj u to 
Nd ia placrd in > nuall hulb. A, 
<m tho h^fi uf ibc HKiirc. Tli« 
han atalal and w4gh«d: the 
IhftBquJd takaa ia ob^iotul^ th« 
Ihe hitib wh<Tn IIM, mhaiw lla 
ih) fiuply. Tho bulb U than 
bito Um jar C, and iko lii|nid In 
f luatad aooiewhat liiKbot than 
p^t of tlw> liquid ia iho bulb, 
■■ee uf thv «xpaaiiicu of thU 
nib faraaka, and tbu li^nid b«- 
rstad Info Taponr th« muKurf 
I, Bi np«Mai«d in the Ggnre. 
niHt be ao amall thai all tb« Pigt.SSH. 

I i* raporMed. Tbo TrJuTuc of 

ia piTm by the i^adualioii on tho jar. Ila fmponHiu* ia 
r the Uiennometor T, and tho pnuuniT«< ia indicated b^ the 
■aCwaan the h«i)<:ht oT tho haroiti'.-t-^r at th« Unie of the 
,MrfUi*b«igbt nf tbo tolaiuiKif mon^ur^inthn ^ jnr. It 
Muy tbni lo calculaie Uw weight of a voIuiuh uf aii pqual 
tlwTapcnir under the aame CMidiiiona of teinprmtun> aod 
[b <|iKitfauit, ob4ain«d by dttiiding ihr weii^ht of th<i vapour 
b* lit, givca tbo required dooutj of th? va)iour. 
A> waigbt of tlie vapour in grain*, v ita toIuuc in cuhie 
I la lawpirmlvn ; If U be the h«ifbt of tlie haroin«t«r, aitd 


H tlataf lli«iiUTCury in tbepuJM.IhBpnMiire cm tbt" 

It u Rfjuirwl lo find ibe welftit jr* of a toIuibo of air t, ' 
peTatiiT" /, anJ undnp a proeurc H — A. At wrrn, uoder 
T60 uiilIiiDPU>tv, a ciibio incli of air weights O'SI ftniat; 
under the ume conditions c cubic ini'liw will vrui)^ 03t r j 
tfaenfora the wrigfct of r cubic inch4>^ of air, at /° and tht 
mtUiiudurs, in 


gnin* [S83, pmh. ti.]. 

Aa ibe xwght of a tolum* of air i« jiroportiona) to 
nboie nrel^iit luay he ivducvd lo llio preeoare H— A bj 

?^*, which giTM 

o^wn — *) 

(I + -0 78d" 

for theneiirht /I'of tbpTo1iini« of airf. at th« prmiimH— 
C'aiiu«(ju«utlv, for llii^ desirad dennt; we fanro 
■a — P _ pel + -t)7m 
p- SilVTH - A) 

Sdl. B«mu' metltad.— Ihe methnd just dncribod 

to tiqiiidf "bone bi^ilin^ point 
or UW. Ill onicr to raiim tl 
cjrHn^er to thi* toinpetalutv I 
n«s*»iiir lo hpol thi- mcrcni 
Ai%\vi< thnt iho mvrciirial m 
ho dnDfroroiui to the open 
tiinrfovpr, lh» (nnsion of t] 
vnjintirs in tbp frmd tuitiHt jar 
tlii> [■■noinn nf tbo vn)iiiiir of llii 
«ti fur Tiliatr tb? miiilt- 

Thfl foUnwinR' method, 

M. l>iiiniiB. can N- iwrd tip' 

jn'mlim- nt which e^nfa begil 

tbnt i«, about 400°. A 

i» iiapd with thft ii«di dra' 

(iuH point (G^. 2S0). The i 

been drind cxtomally and I 

wi^i^lied, th« leTiipralutu I ai 

^■'^' -^'■'- height A bpinfr noted. Thi* ■ 

th« tr«ight of the gluaa ii in aildilion to /i, tbe weight of th 

laius. Th« globe vt th«a geutiv wumed, aad it« point : 

Tapoor deiuit_r ia to be ilelermiiiHl : on cooling, llie 
■nd • 40ai]tilT of liquid ciiirra the plobe. Tim globs i» 
Itaed to n bnth, tilbur of oil or funble inetnl. arfordiiiK <'> 
■BUa« to whirb it id to br rmi««L In nnlor Ii ki-np ttir plobu 
ed podliiNi • iiicullic support, uu wLii-li » iu<>i't«blv rudslidn*, 
n tW Mile of lli« vcwuL Tfau rod ho* twn ting*- bctvwn 
I gk>b» in pUcrd, iw ibnirn ia th« figure. Tlitw i* Niuthcr 
lieb • vel;^--!!! thtrmoiDtTleT, D, is atl*i:h«d. 
lob* and tbcmuiiDPtcr liaving hnna immened in th« iMtb. 
'iibeal«d UDtil tlighll* abovu (li« buiUns point uf tli« liquid 
nfce. Tlie JWfOna wbich pajan out bj thn point rxprU all 
I tha burior. Wtien th« j«t uf vapour (eawt^ whieb tn tli« 
I all tlw liquU lioa bi.«a i-onrcrtMl into vapour, tbe potut of 
I li kannaticaUjr naled, the U'liip-'nittirv of tbe bath f, and 
betrie Mght V, Vlng noted. When thu globe i* foul«l, It is 
deaned and afrain wnghed. Thi« woiglit. W', in tbnt of the 
^u* f^, Uie weight of lb«> vapour wbicb fitlt thi^ gloV at tha 
m f aiid pRouiiv A*, or W = + /^- To nlilnin Ihr wpi;(ht 
Maaloaa, th« vHglit ji of air niuM liti kiiowu, whicli I* d«t«r- 
:lht fbUowing mumn': Thi- poini «f tbf gkihn in plncwl uiidrr 
nri Uia axtniinitT bn-krn i-ff witli a rmall pair of pinof r* : thit 
liag ccodewnl, a vacuum is proilucod, and nuneury ruib»i 
tibtij BUiag tha globo, if, in thn o\p<;rirn>'iil, nil llx' nir bn* 
flatalj expelled. Tbe w^reurj- in iIk-h poun-d into « ean>- 
oalcil Hi—miro, sbich gir«* ihn voliinie of llit- ^lobr. From 
tf Iha (oltinie of tbe globe at the tuaipemtun? (' any be easily 
\f awt ooaiitiiiMnlly the volume of the rapouc. Kmm thia 
of tbe Tolume of the globe thn w^iglit /■ of the air 
ipetalmv ( and prMMii« A is ftadilr cakuliil«l, and this 
btnetad from W jpra G, tbe wnighl of tlio gliiu. Now tho 
I IIm vapour p" is W' — G. We now kuow llie weifjbt ;/ of ft 
(if Tapour at tbu tPiup«nlure I' aiid prpsiure A', and it is 
MUjr to calculator ihn w«i)||ht y/' of lh>' Mtniif Toliimi' of ulr 
condlli<dui, whicb ii riualj accumpttsbcd. Tbe quotient 

aqund dcnaily of tbe vapour. 

Itrmitiet of f'apoitrt. 

.... lOOOO 
pT water .... biTi.'k'i 
alcobol. . . . 1«1.1S 
etber .... S-WOO 
faiMlpkideofcartKiii :I-U47 

Vapour of pboapbonu 


„ turpentine 


„ aulpbur . 


„ nicrourv , 


„ iodine. . 

. STlflO 


ox lltAT. 

rU tompccklima f, a, moni ■Mumtch, (Ki!i2^ of the iwriljfl^j 

^e Min^ t<°ll<])-Tll>Ire Mid pRMUIV. I 

93::. SoTlll* and TroaM'a uMliad.— IhivUle and Timet btnl 
fi«d DimiM' Dwiiiod *» (list it CM b* tuad fot datMiMaiofitkli 
dunmly of liquidi «rilli ''vry Li^h builinf poiatt; Tb« glolw MM 
Ml iron cjltndnr in tho Tn|>iiur of iDnmiry or of lalplint, th* tenfwl 
of which are fonitout rts]H<cliv«lT M '•iM' >ad 400°. In odur b^ 
thn ibt«nniaati<in b tlin muim ah id Dudmb' method. | 

For diflrnuioBiioDe •! liigbur tempt>raiun>«, Devill» and Tnwti 
*mploTod thp T»pour of lioo, the l«nip«nil.ure of which ia lOKT, 
fllaiis *umJ« are softened hy thii heat, tbn^ '**<' pnroolain gl<llM, 
fLaely drawn out necha, wbii-h an; smili-d b_v □ifoiui of lh« OKjkj" 

SftJ. BAlatton b«nr«eD tb« Tolnma sf a llqald aad (Ml < 
»ap»«r.— Thi' dfiniiT of vo|K)ur bciut? known, vri- e«u roditvok 
the raliii biitwfpn tlio vi^hini» of • vapour in Ihe nluraWd iWI 
gimi Ivrnptrralure. uiid thnt of its liquid at i«ru. Wh vty ufe^: 
•xamplc, thn rrlation bnIw«oo watnr at uiro nod Mvam at 10Cf.j 

The ratio between die vrtdghl« of m)iMl voIuum of air : 
the Durnial hnromctric prataure, nnd i>f water under ttia 
MAnci)», i* M I : (73. But I'niin wbRt hni. bn-n alrvedr aud (SM 
d<>ii«it; of lur at luro ia lu ita dMisily at K)I7' as 1 -f a' : 1. Bn 
ratio Ixitnt-cn ibn n-ri^ht* of equal viilumtM of air at 100° and) 

'^''' nrerw-xiu. = ^«. "O'^aire ; 773. 

No \¥ from til'- filiiiv" tftbl"' ihe dcnwtv of fl4«ni at lOCC, al 
normal pcwuro, coiii|Hiri<d with ibat of ak under tho aama i 
i* na Ott'i!'.) : 1. Ilniire thn nttio batweui tbo weights of i 
of aieaoi at 10U", nud wiit«r at ff", la 

0'73I78 X 0(^35 : 773 or 0-45M ; TT3 or 1 : M 
Tli^r^fijn.', as the volumes of biHlieB ar* invprwilj na tbwr i 
0D4 volume of water al Lt^m •^xpandu into lilflS volnmrn of «l«att i 
C. Thn practicnl rul? that m cubic inch of wnti^i yiulda a cubic I 
steam, though not qiiitn nctiurate, expraww the rvlatioD in 







chaiteh VI. 


as at h7(T0Bi«lr7. — Tli^ obJMt of /ii/j/rom»lr^ is to <lt<ttv> 
•Btity of •qui'oiu Ttpour cntitAinRii in a ^vea volumo of I 
imtity i« TeiT Tvisbl* ; liiit 1I19 AltiiiMphcre i» uvTervom- 
itod witb rapour, at «iiv rote, in our dinuiUa. Nur ii it 
leif 'Ir; ; for if Mygrvmitnc tiiti4mtt*t, tb»t is <■> My, eiib- 
jkprst niTiiillv fur nl«ir, hucIi an cliluricle uf ulciuiu, sul* 
^ b« «1 an; time MpoMd to Uia air, tbcy ab«orb nqiieoii* 

rMuatrfo aMU.— A> in gcot^nl the nil is nr^vcr Mtiirittnl, 

ibe qiiKiiliti' -if aquixiut vapour actiially [jnairut in tliu 

lo tiiatwhi^li il vtoutd contain if it were aitiunteiL the tcm- 

fig ill* laiDe, U coUud ibo k^ramttric Mata, or dtyret »f 
mntjctiim dow not il*pnnd em thn abmliito qiiftntity of 
lUT imacDI ill tilt nir. bul on ibu ){rviitu or Ie» iliKUiici.' of 
. [la point of vUuratian. Wbi'n tlir air in crAi, it iiiny bn 
9tJ Uule TipouT, Mill, ou Ibt' ci-utrurv, wli«ii it is warm, very 
th ■ LuK'' ^anntily of vHpaur. In siinimnr the nir uauullr 
n aqtieoiu tapuur lliaii in winter, iiotn'itbFiUiiiUin).' whiL'h Jl 
t-r™"— , Uie tMupptnturc biunE- hi^hor, tbcT«pour i* farther 
tot sktaratkiii. When & ^xrm i« vrarnici], Iht> qusiititv of 
«t dimtniabod, but tbo humidity of the aici>luiacni>d,bunuBo 
■tatrarioa i« rsit^ The tur niny thii« becomn to Ary n* to 
tai tbe bealUi, and It is hcnw usual to ^Xace vi<bu1s i>f water 
I Mad for boaiinif. 

Uf* low appUM lo Bon«aturaI«d vapoun as well m to gsew 
Hows that, with tho unin tcmptrraturn and volume, tb« 
ipour in a niH)Mtiir«l«d s]m»> iocr<'iwe« willi th^ pn-MUrn, nnd 
lb lti« InMnoo of tile vapour itwilf. luntund, tberefurv, of llie 
giiMlilioa of Tipour, that of the ronv.tpnndinK trnnon* tnoj^ 
id, maA it ui&y be ruil ibnt i)ie hrf^romctnc etnl'^ i> M" rvitio 
• o/^ the a^atiMit vafioitr ahich Ihi air actualli/ fiiUaim. to thr 
\ Mpovir vAifi i uxnUd eOHUiiit ot tAr taint Umperaiurr if it 


im BEAT. 


wo h»»eE=/!,itlti!iice/=5F X E. 


^H ir/ls llie sclTiftl tenrioD of iiqu«i>iu vapntir in llie Jiir, an^ F ihu rfj 

^H Mluml«il vapour at the oame tcnipantUK, uid E the bvtTomiilhc Ri 


A* ■ roni>n|iii>nfe of thii oeroni! i^i^finition, it i* important 1-' rv.iet 
that tlie tciiipuniture baving vaiiFd, tti« sir iiuij oiiuUiin lii- uep 
r|ii>nti^ of rapoiiir nnd vt not hare tlic nunr brfffurapbic ntat*. 
wben lli« leiu[HM«lun) rioea. tliti t^nsiun of the vapovr which d* 
wnald rontnin if Mturnted tner«n«w more mpidlv tJian the 
the vnpoiir nctnallv prMenl in llui ittiBiM]ihen, and huiM tb* 
botwri'.n thn two forcoi, that i» lu aay, tbe hjgrometrio atale, 

It will prowntly be expkined (MS) how Ui* w#i^lil of tb* 
prvwnt in « Kivon Tolumo of >ir may be doduc«d from the hrftoi 

3.'iO. Durereni kiaili of ttrsrenieiet*. — Bt/:iromfiert an 
ninnln Tir mcntiiriii^ ilio hyi[n>Ri>itric ilnlo of tlw air. Thai* wt 
Bumvraiii! varii-li'<4 of ibeiu— <dieiu!cal faj^ftmnetan, caMendof ^TP^ 
meters nnd pM-rlircm'-tcre. 

3-17. Cbemtol brrrometar.— Th^ method of tbn cli«cnicd farpo^ 
mBler c-m'-MlB iu ])n-viii|; m known vdluiu^ of nir ureta mihcUBnlHlidki 
Tondily nlanibs nioi:iiun> — cbluride of rnli;ium, for isxtaam. Iha 
itnaee baviag beeu w<?if;lit<d b^font tbu pawui^ of the Bir, ud l^w 
aftcrwnrd«, the increiuc iu wi^i|;ht rrprvwDta tbc luitiHint of wjMOM 
Ta|iour prpHent in tb<- atr, Jty iiipan* at the npparatus rvpt«ten1«d in 
S(f. i!40, it is pi>S!iblc: to eiuiiiioe ony jfiven Tolum«. Two braM TCMt- 
voir» A nnd It, of llie Mtnic *]>■« luid conslruotion, net ii]t«nuii'>ly m 
Mptratun. by bcitit- iLxi-d to ihv finiiio nxis. abuul whicb tbcy oui taa. 
Tlioy nro coonectod by a central tiibuluiv, nnd by mi^niv of two IntelBW 
iu tbt- KxiH tli^ lower reeervoir in alwayi' iu catinection with the alnw- 
■phore, while the upper one, by meiuin of a panutcboui? tiibo,ia cwna tc tel 
with two iube« M Bud N, filled eithvt with rblnride of caleium, or 
with pumice stone imprepiatud with »ulpliiiric acid. The tint ahaotht 
the vnpoiir in the nir drnwn thmiiirh, while the other M vtoiM tBf 
rap-mr which luijfbt diffuse from the nif'^rvoiM to the tabe N. 

The lower reeervoir heiaf: full of wiiter. mid the upper on* of air, Ibft 
nppamtud h )DTt>rled no tbnt Ibe liquid flows slowly from A to B. A 
vftcunm bring formed in A, lur enters by the tuV* NM, in the timl of 
which all lbs vapour in absorbed. When nil tbn watnt ha* ran into II 
it ii turned ; the anuie flow ret'ommunceti, and the mine roiume of air h 
dnwn through thn tubn N. Thua. if nach Rnrruir bold* a galltfti, fat 
example, and the apparatua buii been turned Ave timen, A gatlnun of aif 
havit travcnicd tbe tube N, and hiivc been dried. If thus, before tbt 



, ib» tafao with it> conteaU lias been wrigli«d, the uicrmtM 
bt ^na th« wri^i nf a^utoai rapour fnaont is 5 f^allnn« uf tit 

0«Bd*saUc brrrem«tera.^When n briiy frmUniilW coola 
•iMoiplMm, ibm Uyer nf air in itnincdiate coiiUft with 
■1*0, tot a point ia ultunalelr lecclicd at n-bkh the tnpour 
la juM Miflloi^iil to Miliirnlt ilin nit : thn least diminntiou of 
tliDn cauara a prccipalatiou of luuututv tin lLt> boilr in tho 
' daw. Wbeo tba tMnprnlun) rises agiuD, the drn- diiajipean. 

Txg. »0, 

nf Iheie two tempeistarM i» taknn as the dm- poinl. and tli« 
' oMid«t>aBtiii|7 byiTTometeta !a to ab«erv» thia point. IlnnicU'a 
Jt'a bjrgroiBi^Un twlnnfr to thin daaa. 

il"* bycT«iM«Mr.— This ronsUtn of two glnu bulb* at th« 

I of a gUjw tube bent tw.'ico {fig. 241). TIlp bulb A U iwo- 

I of oih*r. and a T»ty driicat^ thnnnoniutcr plunii™ iii it; the 

l>H toMee MntaioH notkinji but ihe vaponr of I'thtr, the nther 

|>oilMl befoi* lhobulbHwa<«nJi!d. The bulb Biscovcrod 

uii) pfhcr ia dropped opon it, The (•tlici- in i-vaporaiiny 

balb, and the vapour ctmtaiii«l iu it i< condcnwd. The 

twndoa being thna dinibiiilied, the «tbii in A fornia vapoun 



on nCAT. 


which cond^DM in the otbor bulb R. Tn proportum m dw liqaU ^mllj 
bora Uie Iottm U tbo vppvr Wb^ tW ether bMuoica cMkr,) 

nllimkldy tka MHipvrstuTS tf 
sir in imnivdial* oontaot with k I 
to (hat point ta which iiii nyMtt? 
moiv iliftii tuflicicDt ti> Mtvnto lit I 
il ia, iccucdinglj, dopnatad on t 
>ido M n nof of dew r 
the surfHit! orth« «tbcr. The i' mt-r^- 
tum of thu point in noted b; iii'^i:j <l . 
the ihemouieter in the iiuidh 
luJdilioit nf nthcr to th« bulb It ii lh(i| 
diKODlJDued, the tanpMstiire nf A I 
riiKMi, and the tcinpnn>tnn> at which tbt J 
dew disappean ia nuled. Ia otd«r W I 
luider the dcpoMtion of dvw nun pt^l 
cnptibtq, th» bulb A b made et kMcJ 

ThMB two pMDbi burin; bMB dsrl 
t«<nniDfd, their tncut i» biJu 
that at the daw pdat. Thn tMopo*- 1 
tur« of tlie air at the lini« of thai 
pxpcriment la indicHti-sl by thu tb«fr I 
m«in(>tnr on the hIpui. The VadMJ 
/, cMntpoodlng to ihv tvutpfTnluw of 1h« irw point, ia 
fnund in the table of Irniioiui (''tOtt). Thi> tiMiunn in oiactly thall 
iht vnpiiur pr^tf'Dt id the nir at the tiiun nf th« eiperiiMal. ttt] 
tensicm F of vnpour Hntunttod at tliu teinperatiini of th« ittmoifSkM | 
is fniind bv wtfuia of the imma labia; th* quotient oblaiwd b; 
dividing! /' by F, ^.>p^L'el^lLU tb<^ hytfrum^titc atate of Ihu air (3SS). 
f nr inetnnco, the tuttipF'rnturc of the air heing IS', euppnitr thndowpNol | 
bS". From the tiibl6 the cntrwpoDding tanuooa ari!/^ tl-61M RlUi* 
tneiTa, and F = VJtSM iiiiUiuicteie, which (rfrea 0614 for the cuiio etf | 
to F, or ibe hvgronietric atate. 
Thcr* are uiauy aouroes of MMr In DanioU'a hjeroroHet. 7k»| 
bprincipal arc: lat, that ui the rmpiiration in ihr bulb A anij oeobj 
^tbti liquid oil the surface, ih« tht<miometer dipping oo it AoM Mt 
exoctlr ^vc th» dew point ; Snd, that the observer atanding Dtar Ikt ' 
instrnrnvtit iiiodille^ tlie hygnimetric itato nf th« »iiTroDBding tit, aa 
well on ita tmnxnitiire ; tlie cold ether lapour too flowing &om thi 
. upper bulb may rnimi inrwcurncy. 

340. Bernaolt'a brcromatar. — HtigTiault's hygTometer is tnt fitm 
tfiowurcra of vrror iiicidpuial tu the um' of UanieU'a. il conaiataortira 

Rg. HI. 

I araROKETRy. 299 

kin pTklwliMl Hirer tiiitnUM t''A incb in height, and 7Q iacb in 
Mr (pg. 242). In liiMt an fix«d twu (cliiw t ubox. I> nod 1-; in eaok 
cb i> ft thennaoiDtef; A bent tube, .A. opi-Q at bnth vodn, pamm 
:li iki! covk or lb* lube D, tad ivachwi iivailv to the battom of 
iubb. Tbera ij a lubvluni aa tba nile of U, lildiig in a bm* 
Aidt fbrau ■ aupport for ilia apiMratw. The end of tbiii tube 
Hct«ii with (a M]iiniur G. Tba tuba E ia not ooinMted witli 
|intor J it* lli«raBMucta( iiiniplv iDdicatM th« tmniwiMuru of the 

I i> ia tlirii balf filled with ttbcr, and the itopcAck of tbe 
r«|M«d. TbawatcroontatBodiBit niiw«ut,anilju8l Bd mucb 

Pig. 141. 

litfon^h tli« tuba A, bubbling thrtni^k the nth<>r. uid criiutl){ 
Tkt* eTapamUoji ptoductw a ilintiDntion '•( tMnpuratun^ 
4>« it depoMlcd in the aUnr jiut aa ou Uif bulb in i>iuii«ir> 
r, the UwnaocaHtar T U tWn ini>t«ntlj to bo traul. uid Ifao 
tb» widralar (topped. Tlie duw vill mod diiia|i|H'nT nimiUf 
thaiiiiaBi«ter T b if^ain la b« iMid; (hn idpui "f thv two 
btakra: th« thtfrmotnoler ( giTMllieoorTMiMinding tvmpt^nitun 
b, umI boact' thnv am all tbo dement* ni'octtiiiTjr for otlculatiiig 


OK tlEAT. 

A* in tluii instrmnml, M the olhnr ii U the tame tca| 
iM)Mt<r)iience of tbe mrilHtiou, and th« tmuperaturM an nal 
dulanre br mriju of n tcliwcoix-, tim aaarcM of error in 

A much limpli^r form of ihe Appmtui nwy bo 

Crtmiiimi t«»t tiiV ffiHWinitig ft d^plh of ) J inch of adlMt 

kproviiK'd vitli u luowty lilting mrk in whioh iH H deliclle 

' ■nd n narrow brnt tubn dippinir in iho nthor. On blowinff 

ether, W a csoiilehoup tiiV iif 0''ii"id"rAble lenglh. a iliminiitii 

pomltiro is cbu«wI, aud after a little pmcticu tho wbolo proa 

condiirtoil almont •• wull u in RtigDKult'* cninplnio inntruai 

tonipLTHtuTi* of th^ air la indicated bv a trw t)ii?rmuu](*ter. 

•t41. Vafebramatar. Wat bulb tvgn>Bam%»r, — A 

eraporatUB In t)ie air mure npidlv iu ])rupi>rliuu us tlw air \» dA 

conatqiwitico of tbi« nTaporatiqii thn Irmprntiir" of lh» hndy nil 

pifichnnitltr or uwl bulb hy^amrlfr iir bii»>.'d uu Ihin priutipb 

plicnlion of which, to this puTpnsp, wfui firrt 

by I.eHlie. The foriu usually adupl«d in tbli 

duv to .^Inaon. It coDiiiti of two d«lii!ata 

plnciid on a wooden eland fflg. i^). Oi 

I'ovBrt'd with muslin, and is kept oun' 

beinfC cnnncictod with a roMrroir of wal 

ntriiij;- l.'iile^ lh» air is Mturat«d wjtb 

huib thormometer alwaVB indicaliia a lo' 

tliuii tilt' otlier. und thu difl«rrMiro brtWMB 

of tho Iwo thiTmimietora b grrator in 

can tiihe up uintv n)>iifitui«. The t^neiun • 

vapour in the atuuispbore may be cali;u1 

indicaliuDS of tho ihormomoUir bj meana of 

lag empirical formula : 


tn which r" is the uiaximuni t«n«Ion c< 
temperatiirx of the wet bulb thermometer, k i 
(iietrie height, and 1 and (' the rwpBCtive 
of the dry and wet bulb thermomutcT!- If, 
h = TOT inilUmelers, / = 15° C, /■= 10" C. j 
the Wble nf tensions (iW), e" = it- 105, and 
e = Bias — 0-00077 X 6x760 = 

Thii tension cotrfsponds lo a dew point of about iS" C. If 
hmu Mturulcd. lliu k'lisinn would hMV« beau 13000, Kud tho i 
foro about half «aiur«ied with moifture, 
Tlii'> fonuulu i-Aiirestt^a the roiilt with tolenltlfl 

Fig. 313. 

^^^^^H ^^ 

HTGROXEntr. 301 

miuUBt 0-00O77 requins lo be contrdlled for diflureot pooitioiM 
iiHtnnntBt t in snuU cUmmI rocoiu it is 0<iOISS, in Itajft roomi 
MIOlOO, Mul in the opeo air wiilioiit wind it U 000000; iha 
t 000017 i» iu value in a large room with opcu wimtows. 
all (aaoA Uial ibe diffsnnc* in tcinpcraiuro of the l«o bnlba 
• <■ ths npidttr of the CUrK<nt o( air; lie aliu found that at 
latnpefstiue, and in vcrv nioiit air, tlie fviulta obtunod with 
«konwt«r itiflend from th'jtrf yielded b^ bis livgri>inel«r. It ia 
b tkat thf iodicatkiiM of tb« paychroinetvr are only lru« for mean 
^ tguipc«turaa, and wh«n the acmocphprn U iiot too moist. 
brmiUa fmiaeatly uat^d la thia country i» that git-eu by Dr. 
u Itu 

di <f ia til* diflcrenee of tbu nnt and dty bulb thcrnioinetcn in 
imi Jtiftiiw. A Um banxnatnc hm^rht in incfae* ; / tb^ tpnuoo ol 
(or tbc tctnpi.Ta(iiiv uf the wel Mli, and F tb); i-luHiic force ol 
out at the dew point, fniin whirh tlur ilr^w pnint may if nrrmiHry ht 
|A6oit tiia tablet, 'i'be rouslunl cxHrtliduut **'i, f»r Iheupvcilic haata 
H^d flMnt, in to Iw nwd when Ibi! reading of thn wet bulb U abovt 
Band 86 when il u b•^ll>w. 

^knDllg to Glaiahor the tempc^rnluri! of the dew point may bn ob- 
H hy naltiplyia^ the difTnence betwasn the t<<iiip<^rntiirv# of th« 
Ha^7 balb by a cuoatant depending on llie tnnitiriuturD of tbf air 
^^^haf ulMcrralion, and ^ubCnu'lin;; thn prodiicT tbu* obljuued 
^^^HM tuuncd teinperatUK. Tbc fuiluwiug are iheuuuiWn: 


EsJ^v.'- ' ^•^"^ 

Tfmpnrattue F.° 




2B— 30 

:m— .11 
SI -32 





40— « 
4&— 50 
W— M 
fi5— 00 
00— rtS 
70— 7S 




an often known aa GtaMrr't faelor*. 
■fgiwiiiatara «r sbMrptlDB.— Tbeae bygrometen at« ba»«d on 

- A 




tlw ptupcrtv which organio Bul)«tM«« h»-n, of elon^tinf irb 

and of (wain ronitaFtniK a* tkttj b«co«iii^ irr. llic mart csMum 

tbe A«i«r or Smimirri igynmttttr. 

It eeouul* of a htan fnunn (fi^. 344), on which it fix«d 

frslMiod U iU u|i[«T •■xtriMuitv in a claiap, a. pn»-M«d wllli I 
Till* clam]) in moved br a tcnv 6. Tbr 1 
of Ihv liair psMiw Tntmd a puller, o. and < 
ninrUl wifight, p. On th* pulley there u 
irhirh movm ainnfr a gndiMled *ctkh. ^ 
hair bncomio ahorter tlie iie«dl« riiM, wl 
camM Iflnircr the w(<tght p maltM U rink. 

The scale i* p»duHted hy calling Uiat ] 
at which the nerdlc wnnld ntnnd if thn air « 
pli-ioly dry, aud 100 tlin point al which it il 
air oomplFtciK- >ntant«d with taaitture. 1 
taucH betve^D tbete poinla la dlvidvd tato 1( 


H<>giiRHll hn* doTotnd mwh tbtij 
Tender the hair bjfiTomnUt icientiScailjr 
without BUCMM. And thn utinwit that can 
for it 18 thitl it can be usedMaAyyeuarapf ; 
inatruinent wliicli shows nppiaximaielf 
ftir is mom or 1«m mraat, without giving 
lion M lo the qiiHutity of moistuiv 
Fin 244 dnts belong' the chininer omnnwtita, one 

coninirni forms of which is that uf a 
fijTU)^ *o nrmnprd in rwferenee to a little kotuc, 
when it is nmiat the man ^niis out and (ho woman 
vcTnii when it i« lin«. Tlicy are fnuniied on the property wM 
atringt or pi>?j'ea of cat^iit po&je^ of untwiating wh«n mol 
twisting wliuu dry. 

An t1ie« hygroscnpae only change slowly, tbvir indicatioBa 
bvbindluuid with tho t>1at^ of the weatberi nor ara tLi»y, 

343. Vr«bl«m on brFTAmetrT'— To calculate the w»igj 
^Totume of luoinl air V, tli<> by^omvtric Male of wliich ii ^ 
enttar» (, and the pn^ssure H, tiio density of the vap'iiir btinf 

F>om tb* second law of the miiture of (;aiK>a and rapoun, 
aeeu that the mi)i»l air i« nothing more than a mixlnr^ of V'ca 
of dry air at f, undi^r tbi* prewui'V H minus that uf Ike Tapani 
cubic inchM of Tapoiir at C and thn tnniaon given by iii« h, 
i; thew.- two values must, therefore, bu found se-parat«ty. 



foni«il«/3= F X E f3S5( pivm the teiuion /of tbe Tapoiir in 
',farE li»a ba.'m ilplfniuiifd, anil K in fnuoH in (lie Ishlm. Hi* 

/beia^lmownif/ U thn teiition of it»Bir,/ + y = H, faun 
/►sU— /=H- FB. 
yt w iiM oooMqufailT kmIvm [twlf Inlo otlculalbg tlie weight 

lUe inelMa uf iItj' aii at ^, and tlic ptnaurc II — PE, and then 

V rakic inctuM of rapour nl*i> al (°, Imi iinilor tlio pi^wiun; FE. 

\ nbic inckei of dijr air uitd«r tiic givi<u voDdiliuiu n'<ri|th 

ji".~^**.\«»d we wadUy m from problem III an. 328 

Mbjc inolwB of T^muT at f, and tbe pKuurc FC wdgh 
1,41 Y pp 
^v- . , ^. Addiug iheM two weightx, and Kductug, wo get 


(1 + rf) 700 

www mtambid wo ohoiilil have E = 1, nnd tho formulft would 
dianevd istu thAt aln-aUj^ found fur tlie mUture of gtatm uid 

fmnuls contaliM, IwcidM the weiglit V, mnny variable qiiAnlitiet> 

I, mad t. Mid, eOIUK^KMly, hr Ulun» stlci^eiHivolr Mfh nf thvmt 

unknown . iL> munj" diiiwnl ppibUoii" nuilii hi- ]iMpLi>.'>ii, 
B ti a clto a nr ttt* lo«a of wel«Iit experleaoad hj ttodlea 
tB tba Mr. — It ban hnea neva in ii))ciikiiih- of thp bnlnnri', ihiit 
iffUt wbkh it icdicatea U oulj- an appAreot wui^lit, auil in Ivn* 
fl raal wrigfat. Tbo latter mny be dedun'd from tbu fdriii^r when 
iMrml diat trtrj bodyweighed in thx air InicJ) nweigbt eciiial 
o( tha djjplaoed air (ItWj. Thin probli^ui ii tiowevw vutr fom- 
BOtoady doM ^e wiiiKht of the diiplnrcd fiir vnrv with the 
th* |iii»»iiiii, and ihv hy^iuux^lriL' atiilv. but tbe volume of 
ba WMghod, and that of thi! woip^htu, vary alio with th« trm- 
tkat a double oomcuoo haa to be inad^; one rolalive to Hi» 
otlirt In th« body weighed. 
rrlalir* to Iht wtijihli.^'in ard-r to make Ibi* comctioii let 
aiflit in air, and n thi^ir reid wrifcht iu lacuo i fnrCber, l«t V 
volume of tli«*u w<>ights nt 0°, l> the daniity of tha aububuice of 
mm made, and K ila cocllioieDl uf lineaT expanninn. 
le V bMnowa V (I + SKl) M f, btuci' thin is the volume of 
by tlie xtri^U. If « be the w<^i^ht of a cubic inch of air at 
Mnwrs 11 at thu Umc of weighing', we have 
P = n — » V (1 + 3K() 

Iko (braiol* P = M) (106) V m*}- bo rupkcod by £^ and Uw 


30 f 

fcrmuU becomu 

tm HEAT. 


= „[ 


» f 1 + SKft 
T) J 

whiirti iI*M Uw nlnts in air. of • Kvijiht n, wli^a „ U nf]itfi hfi 
vftliio. Put »inwttUthBwi>i)(Iit of »«iljic incboTitirinoreiM'lM'" '■- 
at tlwi l<mtii^rntitr^ r and th(i pr««iir« H. its vaIup inaj b* calnU'' 
mMM of t)i<i fnrmiila in th« fonfroinit pamtrmpli. 

Corrfrtian rrhliiv to /Af An(i!|/ hv^/hI.-'Im p Iw th" opptmil ^■ 
of tW body to W wi-ight-d. • itsroal wpipht in riwiio. rfitt dfiutt?,ti 
OielfidpDl of «ipMiaion, and t its temponttiiro, bj th« mdio rMSooinl'l 
abova wc bnr* 

Bj anng 11m method of d-)ub1« trete-binjri and of a nitmt«riMJM i 
iipparnttivWRtit i*/i'.thc tvnl weight i/itho diMirity tf', and the i 
A', awl ikwiiiiiliji- tbat the pppMiiK doo* not cbaog«, which i» aaUjf 

rnio, wn have ugaln 

If « and 6 are the two arm* of tlie bwim. ws have in the Snt wrigliio* 
o^ = /i^' nnd in the snmnd a1' = bp, whcti^n ;» = P. It«>pliiciiisFMl 
p by thuir vulue d-^duced from th» abovu quantities, wo bavo 

. ll->-(i+m-j =n [l - K'-gKQ] 


irhioh solve* the problem. 

• = n 

cnAPTER vn. 

comnrCTrnrr op solids, uotms, asn oista. 

•'UK. Tr^aaiBlaalan of baat.— WhiMi wi> utimd at a little dLOfl-'' 

from n lirii cir oth'^r «niiri-e of hfial wn pxpnrifinw the«i^ii»itlioiiof wnmil'i 
Thii hi-nt i.i not Itnnimilti.'d by lh« Interveniujt nir: it pa*«c« tbrowh it 
without rniiiing it* li'mpiTnliirn, fiir if vcp plncn n KTiyri beffiro l.hofi«tbt 
tpiuintioii ofiwHs to be felt, Tlitf h*Bt fn>m thB dim rrnrhes lu in ll» 
aamu manner. Thu bent, whivli, ui in thi* casa, i> tnummittcd to a hvdy 

•] coKDCvrirtTT OF mttML 805 

■ (lia vMim of ba«t withoul iiflVcting Uw I«nipcniUm of tho intw 
i^ Bndiiun, u ukl to be nulialtd, 

iMt U tiatuimtUsd in aBoilier way. Wh^u ckv end uf a in«Ul bar ii 
»i, k mrtain iauoaw of t«iBperaiuni ia prrninil^T oWriod along ilia 
Wkan> tba k <-at U tnawnitted in tlia ntAM of IW body Itttlf, U iu 
it ia Milt to 1m coHdicUd. We aball tint ooimidcr the iianrb 
crf Li«t I>v «iDHuclioii. 
Ufc «aMaa«tlTK]F af aollda.— ItodJea conduct luvit wilii diilereat 
cf &cilitv. 6'oorf nwiAirtt'ri are tlioau which itmdiljr inuiainit 
t, taA a* aro ths nwUliii whil« AmJ 
iMwiL lowbich cIsM bdotog llie r«aia^ 
%vnad,aMl nii«H ispodalljr lii{int« and 
•it^r> pr^<*^ arli-«ai«HMaMa(otl)e 

ot hmL 
h Mler to compwn loujthljr Iho ttm- 
rAf pawar at amdnitirrly of (lidL-runt 
ihwtf Con»tnictcd tlieappaniluii 
hou* fcb Dane, aad which ii lepre- 
Id fig- Hi. It ia ■ motaUio trough, ji^j^ 24i. 

1^ mean* of lubulutra aud corks, 

rod* of ih« MmD diuienmoa^ hut of dilTi'rcnt mstorisl* ; for 
ifon, copjMir, wood, (rlaa*. TbeM tvAa vstcml to ■ aliKtit 
b th« niMgb, and the parla outside are ooalnfl with vfti.wliich 
ril* at fll*. The bos being 61lod with boiUng wHi<^r, it >» uWrved 
M tba was nwdu to a certain diatnuce on the mrtallic rod*, whiU* 
lb> olhrn tliM« ia no trace of fusion. Tbo c(niduolii))r ]>owet ia evi* 
n^f iiaalai ia Frajtortian aa the wiuc haa fiucd to a icirnlir dialancr. 
l^cpiraieMl ia aometinira mndifind hjr attaching glaM balU i.>r inarhU^ 
Kaodi of the roda hj mean* ot wax. Ad the wiu niclta, tho bnlU 
Ifat, tai thia in th« omlcr of thdr mp«ctiTe cnnductirJtiM. The 
icIiMM with which oiettiog tah«a place u» how«T»r onlj a moature of 
I aonJacting jmrrT in caMi the uctaU hare the aame or nearly tho 

H. Daapntt haa conipaNd tlie oandudiisg [)ow#ra of doUds bv mnuia 
tha aypaiatua reprmcnlcd in fig. 'IM\ It U ■ bnr in which iniall 
lUeaavnuida at intervalsof -1 iiidiiw: tlii?-a^cuvitt-.-i<c>.>utain nurreiirv, 
I ■ deUaU thennoinetcr ia placed in uach uf llifiu. Thin l«r ia 
Mad ■( <NM Old to a couataat *outco of liont; the ih(<riiinnii-i<:'rA gra- 
Mj riia mill th«7 indicate lixad tcniprmtiutM, which nrv 1cm uccuTd- 
fM III* tiwrmonirten an further from th« nourcc of hrat. Itv tliia 
ilhad l)««pr»t< vcirifiL-d the (allowing Uw : Jf the dulmicn /mm tit 
fff *f Jbrf VKrtam in imKAnwiawrf progrt^tion, (Ac «f<«u of trmprralur* 
W^d ^ iht turfWnJiag air Jtcrtatrt in frvrnttncal progreitiim. 




This law, how«v«r, oolv pnt&ib In tbe eue of t^ t 
I aueb M gold, itUliniini. >ilTiir, Bad «oppi>r ; it J- 
true fur inra. line, It^ad, muI lie, and doM not mpylj «i uil Ic i 
m«t«Ilic bodies, audi as marlilci. porcclMO, etc. 

Tiikiii^ lli« condiirtinK pnwnr of ([aid at 100(^ DespwU fau i 
viniutol till! fuUuniug lablo oi ounduutiviliM : 

Plaiiuum 081 Tla . . 

.BilTor ... . ur» lx«d. . 

Cwppor . . - «»7 HiirbU . 

Iron . 374 t'orvulaiii 

ffinc •'M3 liriclc owiii 

WiodrmAnii nnd t'roni b>vi? modn tnmn raluable !iir«ti|;atiim <■ 
tbe cuuduullvilv of heal iii lUfMls. lijr initkiii); caritiM in iht ban^W 
in l>eiipti!tx'* ninthod, thnir form in &lti>red, and Um coqtiDuitT parliillj 
(It>str)y>>i1. %Vii-d^iiiann tuid I'ranx bavti tivoiil«d this io\itv» of amv hf 
mc^iuuriiip th« u-ntpi^rBtiira of the Imr* in tliiTeivDt places hj appljing t* 
tbcm thi' jiini'linn of a tln'rnio-elcctnc ci)ii])Ii>. 

Th* uieUllio Lara wtru luado as ri'ttul'ir (w powabli* : on" nt ibn «oJ» 
vnu bvatj-d lu 100°, lh<^ rent nf ibn bArb^iiiar tiirTOundnl bv air atacM* 
Maot Wmpc'raliiru. Tbt> Ibenurvvlectric couple wax of amail iliwiiiiW 
in order not to pxtract too much boat. 

By thii nivtbiv) Wii'^tPtiinnn and Frani; nblairii^d TWulta irbidi dlAr 
ccowderablj: from ibune of Up9|irotx. H^'prwi^nting tb* (yutdiicUri^ tl 
' by 100, tb(i_v fnuud for the otber iiiflala tbe fullowiug nunilwn: 

Wk] cuenicenviTT or LtqoiM. a<yi 

Uirr 10(H) Steel It* 

^pr . 730 L«kJ 8-6 

Md fi3-S PUtiDum 8>1 

. . 14G Hcwi'aaUoy 2-8 

lt-0 Affnutii ....... 1-8 

tie fabrtoncM conduct b««t badlv. Dt> Id liivu nud d« CwiduUe 
I ihawn ili»t wuoda ooiulucit better in thv dlcpL-tioa of tlmir Abnw 
ia a inuwTorM ditBctiini ; wid liavn remarked npoo tlis inllaenw 
lliia fnrlile comlucting powpr, in ■ tnuiavuittF diruction, «iiirti m 
liajr ■ tfM trom audilMi chan^ of tf^mpiMKhiTn, rnnblin^ it to, 
Ml* k nadden abatrKtinn of h«at fruui nilliiii, aiid tliu euddMi 
of bnat from without. Tjnilnll hon bIbo stiuwD tlial tbia 
,' is ■idi<<l br tliB low condnc^Dg poir«r of the bntk, which U in 
U ^H* Im iliaa ibHl »f tli« wuod. 
^itm. woiil. tirikw. limn. rif.. ttn all bod coDdurtori. 
M7. Baaannont'a vsp»ria>«nt. — tt U onW in h»iiiiipen«H>iia bodiei 
hal biMl i> rondactnl willi njual bcilitv in all iliriH^ioo*. If au aper- 
«« W* made In ■ drruW piocn of nniinnry glaMi cciT«T«id wilh a thin 
mr of wu, and a giUitinntn wjrv ij^uit^d by n i rdtaii^ curmit be hM 
bos|fh Uu> apFrtorv, Ibe wax will bn mrlti'd miind thiF bok In ■ (■irt:iiliu 
tm. Senarmiiiit luw mail*, on lliia (irini'j ]>!<>, a MrJua of vxiivrimunlii nn 
M crmilaiMivitT of bmt in cnstali, A plate cut ttom (i I'ljutal of the 
■■lar (Vrti'iu w»* ooFcitol with wax, and n livnti^ ntoullic |iranl naa 
till Hfataat it. Tbe pari milled bnd a t-irciiUr fonii ; bul irbtn plule* 
t ayrtaU b^lotiftiii? t" othrr nyiilrin* ircm inT['«ti|ial<'d in n niniilar 
■nsi-r, it iru found that the fonn <if tliit liiiv' of equal tfiiipvrnliiiv.lljat 
, tbr limii of ibi- molted pfirt, vnrit-d wilh the dilFi^n-nt svwnis uni 
Ml Ibe piMillau of ibe sxc*. In plnti-ii nf iinia^inl cn'ilnlti nil 
ITbIIbI tn tbn principal aiin it wa« un nlUpsc. thp majnr axis ot vbicb 
M in tbnrfireciinn of tb« prindpnl nxii. In plnlMciit jHTpi-ndiculaj to 
<• pritici}ial axil it ta a (irctu. In hittxial crvatab tli*^ liui! ww always 

M& CTiiMllillj »( U^bU*.— Tlif Moductirity of liquids ill •nry-. 
Ml^a« ia aMd from tb<? ftdl'twiiiic riporinicnt. A d«]iual« tht^niiuMcoptil 
^ liwIWiiifl oS two glaM bnlbi j.>iard by a tub*, m. in which there i* a 
hB tadax of colound liquid. i« placed iQ a laryri cylitidrlcul ulana 
MmI, D (%. 247 1. 1'hi« v<!ucl is filled with WKtcr nt the ontiuiiry 
■pfmliii*. and ■ itn vijui-l. A, n>nl*ining nil nt a Irtnprrnlun' nf Iwo 
ftknaksadred (ln|n««*ii* dipped in il. 7'he bulb near the lessvl 
I li ffply nn aliitlltlf boated, and the Indi-i m mnvoi thronj^h n lety 
id dataao!. Othrr liquid* giivu the *auie rebuilt. Thiit liquldn 
I rarr badly U alw douonrtratcd by a liniplur experuuvjit. A 




long taat tulw i* h«1f SIM iritli ynttr mi aom* ion k> flvra it il j 
Uhi ii rantx)! riM (q ilm stufiuv. Bv incliniitgr the Uibv uiil bMiui;A»1 
mrfaoo of Uie liquid bv iiir^nn* nf a ipirit Inmp, the liijuid M lir Hfi 
mity be Disdn tn bi>il, nijiU t)i<.< ity^ at llif billniu Kmum iiniHrilrd. 

Unqtreli nude a tinict of cxporinirati with an uppcnUiu i 
that which hn# bwn deooribed, but ]ir mtiaUitn'd th« Uqaid ii I 
TtBwIA.atk ctinstnnt ti'tnix-raturi'. and ammgr^ aieriesaf IhMnui 
MM b«inw the othnr in thi< viiucl I>. In iliia miutuer bo found tliM| 
couiliictiviiy of heal In Uquitb ohvj^ Hie Miae lawa as In *olJdit I 
raucb motr fnrblR. E-'or Pinmplr, the canductirity of water U ^ I 
of cnppor- 

M'.K Kanawr laa wbtoh UqMlAa ar* beated. nMi- m 

lir^iiid ii hcati-d nt till: bottdiD, Mcmtlintt nnd nr <'< rniii 
)>n}ilut.'Hl. It in bv tJiL'ie thai tieal is uiaiiik dieltibuled ikn.'ii£i li> 
liijuid, and iii>t br its conduotirity. Thcw euncDU aiis« tnim tli« *!• 

Fi^ 247. 

i-if. :!is. 

' P&ubIod of thp inf<<rior lavi^r*, which, b^oomini; Irt* deaMi, iJM i) 
liquid, anil nrv rtplii'^i^d Tiv uoldt-r Aud Aeaiei \aytn. Th«j imj bv 
vi"ililn hv projirtintr bmn or wooden »hBvin)(« into wati-r. which iw« 
and ditBcctid with thi- ciirn>nM. The experiniput in *rr«ng;od «# iJii)«n in 
fi);. 248. 'I'hr mode in wliicb bunt ia pnipagnted in liquiihi Bud la gMM 
is aiud lo bn by mnivificn. 

SJK). C«adnotlTlt]r »t sajiea. — It is n disputed qiMVtiOD whelherfHM 
bavo n tiui- rnndui^tirity ; but cortninly when tho; aro reMniincd in ikAt 
motion their condnctivilv le vetj »ri»11. All suhslancoi, fur inibnocv 
botwooQ ff hofr pnrticica nir TcmuiQi itatinnarv, oiler j^reat rMivtann i» 


» f i u pigrtfan of hMl. This i> troll •een in »tnw, eider doini, ud fun. 

» fnfi^itiMi of licM in a gattoua maM is effectni by nieitna of tbo 

■ad dMcending cuircaU fonnod in it, a* is tta case with 

n« follawtng eipniniMit origfaalljr devisud br Grore is coneideivd 
pron thml gura bare a eenaia condiictivilj. In h glxas wts^l 

I with ilaliTMy tubes b; which any ftu^t fsu ha iiitrodiici>d, nr by 

II cMU be exbaastnj, is b plstiuum wire nblcli can h>- btaled to 
by B TDltak bsttorr. When the towsl is exhausted tho plati- 

rim is gnduall}' miscd (u a bright ledneas; oo thiin allowing 

t M soter tlis lumiooaty ia srHitly diniiniahnl. and if lli<i vaan^l he ex- 

and Attt hyingta aduiitttid, Iht- lumiiiuMty quilu dlMppnnm. 

I y wt CT chiltiag of Uie wtrv in hTdmfrrn Ihno in air Is consid^nd 

'Ha^uatobe an ell«ct of roDdnction ; whila Tyndull sscribm it to 

I jcraaMr inobiUty of Ihs particlu of hjdni^Hi. 

331. ApFUsatUvaa. — Tb» grcntsr or Im« r^nducttiity of b^M 
• »ilh muneious ipplicalions. If a liquid is to lit- kept wnnn for 
tloDK tint, it is placed in a t«9*ul and porknl rniind witli iion^condiicl- 
[ mliataniiiii, surb as sliavin^ stinw, bniiscd i'IibjcuhI. Fur this 
I water ppss and pumps am wrnpimd in itraw nt (ho nppniarli of 
Tie Sams bhmhb ar» used lo hinder a body fmm becoiuiui; hvsti'd. 
is tnusportod in suininor bv packing it in bran, or folding it in 
ItoaUa waQ* eMWtru«t«d of thick plsuks Laving betwcvn tham uxy 
tU dlTtdad inaMmls such as shavingii, lawdust, dry lunviw, ntc„ rqtaJn 
1 exbrnnalj well ; Bud an lilt«wi«« advAntagi>ous in hot tountriui, for 
r pntMit its tuxi-m. Daring thr ni(fht thu window* aru i)pcni>d, whiln 
:UmAty thtT at* kept close. Purcsilieninllicslnl.'of rocli i-rv*tal 
1 hntttf cooductar than lend, but in & state of powdur It conducts vi-ry 
Llj. If a lajvr of asbfslos is placnd on the band a inl-hnt imn ball 
be brU without incouvt^Tiifut'e. Kcd-hot riinttoii bnlln I'un bu 
einl to th« gun's month in woiidon bnrruwa psrtislly tilltd with annd. 
Ijaia has bmn hnuwn to t1i«r ov^r it Inynr of sibrj imdxnii'ftlli which 
WM a bad of im, and the nuncoiiductiiig puwurof tbeash«Hlisapn.-rc>ntpd 
tfc» ice baga fusion. 

TIm elodiaa wluch ire wcw are not warm in themselves ; they only 
loiKla' tbu body trom hNUg hoU, in con*■^quMlcv uf their spongy texture 
anl tbe air lliry enctcM!. Tbc wannlli of bod coTf'n luid of ooiintorpsnes 
baxpJainediii a simjlar manner. Double winduwiiiLrL- frequently uiwdia 
mU cfinuKca to keep a room warm— they do this by tin: n-in-ron ducting 
h^ at BJr iolerpOMd botwrco thi>ni. It is for ibe same reason that 
twa lUiU aro warmrr thsii oui- of iho Hnmn ninloriii) but of double the 
Uencw too tfag wnroilb of fun, eid«r down, «tc. 


Thnt vrnter iKiils moTOTapidlTiii a meUUk tou^I than ttiMi>t(| 
Ma of tliv *«ini^ ihidcnow ; thai a bnrning piooe of wood au 
elcmr ia Ihf burning pajtnilh lh» aaSttd liMul, wlule a pcwofl 
liiMl^d At i>n<- pnit fan onljr bu Ilrld at ■ prpul dinfaiKt, wo i 
piaiaiHt bv retvrvacf lo Uivir varioas eoiidu(.-tiviti<<&. 

Thi> Minaliim of hunt or cold wbieb wr ftel wbon i» omlMii 
(vriHui bodtiM i« tuatwially iaItiiMiCAd by iheu' conduciiTitT. Dl 
i/iiiippnlurn i> lower tlan our*, thav apjwvtr colder than tbc^ '■*ltf ■ 
liM-MUM (roul llit'ir coniiuetinlv hi^nl pMu<m arair Onen ns. ICi 
cnnUaty, their tcmpenluni U bigbur tlian tJiat ot oiir body, ihrj I 
iranDer fmm the hnat whir.h tbry give up at didiirenl paiu < 
■MM. lUmcD ii U clear why L-ar^t*, fur Maiiiple, an tnut 1 
woodM floots, nod why th« latter are wntmor tbaa tioae floon. 


IU11UTI0X or SK-tT. 

!Vi2. madUDt baat.— Ttbs«beea alrMiily »iAl«d (34S) Ibailwat '^ -■■ 
b« transmitti^d fruui laiv budy to aaotli«r without altering (hvMiBpcialun 
of thti iaIerTciiiiifr medium. If vm stand in front of a fit« v« exp««iRMt 
a BeuBatiuD uf warmth wblvh in out due to the brmpcratim of iV KT. 
for if a iHTfien bu iulerpawd the inniciition immndiat^ly dit^pMH^ abk^ 
wuuld nut bo tliM cawt if thu «urt>juu<]iug air bad a hifflt tsnpcntan- 
Ilcuce bodies uiui seud out m,vii which rxcitc bent, and irhicb poMtnU 
tbtv'tieli thn flir without b^nlin^ it. tin ray* of light tbruuj^h tniufaraU 
bodies. Ui<Nt tliiia prupii^nled ia Miid to bu radialttl; and wa tbalj --' 
iha Wna* tvi/ii/ Amt,or iJlfr'nnl »r /.•nUn-ific ray, in a liiilllllll iMinitl %•' '''"' 
in vbicb we use lliu Isrui I'uy ii^ %A( ur tmiiinout my. 

W* abitll liud that The pMpctty of rndintlnif hriat i* not oonfui'<- i^ 
luuiiuuiis biHliug, f<iii.'h a« a ttru or a red-but bnll, but that bodis 'f mI' 
tamimratuiva radiate hent. It will bs cuuTcniont to siaka a ■*»'■■■"'■■' 
betwwn luminaiu and abtcurr rAj« of heat. 

36$. Xaw< of radiation. — Thu nulUlion of beat ia gomn'd ^y 
tbiw law*. 

I, Sadxotiim lukfi jiUicr in iili dinvtiont mHiid a bodji. If a tbei- 
momailaT be placi'd in dilfen-'ut piudtions rotuid a heated UhIv, it LndkatM 
ocorywbere a ri'c in i>TmpiT«iiir''. 

n. in d Avmu^enwiH rnti/i'uHi, rot&itwH tahei piaet m a r^^ imf. 


RjLDunox or meat. 


-, ifavTH-ti bo plflfwil in Ui« ritrlil line wbich joilM tbe«MiRc eShtM 

^. m \mtainp ubliqttel^ fruui ime niirJiuin mta uiothtr, n* trmu air 

ftf;UM,«*liiri6c-likrluinuioiu raya lM(»in«doiMUd,aiivfrect known 

Th^ Iaws of l)iit> jibi'ttOBieDOU ■» the wmu ftir bfiil a« 

Itfit, uxl tbf^T will be taort fully dMiuii-d uodi-r the Ultvr ruIh 

IIL Atdnrf iUa< u fropaji<Urd m ranro 4u trwtf oi m aiV. Tbla ia 
•mteil hj lh« foilowint; rxpcriniont. 
' ! boOoni of a ^Ibm Auk it tticntiowetor la fixed b «ucb 
If ibat iu bdlb occupi«) the centre of the Oiwk (tig. 
Th* nv-'k of the fiaak i* ihra cai*fiilt,v DArrowfd by 
■ aftbr lilowpipv, •nd Uieii tlip ■ppjuntun linTing beta 
■It atUcbd to an Mr pump, a vacuum is pmduced 
ti- Meckir. Tbu bavuig breu done, tbo lubo ia ii^aJcd at 
1^^ auTVm fKiU On uomcnjiiftlhi' appnnituii in hnl watvr, 
OD fariafiiiig oonr U mmdh liol cbarcual. th« ikvnuonwiet 
M> to riw. Tbi* could only oriae 6ona radia- 
thnngb tbp Tacuiim in the interior, for glan is n 
! a etnduelar, tliat ihe biitt tould not Invrl with thia 
\tj tbrougb thn hiIm nf thp flai>k, and tlia turn of 

■a wbtcb D»dl(7 tlM Intaaalty »f mdlaal h««t. — By 

I MfMniry ^ rurli'iinl iraf L( Dndantood tho ijiianlity of |it«| Rcci\-ed 

I ibe mit ^ iwArDB. Tiuve cauwa arv fouud lu modify ihii inloiiMly ; 

I tfapataUm at lb* afurtw of boat, iu dinlanrp, and iliv ubliquity of 

talorifie rayi in rehntKt' to tbe siirfuci.' wbieb t-mitj them, Tlio 

I wliieb •vgaUtv tbeae modifintionii may im ihnu «l*lvd ; 

Tit intnuHtf of iWtairf Antf m prtipoHioHiil fa M0 f«in/in-iifu>-« of (Ar 

rir mfmnt) i* inrrriefy a* l/ir n^ioww ^tAr ^idamcf, 

tUtt rmS M J Mf naface. 

^ Tba fini Uw la daOMialntad by- placing a metallic box containing 
' at l(F, ^ff, or 3D'', auco«MJTely ai c-qual disianivH fram ibc bulb of 
USenatial tbi^nuamctcr. Tlia UmpEratiircn indicattid by cbc lai[«T 
a* (faMi fiHuiil to b« in tba name ratio •« ihoAv of ib« \nx: fur lostancp. 
If tha n-mp'ratiiTe of tkal eormfwadtng to tbe box at 10° be 2°, thote of 
iba oilMn will ba 4° Mid fP i««|i«etivo1y. 

TWaMMld l*w ia d«mooMrnl<d (^iptTrimcntAlly by placing thn diffM- 
M&d ihRrnMatM*!* n > rrrtain dintanc^ fmin thn onuice nf beat, 
nd tbm nnvring ll to doable tb« distance. In tbu latter caae, the 

Fig. !iO. 



tMnpcntan.' » founil to bo oii*-fo«irth of what it wm tntli»( 

Tho truth of tb^ »i>rnni1 law alia i 
from 1li« ^oaiKtrical priu('i|i1>.> tbm I 
fiHTe of A ■pbiMW' inrrpAvii at ihn nqnuei 

MllilU. SuppOH A liulluw H|lll«». 

SCO), of nnj gtvcD ndius, iind > . 
hMt, C, io itn cratn ; mcIi anit of t 
Hw InWrtor ncvtriM ■ certniu iju 
))i>aL Xnw, a uphfT^, *f, of dixible ibt i 
will prewut K lur/iuM! four timii* •> gfMti| 
iiiternnl curfnci^coritiuru, thcmfon^ (bar I 
_. aa lUHoy iiniu uf »iirriu:i>, and m 1Ii«^iui4 

of betU emitted UthBMiu(^.<-'ach tmit will ivcM-iveaiiic-fdiirtlitlieqaNM 
Tba thiid Uw w domutiAimtt-d by mmm o( th* following «i]>«riM 
dviiit-d by Lvalle : a flat cylindrical tin caniaUr, nm, ia pUcvd Mm 
(iMienvn niirror (&((. Wl|. Tba bos tunut ou u ItomonUl axU: tlUf* 
a tubuluruat lb« u<p, by whicb it maj-bn fiUnd with hot mitr.aill 

Fig. no. 

Fig- 2.51. 

nnlerior (ace ix covered with Uiupbl&cli. Belw(«D tliii box nd 
mirror thcrv oru two siTtn^tu witti equal aperture*, il aud K, M ■ 
allow a pi.ncii a! parallel raj-s ti fall on tlie mirfate of lh« mi(Tt>r. 

A difforeolial thorTiionMt«r liavlni; been placed in ihn focua of 
mirror ihc couistpr is Hiljuated ia tha vcriical po«itioD iiniKimlwl 
the dotted ]in«8, and is kepi in that pimitJun until tli« tfaormuaicMr 
become vtationary. The cimiatei is tben incliiicd in tba porition an^ 

REruumox op hut. 


i« irtill foand to iodJcaW th« Mine tMDpenlure, which 

I tha Uw. Fof in lh« lint cu«. tbe portjon of Uie siitImc of 

I wiaek mitd» f»y» tow«nli> ihn mirror is i«pre«Hnl«d by a circle 

|AwiBter te oc, tad which u omMqucntly c(|ua1 hi tfac npcrtun 

to Ibit wieoad rate, thn (urfnco i* hd eilipw. thn inajai 

Iwhi^ M at, and tha minnr aild tbu tliAim^tcr of tkv ktwiu, tliut 

I Th» Mcond MliCkM U larger thou iho iint, and il thtmfnra send* 

Inn lA Uu n>irT»r. Itut la ihn accion on tfae Ibennometer is do 

Mb than in Uic first caw. il folluwa ^at ia th« MKwnd muk-, when: 

kllft aw obliiiitf, the intcnnt}' ii lew than io tbo fint caw, whar* 

9 m* ppTpMidicii lar. 

p Mder to expTHM thin in a formulB, Ii;t ■ bo thn ialciisitv of tho Ttyt 
btti papaodicnUrly to thn aiirface, and V Ib&l •>r the obliqiin rays, 
ta iuiouBtk* tie oecMaarily uivvibcIt u tfao surtkoc?* ab and af, for 
lafcat i« tba Mma in both oMtui, and therefore i' X (nirfacc ab =^ i x 

In ar : heaoe t* ^ ■ " - '- t = i "T = ico* inc: which ariniifie* that 
■nrf. ai ab 

mlmmlf ef aUiyar rayi U pmporlitmal U> the cotmr of On amjU vAicA 
<r rwyw/orm kwTA (A' itomMif r«M« nir/ncw; fur thin nn^lc ie ecjual to 

n^la lar. This law is known as lh« lam «f tlu cmmf ; il ts, how- 
ff BOt gaoanl ; HM. UMiina and !)•> In I'tuvDHUfe hiivc «kowu thai 
I Mljrtna within I'-ry iMrKiwIiiBitstbiil if>, only with bo<iies which, 
ilBnpUaeh. an cntitvJjr dv.ilitule uf rvBccting puwer (362). 
fL Mafclla •qUUbrtun. Thaary nf aacbaBsea. — I'rnvoiit of 
■ra wmiali il the foUinring: hypolhmiii in n-rnvucc to rndiant heat, 
wa am PKvott'a U^my o/cxehangr*, which is now univenoJIy admitted. 

kxiiaa, vhatcrar their Ivrnpentun.-, conatautly radiutv h«at in rJI 
Mioafc If w« imauiiH two bodica nt di9'i.Ti>nt t<iiipi.<nitiirps placed 
•vmm MWtbar, U>"i niwi al a higher ti'mpnmtiirti will nipcriiincit a low 
hat, ha tempersturv will gink bpcauBe ihe niys it tiuila art> of greati>r 
■Hty than tboia it rocriTOJi ; l\\f colder body, nn iha contnuy, will 

In tcmpentutv boCMite it ivct^ivea rays of gmalvr jiilviuity than 
a which it ntuila. Ultimately the tenipcratun; of both biidiui be- 
ta Um NUBe, but heat is still exchanged betweeu ihein, ouly each 
(«ca ■• much ai it Mnita, and tbo ttunporAlurn mmains constant. 
I stal* ia callmi thn mMir njmHihraim of temprratvre. 
W. VawMa'a law ar «o«Uac. — A body placed in a vacuum ia only 
mI ur heal«d by radiation. In tli« almoiphnre il becomes cciolnd 
miud tif iu oonlact with ihe air aoMrdiii^' as tbe latt«<r is colder or 
lir tlnn the tadiatin^ body. In both comi the velocity of coolinj^ or 
kMlae — that is, fA* finality of i»at iod er yuiwd in a iccond^it 
Hw atearding a* the dillbrcncc of tcmperatarc i* i^nter. 
lawtoa hw Miwiciated tbe foUowiaf; law in rvforcncc to tb« cooling 



ta aur. 


wbmHnif of n IhvIt: 71* jnantSy of hait tctt or ftiia*J Sfi 
■ivMnif it jtrejtnrtinital In fV difffrrmx idTicrnt Um Umptrvbm i 
tht iitrratmilitiff mrdiiim. Dii]a«ig and IVtit h*Te prnvecl llMt j 
not M g«i)cral k» NeTton BnppMed. miiI only iippli«* whvrp tfa(*l 
of bMupctuUiw do not exwwl IG* to SO". Bavand tttnt, tha i 
heaM Ion or gwned ih gnntler thun that rcqiiind by thia latr. 
IVn eoiuequL-iices fotlow limi Newton's lair : 
i. 'n'hfm a bnily ii nxpoHfd to a cnnitont noiinv of li«at, Iw J 
lure dovH Dot iQcrfRFu- iDd«fliiil«ly, for (hv qnnutity whieb it nn 
lb« MiniP time i> alwny* tlie snmc : while that wfaicb it Iwu. !■ 
with the (<xi.wi.if th" tpmpentnire over that of the nimxiDdiiig ■ 
OonMqacQtty ■ pntiit is returhctl, at «rliti-h ihe qiioatity of hnll 
it «qiial to that abttorbm), and tho tcmpcmliiTv tii«B nunwst ftttil 
IL Xcwifln'a law. On applied Ut the difrMvniial th tim wn w hrf 
thai it* indiratinnn nn> pmipurtional to tho ijiisntitlM of bMt« 
MC«tv«CL If ou« rif ili« bulbH of A difTcreiiliBl thennOBeCer ncct* 
nf b«At fniiii a conilont imurco, the initnuannt nxhibiti fint taa 
ti^mperHCiirva, hui nfterwaide b«eMiiM ttstionan-. la lh!« eu 
qnaittjty of hi-at which it recrirfB ia rqunl lo that which it tontl 
the laltiT iu proporlirinBl to thp i-xcpm of the t<-n)p«rMa» of lb 
■buTe Ihat uf llif nurn.'imdiDg iitmnkpber^. that is. to tltc nUB 
doBTcT.t inilicntcd by th" tbtrmom^lpr : eon»t()iiiMiilT, tht tempi 
iudical^d by the diffetvntial theniiiiiii«t(-r i» propurttonat ta tb» ^i 
of heat it cvi-oiica. 

KKrLnmoir op beat. 



aw« or relle«il«n. — When thermal ny* &1I upon i 

an, npfnlriiiR iirncraiiy, difidcd ia 
p&Tta, oni^ of which ptnptnli* tbi 
while the atbnr twbnund* ■» if I 
Inini the mirface lihc an etastic Ul 

is mud to be rrjirctrd. 

If mn bfl n plane wflMltiiS' Mifi 
'i^i), CB an ineidcnt ray, ItU atiaa; 
diculitr tn the Kurfare railed tlieiwn 
BA the r^fixUd rtiy; the angla I 
rjtUed tii4 taiffle of incidenrr, and DBA ibc taufi* of rpfrwft'iw 
ntflectioii of lieat, liliu that of Li^ht. ia go*«rued by tli» twa^ 

L 7Aa ofle of rifhetum ii ffoal lu thr anglr of iiKidenft. 
n. 3M iht intidnU imd the reeded ray ore in (Ac i 
mnmd to |A» Trjtr<iii\g mirfae*. 

Fig, 252. 


! Um mav be |«med, as we ahall ae«. 1>v iiK«iifl of roacitve mirrora 

I XcAactloa (ram ovBoiTe nttrrora. — CmKntlir mirrtr*, Ot rv> 
, u* jiiTlUhrd >|dMnoal or pwatiolic «tirfaM« of meUl or of kI>>*» 
. m lupd (o coBoeMrata huninou* or calorillc n;« in the aam* 

lAtll oalj MDudar Um auw nf (ph«ricd mirroni. Vtf^. 254 wpre- 
lafUiMo nrirroni %. 3ft3gl*«aa mmlial leciion, which is »U«d 
•w^Mwi. Tb* eeatK C of tbo (pherc tu wbiob the minor 
i k ctUcd the nntrti ^ emriMlKrr ; tito pniM A, thn ntiddlo of Ikft 
liAtkoamlrao/tAeJtfwrti the vtraigbt line AB pUUItg ihtougb 
DM, It tfaa fftndjuJ aiu of the mirror, 
dn tu apply to opliuicAl tairron the l*vr» of reflection from plans 
, ther an eoiMqdi.-rHl to br ajanpowsl of an infioitc niuubur of i&- 
} lauU pbne Burfuva, eacb Wlco^g to ilie corrupondinif tangent 
^th« Durvabi Eo thwaimttl ■uifacca are all ndii ot the Miue «phore, 
llbvefura mtKt nt ita c«Btr», ilia renUe of cuiVBture of Lbc mirror. 


B f y w BOW, mi till* kxi« AB of the niinor MX, a aource of heat «o 

iMt tlial llie r»Tn EK, I'D whkh pmnnntn from it tnaj^ be 

■idMMdaa ■ pMT«kU«l. Frnm tbehypi')llie«i«tbnllL(' mirror in compnuod 
IB nfiBitudA of tmaU planta, tbc t*y KK ii roHcctcd from the plane 
fmt M tram a plsM mirror; ifaat i* lo esy, CK b«in|t ih« normal to 
b flMM. tbe mbwtad rar l«kea a direetiaii lueb tbnt the anfrle CKF 
«fMl M> the anfti: CKR The other nyt PU, 01 ..... arc ro* 
etad in tiir wunv manner, and all mnverf^v appiuiimHlul;' lowords the 
■a poiBl F, aa ihs lian AC Tbimi ii ihtin • cnDi-nntrnlinD of the raja 
dua prant, nnd tonaaqNMilly a higher temperaiuru than at anv nthor 
nL Tbi* poini ii called ihie/ocat, and the dinlancr^ from (he fucua to 
■ matnr at A to thmfaral ituimnt. 

ve tgnie the keat ia propagated along the liivvi EKF, I.DF. 

he heated 






placed at F, (litt h»U U propagated BlvDg Uie Ubm FKE, FD 

ibc ray* vmittiKl frain th* noiu m nnarlr cftrallel nSlet rv&»e6 

•1W. Vcmonitratlan of tta* Ikwa •rr«fl««U*n. — Tbe (bB 

p«riiDCiit, wliith vt4a niiuli- fur tlie lint tinin bv J'ictoi and . 
which ij ktioira u the npirinntt of tha catfni/aU mimir*, i 
uut oalj Um «(ittt«DC(i <ir ihu iaiA, but also thii Uv« of nSceti 
t«flccUir!i, M and N (fig, 3M), an ■muigL'd at n diatiuiee of 4 1 
u)d M) Ibnt thoir »xm cnincidv- Id the tuciu of one of Ihen, A 
a autall wire basket cunlainiiig a r«d'hot iron b«U. In Ui« Cm 
other i* plRcrd It, an intlnnimahln bodv, Mich as gun-roUooorph 
Tbe m\t- uitiitlcd rp^iu the fui'iu A are fint rntloctcd tnau the I 
in a diriKliuti parallel to the axl* (itSS), and impingiDg M 

Pig. 364. 

mirror, N, are reflected so that thny coincide in the fooui B. Tl 
is »o. in proved by the fsci that (he gun-cottou in thin point tal 
irhicli IB uciltho case if it is abovt- or bs low it. 

The «ixpcriu]i.-iil Hi»f> »erv<'6 to uliow ihjil light and hcnt am rt 
iu the aume manner. For this purpose a ll(;htecl uandlc ia )ilac«d 
focus of A, ojid n ^oiind rIiuu ■r.nM'n in the fncii* of B, when a 
nous fociin i" "Cfn ou it exactly in the spot where llie fnm-couon i 
Hence, the luminous nud thu caturilic liKt am produmd at dm 
point, and the nllectioD takes place in both <^iimii according ta Of 

Kzn.Kcnox or iikat. 


it will be aflnnntriU Hbiiwo tliat fm- Ujclil ihe aiagle of reflpcltMi 
to Uw> uigrle «f (iicM«iMO, and ihit bulh the incidont and Iha 
n; Mv in tli« atas plana peqMDdicuUr to the pluie re-!lccCiDft 

■MpMHtM oT the bigll tempentuTn produptiil in the fori of «<n- 
tbejr bani bfwai Raltul Au/Wny mirvr'. It in slated that 
burnt the Booiaii t»»W'1« Iwforc Syracum; bj nn'uns of taieh 
Bnfliin cMUrtmctcd iHiming miTmn nf iiicli powor at to prove 
fnt Btiributed lo Arcbim«dea ytaa p>)teil]l(>. The mirmn wi-r« 
• DumbcTi>f ailrered plane iiiiTTDniiiWitr^iiichr'alooKhjr A broad, 
bi> lUTiMu) tiid«pMld«nt)]r of «Mh uthur lu nuch a mnnnrr that 
nfladBd from each ooinriiled in thn hiiiir point. Wjtli ISS 
1 ■ bcM Hiiutiutr'4 iiiui BulTon ignit«d a plank of turvd wood M 
of TO _VAnl». 

S«aeeiloB IB a Taonnm. — llnnt in roQect/v] in a vacuum a» well 
', a* baetn fnnn tli«> folio wiDjc riptriiDcrit. due to Sir IliiuphicT 
Two Mtall cdoicavc rnlJectotB wrm plw^nd opptwitn cncb c^tlinr 
inir of an air pump. lu the focus of one wh« plnccd » 
tbennmaeter, and in the focun of the otbrr a platinum wire inado 
\iy mixuiii nf a galvanic enriMit Tb» tbennoniei«rwaa im- 
^TM3FnloriH> fevera]d«9nM,«rbichcoij]d vnl.vbodaatoroflMlHl 
|br tli« thicmMmctur did tiut thow an; incri'aaa of temperatUTo if it 
itoi «iactlj in ibc fociu <>r tlie meooA tvflector. 
I aifpanal r«aaeUoB or ooM. — If two mirrom ant armn^d a» 
IMmI in fi)(. ^*>i, and a piei'« of ioe is placed iu ouu of thv fod 
of Ibfl md-bot twll, tliu lummndinf; tuDipumture bciiif[ RTcater 
diflcrmtial thcnunointeT plncwl in tli<i {<.<en» of ihe tiet'ond 
womM vzhiint a divreau iu tvinprature uf wrt^rnl dcfrraeo. 
al (ir«t to be ratiBcd by tbe rniiMdon of fngmifif rnys from 
ia^ bowwvnr, natilT «xplain«d from what bn» bi>'ii paid about llip 
Ubrium of t«nipetalui« (S66), Tb<^^e In niili nn fxchongn of 
I, bat ham the tbcmminittcr U thi' wiumnxt body. A)i the 
Ibf lh«rnMin«t«r «niit« an mora intvuM than thow (^nlitled 
tbo former givM out moN htnt than it ncoiv oi, and honcn it< 

tion i>f cold experieneed whon wu ulaiid ni-ar i pla«ler or a 

Hwhoag trraperatuiT i> lovnr thnu that nf our lindy, or when wc 

1 i4 a «'«11 ('f ii-*, i* e\pliiiiiL-d in ttip Biiniu way. 

etlBs p«W*r. — The rrfifftiitg power of ■ Mibittancp is iU 

of tbrowtBgoQ' HRTeateT ur \vv» pruportioti ri ioi-ident heat. 

power mriea In dlSurunt lubntancv*. In unlcrr to study tlit* 

diSamnl bodtn withnut hnvin|{ rfooiiroe to ax many rpflcrlurs, 

hi* exp«rimeDU aa iliown is fi|r. 34&. The wtirce of 


tm IIGAT. 


he»t U * caUcal caaiaWr, M, now imawt) m a LrtHe'* nAt, Oki^ 
hut wktM. A plMT, a, uf Uic Hul>*tiuice to be cxperiiiieali^ i^ 
plncwl on tbo nxi> of ■ rslltccintt mirTGiT betwn«n Ui4> fonu nl 
mirror. In thU niuiner tbe rsva »inltt»il by tlie aource tut Rntnlj 
frocn the mirror aui) iinpiuj^p on th« )>laU) «, wbors tbc; cm tfU 
tecU^d and coiiTrTKo to a (oea* WtTtieTi tli« plttto sitd ibe numir.ii* 
point a liift'i-nTuliHl iLeniiouiviFr i« pltuwL Tbv rvflMtut Hodtbt 
momi'toi tm olwny* in the inmc pMitioti, and th« wiUir of tbe ei 
alwBvB ktfpi ni IOC, lial it li fouod tbat tlie tempttniliiK iodioli 
til* Ui«iinoinel«rVBriM with th* nntUM of tbv plate. Tfai* in*(hidi 

a nicnns of JeterniiiiiD<r. not (he absolute ivfUctiiif; pow«r nf ■ boj 
its |)i>w«t ivlnlivi.-l}' lo tliat of nome hodf Ink«D an & atan<Ui4 • 
parlson. For. from whiit hna bet-u mid on tbo upjilicktion of N< 
law to tlie difT'T^ntinl Ibpnnninntr'T, tbn t«m|vrBtiir<i« which iM* 
mant itujicittnii urv prbporliouul to the quniilitii'* of b«at wUdi 
OHVM. lli^ncc, if in thn nborn rxpnrimi^iit, a pkti! of iflniw cMU 
Umpentiirt! to rim V. aud a {ilntv of li^ad (1% it followi dii 
quMtity of hunt Tulleati.-d by thu Intti-r in lix tintcj as fcn-M n tl 
fleeted by the furnwr. fur tho hnnl fiiiill'xl by the miuiv« rsinai 
Mune, ihe t'outavo rcU'-i-Ior iw^Itm ihe iium>- porliou, aiKl tbo difi 
Mill only itriic from Ih« roilM^ting poorer of tbe p[iit«* a. 



I natind Loelli? delennioed the rellrctin^ povoM of ibe iol- 
|h lM>M «, RUtircly tn ibai of br«w, taken ax 100 : 

knM 100 iDdi-n ink IS 

f 1M Amnlgainatvd tin .... 10 

tia M tiisM 10 

70 OiUd pUw S 

m L«nipblai.-k 

nb«ts ontr reprvBuDt thf rdntirr^ n^fliTiinir pnirrr m coniparod 
ot bmuv. Tbair attotatr pnwer in Of •••iaiu-n o/ thr ^tmtily o/ 
llrd la (Ar ^tumtily wf Anrt ravtmcf. MfUoni tint dt^ti'Tniinrd tU« 
nflcctis|{ power of aoert«in nnmtwr of kixlini. ni>«nini> Rnil Do 
itave, wIki aUn (•xsminod it fnr cerlain uii^ihIv, cib(Aiu(>d tlii> ful- 
•olb bjr meaoi of M«Ilom'i Lhi'ruio-iiiuhi|)1iFr (37^1), the lirnt 
iMtod Ktaaasgkof A(r>; 

OOT StMl 0« 

\ . . . (HVi Zinc 0-81 

I OflS Iron 0-77 

' 0-83 Cm* iran O-?* 

pmnatlr ate (^fM) whit am th« enam which modify Ifis 

tftairfctaf p«wer. — T)iv A»9rhmf po'rtr of a boily ik itn pin- 
kUowiim ■ ^alrr or li>i«i ^uaotitj nf ini-iil«<nl heat to [iiw bto 
Ila aWlule yaine Is lh« ratio of ttic quau^tyof lient alianrbnd 
■nti^ uf heat reciuvnd. 

MortiiiiK |M>vr<T of a body in alwayi fnrenely h» its rcflMrting 
iMidy whicb u a i/ftoA absiirbRnt i* a bad nHcctor, and kuw vrrtd. 
ttONly nuppntiid Ikat tho two pdworg wet* exactly t'oitiplpnipa- 
\ ifa* anm uf lh« rvHrcteil and abwrbHl beat wa* iHiiinl ti tb« 
•fil; of iaddent heat. Tliii U not th« CmM; it is slwaya !(■»; 
Mt ImbI U diiiilfld into tiirw part* — \el. oav wliich in abiorbnil ; 
Ifcer wbicb is refluctod rrgularly— that \%, ni'irording to Iuw« 
r daaioiMtl«t«d (•1A^)t -trd. ami a ttiinl. whicli Is inv^ulnrly 
In ftU dirvCttMU, and irbich in (nllid icatta-rd cir difutrd hral. 
tr M dat^iraittiR ibn nWirViing powor of hnditi>, I.L'xtii' iihvd tbii 
f wUcb b« enipluyiHl iii dutprminiiig tliD rellcL'tiu;; jHnn-pn t,3<U). 
IpfnMMl tb* plala It, and plntwid tbn hulb of tlin th€Tiiinni«t«r 
pa af ibv rvdect^r ThU bulb b^Lng ibni covprwl »iicc(^wivvty 
ItHnrK oc Tanttah, or with ffold, nlror. or coppvr foil, etc, th* 
Mer w(titbtl«<I a higher temperatun under tlia iofliiene* of 11m 
I htl. U, aioourdu^' aa tbu iiubataiice with vtliicb tbu bulb waa 
iMuibnl ttiom bsaL. LmIw found in thi* wny thai tho nliwrb' 
body i* givaler the hwt its luSvcdu)! puner. Iii ibuw 




■KptrimcntV iMwwvor, tbo relatioa of the kluwAiiiit powen 
lodaMd from thnl of t)i« tnai|wi»t<ne« IndicHUd iij Uie 
for Newton's Uw in not «XMtly spplicftUr iu (fab (so, m 
laiU Tir bodiM whom imbMaiiM don not ruj, uid b«n: 
the bulb vKried with ««rh obMrratioD. But «e •bsU 
(S6S) how tbn companliTP nb«ariiui|{ powora ms; be deduCfi 
niioe of ths eminive pow«n. 

Tftkin^ M » aoumi nf hcM • mnittar 61U<d with wata 
Hellwi found bj nMww of the thmno-multipUer ili« foUo' 
ibwwUnff powm : 

I.ntiiphUcIc 100 Indiui Ink ... . 

White liHtd 100 ShnllftC 

Imnglwn dl Mi'tals 

304. XadlatlBC p«war. — TIii.> radiating tit fnimw 
iu rjipabUiiy nf t'iiiillin(t at tins «mo twupcmlnre aali 
Mftnt of nurfacn )(rfHtfir or Ipm quaiilitiM of heal. 

Tile appunitiii rcpnuvnlvd in fin. S^O wm alio lued 
milling Khv riiiliHllii>; ponor of hmjiM. I'or lhi« purpoM 
thcrmoaiPter wiui plnmil In Ibe foruHof lU^i n>flifrtor, 
the CAtii»t«r M were furmpd of iliffi-rpnt niotAU, or covered irill 
mibitaiu^iHi, *uch lu Inmpblfink, pnper. *1^. Tfie cubn bBing i 
but watur at lOO', tinl all uthur canditiDim remauiiuf^ tbit 
tum»d each fnuo of tha cuba HteoeaaiTelT tnirardi th« ivBei 
notvd the t^iinpirature each time. That fai-e wbidi «** ta 
lompblnt^k i^uuawl lht< fp^alMt (>loTAtian of tcmpcratun. and 
ffiO'V" tht: Iniwt. Applting Newton'* Uw, and rtpiwatiag 
emitted bv an 100, Leslie formud the foUowuie 
r«di»tiii(i powcni : 

LainiibLick 100 IsingUsa . . 

White lead 100 Tarniahed lead 

PKpec 08 Jlercuiy . , 

Bnalinj; wax W> Pnlished load . 

Oniiiiarr white glau . . . M I'Dlished iron . 

loduin ink fls Tin, gold, rilver, nopper. 

It will bo Mvrn thai, in this tfibtn, thn ordur of tha bodio* 
the rvver^o of IbM i[i the tablu of rvflurliug' powem. 

The TadiBtiii)f powen of setrrnl nubstancM were deter 
Mellon i bf niPiuia i>f tbo tlienuo-multipllnr, and mon s 
Dcaainv and I>e la Prorostnve, who uiied the M&ie intlru 
f'STcidod mrtain wiurcei of ermi Jnt-idonlnl tu jimviuiu metha 
found in this maiineT the foUowEug iiufflben compaKd witli i 
a* 100: 

xaatMrruai or iixat. 

lll ti fl *l 1 H w 



PuM aili«r laminntcil . . . -tOO 
„ buruifhed . . . ?J|iO 

catl^ mid bur- 



>, tlmt th« radiadii; power found hj Lwlie for tli« 

nwer f>r a V"dj ouinot bf ncniiiiii-Iv liiMiiic"! fmm ils 
awpT, bfcatiM tL# Ivro ar^ not cxactljr t'oiuplomi-uUrr. 
orlwng povfrr would bo ilelcniiiniil if it could bfi kliown 
baJT it ia equal to the radiatinit power. Tliis oon- 
dnwB bjr Dulling anil I'etil from the foUowin); cxpitri* 
a Inge gUia glnbe, blackmnd on tho inndn, wiu placrd a 
f at a cntaiD tMupemlun, I&' for «<xaiii|)lc : the (flube wiu 
bjr aunantdinx it with iov, wtd bnvitig bcnn rxliaiititnd bj 
nbulnre eanaeel«d with tb» air pump, ihi.- tiuju W(ui uoietl 
td wliils tba tbtrmoinetpr f«U through C. TIir oxpnrimnnt 
de to Uie conlnt; dirrctinn ; thnt in, tbo aides of tlie globe 
I to ltt°, wbile the tbDrni>jiu«l«r wsa coolui] to xcro; th* 
ben obaon'ad which the tbcniiomL-Utr occiipiiKt in rlUDg 
It wM found that this tinio 
IIm Mm« aa llutt whii^h the 
r liad taken in unking tbmuKh 
<W tlMnoe concludad that lh» 
i« (iqiiBl to tli4< abiorbiai; 
t MSM bndv, and fur th» samo 
tween lU l«nip«niiun> and thv 
tt th* miTaundiDg medium, 
qvMititiu of beat «roitl«d or 
tbi!> nhw time aro equaL 
\ mar alio bo d«9Kins(nt«d hj 
)■ fntlowinp appamliu dcriaod 
W\g. 330 rxpmKnla what » 
diRomotkl Ihwmometct, the 
ullia of which are repUwd by 
•iciU pmwTTodm B and (', "T 
full nt air. B«twei>n ttivm ' 
lari,*>'r ram A, whieti ran be 
ot water bj mvaun n( a liibu- '*■ "* * 

•CM of n and of A, wbiob fnct! tli« right, m^ ruat^r) with 
iImmb of C and A, which faro tho Uft, arc citbiu paintMl 
I- J 



vhhe'^ir ue conted with tUv«t (60. Hiw of th« twti bcM i 
Otlur, one it h\»A and the Ath«r wbtUi ; bram vrhta tko i 
filM with hot tmter, iu vhito fMw radMtoi towards tb« 
B, and it* bUck face t«nrda the white face of C. Cn 
eireu instil D<«a ibe liq»>d in i1i« Kma do^ not inoT«, 
tho two Tr^PiToirii tn at Oip same temperalan.-. On tbe one 
gr^atnr AinifgiiTfi pnwi>r of ihn hUrk foea of A ii corap 
uniallKT nbnuqitive ]x)w«r of ihit white fac« of C ; while, on 
h»nd, lh« fMbler mdUtiiig pom of thr wbitr fncp cf A ui 
bj tbn |m*t«a' shaorblag pow«r of the blitck fno« of B 

Th* nxporiniciit may b« raried by ippU«iiiK Ihe two wbtt« CmH 
dian of paper, gins*, porfi-liiio, i-lc. 

SOU. OttnaM wiu«b modify tk* T«a««tlaci BtimorMnc, i 
i«41«tlnK p*w«ra. — As the radtatuiK and abiuffbaBir powon an t^ 
any auine which *tr«<t« the nae aiTiTU the other abo. Aid 10 
nAKtin^ power variM in an iiiTerw maccm', wbatenv '"'^fl 
dinliiiahM Uie rsdiating and abxirhin^ piiwrni. and n'lii Hiri. ^| 

It haa tNMfu aliVHilj Matv^i that lli«« dilTi^TeQt powor* jnfl 
diQimm bodic*, nnd that mntoLi ham tho gmatHt mBnctliig P^'*^ 
iHnpblack the fev^hlesi. In the Mma bodj tbeae power* ani bmAH 
tbe dngnw nf polinh, ibn dcnaity, thu lhiekn*M of tbi> radUtln^ MibMi 
th« obllqtdly of th« incident or einitti^ rayit and, hutly, br tbe H 
of tho •ounro of htat. 

It has been aniiimnd nanftlly that tb* reflecting power iiii muni 
the poIUh of the ntirface. and that the oth»r power* diminitb tinm 
But MMIooi ihowrhd thnt hy >cnit«bing a poliabfd mrtalUe auttm 
nSecting power niut *oi)i<>1iniM diininiAhed and notuotimiv tnoe 
Tbiii phonnmennn he atlriliutiKl to the ^trratrr or Incu dentilr df tt< 
dectini; «urf)ict^. If ihri plnte hnil h^nn nrigiiially hunmerFd, llibi 
gmnitj' would by di-slMfj-ed by thin proonu. iho moWulM won! 
clmer togethur on the BiirTnrv than in th" intiriiw, and tbe nt» 
power wo u\d be iuun-MMl. Itiit if thv surface isHcratchnd tbe iflt 
Knd Inwi d«n«i nin^ bccoinei oxpnspd, and the rrAnciinjf poww i 
riished. On the contraiy, in a plalo wliich htm not been luutnmml 
which U h'mio);['neuun. the refleduiy; power in incrrnicd wbnti th* ^ 
scratched, hemiiM thnd'-naitynl thn nurfacn U increased bjr tbeacnl 

The expL-riuicnU of Leslie, Riiuifcird. nnd Melloni ftirthpr pto«* 
th<i thickness of the mcliulic); dibiitiinrn a1*o modifies ita «n 
power. The latter phiK<>op1ier foiinil ihal wlieo tho fanw of t^ 
fllltid with wntor at a L-nusliint Imipcmlirro wit* rnmt'hpd, tbti' 
nive power iiirri'a»cd with the nonil><>r of layera U|t to 10 U;«a 
that above that point it tvioaiiied conKlnnl. whalerer tbe number. 
C>t)culat«d thnt the thickiiMn of thu 16 litvnin wan 004 of a 



i fdcntiM to oMiUl*, gold Imtm of 000?. OOlM, uul 0-002 of > 
laaWr in thickncon, liaiinf; bno aufvouiTfily iippli»i) ou the miIm ot 
of flau. tlw tlimioDiinn uf raiit;iiit )i«at wiu llic wuiie iu uwli caa:. 
thenfora tUM InlwecMi wrtiuii limiu, thi> thir-knoN of thtt 
Hlag UvBT of lUffUl ia wilhoul infliiHiicp, 

n ■h-iibliig povrer varies nilh Ihi- iuclinatioii of the inddnnt 
It i» gTn»t*«i at tbo Domial inciili>nr>t, that u, al liirlit aagj«a;. 
it dimiciiahca in propoKiotl aa the mi'iiluit rnya (Icvialc trum th*'j 
wL llii* i> ooa of Um PBMona whjr th<i aun w liottcr in mimnwr j 
in winter, becauae, ill ih» tanaex cm«h, iho Mlar tvf» are l«MubliqiM. 
W radiatioK pnwoi of gMeoiw bodioa in * nUe ot combuation U 
imL. M i» M«it bv faria^ng th« bulb of a thcnunniatsr iMar « 
dsmo, the t»iiip«nlura of which ia venr itifih. But if a 
•[NraJ be placid in thia flamo, it annuaoa tlin tvm]HrniIiir« of 
111 radiate* a ooMidetable qtuuitiljr of heat, aa la inilii:a<«d 
M tbwKaaaBlsr. It ia for an aaaiofCDiM raaaon, that the flame* of 
■d of gtw UtBf* radiate nMm titan a hjdrafaii flaiuv. in conaequawM i 
■■ rxe«s> of earbon wliicb tlui,Teantain,atul whieh, not bvin^ eutiiclf 
Md, beMimea LticandMomt in the flaiiie. 

17. UilluMl'a y— aarc b aa «a r«4lABt baBi.— Fur our Imnn'ledR* 
piMfioDiMM of the r>*flncti<iii. «miA»ioo, and abv^rpEinn of boat 
lure up to now been ilmcrribcti, sduncc it initcbleii uoiuW to 
Bui wnce hia tima the di«<i0T«ry or olh<T )ui>i far lunn? delicate 
deiaeiiaK and Mewurias h««l has not oaly extundiid and 
owf proTtntia kanw1*d|i», but faaa ]ad to thn diwororr ''f other 
of ladiAut h««l. whkli without aucli )ui)>rov0d moans itiuM 
lad nnkbown. 

ia iciance tt dii* to an Ilaiiao philoanpber, Mnlloni, who 

. iBatnunetit called the ibi'iUKi-rlcctrii^ pile, icvcnied by 

mMWiMiMint of Ti^ry aiuall ilitrem7)ci^B of I(>in[Hiraliiro. 

llie aclloa of the appsmtuFi h kuuwledgv uf ibHrm'-)- 

bat for tba pnsi'nt piirjinM it ia xuSicient !■> 

very ilifrhl dlffeKaoa In taupcrBlure bt-twwD tlio two nnila 

ihaiiiiii bIiii nil pile m Mtfficient to produm an electric ctureul. and 

m a iloflectioH of tb« maicuetic iie««lli« of • delicnW galva&o- 

and that, witbin certain limils, lliu deflectiou l» ))roporti<inat to 

iperatura. Th« HMibtlity of thn ii»:riiinrnt Li aiirh. tlint the 

td tba tmnil at a diManoe of a raxd ia auflleient to derelopi' in tbo 

Llacwmitr»pab1aof dofloetinfftbanaedleaf the pdranoinot»r. 

at Ifau dellcMj and aMutncy of it* indicationa the thenuo- 

invariablj* enplojed for rracarchM b radiant heat. 

Srna^lcal tbmoryot baat.— Ilefom dMcribioK the r««iilt* ar- 

by Mellooi ncd others, it will be cinToiittal to flatc ben the tiew 



now founMf tak^n of the thiihk of heiU «nd of Uib motk m 
ftOftgaUA- For Additional lorornuition the diapl-r on th« 
TliNijr of Hoat and the book on lAghl shouM bo ratd. A 
wImI U oiIUkI th« nwcAonina/ or JjmamukfW (AM>ry o^ ktal, a 
nalhlu); muiv Ijian one wlMite piuticlm an in s «lalir oif vibj 
bi|thcrth(- t^iDpnmtaroof thebodrlbomontmpid arc thrscii 
t A diaunution iii Ifiiiiiwrntiira i* bui a dimintabed npiiiitr nf 

I particle*. Tho (irojxigatiuD uf brat tbrough a bar u ilu« U 
leommiiDicMtiiHi of this vibrat'iry niolion from tlif biTalfd part I 
Lflf the bar. A ([ood conductor in unu whicb iwlily lokiii iipi 
J nita th« vibratory motion fnim partiole to pnrtidp, wiiilo n bad 
* ia one which takeii up aud tranamilA the nioliuu with diiGcl 
flveo thruugh a bad conductor tba pmpiij^lioii of thin mntioa !l 
tiralj iloir ; how tlien ara w« to explnio tlie iostaDtiui^uua pM 
hi-M fxp^ricncnd wbon a M?n«ti in tcmoml froto a fire ea «h 
la ilrirtvd from thofacvof the «iin? IniliiKca*^, the beat piM 
bixly to nnotbnr withcmt affwrliiip the tempiraluri! of the med 
traDHmita It. lu order to niplnin th<!ai> phrnnmnnn it iai 
•pace, the interplntipliu'ir Bpnce« a* well aa the iulir: 
crystal or iho biwiifst mntnJ, in short, mnttcr of any ki 
by aniediiim having the pro|)«rtii"* of a fluid of infiuil« 
fiJuT. The partiL'lnt of a hrnted body being in a iitate 
Tibration, ronimnnicintn their motion to the <ilher nrnnnd 
it into a ayntem of warp8 which travel through itpoce and pai 
body to another vith the vi'locity of light. Wht^n thn qbA 
the ether reachagiveu bo'lv, tho motion la acniii deUverfid 
particlo* nf thut body, which iu turn bi>^ to vibrDti>, that il 
bei'ouiea heated. Tbi* piMiagn of motion through the hypotkt 
ii titrraed fBdiation, aud n so^caUed ray of heat is merely til 
of the lootinn of on* ucri-'s of wavfu. 

It will Cnciliinte ike tiiitti^rstSDdiDg of thi« to MHiaider tba' 
mode in which noimd ia pniduiH-d and proprijnited. A •oundi 
oufl whose entire luaax is in a klAte of tibration; tfae t 
the rain of libmtion, the mor« acute the sound ; th« liowi 
of vibration, the deeper thn sound. This vibratory motion M 
cnted to the lurrounding air, by means of which the vibnd 
thn auditory ncrrc and there produce the wnMition of Kound. 
ball be healed, say to the temperature of boiling water, wa et 
that it mdint<'8 beat, aIthout;h we cnnnot nee any luminostj, 
t^mperaliir* lie graduniiy ralwd wi» «oe it btieiime aucrMdre^ 
nd, biij^ht red, and dnixling white. Here it is aaaumod tk 
puticiilar tempfiraliirn tho hcnti'd body emita wnrea of k d4dl 
in otiier nordv, its particlea Tibnte iu a oertain period. Aa il 




I U aciMU out atbur aail mon rapid undulations, whicli eoiMiiat 
rvilhall ihiiw which itb«d pravioual; emitted, Tbiisthomotioin 
I inmAvc tompiiratUR b ocimpauiid«l of ■)! ptvcrdinfi aaet. 
t U* b<«B MMI UhU Tibntions of the sir below nnd above h certain 
IBOlafiMA UlaRUidJ(OI7Mtrr«; U nn only tHliu up nnti tnununit tu 
l*ibntiafM of * ecruin periodicitT. .S>> too with thn rilimlinna 
lymdan h#«t Tlie n^u Dcrre \» uiaeneiblo to h butp- nmuUrr uf 
(teftfa*. It OKI appnlMnd onlj tboM wkt«i that form tbn vinbln 
If Um mie of undulation be ntnwnr ibnn ili» r>.»I or fii^t^t 
I Ibr tiokt, tbaoftti inteDH motion iii>y piUB tbrv>uj;h the hunmuni 
bt ryn vid fall ii|kib tbn rolina, ynt m> ahull Im utterly unconMnoii* 
he hct, foe the optie aerve vannul Inka up unil i-etpond to tli» rule of 
I which exiat bryocid tho Tiiiblo ■pcetmm :□ biith dirrctiona. 
UiBa« are tMnMd mrttible or itbKtirr r8y«. A vniit qunntily of 
, dWim raja are Mnill«d by fl«me<< which, thnugh intonwly hot, 


nt jrt afapoct lum-lutniooua, «uch a» tba oxy-b^drogM fl«i)« or tbnt of 
a Baawd'a burrM-r ; fur lli» tibrationi which thewi emit, though capnblii 
in |Krt of pTDetniliiig t)"' mndia of the cyo, AM incapabli; uf iixoitlujj in 
tkavplir iirt\<- the irii>iiliiiii of li^'lit. 

3W. TiMrouU muMljtU af aotKr llgbt.— WhtMi avolar T«y (fi^. S1S7) 
admilti-d ibmuiih lui aperture In a dark room, i« ■:uii<.*eulriit«l uii n prituii 
tif rock aalt bj miauM of a Lena of the wmc mnlcriol, and tbca aOct 
•BUTfinfr fmta tli« prism i« received on a trreen, it will bt> found to 
inaest a ImuiiI of colotln in the following order : red, oiTMif^, yellow, 
IpHK, Uw, and *Iol«l> This 1» called the tptiirum. 

If ui>« ■ narrow and delicate thenuo*pile bo placed snccvMlvely on the 
apK« f<mpiod by Mtch of th« ttAatxn, it will ncanwly bo nllL'iitd aa lh« 
■iifal, but Lo p<^un? ovur th« Otbur coluut« it will iiidicnti; a iimdital 
lam of tBmpcnture, wbivh i* gnataat at the red. I'aintuiv thu^ ((uidtd 



fay a ooRMt but anoaudouB feeling, always apttk ot blue nd , 
oolotin M coM, and of t«d and onuigsaa warm 1od««. If thxpiUkB^ ' 
movnd in the Hiuia direction bejaai Um Unit* of tbc liunitiaua i 
the Wiapfralnrv will gta^uallv rtM up to CP, at which it 
mBiiinuni. Fmiii Ibia pubt tbe pile iiidiratai a (lcei«»*e of I 
until it rcoLbi^s n pnint (>, wh«r« it MMM to be aiTsctAd. Thu] 
about M ili-ilMJit fn>iu R astlie Utter i* from V: that is, tb«fv ital 
ill H-hicb ihcroutl (iflecta are prnduMd cxteiidinK ■* f^ boyoad I 
nnil of tlin iijiivtriini ir oqh diMetioii aa the rutin leo^ of tWi 
Dpci-lTuiu in in the othvt. In accorduice with what we have (tWdt 
Run'ii li|;ht cnnniln of my* of ditlVivnt mo* of vibntloD ; br tliMi| 
M|^ Ihruujfh llii^ ))[utu thvy are uDaquatlr broken or tvfnKtei; iLCMl 
KnwtoM wnrc IraRth or nlDwant vibr«tin(i period aro liuuit bmt 
aK said 1u be tLt< b-iuil t»&M>gibU, wbUa ihoxe with sborirr WBte Id 
ta« the nicut rofnutpblc. 

The«e Don-luminoiiD ray* out«id« the red art- cailvd the «xir< 
wd nyra, or unmet i men ilie JltriKheliaH myi, from Sir W. IK: 
finit di»cov<ir^ tli^ir *xi*Wniip. 

If b tlie abuve cat? priniu uf ulhsr taateriali than rock aalt ht vmi, 1 
the poritioo of ninximuni bi-'at will bn found to vary with ihf nMan «( ' 
the prlam. a fm-t linl uoliccd by Secibeck. Thun with a pnw «f 
water it in in the ytllow ; with oiio of crown fclasa. b iho middle *( ii» 
ted, and M on. TIimc- cljaogi^Mere dne, ae Mellooi siibM^ueutlyfoairi,le 
the circumiitanMa thnt pmnii of diSTereat nmtpriidii nbantb r>y> of difftnM 
refVnn^bility to unciiiiinl mtenU. lint rork *nU pniclicallT allom IimI* 
of aU kinds to puMwilb i.'(|ual fnuility. nud ihuB fri^ea a normal fpNtnni. 

370. Tjndall's reaeareliaa. — l*raf 1'yildiilt has n^crmlly iovatifMfd 
tbe spei'triiin prodiic>.Hl by the electric liu'bt, aui.1 ban arnTed al waw 
highly inipHrtniit results. His mode of i-spL-rinn-'ntinj? wb« w foUon : — 
Tbe electric light wbj" produced belwepo charcoal point- by a Gnwe'l 
battBQ- of lil'ty cells. The brnin, renderrd jiarallpl by a donble rock Mil 
teOK, wa* caiUNid to piws thmu^h e narrow tilit, and thnn thn^iigh ■ fKOUil 
leoa of ruck laJt ; the xlices uf white liiibt Uius obtainrd bein^ dFComperd 
hy a priun of the HHmn mattvial. To invciititrato tlio themial oonditioai 
of the apectnini. a tmrvr thermo-electric pile wh UMdi that ia,t»t CM- 
«tj<tina of n nurnhpr of elements arTHnged in a line, and in ffirat of «> i-*: 
waa a elit timl coidd ba nftrrawi>d to any nxtnnL The ianrumeiii " 
mounted on u nioveahle bur connected with a fine acrew. ao I'.i ' 
turning a liondli! Iht> piln nould be pushed forward thn>U{i:fa the mi~' 
■pace. On jiIdi'ius tlii.n uppuratiM, ori^nally deriwd by Melloai I' 
raaearebes on the Boinr ipectrain, JUCcesMvely m each part of the fp-. ' 
of the eledrii- liyht. the hflfttinp etfwted at varionn pointa neat ■ 
othar noa delarminiMi by tho indicatiODH of a rery delicate f[mlnniotu!;:'-. 

Wj UMANT hkat. ftt? 

in Ihf «aM ot tba aokr tpnftniai, lli« iMttlJnp efliwt graduftllv in- 
I*hJ (rwn tlM violet Hid XDmtit ihe red, and itm Rn^atiut iu ihe iluk 
n> bcvcmd (bit i«d. Ilv poMlion of tli* KraiitMt beat wu >b»ut m 
fciD ih* limii of tli« *MiUe nd m the iMter won Irom the f^nan, and 
|iMal emcnt of Uieir ristUe iptclrum ww fbiind lo be twiau that ot 

«- y- 

Fig. 318. 

I facw M * of tanpHstnn in Um <)Bf Ic *par« ia Tery coiMideKble. 

I tatHMiiUM ut TcprMeni«d hj pvrpenilioulaT liiu^i of propor- 

M«c(«4 «l tboM put* of tb« ■pcctniRi to whicb tixtrj 


Tit- 3S9. 

, an pwNng b«ruad the r»d end lii«»« liim* infmuw rti|ji<lly 
■tJy in Ungtli, n»ch * nuimuin, and ibpii (all «>iniflwhat moro 
^ , ' If thepo linw •«! oonnui^tcd thflj- form % cime (liy. 2r,tt), 
K^tinvond tie rwl Wp»Wiin!» > iiiaiuiTc )ti-alt. wbich quitii dwarll. by 
ni'tuatr ti»t of Um Tutble >pw:liuiii. Id li|;. 'iSO the dark {•bru »t 


ox nuT. 


aboTC Itetod, on th* nmlta nbtotnnl hy pMf. TyndoU with tW (torf^ 
1I(^L Thie iippFr run«, la ll)r. 2'it>, r^nwnu ihe ppvcUvm oThIM 
liglit ftoin thn psprrimpnta of Mu!l«r with • rork wit pritin, vliil* tin 
l«war enrvo repnwot» th« rmult* obUined witli tW lun of « fiint ^ 
pifm, wliicli )■ thu* ■Ten to abaorb aom« of tli« utlra ml radiMUoa. 

rrof. TjTidaJl roiinii that lif istmponng vuioiu) nAfVaicra, man itfi 
dall/ viiter. in ci-rtatn IhicknMseo, io [be patb of lh««l*«tric li|tbl,Al 
uUm-rciI nulintion nn> trrrnliy dimininhi^il, tba jx-ak wai not saMtjl 
Now oqupous t'AporiT would, lik<< itxIht, al)»orb th* obacnni laja iM 
mort ptobfiblr tlm rcjutnn why thn obMum piirt of the ipecUwin it M 
»nl«r iig-ht i* iiol »c> intenw an in tho cane of (hn eloclric liglit, iiUnttW 
oboiruTc myc bavv b^^rn partially abmirbpd by tbe nquMiiu TajKiur it ■■ 
fttinoipliprfi. If a «iilar •pfflriim cniild bn prn(liir*»i (mtrnde tll« ttMm, 
gpliprr, il duublli^Ha would ^'iv(< a Hpwlnim iiiuk tiko tbHt of Uia *l«>dl 
U^ht, wbinh il unintiunnM-d by tbn RtRifaphrric abiKirptiiin. j 

Tbis liaa bevu remarkably conSmieal in otli(ir way«. MoUooi (ib«in^ 
that the paiilion nf tbo mnximtun in the aolar upcrtram diScn oa £AA 
ent <lBy«; wlilch is prvibably due lt> ibe Tnrying nhforptton of tbe MM 
■pbt'rp, ill coiuicquciicr of ita TsiyinK bygromvlric atate. lUmitlj 
^oi^hi, in Itoni^, ]im fi>mi<] tb« Nunc ubiftini; of tbo niaxiinain t>4C(i 
in the difr^n-nl ifessona of the ymiri hr io wiiitvr, when then iiM 
mmstiiri^ in Urn ntmonplipm, tba maxtmum in farther froos the nd tbi 
b Binnnirr, wbnn 111" aijiit^iiuii t-apour io the ur is moM ahondaitL 1 
ituporUnl ubservaliun mi tlir lumiuuus rays hax also biwn madi^bj Ooefcl 
in AimmcTii, who found thai ihi^ faint black linnt in the aoUr iptcUW 
attributed to ibe abMrption uf tight by our atmuHpbero (ace book o 
Optiw) arc chiofly cBUBed by the prturnpc of aqiipous vapour, 

371. Kamlnona and ol>««tire radlatlaa. — U btM been rtaladtti 
the mdiutiou frt>m a liitninoua cbjcrt, n Rai HnniL- for t-vample, > t 
a eoiiiponiti' chnnieter: n portion consisM of what wo term tight, h 
a far frrcati^r pnrt conNista of huit rayii, vrhit-h an- iiiiH»uiiibl« W M 
eynfi, bnina iinnblo to afTei"! tho oplic nnrre. Whfn Thi» miird ndiauo 
fklts upon ihi? bliii-'kened fniv of ii lberuio-«Wtrit.' pilf^, tbu wbolioti 
ia taken to W nbsorlied, the liKht by thin ni^t Wmg cnnvi^rtcd intoM 
and affettiu^' tbp iiistrument pniportiooftlly wilh the purely calorific rW 
Tho lotfti radialina of ii luniinouii kiuivb, r»prM»ed in units nf h«l 
force, can IIjh* be vnea*iired. Ity introdncing into tbe path nf tbti^ 
a body captillt.' of Hlopping citlier tbe luniiauuii or tbe oIibcutv radi*t!M 
wo can Bicprtjiin by tho oonipBrntivo artiiin on the pilo ths wlati* 
quantttie* of heul and li^^bt radia1i.-<l from the •oum. Mrlkini wu^ 
to do tbi* by piuain); a luminous brnm tlirongh a Uy«r of waUr crt 
taioiug alum in «oliilion ; a liquid which h« found in ptviioiu aqtn 



laO tt« rMli*I»3n rfoin builied bcatnl undrn- incnndfuorneo. 
le iTBimiBunott thfough tbiii liquiil — which allnwod the 
I of Ui* bdUii to pMMi but <]ueii(.'licil the oLncun- )iarti<m — 
iminjoa througk a plntc nr rocU init — whicli nffri^tod 
amnowi nor ike ohttvtv nuJisUon, but pive tbc Ecus due to 
dlmi RTCokd the MtonUbmx fact IhM DO per erat. of thn 
I an dl Amm and W per cenL of (he ndiAtioii frain ui 
eoadat of inTinble calorific rata. This prDpurtian liu buon 
incKaMd by the kmrI rxpnriindnts of I'rof, Ttndnll, who 
ifuid free fram the objiwlioiis whirb hnve caused a eli^hl 
ni*a racthDiL I'ruf. Trndall diacoYrrni that lodiDn, wbiUt 
1% i« traM|ianait to tb« obMure fa«at rays. DiwolTJng ibis 
UiolpliUe cf carbon a aolutian nw obtainiKl which waa 
tb« moM itttnw* light, but wondnrrally pprvtoiiB to ndiiuit 
■Sglit ahaoiplimi he'mg effepti-'d hj thv bi»'ul|ihiilr. It; 
oipu in g the tunimiiiidon ihrougli thn trniiipiininl liquid, 
oinlaa timiigh tbu tamo liquid n»idvn<d ujiaijcii! by iudlno, 
hv lunuBoo) ndiatioti from Tarioua naurcva nu found to bo 

ma. LuminoU). Otucarv. 

rtipinJ 100 

{00 fluM ..... 100 

M S 97 

■M 4 99 

•liotapjml 4-0 00-4 

cBgiit 10 90 

«ct vxperimtDt tbc raUo of luminous to obscure rsya in 
^t i« fnund to be I CI per cent nf th« tnln! rndintinn. Kt 
THs, thv carrv Rhown in 6g. 'iHH wu o1)t«i[ii?d, j^rbfliirallT 
be proportion of luniinoiu to ob*cure nya in the rlpL-tric 
lenUtiS); the aciDaa ot tho two kpaciHi in the diagnim 
watiQa i» found to bo nsM-ly 10 times aa larga as thn 

inBtalloo of Obscure r«y>.— We tdiall find in *ppftkins 
us s^MTtnim ihnt iiurniid lhi> Tiolitt thorv< are nyn which 
tlio cyr. but whii'li &«> distiiig-uJAliAd by th(>ir chi-mioal 
ttfolna ol w the aetmin or rhi-micn] mys ; th^y nzn al«o 

JNUrrw rmya, from tho philowphifr who timt diecovewd 
also aes in tbn book on Opticii, rrot. Stokni Ims siicciodcd 

Umm rays into rays of lowi-r n>fr«ntrihility, which then 
i; aa Prof. Trndoll haa recently cflMted the vorrcapunding 




but inveno chBn|!iN and liiu iucTMwmt the i«&«avil>iUl,ir o( llw 
cb«lt*ii or oxtnl rixl tut*, uid than r«iider>Hl thom vuiblo. 

Truf. TvuiIallwMkcdwith ibf plt^lricli^rlit. The cWomI |^auu 
pltoed in front af ■ irancMm (iivi-rBl K^an mirror io sutb • numm I 
th» nvs from l)i« poiau after reflecliou w«t« c«iiir«ntrat«<) in • f 
■bout A ioehci ilintAnt. On the puh of th« beani wan inUtpotnl i 
61II of A Mliitii-m of iodine ia bi«alpbi<l» of carbon, wliicb, v tn I 
Men, hail tlio powL'i of eoinplatel,T utoppiag nil )nnui»uu* ndialim,) 
givM free pnua>ra ti- the nnu-liiiniiioii* m\». C)n bow pltctnc ii. tin 
focuB of tile lii'Ain tlitu nifted a piece of plHtiniiin. tliu wa* ri»vd n 
iacandnwwnrf by ibn imjiiirt t>f pnriViRtly inririblo rays, in Uko 
a piecDof ckarroHl in lacuo wh» beat^d Io redn««a. 

By a pmp'r amuiiivnipnt of ibc cIibtcmiI pointa n metal nmy b« 1 
vbiteniwS' "^ ''■<' liK^c DO" emiUed by ibc ni«inl yidd* <in ] 
hnalyiia a brillinci lumimmii apcclrumr wliicU is lbu8 cfitir«ly 1 
L tli^ IntiMhlv Tay« bnynuil ih* ir^ 

To tlic uf w gtheuumtninu Lerv dMcribed. tbts tranamutalioa it I 
luminoiM into Imninou* h«Bt, I'rat Tyndoll hni< applied tbc tma < 

Whi'Ti llio eyp wnii fnntiomly plBecd in the fw-ia, Ruarded by •< 
htilo being piern^d in a ui^tal screen, "n iliat tbn cnnvi-Ty-d («y» 1 
only «nter the pupil and not aJInc't (be numxindin^ port uf ike «i"i f" 
impn\Minnar lipibt wa* prnducod. and tbcn! wn< ■enimly any Muuathl (f j 
beul. A eonitiilcrabU portion was abMirbod by tbe biimour* 0/ th* *fk] 
but y«t a pawprriil Wnm undoubtedly rcaflicil the iDtioa; tar, a> fVdl 
Tyndall abowed by a vepnralo experimeRt, about 18 per coni. tl tb 
obiiniio mdiation from the electric titrht pawwd tbroajfh tbc bimanB 
«f an ox'ft *yo. 

3T'i. TTAoamntatloa «r tbcnaal r«ra.— MeUoni vtm tbn fett^ 
examined ■'ilrn.iimly imd ncciintlnly tht< ahmrplioii i>l h*M by nlidi 
moid liquids. The apparnlUB h« eiuploycd boa alrMdy licca ttdemdM 
A %iiTo of it in ttiven in tlie annexed figure, 3ti0, wbeta AB it tk( 
tbermo-olectric pile, con^ialin^ of a iwrina of i>l»nd«r bar* of atlSmiJ 
and bismuth ijternol.'lv ncildered together. Tlie tcnuinal ban of Bili* 
moiiy A, and of bismuth B, am connected with n g&lvnaoiBHer P, tr 
lueanfl of wires. 

The niliAF pnrta of tho apparatiu arn madily intnlliiribln. Tb(M it • 
luatt'd hroM «ii;>|>ort about a yard Uui^, on which ar» plaoel ttf 
pieces of Bpjmratu.i, and which jide, and «*n be fiw4 •* 
meaaur^ diMances : a 1« n support for thn sourcn of h*rAt, in thi»M*» 
I»CBtelli'i lamp ; F aud E are acreeus, and C ia a support for th* Mj 
experimenlod upon ; while m in thf pil«. and 1) th« eaUanoowM. 

Melluui uaud in his e.xperiiuenta live dill^renl aoutvw of beM: H 

UMAin- BKAT. 831 

i'a liB|h— *]wt 11, u onUiarj oil tunp niih a r*flac(cr, but 
. « cfcdOM^; Sod, »n Aiguil Lunp, whicb had • double ouf> 

' »t, tati % diiniEiej ; Snl, a (pin) of pUlicutn iriro hnUod tQj 
in tb* fluno Oif n w^int lamp ; 4th, a Kiunll coppw canlstel 

rjlb waler at lOO"; uid ftlb. a plat« of copper krpt at a («iupom- ' 

acM Uic fMnm irliich liudJM hate of tnuiMiiittin^ h«<Al, Mrlluui 
' tons tKalkiTmaHty : diiolicniiaiicy lican Uiu nmi- rrlntton ti> 
■•M Uial tniii*(iiirriicT do«t tn light; and in Ukn manntT tlikl 
rof Mop^t' mltaat btat in called atkrrmimry, wkich tlius iHims* < 
I lo "facitjr for ti^t. In npnrimnnting on iho diatbi^nnuKT- nf 
, HvUoni uwkI glau troughs with piurallvl »!d««, tli» thichneM of 
Ihtfcrbcinjt 0-3(1 in. The ndtont bnat of on Afpuid Umpwitb 
icUoHWf waa tint allowed lo fall direcllv nn lb« faco of lb« pjlo, 
ifcfcetioD pffoilni»d in the galranomntcr tnki-n oa the total ladin* 
Nb>taaon under <xaniill«tio4i viu> ibnn inturpati'il, and thn 
I noted. Tbia corrMpouded t» Uie quiuiiit,r uf b-^nt trauniuitted 
■abcUnce. If ( indicatu iJii* latter number, and f tba totnl 

f :* :: 100:* 

I b th« pcwenta^ of rav* iranainittml. Thua, calling the total 
. 100, .MeUunt found that 

I of urban tnuwmittcd CLt 

• oU „ 30 

..... SI 

boric add „ 17 

Umbol , \T, 

I of aliiiH or Mgar „ \i 

] watvr ,. II 

i|Kfitn^ntin^ with mIii^* tli* anlBtMiCM n-nrf< cut inln plnteaO-I 
a thichaeaM, and it was fonnd tbal of ei'uty 100 ny» th«t« waa 


kT and pUt« gla« V'J 

qnarti ft7 

at cnrbooat* of hwl QS 



' of copper U 

traatniMtuD of heat llirau^ii tiquiij» hnn txM'n re-viaminad bji 
^all b; a Btore pnfcGt mode of rippriiupui iliau that omployedi 


ox Kt&T. 


1)j H#Uoid The expnimeou yrtn made in tb« toOa^ag ^nr-.—l 
of amploytng a ftUu* vcwwl to bold the liqnida andcr viuumalM^ I 
mad* urn of R lilde («ll whOM «nd* wm* Moppinl bv puridliil pUW uT t 
mIU The pUi«» WT<r« M}tBnted b; * ling of braM, -with ui aptrlu 
tii6 ti^ thraugb wliich th« liquid conU b* pound. A* tbi* plaU i 
}» changed at will, liquid lavera of Twioiia thi<-ln)(<M>>« w^ro mwI 
tainalile. tbo appumtiu being maniljr •crr»-Dd tuKHther unci nud«liq 
t%ht hy paper wiuihtir*. The iii>triini«>nl ^n* mounted on k 
'ksfon an opviuii)^ in a brass ncrvt^u pluoei) in front of tli« pjlli 
MMirce of boat emplajrnd wai n ipiml of pUtinuu win nund lo i 

¥ie. 860. 

dcsi^imou by nn eloetric piotpiiI; tho spiral being eoflowd in a nntll sl<^i 
globu willj au apt'rUira in front ibroiiicb wbieb tbf radialion puwdl*-! 
chan^il in it* ehntiwlpf. o point of sjunnlial importnatw ovMl>.">lifd h 
MelloDJ. Tbi- following: 1ab1i> oout^ii* the raMilU of expcirimnnti nJ* 
with liquids in iho viirious thickncastu indicatMl, the number* tiipn**^ 
thi> ahutrpliim per rent of tbn total rHfUMion. Tbe tratumitMOM fft tMt 
can bv fouud io uach t?iui> b; sublriicttu^ tliu abforptino from l(Xl 11* 
a Inynr of wiilnr 0*3 inch thick nbiiorbii 807 and tntnautiti IM |i«M* 
of the ndiatiou fJniin a rud-but spiral : — 

jfiMfptiM iffirat iy li^md*. 

IVckiuM of li^id in (Mtit of Mt iaeh. 


AM 1 o-U 




iJde at rarhaa 






rorai . 






of nMik/l 






of rthjl 









































B » 








tma theM toblve, lli«l tlicre is no tcoMOtklt bttwWB As- 
ry iod tmufiucncT. Thi- liiguid*, eieept olin nit *** '^^ 
■ml tian<f«tVBl, ui>l jvl varv lu much m "!!> pt<r cniit. in the 
if heat u«iumill<^. AmoDf,' the BoLiitii, mioky iiuarti, wliich u 
paqw to U^hl, (janimiM hiwt vnt; wnll ; whiln nlum, nhirh i« 
b ii p w enl, ntlaoff88 perMui. of hvst r»_yti, A« there fti«<lif- 
pCM of tmupucDCf, M there are ditTcront Acg^eit of diathei'- 
•Dil tiiH Mie caanot bo pmtdicittml from the oiliir. 
•Ifisf the tnuumiMion of heat from diffen-ut pnxta of the xpnc- 
Italy til* cnniMiclion b*tw*cn li((hl and bi-nt hi-com..-« manlfeit, 
liTPiw UavuD and Jamiu ivcMivd lliu «^pclrum uf tho (olar 
hjr a prUni of nwk imll, rm n moveable waren pri'Vidcd with 
ifB, to that br rnii'iiift dt luwi^riug th« Ben«ii the ui-liuu of anj 
oftha (pcctnuD on diflercnlpialpn could bninTcstitpilrd. Thejr 

^■M^ rock, erytitX, ico, and gen^'ally >ubc(iuii'<^> tnuupurcDt for 
dm illathffmanoiis for nil kinda of luminout hrul; 
n4miir<l glaai, nd fur instnui'i'. which unt)- IrniiHuiita t)i« red 
* ^ectrun aod axlingiii? he ■ thn nthen, aim cxtinguinhn* nv aiy 

iiniao«M h«at, csceptinf; thut uf the red rB)'« ; 

|ll« ud nxV rrjntal, which nf diollicrmanous for luraioouji 
tiHunil thu obecure bent ui^iir the red, tbM U, tho motit r«- 
bttl «xtinKauh tho nitccmir ob>cut« nty«, or thOM! wbivL ar« 

drfeetcd hj the fjitm. 

OH nuT. 


Alani nxti^rviibM ■ atill gT««t«T praportioa of lli« ohteun 
mai 'n» rUifa ilallog«llMr. 

37*. XnAuaaee at th» BMors «f tb« tt«*t. — Tie 

powi^r iltfr»i« fri.dtl) wiili Uwi WfM froiu diffvivot •i>urcc>,*iU«Iluni 

kcrridcat Emn Uu folluwin;: table, tn whicU ih* Dinnbcn expnia ' 

. fnpoftida of snry 100 ny* from the iliffercnl amroea of bwl in 

lb-) p]Ml» U InuMmiltod. 






RoekMh . 

. m 



Fluonpur . 

. . 78 



PUMftiMM . 

. 39 



BfaMleilaM . 

. M 




. . 14 


Alnai . 





. 6 



IThoM diSmat mukw «f lieat eoRMpond 1o tight front diflnirnt i 

Rock Mit la here tiM»i to tnaawiil all kind* ot heal with equil I 

and t« be the onl^r ■ulatance which do«a w>. It !■ analopiu* U < 

flui*, which i« tnovpurtf-iit for light ti^m atl (onrcM. Flunr f|W I 

1 76 por oeuL of thu nys from a lamp, hut oolj SS of thoac {ram ■ t 

Lvae^ Nirfiaon at 100°. A pi«ce of jAno glaM ool; onp-Irnth nf in 

thick and pcrfoctly trtuitipanait to lif^hl, ih opaqiiv to all ibe radiatiiiii feOB '• 

t-B toura) at too*, tTanamita only 6 per crnt. of the hoat (ron a tnnm <l 

\ 40IP, and biit ■% of the racUatiou from th« liu»p. Black gbat, "n ^' 

J ccmtnLTy, ibou^b it cub off all heat fran a aoutre at 100°, allom lip* 

li«Hit. of the hiiat at 400^ to puv, and it oquallr IruifMtvnl tu tbt W 

[irDni tb« spind, hutuu nocuuut otiu blaclawwiamwi! opaque to the hrfti 

from tbo lamp. A» wp hav* alrnailT (■*«, et^ry InmioniM f»j it a WJ 

raj ; now an several of the auhstaiicni iu ibia Lalil« arc pErriooi to d|I 

luminniu rnyii, and yrt, nn in ilic mw of iro, tntnonit but |ifr ( 

luminoiin heat, we bttve an appnmil anouiBlv : which, bowervr, M «^% 

cnnlirmntinii nf thi^ rpninrknbly amaU proportion whirhthclBnUDOMI 

of K kiiip Vnr U' the ohwim". 

From the.e eipfrimfiitH Mellonj conrliidi-ci Ihnl lu thr tMUppralorf rf 
the «oiirc* rose mnre heat wnjt trannmitU.d, Tl>i* may be takrn it» » ftam^ 
law, which hna been nioeiilly eoufinuwl hy wimo n!Eu(>d expwiBtW ' 
of Prof. Tyndall. The pUtiniim Iwnp, pre Tiniiely doKribed, wi« M» , 
H tlie aouKe, the lempi<rstun> of which Prof. Tyudall waa MlhWl] 
to \art from a dark to a briUiant whil« hunt, without iliitiirlMllg iO vf I 
way the potation of the apparatus ; the gnulutitnis of Uimp^ntora hiilf 1 
obtaiiwd hj a gmdunl augmuntiition of the itrdngth of th« eloctrie curat 1 
' vhich lieiA«d the platinum vpiral. Lmtead ef liquUi, T*(Miin w«t 

BADiAirr muT. 


li Ok nbJMi of trspetiawait, mil nMnined m • mnBiwr ti> b» 
I wW^ nmUy ; tli« BaoMwvineBtB ue given b llie f<hUoirtii(( 

Aittr/Mmi ^kni ty v^ma-t. 


Some*, piBiiaiiw npinl. 

X»*( of V«po«r. 







fUde oT nrbon . • 









) gf uetk;le 








!• . . . . 




MB ... . 




i_ _ 





IciUiBr . 










(wniligB of nf abwirbed b bere M«n lo dhuiiHb in web MM 
iBfimUM of ibt) ai>uK« riwL McK •kruioa of iMapenton 
ilmvner, invuiobty pnxluM a high ptoalMttv* power b th« ntvn 
I br Pnf. IVadaU hai ibnvn that tlie njw (roro K>urc«« of fu 
Upentun Uun anr of the fbni^raiBg ■■« mmsv laifclj abMirb«d 
y kImucm UiitB an the rajH «imtied from anj <iae of tb« 
p jat UMtioned. Tbiw it wu found that tbu ntdutioD ftma ■ 
I InM wa« cotnp|rt«'ly juierceplod hj a layar of walpr <>a\j ^37 
h Aide, the Hune Uyiir tnnMDittinK 9 per cent of th« nuliatuD 
I nMot apinl, a toorce of much lower tcnipBiBtiuw. Th« «x- 
|if 1Uab,that tkoM Tayiwbkh bt«t«l loicr eniu (luul water, 
^o(emnliMMiaa,ia UMtiMinTadiMitiD a hydrogen flamr), arc 
tnawliicii thU mibslaiice moat larf^l* abMrbs. lliis mal«in«rit, 
D fcaUMii clean-i afUr muliif^ th" uin3o^(ius phcuonii.-n& in (he 
ll^ WW (trikinglj <>i«mpliliiil bj' the powrirful alworpiicm of 
Aom a catbunu^ oudc flaiM b; carbonic acid jnu). It will b«< 
tl|f (377) that t.f (he ra^ frnn a huat^ji plaf- of copper oletiant 
b 10 llnea the <]taaatit]r nrtMVaptvd bjr carbuuic ai:id, whlln of 
^■in eafhcnk oxide iame Tynd&Il found i-Brbmiic acid abKirbed 
^aA m oMlnt gim A tenth of an iiUuo4pIi*'n- fi cncbonic acid 
U K tube 4 Cm! Inag, abtorha (K> [wr c«nt of tliv nujiatinti frvm 
1 0>Ua hiBe. Radiant h«at uf this cLaracfr run thui be lunl 
^ teat for the pruwui of carbonic add, tl»^ amount of wbicli 


091 HBAT. 



dm nven tw BoeiimtelT moKiured lij iImmuMWUM. TU*! 
Iij Mr. nAmttt, nli<\ in tfaU way^ bu nadc • figwuot Mwl^ 
hnaiaD lirvulli. In odo uKpprimest the qautitj of Mubonic tt 
rtuund in bn'nth phynRally uudyMid vtn* huaA to be 4-56 pet ec^ 
the MDiK b)<Mlh ditmiokUj^ tnalvcied g**» I'M, ■ difl«KtK« atm 
truth por cent. " 

S7li. ZBflneBe« «r Uie ttiloksvaa and DBturc of K-feiw,- 
bo MRU rraiu ihc ubie <'(i4t Uiai of t^verv 100 nj* rm-k mIe ti 
92. 1'lie'r 8 msv (tithir havn hwn absorbtd or reflected f 
■urfMrc^ of the plate. AceonlinK to Melloni, lb« Utter is (lie tM 
ioKtoivl vt <in fina pUtn, httiil b« allowi'il to fall do two or bcd 
whow total ihirkncas doM not exce^ that of lb* oo*, tbe qw 
hfat aiTcitpd will bo propattional to tJie number of nt 
He thorel'ciri? cunoluded tnclc wit to br quiln dikth«nai 

The eipiTimont* of MM. I'rovonUiie aud Demliu^' 
Stewart, aiid ihoM of Prof. TTndall. ibow that thii c(«cliutg 
■trictly correet ; nick uilt iIum abcorb a vwf amtU ptopoitio 

The quanlily of btint trniWBiiltcd thmuprh rock Mlt b { 
mmn, whnther the ptnte bu 1, 2, at 4 millimeters tUcL ^ 
alhi>r bo<lii?H, nbanrptinn incrcaws with the thickncM, altbeof 
mennB iu dirf^cl |jniportii>n. Th<« L' ffn to bn th« urnu in tb» 
absnrplion by liquid* at different tbii:kiie9se<i. The foUotriog ll 
whut pn)porI.ion nf 1,00(1 rai# from a Locatelli's tamp pan : 
flaia plate o{ the given thickneen ; 

Tliiohrnuuin iiiillini«ter« .0-5 1 2 .1 4 5 6 
itavn tcHiLxiiiitled . . . . 775 733 I38£ 003 0^ IS20 

llin abiorption tuVm pliu^c iu the first layer*; tli« rajsi 
pawed thesu poAveM the property of pnwun^ through other '. 
hiflhcr degrnc, no thut beyond the first Uyeta the beat i 
{■rotLchct a crliun conntAnt value. If a thin glajH plate be ' 
■aother j^liuw plate a (.'(.'uliiuelet thick, the former dinJai 
tTannmisNcin by little more thnti the rcllection from its nirCmi 
ft platu of (ilitin wi.'ru pUccd bi^hind tli*'. jclm^ pltti«, th« nwuU i 
diBettint, for the latter b opaque for much of the boat IM^I 
gits*. "^ 

Unat, Ihertfore, wliifh line tmversed a (fined plotn tntverael 
plAtii of the mmf. ninti'rini with very iilight tiui^, hut 
diminisht'd by n plnte uf nluDi, Of 100 rays which haidj 
gTMin ftlon* or louminlinn, only fi luid 7 werr lenpectivvlyl 
the itaniv plate af aliiiti. A plate of blackened KKrk salt only < 
obKiUD ny*, while alum cxtiiii^uiBbca thorn. Ouiueqiieotlj, < 

iqaeotlj, tri 


aOM It M)p«rpo(Ml, ■ ■Tflcm imponioiu to liglit ud bf«t is 

btBo nwa a find tbrir exact analogicii in tho caho of light The 
MRTM nf b<wt CORMpand to flunea of diffvnml i^uloun, and th« 
KCM to gluaM of diffinrait colann. A md dune looked at 
rtd claw Bfippan quitn bri^lit, biit thmiij;h a gtt^a glaM It 
lln or u amrcplv Timbl?. Ho in like iiunni-T beat which ban 
• nd S^aaa fiaMaa ifatou^h anothxr ivd f!\iu» wilh littl* 
I, hut la ftUsMt ooinpl«t«]i( »ti>[i|>(id by a ^rrcn ;.'!eiv. 
t InUDOO* raja bctn^ diRlia)(iiiabcd by tbrir eolowrr, to tbiuc 
hteut ealariAc raja Mdloni jca* « tliv nainv <>r iherinorrom <t 
•tioB. Tbo inriiiUB partioD of tho (pnctrum U aMordini^lv 
It lalo ft HriM of (p«c«a, each |)oeH«un(( iu own peciiliiir 
MiMponidiiig to tli« coloured apace* which ore teva iu Ihti 
Otm tftettuta rUibk t« our «;«. 

fhiflriMaa ftnd colour, l}i(< puIiHb of a (iubiiBa<.'« intluoncvs tlie 
n. GlaM plaba of tho Munn kind mid ihichniHn itsnanitt 
aa tlivir twbee U more poUahed, Boditv wbk'li tranamit heat 
id verj ttwdilj an: not heated. Thua n window pnni; is 
boated hj tb« atton^wt i>un'a heat ; but ft |iIm8 acreeti held 
BUnon ftre atJipi mmt of thn bnat, and is itidf heated tbiTi'bv. 
I of this ii that by far lb«< givAter port of iba Leal from a fire 
and to till* kind of hnnt glam ia apwjuc. 
IWtoB or b«Bt> — ^V1i«u H ny of light falls upon an 
■orfacr ID a dcfinjlu dia-clioo. it is di>comp<wd into a va- 
in whidi are rwflectod from thn (.nrfiM^ in nil dimctiniu. 
lar roflfiCtion ia culled liiffanmi, niid it ia In liilue uf it that 
ridble whfn light fnlU upon tbcui. A further pcculinritj is, 
Lnr ravi ore nnt equally dilfusvd from the «urfaca uf liuditw. 
dieo dUrnnc nrliun rays and absorb olbura, and aci^ordiiif^lj 
■nd. The red colour of a goraoiiim i* caii«(-d by itM abnorbing 
«, exccpliltg thn Tod, wliic!h are im^uUily ruflectcd- Juvt 
caM with inndiuittcd light in tntnuparcnt hndioo, an with 
pht in opnqun onca, for if a red body U ilbtiniuHt^'d by red 
fmt* eS a bright T(<d colnur, but if grvea liftht fall U)>on it 
I Mark. We ahall now bcv that here agaiu au&togou» pLe- 
«ail with heM. 

(nhaianec* difltue diCEmot thermal raya to a difTpirnt nxlfvt ; 
NM a peculiar tbamocmM or Ileal lint. Mt^tluuiplactsliiiiuiiibrr 
I' ^M»M foil between the aourco of bent and tli« tlierinn-pile. 
M«l«d on tho ndo oppoaite to Ui« pile nith Ismpblnclt, and 
t afafe witk the aubrtaocm to b« infcati^tcd. ICepniMiutiag 







Wiiito !r*a 






Indian ink 






PoliatiHl metal . 



lli« ^stntily ot Iimi nbtavtMil V t*** UnpUftdi at 100, tbi 
of Uie other bodiea ww aa fuUcwi : 



Hmoe, wbiie lead aWrb* far Icuw of the h«M nidiiti«id tmo in 
doeemt plntiniun than iHtnpblnck, but it ubourtiB ib« uboctm r«js I 
cojiptir at )00° m cumpletel; m liinipblnck. Indinn ink it tlie irrNiti 
thin; it uliAurbH obscurv my Itm c«niplel«lj thHu lumtaom nrai 
bIfM'k abiiortn.'il tbn iical fmni all lourRra in rquiJ qanniiliv*, uili 
noiLtly tuiu|)l(-t('lv. lu (unnequcuM of tliis propertir, all 
wliicU arc iiwd for inrcjiti^nitinK' rudimit hi'Dt sro cornnxl will ! 
Uack, M it U tbu iHMit known tibH>^rb<'nt of bent. Tbe bobtriav^ 
motali ia tho rttTcmo fif thHt of Iniupblack. Tbcj r«fioct thi I 
dlffervnt tonrvM id tlie tame de^Teit. 'I'hoynrc to beat »liat arttrln&lJ 
«n) to lifibt. 

A" ociluuriH! ligbt in allenMl by diRuaiim from ncT^n] boriiM, i 
Ifjioblaucli ho* showD tbat tbv djfiuteiit kinds of h«at an altaRdl 
tleelion from diU'ercnl aurrnaii. The bent of ou Ar^nnd bvp • 
IVom whit« pnprr pHBxeH ition- va»iljr ihrciiigh calctpar than wtal 
btetl diOusi'J from blnck papu. 

: t%jt of beat, like liie raj* nf tight, ara *u*cep<ible of [ 
[ double ivfrsction. Tbme priiperlifd will be brttrr mutenriiwdl 
trcntinK of liirlii. 

i)77. Xslatloa of laava and v>p«ara to radiant !)•■*. — Fecal 
time it wm bntievcd thut f,iuwimt> btxlim vtetc u p«nn*AUe to hMttfl 
VHVunin; and thougb aubaeqiii'iillv thin wah diapiroved, vet down 1*1 
RKvnt period it wua tliuu^bt that wbHtei-er abiorptiaii tatck btAM 
ntigbt eiercion was slight and ^niilar in dejniin. The wknle 
hM, however, been invtvtl^k'd bv Prof. T^udall Ui a mrira of 1 
RXporimnnlJi. whidi, with r>-t,'nrd to the uhmrptiun of heat bj'gUH^artl 
eqnal imporlnnee ti> tbow of Litelie, and afU'rwurde uf Melloni, ia I 
noee lu aulidii and lii^uidH. 

Tbo RjipHiTitus used in these experimcnta w mpnveDted, in iU ■ 
feeture«, iii the adjacent figure; the arrang^uient b«ii)gloak«d npcot 

A ia • cybodnr about 4 feet in length and 3) bchM ia 


IkmoMiUr, ibeeuiliioi'wbkJi can iMclowdwiUi rotukMltplktw; 

I ot m hUctmi lube at r it cu be oimiFcted with tin air pump and 

TbU« Ml is BiMlher (atw which icrvi>« for 1L« iiilriKliiclioD 

I MkI T^ratm. T i* n acMitiT* tbermo-giite conoectDd with aa 

I iUicat« giUvKaoiDtWt U. 

I dtdcctium of thU galvuMOMter w«ra praporlioiui] to Die iluf^reua 

1 iqi to about 30°; bejrood Uil* point the proportitmalit^ no Uyager 

and acooitUoet/ for tlie higher litigiMt « tabli» was eiapiricaUx 

' , in which tho talog of th« higher <l«<WtiiHu wsa expnaaed 

lh« vxit bciii; the UMouiit uf bc«t oeecwar)- to moro tho noedla 

qve rf the Iowa d^ree*. 

mues of hMt, which luualljr wu either a Lcidie'* tube aUed 
; wUer. or elw a ahool of blacksned cupper bv«t«d hf pm. 
I the aoiirec of hi-nt van periiiiited to raiUate through the «x- 
I cube, it caiMod iht nenUe to iWBumc a vm,v hi^h dadaction ; and 

Fig. Ml. 

I patitdi ft very cmMikrablc dcftrcc orf abwrption would hat« been 
llS|ndiic« anallcniliiinof l^of ihi- ^Ivaimmnti^r, Ani) if to Iciemi 
, lower MHirec of bfat biul btipa iiwsi, the fnii.-tiuuab«n rbed 
IkiRnMpoDdiDgtir lMa.and slight vnll havcb^pQicscniibli!. lIuniK 
tl^tdall adopted the followintt d«vi(^c, b; which he va* enabled to 
Ipnmfiil Aiii of hif«l. and at thnHuiu! time discover amaUTnnationt 
IfWBlilj falling on thn pU<^. 

I of bnat at C wa« allowrd to radiate through the tubn at the 
f«Uth the pilewat plw«d; a drltirlion wMproHuenlo^ ■sjrTO'; a 
I (if butl, 1), wim thm ptoL-vd near thi? other facn of Iht pile 
1 of btai CaUtngr on th^ pil* tmja thin compauatiitg etiim being 
Ibj iiiawiw rif II iiiiiiialih m ii i ii f Wb^n both rntyaafthepl* 
, two coTTml* anf produt^. which nrp in oppoiite dimcliou, 
J thav(<>n- to neatraliw each oth*r : wlir.n tho h«nt mi both 
lyMfatlj oqiial tb/1 ni-iitraliintiuii in perfect, and DO current at all 
fbiTWeTeT hi^h mair be the t>.-inp>imtuce mi hoik «d«. In the 
I jnat dewrilicd, bjr nietuu uf the Ktreen S, (be mdialion from 
atln^CvbewaecauwdloneutrallM exactly the radiation from 
I C; tba needle ooMeqaently was brought down from 70° tM_ 

840 OK HEAT. 

icro, nvd mnAiMd liherp M long M both sMTces ir«n« equaL tfi 
or f apour ba aidmittpil wUt ttia cxfawwtetl tnbn, aay ^ytta uf i 
it nMT pOMKM will be Indii-atMl by the dMtnctiaa of t)it» «q« 
mmI p««poBdaaBoe of ibe radUtioD bmn tbti compcuutidfr i 
waoont ooiTMpoading: u> the hf«l cut olf hj tlie gwL nxami 
iK}',Hr,bjdFi)g«i,Hidintrop-u. whvii drietl b^rpHHtn^ tlirougbl 
•dd, «M* fOM^d to tmn >B alicwt inij>pmd^)lo «ff6cC ; tbfir ( 
Kfud* ndiaat bMt being but lilil« diffptvut to a rKtiinii. 
dlaSuM and olber cooiplcx pUNB tbo oue wto cntiroly diflemt 
•eating bf Ike mimber 1 tb« quantiiy of ndianl heat ■UnrUdJ 
ol«itaiit pui abaoirtw 970 tintM, and amnuimacal gM I1W> 
amtMuiL In the fnlloirinf Mblo in given the abtoipticqi of ob 
hj wioD* ff», rdemd to nir lu noitj ; 


Oifg«« ........ 


llydrtigMi aa 


llvdivcfalnric acid ■■■... 

t'orbonic ai^id 

Xitr»iis oxide 

MuTsh ^aa . . ... 

Siitphuroim acid ...... 

nii^Iituit \gia ....... 

Ammonia Ill 


If iiulead uf compBiiag th« pwo* nt a ecnunon prnminv of ant lU 
•phers^ tbaj- am Rompnnxl nt a cuiuiuod fOMCiilw of an bcb, ibw JU 
woea in ab«or])ltou ■» still raun Btrikbirly •ten. Thus awuidaf i 
abnorption hy 1 inrh nf Ary air lo b« I, tlip abwirptina by I iiii'b cf «l 
•nl gaa ix 7f).'>0, »iiil by thv saiuu amount of tulpbiiroiu adil tS^OlX 

itT^L laillienoe of prnaanr* aAd Utleksoaa ui Um «MM|i 
•r IMM br saaea.— Tbe ab«i>rplioii of bi-tiL by gaa» varie* * 
(b« |irv«Hure; ibia vnriation canDUt be twi-n in the ciun of «if,l* 
total abKirption in ho uniall, but in the caw of tliiMe ga«a« wbitk k 
eooNderablfl atworptive puwei it is voiatj nhuwu. Taking th« Mli' 
MTption by atintuphcric air undi>r <inlinnry pioMure at mity, ibiH 
Jmh of dcflnnt gM under a prrnure uf 1, ;!, S, 7, nod 10 bchi 
' encury an- iVF-pftively 90, H2, 188, IgS.and IKJ. Thus onn-tbil^ 

an atiiio>p)i«ri> of oU-llani f(M oxerti DO times tb« alnaqib 
eiitin atmospLire of tit. .\nd Uw nbsorptiun, it ia aces, ii 

KADUm* UaT. 


:h BOt IB B dir*ct nWio. Trof. Tyndell shoirpd, how- 
feeul Bxperiments, lli«t for very low pn-Mures the nbwrption 
|M wilh Um denritr. EtnplnTing u ■ unit volumii of lli« gaa 
If -irblck BUttsurft only ^ i>f k cubic incb, uid udmitlmg 
g miraiiiimi nf okfiuit g*a into the RXpi^rimfliital tulw, it wm 
I up lu lA lUMatUiM tb« absofptioD wm iliiyctly |)r(i|Hirli<uula 
iMt; in MUifa ca««^ 

It ex]ieria)ent« tb* IflDRtli of tha cipcri mental tubo )«mam(s] 
Irhiliit the prwHore of tlio gna tritbin it wftB caiwed to vury : in 
^u«dt exp«(inii>nta the prewurc of the tnu *riu kapt cniutant, 
^ knftlh of th« tuhe vru, by «uilable ni«iinR, vtiriod from 001 of 
|p to 60 ineliMi. Tbo wiurco mw « bentnl pint* of copper ; of 
kHdutttoa from ihla aearly 3 per cent, weirr iibiorb«d by a Him 
A g«i t)! of an inch tlitek, apmrd* of 9 per c«nt. by > layer of 
Igiw O'l of an inch thick, 33 p»r c«nt. by n Uy«r -2 incbnt thick, 
|nt. by • fohimii 90 iuefaea long', aud 77 per cent, by » column 
tre than 4 fiMl Icn^. 

M«orv<l*o pow«« «t T»p«ivx*t—fitva,t u l« the ulworplivc 
', oleliant ^tki, it i» CJKvndm). ni I*rof. I'yudnll found, by that of 
tpMiia. The mode of exp«rinii»Rti»g wm analogous to that nilh 
L TIm liquid fmni which the tapaun vmn to fao dnriviHl wm 
III ■ ihmU Bank which M»ild bo attftchi'i) with n dtnpcnek to tb" 
I Kiprrinututal tube. Tlic absorption waa iht-n dctnnninciJ 
^liufT ibi^ vapour* into Iho tubo in quontitina mnai«iirv>d by tViu 
of tbn Ixniuuett^r irtup; u1lai^h»d to the Air piiiiigi. 
Ilowintr tal>li> ahitwi the aLnorption of vapoum under prriuiiPM 
buaiO'l bo I-Oinch of nMrctirj: 

Phnu qJ vapuun. 

If hide of eaiboB 


I0lai*i , 

Abiorptioa under prr^iur^ 
ID incbiK of morriuy. 






















wuahn* nkr to the abBdrpiion of a whAl» atmoaphere of di^ 
Ironiti aad it ia thu« Mf.n thnt a qunntity nf biHulpbideof car- 
or, tbe frablert absorbvnt y>.-t <<XHiiiineit, wliich only cxurla ■ 
rf ^ of an inch of mnrtury, or tbn ,i„ of iin atma^pherc, navn 
Urn alwDiptian of aa <at)n alniOMpbero of air ; and ,', of an inch 
ISO tine* k» much. Comparing air at a preMure uf 01 

on HEAT. 

with MPiic MLm of tbe Hiii|iiiiiiii, tb* •bnorytioa of H» buor i 
W mon thm 17,600 linwa m gteiH as tlial of Ike (brancr. 

The itlMMptiaa hr tk* iiiiimtainMlIir MaaU qasntitf of nmlMr < 
tatiiifCit perfumu chd arm b«i neuuredi for Prrf. Tjndatl bud i 
tbe odour* fram th« nHvntial oil axercwd ■ mkrlctd iDBneDcn qa i 
bMt. i*rrrMtlj iiy kir «<u allowed 10 pan 11iT(M);h k tube 
drisd p^por imprcgiuUod vitli rvioiu eMtntul oil*, uul tbui 
into lbs esperinMiital taW Tgliin; tb* abMiptiofi ot liiy Mixti 
Ike folli>wiD|i WMD tlw numben ra*pactiT«lj obniand for mt 
wiikwiwu oik: — Piiicliouli SI, otto of K»e«37. UvmAct Wt 
68, mifiiij 74, cmbU 100. nuuMd 873: ThiM the pnrAuiM of a I 
bad alMfirta a Isiga p«rcpDlag« of tb* h««t oT low rvfraugtfeUH; i 
bota it. 

OioM prvpand br •UeUolymft wator wax abn fiiabd 10 
rnmarkablo abaorptiT* tifyt%. Hifr aiuall quantil3r ot mam pt uw l ' 
idMtiolytic «X7tinn in* fouml in noe Mpcrimiint to luwiciaa 1361 
the abaarpUou af ihi^ rnur« niaM of <li« oxygm iiaelC 

Rut lli<> iniwt Trmnrkable, pciliapB, and cvrtaiBly tho tnoat uapntini' 
naiUu nhiob Pruf. Tvndall baa o1itai[i«<d am tboaa wbick follow una 
bi* yoTj nQmrnniB oxpi^riinenla on the bt^nour of atjumKw h^vu i* 
radiaul fai<*i. Tho eiperimMtal tuW wa» filled wjib air. drird ■ pM- 
Eeetlj a* pooabU', miitI the abaoqitian it rxmuMid wa* found to be i 
uaiL ExhaiMlin^ Uif tube, anil admiltirru th« ordinarf tublriml. bal oatl 
•podallf mobrt. air tnm thf> liibonitury, tlie abuvprtion noiw Mac tu TS 
iinita. Tbia dilfnntnfa brlwivn drim) and uadried air eui aHj \» 
■acribiMl to tlii> aqueiiiu tapoiir tb«i Uuar oonlaiiu. Thna as a da* af 
arpMirc humidity thr nluiorptive i^Srct do* to tbo tmupareni tqamM 
lapour preMrnl iu tlx.- aliiii>>'pli<*rT< is 73 tlmea a* fteat «a tliai of the lit 
itiRir, thaUKb in quantity ihc Intt^r ia about liOO tiram gri-atpr Uiaa lia 
former, Aiiftlofioim r<^iilM wore obwiued on dtlTt'TODt dayn, anil wfli 
upocimeni of air tnkt'n rrom various locnlitiFa. Wkon air wUeb had 
bMn specially purilind wiu allowpil tn pnni tbrongh « ttibo fllM "ith 
ftagnenU of moii-t<'ii>:il gliuq and L'xiuiiiued, it «M tuond to axnt u 
abnorption 90 timm that of pum air. 

In dome other experinienia Prvf. Trndall »npprea*ed the ow of terk 
HiU plfitni in hii csprrimRDtnl tube, and »tmi the tube itadf, and jel la 
every ciu« thf n.-rulln wun^ »uch as to show (be ffntt power w^tb 
aqunoiM vnpnur poueMci as an nbsoFbiMit of radiant heat. 

The ubBorptive ai'tion which (he nqiipmi* rapmir in tli« ainioaphn* 
pxort* nn tbK lun'ii bent hu been calahlinhed by a writis of n^Dnmctrkal 
cibserrtitiotu oiaAn by Bori:if. nt flnnitva nnd on tho (iiujrait of ilotst 
niUK^: he finds thai tbi- inleiii-tty of the tolax li^at on Ihu (op of >' ' 
Blanc ii J of that at Gnn«vai in other wordi, that of tbo beat wki-::; 



It llw hrigbt of Uont Blanc, tilumt I m ab^orbnl in pMmag 
tvttina) U;<Y nf Uie •IiniNiplinrr' 14,4W (^t \a tfaivknum. Thn 
r*tT ku foand ihat with TirlUKllj- i-qiuti aoinr lieigblii th<f« U 
■1 mdialin* na tknw dsj* on which thn li>n<>ion of oqaooua Th- 
valp*t. thai », nhrn then? U moat nioialure in thu ntina*phaT«. 
•diauag power af caaaa. — {*mf. Tvnilull iilu> i>:iniiiin«d the 
faiwvT i)f paaF& A rM-bot copper btll «m phc^ ho that tha 
' bMlnd *ir vluek row fram it acted on one fana of a tKi'nno- 
action waa coanpenaalnd Iir a rutw of hot water pkc<HJ In front 
pMTtx (acA. Un thrn allowiiiK a curmit of drj olrfinnt rw 
■knUar to atreara thmngh • TUig burner over the hi!at«d ball 
(■pplant tha awwndini^ mnvot of hot air, it wm finind that 
dbtad caerfcqticallv. Hr i^mparing in thia manner lh<i a(±ion 
laMit wwa diacoren^d that, u in the c&s? wiih aulids, thue^ paaea 
ika baat abHwbrr* am hImi thi»c which rndialo ninat Ireeij. 
rKAMle t«4Uit*a aad abaarptian.— To another cl««a of 
a whirh i'ttf. I'vndnll diK^i-cTuil lio jpvM the bbrm, tlynamie 

(baa parailted to ent«T an exhausted tube ia heated in conaa- 
tlia CDUi*ion of ita parti<-l<-a a^nit Uia xidrMi of thi> vBfwl : it 
IMa a anum of beat, which ia perftv^llj capable of being mea- 
nf. Tjvilall nXX* tlii» ili/tiamir healinff. In Hkr> mannnr, whni 
I «f faa or vapour b raiiiillv eiihAnalmt, a chillin}^ takM plao<> 
tba loan of hmt ia tht: produeUon of motioii. Tbii I'rof. 
tllf ^aigmi fc tMHn^ or iihenrfitiiai. 

Id dwai <l*lannii>f thr mrlintinu or ubnorplion of n ^aa without 
a of h«at ^xtomal to iji* gaa itwlf. An rxporimcntal tub* 
1, aoe Bad of which wu dxaed with a polished metui pinte, 
(ker with a ptBl-> of mrk H>lt: in fmnt of tbo latter wna iha 
»e pile. The needle buin^ at tift'\ aud th« tub« e:ihiiU8ted, a 
Iknrad qiiii-kly to cntnr until the lube wna full, the etfect on 
lotn«(«r bfbg DoM. ThU bcin^ r.nlj a tranxitnry alTect llin 
la rctnincd to lero; tha tube waa then rapidly pumped out, !>}' 
mMan diilling wm frodocad, and thn noodlo Mhibitod a 
IB tlw oppoaatD dircctiott. 

piait in lliia way tha dynamic hrntin;; and chilling of rnrioua 
raa fouud thai thoae gasM wliich *r« the bi'it R[i*jtli-.'ni an> in 
«r tb« b«>t radialota. 

B aurface* whva paU<li«d are, a« v« hava aecn (384), bad 
but radial* frc*Ij- wh'n covered with TariiiBb. Now I'rof. 
lada the einiou* experiment "f *ftroi«hing a m«t«llic surface by 
JM. A LftaHe'a tube waa ptaeed with ila poUnhfid metal sldi 
r tbe pUa^ sad ila elTei-l nnulraJiaed by a w-cuad cub* placed 




beCm the otfaor bceof Uw pile. On sUowiog, bjr ■ •pecul i 
a imaDi of oMJanl or coal gaa to flow from • gMholder otw I 
boa of tli« fint oub«, a «apio«u radiAUun bom tbat ends i 
long a* til* flw of gM coBtinnoil. Acting no U>a principl* ID 
tdnlbnsvugexpBriiuFDl, Pruf. TjnditUdeteniiiawlUiedjmaiwci 
>Bd sbMipliaa of Tnpoun. Tbc MpcKnirnUl tub« oootainaiKai 
wider ft m«U known pntmn, ftir ma ftUawwl to ^utet nnO tlu ] 
nre inmle tli* tubo va« Uie *aau w Uwt of Ui« HUnnapbttt*. 
w>7 Uw eBterinf tit bj ita Imft^t ogumt Um tub* became beeHd} j 
iu particlaa mtting with thorn of di* utioute quaatitj of nfoia ] 
MCh of th«m bMUlM, eo to tpt»k, coated willi a U;«<t of tW i 
Tbe oilMiiijr air ma ta ibUcaM tbetourceof b«ai, jiut &■ in tbei 
nxpAnmi-nta tho Lnlie cube «■■; her«, bownrcr, one gan 
aaoibec; (be radlaiion and nibnequmily tlie ebMrption «f 
Tapoun«ould ibo* be Ui-tpnniuvJ. 

It wm fuund tliat v»)H>uni ditTnird rerj mat«ri&U; In lS»dt 
nuliatio^ untlcr theac circumaUuicn : t>f those wbicb w«ni triad I 
phide qf i-arbiMi Tapour wm tho trunt, unci bunwJc etbc r the Ivst i 
Aad in all caM* tbose wliii-h were tho btvl alw^rbiMita wrro aUo tbel 
radiatoni. Itv ibis mntlioii Vraf. Tjndnll wiu abl* [o oberrvD at 
isdlativc power witb thv morv puwcrful vapourn when tba ^wlll3> 
prMeot wan immpamirably Hiiiall. 

-18!}. Belatton «r akaorpUon ta Baelaenlar atata. — Up toarMtit 
period it iva> coniidmvd that lb* absorption of boat n-tu [iiaiiity d«p(iiAiat 
iipUD tbt^ physical cundilion of tbe budir viamiucd. Thta Ivd ui \\t 
boliiif tbnt it wo* iiiipouibb' for aMbsIancJM o( tacit teuuitj aa pi.~- k-ii 
ra)>>iiint to abw>rb auy st^tiMbl^ amuunt uf lival; and tbat thn ni< 
bj bodira wbeii iD a liquid state wniild he unlikf tbo aamu K^li' 
Hulid; tuoreoTor, ihnt if all solid bodira wi-rr rvdiiu>d to an ihiubU/ liai 
xtatc of diviitian, tho pneiriit djifcrniicvs in tbair absorbnnt and ndiatitt 
pnwpra would dt«i)ppi«r. A few experiments made by Metiooi <o 
atmoapbDrie air nuppurled tbn first idea, and a arnat of expHrimrnu bl 
Uaaaon and Couri^p^o established th« betif-f in tbe last. But «» bM* 
aeen that l^rcf. Tyudall's rL-senri'bfs bav« rovealud tbu powerful sbntJtiaB 
of beat by vario'-is gase» and vnpoiir*, and wn ahnll now briefly abow Ibtt 
the itrKATchra of lh» Muix phlloiMpbvr hare overthrown tbe but tn 
condusioos, giving us an inngbt into tho cauwtof tbo abaorptfoai^bMli 
which buft>n was unatlAiiifthle. 

After tbe «xaniiaatiun of tbo nbanrption of beat by rapmira, VkI. 
Tyndall tried ibe nauie siibntHUoes in a liquid fopuL The crmdilioM rf 
tbo expurininntii were in botli casea the came : tbe eourM of beat *■> 
iilwsya a tpiral of platinum, heated to redaMs by au electric curtcot ef 
kaown nlrengtb : and pbttes of rock salt were invariably aaopkiyMl to 


I and Uquidn. Finnllj, tboateorption bjlhn vitpouni 
iit«d : ■■ li>i« CM* introdnciiig iotn the Mp«>riineiiUil luU:', not 
iqnal qauiliti«a at THpour, but ninounU prnpnrlionnl to iLu 
\hj» tiqiiid. When tbU litit comiition had Imhui nltiiini'il, it 
IfaU tks ordtr ot ab«afff>ti<u bv a (ii.-rit« o( liijuidi), ui<l hj thu 
whtm tuned into rapour, wu prcdKl^ th<i nurc. Tbiu the 
iMMowliil the fuDoning order M liquid »iidiM Ttjuinr, txigin- 
he lenhleM abMrbent, end Bndiiif; wilb tlio miMl puwerM. 

[tBila. Vsjioun, 

bide of cerhoa .... Uaulpfaidtt of carbon. 

htm Chlorafann. 

«raMkj1 Iodide of mothjrl. 

rjl Iodide of ethjrL 
. Bentole. 

ric vUmt . - « . . Sulphuric ether. 

•thar AcDttc dhei. 

i.CAhttr ..... Formic nth«r. 

. AJoohol. 

dvlantdiulioii of llio pmportianal omnunt of the vti|iour 
, not be nade, aa acoouat of the Iowulvw of Its tvusiun. uid ' 
Opu nator* of the platea of the mck mtlt. Itut thi- n^miuk- 
ideriatiiifT mi^antv of the ab«i>r{)lluu by nil iLu uthtr sub- 
Im liM. wh«B •• liquid and Tnpmir, Dutabliihos th« fitct, which 
lied b^ the uxperimeol* ve biii« alnindv iu<^ii(ioDed, that 
><wr y aou at the mort dicrotic ibBocbrjitd of hi^nt. 
lUe U will b« noticed that those subelonce* nhJch hsv« llie 
uniud oonnilnticiii rtaod Gtst b tb« li>t, w'ttli odd uioamloiu 
Mnelj,lliatoif watar. iDtheabmrptionnf hnntby gases, Prof. 
ind that iho elementary gwwi wvnt the feebltut ubHorbunta, 
[>•(• of miMit ooai|il«X canalilntion wi^rn thn moiit poworriil 
Thmr facta, which were found in u geuural my t» Iw tnii! for 
dik and puxu, hava lad Prof. I'yndnll to infer that nbiorptinn 
Ivyandent on chemical coustitiitinti ; that h to my, that ub- 
] ittdiatMn Bfe moloeular octn inilFpvtidL>nt of the physical cun- 

eoaekunoa eppc«r«d to be contnulioted by th« eiperimenta of 
1 Co>irt«(W* on p«ird«nL rrof.Trndall hiu> thorcfnro repeated 
linn1«, aad found Ihi'm to b» entirely incorrect. Avniditift 
oi error into which the t'rencb expurimeatcm had fallen, 
a iiit9*<r»d Uurf the ndialton of {tovden Is limiUr to tiiut of 

JtA6 est BUT. I 

tte toBd* froB wUdi tfaajr wn* doinid, ntd tlwnlbre diKt» | 
t^w JK The Aaotb wrt pcnr«r ot powder* w*« slao foiuil M enn 
with tbtirradiMiTvpttwvr — ■■ wa havBubown to be tlMCMMWiA^ 
ud fMM. ani Uiou^ a« j*t «« liave no esptriiiiMits on tliv loM 
dnabUea •!» tr»e (h tiijaiibL Tlie powdpts wen Mtacbrd ti>J 
«wCmm «r * IjmU*'* cube, in Mieh a manner tbat raJiatioB Inw 
ban the ■nrfwie of Um powder alooe. The lattowing UUe gil 
nulianon tn units froai wMw of lb» |H>«dra' nxaMined bjr '~ 
mrUl surfMV o( tlie oabc giTuig a ilcllKliuii of I^ unilt. 

SadutHm finm putfdtra. 

RockMh SB'S 

Jbio^i* <it mummy . . 30-7 

Solphiir 4(K 

OUeiUaorWd . . . . K-* 

Ctebeiwte of ealcian . . 70-3 

KwloxMooflMd . . . 74'S 

Satphate of caJciun 
Red i»M« of ixM . 
Hjdnisl oxide of due 
Black oxidn of iron 
Sulphide of iron . 
Lampblack . . . 

It will bo notiMd tbat ttieawt «ab*tancs» niv of ranoaa eoli 
aM white, Mch aa lock toll, chloride nt lead, carbunate and bb^ 
oaldvB, and hjdnltd oxide of dne : eamo am md, iiiicb ■« linil 
■uien7 and oxidn of ImmI -. wbiht other* iu« bkfk, ■» euljiUfc 
and bmpblack : ve bare lieaidea other coloais. Th« coltnn tf 
Iwra »u inflaenr« im thn ndUiing power : for example, nwh hA 
bebteet radiaior. and bvdnited oxidr of line one <4 tht BMMt p 
mdiatoni. The vicwi of I'rnC Tjndall thrrrforr, init«>Ml of bait 
thrown, viTT mifuTO'<d by theee fata InteM ^xiN-rimenla. 

Neurty a ceiilury a^^ Knutklin made expcriinanta on calan«l 
of cloth, and found thatr ■bmiptioQ, indi(«t«d bj tlieir aJnUiig U 
on wliich they were placed, to incmue with the dnrkniea of tba 
But all tbn dotbn wrrn n{UBl!T powrrfiil aluiirhnntii irf obecnra hi 
the effet-'U noticed werp only produenl by their ivUlirp ahaorirl 
lif[bt. In faet, thi^ cunriusion ti bn drawn from Franklin'* exp 
only hi>iib ir<^>ii Tit Iiitniui>ii4 Ileal, eepKcialtr aunlightiauch atberon 

'■IS3, &ppUcattone.^l'h'' ptupPTty which bodies jimwmw of 
inir, «iniltin)r, and r>'t)m<ling h^at, meet* with nnnieroua appUcd 
doraotio economy and in the itIal Lt«lie Btaled in a geaiu ifc 
tbat whito bndiea rcDcct bent very wi^Il, and ab«orl \tTy Ktttifl 
(be coDlmy it the ca»e with blatk aufcetaacea. Ae w« bar«^ 
prindplo b not i^rnprnlly truo, a* I«slie euppo.icd ; for eixan| 
BOB-hundnoue rays whito l»ad has m )tr«ai an absorfaaag pa 
lampUaek |,376>. Ije*lir'a principle applie* to pownrftil abaorlMI 
cloth, Mttoo, wool, and other organic uibHlanoM wbca 




■ hit, AMOtdJBgfy, tli« nioM mulalile miourad FlotkiD); tat 
ia jiut that wbitJi expcricitM bu tAic^ht an ta unn, naincly 
hr ii aiworla Iqm ot tlia ««)'( nifi Uitta blaL-k clothing, and baan 

lolkhed fiiw-iwi befom a fira an cold, whibit tli« binck f«tid*r 
ufcMrabljr koL It on the oooUrr, a liquid is to bv kept bat 
M poaajhln, it miut lie pUc«d in ■ btijilitlT poliafaed ■Mtallic 
kr tl»aa, Uw amJMJT* powM beinf lim, tbv (-Kuliiig ia aloirer. It 
n* naMHi advaatafreoua that tbo aUiun pipes, «I«^ uf lucumotivm 

kept bngbt. 

a Alpa, the moiuilaiBe^n accoltrati^ the funiou of tha unow b; 
t it with mttb, which tncrcowu ikn nbsorbioft poim. 
dir«Uiii|Pi tba outNdait or the Riorts* *uid of liui-wac^r npp«nttii« 
be U*ck, and tba uundca of titeplacoi ought to bv liued with 
, ii ovdar to tncrcana iha ndiAtiDg power towards th« npftrtmnni. 
a eoaaeqiWDW of the gn^l dinthermoneitj of drj aliuoipherii: 
ha higher n^ons of the atmotpbiro am no ro)d, ootwith- 
;thfl fnat b«al whicli lrnv«n>-ii ihL-m; vrhLInt tbu iul«B»e h«*t 
h'* direct ran «n hi^ moBHtiun* in prnhnhW dan to th« can- 
aWtioe oT aqu«oua rapour at thoap high cluratiotu. 
Mrl<r all tlie Imnboo* rav* of iho nun poja throiigh wntor, and 
nadialinn a* wo receive it on the tnirfaM uf the eftrlh consisting 
pr oportion of liuniooiu niya, anddeoti bare oftco nriscn bam 
tgaalM of tbnMi lDiiitDi>ui> rsTii tv boltka of water whii:h act a:* 
la tkia wait guupowdrr vould b>: fired lij thr hi'lit o( Lbi) Rin'a 
tnUad bj' a wrvtrr liiiw ; and thd drop* of watr on Wvita in 
«■ bare, i) in said, boOD found to act aa tenaua, aud bum the 
wbieh I bey ml. 

I bodlM <*D be ii»ed ( 371 ) lo f/rpimU ihv heat anil li^bl radjat^ 
Hne «anro& Itock ludt catemd with Umpbloi^k, or itill bettor 
line, traantita beat, but complrtoly *top> li^ht On tJie other 
BIB, citber am a platn or in aoluliun, or a thin layer uf water, ia 
toligbt, bat irtnpa nil thn hnnt from ntiMiin) «nun-iii. ThU 
ia laaile liae of in appamlun which un^ illiiniiuatud by tho eun's 
to aift the ray* of thnir hrntiaK pownr, and a tc«i1 full of 
a aolulkin of aliiui In uaed with the electijc li^t wben it ia 
in arnid too inteOHi a b«at. 
idMia, Ibe aae of abadea to pMleet plnnW rii-pnuin partlj on th« 
maej at fH*** tor btat from lumiuous raya aud Il« allixmiuiry 
raya. Tbe }i*t which railt«li-ii from Iho nun ia larjrely of 
quality, bnt by eonlACt with the earth it i* rhuitied into 
wkich a* mtb onnot ntntTcne the glon. Thla RXplniiu 
ill wbiob greanbouaea arcuinulato thtdr wanntfa, and also tho 


ox SKAT. 


gRKt heu ezpeiMBctd in tfammtt In roama lu*bg gUm not*, for I 
ijban ia botb cmm EfibctntDj cntrBp* tb« •obtr ray*. On (be ' 
pirHrV ptelM of giM» ar* facqiMMl; um4 m •erasM to jwoUct m i 
tht beat of • fire : tl»p glaw allow* us lo an tb« cbeetfsl tigU «ti 
§n, bat iwtuM pa t&«> laifcr put nf i&o hmt nuliu«d from daf 
TbM^ Ika miilm Unw became yinim hj Uie licat tbcr Imtb i 
}«t •• tkr ndiata t&w bat in aQ dirtcIioM, toiranlK tbn Brs at i 
towaid* w, w« intUj n«e«i« I«aa iMat wImb lh»; uv istetpaBJid. 



3M. C»l«rliB**iT> TIi«nBal nalb— Tbe object of calotiniRlrf bM 
M taa ani tfce imm lHf vfJm^ which a bodT put* with or ■bsorta «' 
liiiaytlaiM kdIo or liMa ibmogh a certain uuiuW i>r degma, m 
~ \ Ang« ito cas^tioa. 

Qwitiliw of heat aiav h« ezpnated bjr ai^ of its directl; miiiuiilll 
aSkdi^ bttt tha noat ooaTCBieat ia tb« alt«nitUin of tompcratan, ^1. 
^naatiliea of h««t sm nanallj definri bjr atadog the astcnt to wbkk ikf 
are capable of rauda^ a luMwn weight of a known (obrtano^ Midba 

Hw uM cbowti for coupaiiMii, and caUed the tJttrmal umt, w ntt 
»hetr the «nK. In Fnnrc it is th« quantity of beat in iiiiiwftl 
' ihr tempirraluTe of etv kiln^TamBie ot wa)«r Ibroogh «m AipM 
^; tbia b called a aitorit. Id thia boclt wa riiall adoptiHi 
1 nnit, Mr ^wmtitf ef Aorf w» w i mry fo rant om fwtaw f <y' a^f 
i «w dri^Tr Cmfi(pnwlr : I cobrw ^ S'2 Uwnnal otiila, ud I tho' 
I mit = 0-45 coJarv. 

3Bu. spMiao haM. — Wbt>D e^ual wM^-hta of two difTennl Mhttaett 
M the aaine temp«raliin9 pUvn! in nmilar tcsmI* an aubjcrtol (bt Ik 
neJeogtli of time to tfao heat of the ume luup, ur nn> placrd tt iW 
nme di$taQCc> iu froiit <A Ui« s&iue fire,it ia fbiuid tiiat UicirlpmpaatlM 
will vary coosidetnlilT ; the monrury will be mudi hotter tbiin tbowiM. 
Bat u from the cnndilions of the expvriuiuat. tlicv have each Utai^ 
OMTing the MDie amount of hunt, it i< clcur that the quantilj of bMl 
I which \a tuni(i<^t to nuse the temptirntim of laercunr tbrouf b > oertH 
Bumbcr of di^^M will uuly raiiv the tvupcraturB of th« mnc quabtit) 
of wat^r throutih ■ loss number of degroej ; in otiivr wurdi^ that ll rt- 
qniw more beat to rnise the temperature of wnler tbroagb Ofte difm 



dniM to niM xlit lenipentiini of toBKurf bj tha Mmo cxUnt. 

ilj, if Ui« aan* qiuntitiM of wabn- nnd of mprciit7 at l<Xf C. b« 
I la cool down Co Um Uonpenluivuf tli«alm(wpbi>w,th« nat»rwill 
I * nock longvr tini* for tlw fiafMe th>n Ihn mprcun' ; beno« in 
t thravgh Ui« Bune Bumber of degTvca, water gtrm out moc« boat 

inidQj Men lltat aQ bodies baio Dot the same speoitic b«at. If a 

I af nmeary at 100° U taiicil with a pound n! wntrr at jirro, tli* 

I of llie niixtiiiv will only b« ikbnut -t". Tliat ia to euy, tfaat 

I A* nnrtniry bas cuoW through 07", tLs lemixmluni of the water 

l«}j bT«a raiwd 3*. Conan^ocntly, thi laniA weight of wat^r reqiurea 

I SI ttawa a« inucb hcai aa mennuy doM (o produi-e tho aanw elera- 

l«( t^pnstnr*. 

I liailar experiinenta are made with otber «uIi«1«ii(im ll trill be found 
Ithr quanlliT nf hnat nquitvil to etfect a certain chwi^ of tein[wn- 
kk tiSnvnt for alaioat averj aubalaooe, and we speak uf ll»- iprej/Sc 
tw eahrifie eapat^ at m})OiyK* lh« qnontit; of h nut which it abaorbs 
I ita l«iit|i«t«Iiir» riiHa tbtoujjrh a pven mnffn of lemperature, tram 
> i* fnr example, cuuipared with the qunuUty uf hvut which would 
, und(T tbn ivuiin iTirciim>Iiinivs, hj tho aiinio weight of wat<'r. 
wvrdi, water U taken a» the Mandard for ihu coitipariiion of 
b«I«. Thun, lo *a}- that tlio opuciHc bnat of Inad in 0-0314, 
I that the qnantilr of heat whii^h would raJM the teiiiperatUKi of 
1 quantity of lead throu^-h 1° C. would only mini) the firappfalurK 
Be quantity of wati'r throutrh 0-0-314. 
I ■wtkoda bare been Hiupluyed for delermiuiuji th» speoillc beat« 
; (I.) tkB method of lb« nmltinii; of ire, lii.) thn method of 
, and (lU.) that of cooling. In tlie Utter, Ihu specille heat of a 
\i» d«t«nii]wd br the time which it takm to rciol thmujih a certain 
atutn. Pi«vi«iie to de«cribit))|[ the*<e mellioilH it wit] be convenient 
I tin trrpmaaoQ for the qiinnlitr of heat abiibrbed or given out 
i body of kaowB wnghl and upocific beat, when its tompRraturo risaa 
• (aUf i hw Mnk a certain ntiiuber of degrciM. 

%<0. Mmwbiw *t U* aaaslblo b«At afiaorbad by a b«dy.— I>^t m 
> tb* weight of a body iii pound*, c iw ♦pfeific li-'Wi, mii! ( iu lenipera- 
tM. Tba qaantity of boat nonwiarT to raise a pnund uf wiitvi lhiou|^h 
■• itgne hviiifr talion as unilj, m of thtso unit* would hn rr^uirRd to 
iv m panada of water lhiou);b oue decree, and to rai«e it throug:b t 
M«aif ( time* as mncb, or mt. Aa tht* is the quRntity of heat nucea- 
Kto niao tbroUfih I dc^nos m pounds of water whoso qiorilic heat ia 
1^, a body of tho lasin wvight, but of different npecifii: beat, would 
■ftata mic. Coaaeqn«Klly, when a body ia h<^alod thti>ut;h t decrees, 
JMQMtitJ of beat which it abiorbii in (Ar prwlact of iU ledght tutu it* 


ox HEAT. 

bunywi-Mrunt mta it ifKfifie kttt. Thin prinriple is tha liwt «f ill i 
Ibnnalae Tur cnJciilatiug »>)>«cilk Iwoita. 
If A boijf i* hniMl <ir i!ai>I«d from f \at dcgrra*, Ui* b<«t al 
, wiU b» t^mHOtvd b/ ike AmnaU 

m (f — p, o' w (*— O «■. 

A tbociiugli coniprclirDiiuD of ifcew fbnuulic vUl |irv¥«Di wir 
IB iho Milnlion of {intblcmi on spedfic bottt. 
887. Mvtkaa or tb« raaiaa or loa.—Tiiis m^liod of d< 
I huU ii bwod oo the fact Uiat to mdt a pound of ire 80 
■I* neoenaiy, or man kimHj 7&^ Black'* calMinieMr 
I) coBd«bi of m block uf ion in which a uvit* » mmAe, ami wl 
oTided with a mvrr nf ico. Tho mibrtanco whoM (fweiBe h«at ll 
'deUrnniniit is hcnted U) « ooruin Inu;H-istiire. nod tbeo placfd b 

cDTity. whkh i* onrrred. Aftw 
tiiiii> ihe bodv beoomia Dotted t* 
It in then (i)iF!n«l, asd both tW 
«Mvioe HtiJ tli« Mivft}^ wipt<d drr r 
cloth vrhir.h hwbr«ii pivijoiutTWtlffaJk' 
The iii«n«w oS wciebl of thi> iMh 
obrioualjr nprMtmt* tb« iee wkid 
faMO ooovw^ into w&ter. 
Now, Mico ram pound of ic* *t O^ivi 
fig. Sfls. mettinir lo water &t 0° >bwwb> fD d» 

mnl imitti. I* pouod* abMMlM 80 P ailk 
_ On Aa otbor hand, this qiuntin nf hmi it «<]iiiO t« th« heat ^t«b 
' thv bo^J in cvolitig fmiu C U> tero. which i* mlc, for it luAjr be 
r gnntod that m cunliag hom f ta teen a bodv giv<i( out m mieb 
M it abwrb* in being h^atnd from mto to ^. Cinn^ucDtlj, froai 


mA: = 80Pweiinvor=' 

It i« difficult to obtnin Uoekt of iiv m Iflr^n nnd piirvi as ihoaa iMldlf 
Black in U* expcriini'niJt,aiiil Lavoisier tud l.iiplttce ban npbndlki 
Uock of lc« bj' A more crinijiticiitcd nppamtiu, wbicb U called ths tW 
catori w i rf w. l-1g. S6.1 givi-* n ponporiive si^w of tt, aod fig. 3M nfi»- 
teats • aMtioii. llcoiuislo ul' ihrw; i^uucoDLrii^ tiiiTcawhi; in thaoirinl 
«M i* pUrod the bad}' U, wlioan npnciflc hitot in ^i 1>« dpl«nniiml, «Uk 
tht l«o ulli«n ua filled witli ]HiiindL'd Ke. The ice in the conijiuimat 
A i* melted by the hi^atvd b-idv. whilu tho ice in the coatipartOKntB c*li 
Dfl the healinu iiil1uonc« of tli« eiirruundiBg atmoapheie:. Tba two Mi^ 
cocha E and D (rive iniue to tho water which ari«o« from the li^aafactiM 
.of the ic*. 



to Sad th» tfodie Iteat of ■ bod; b; tbis appantuv, ila 

, M, It SjM ii(4«niiiMd i it in tkm ntiwd to a given tomp^jatur*, 

f bepum it for MBae l]m« b an oil or water fcatli. vr iu a curn-ct of 

ilaiing bc«ii quicklf brouttfat into tho ontnil ooiuputtniuit, the 

liK ivplwvHl a&d cover«d with ic#, •# reimMOlcd In llie tigiire. Tk« 

r which How* out b; Uid itopcock l>. a oollected. lt« wviffbt, P, i* 

tljr thai of tlt« iiwltcd ice. I'he olculntinn is Uwn mado w in tli* 

I m BiUT obJMtiOM to the IUI9 of thii apparatii*. Fmm it« nut 

I KNUO quantitv of ioc. aud a body, M. of large innm ; while the 

lartB a eiw^tnblR tiiiir. A certain wciffkc of the melted 

rMoialiu adhating to lh« ke.tvi that lh-tviat<>r nhich il<.>w» out&otn 

lani exactly rrprcKUt thu wtigkt of the melted ice. 


%. 364. 

A#. Meiboa or miztarM.— Tn dei^nninin^ th<? Rpecilic beftt of « 
. bodjr kj thtt ninthod, it U wei^beil and rnlH-d to u known U-'iiipsn- 
, hf liepfdiig it, for iatlanm, for mnii* tima in a cloud iipncn hitatod by 
I ; H i* then IsiiurmHl in a luatf of cold water, tha ir^j^t aud tein- 
I of which are kaann. h'tma ibi! trinporature of the water after 
' tha ipedlic h«nl of th<* bodv in di>t»niimfld. 
1^ H be tho weiffht of the bndy. T itn ffliapeiBtuiv, r ila spei'llic 

ti and let m bo thn wiijglit of lli<^ ci>M wnlxr, nnd t itn Icmprratiin'. 
AaKMMi a« tlwi beiitr\l b<yl* in plunpid inti} tbv wnler, the trnnperature 
I btter riH^a until both nrv hI 1)i>> *niiie umpcrstiire. Let thin tuni- 
ftfatum be ». TIm beatcd body has bevn r'>nti>d by T — ; it liiu. tbcro- 
1 qntBtitjr of beet, M <T — e> c. The coolini; witlor ha», on tho 


OK nur. 

ooDtmry. nWirbed ft quanlitj of bmt equml ta m (9 — (), for the i 
lipat of walrr U unity. Now this qnatitit; of beat gi^'un up bj (be I 
to niitnifHktl}' iM|itfi[ to tlinqiiftutilr of ht«t abaorhed bj thewiil«r;l 
M(T — e>r = m(«— (J, from'wiikli 

M (T-a)' 

An »xiiinp1«< vill illiiotnil'' thi? Api>lic)niou of ifai* fonikiiln. A ' 
iron w*ig!iinK 80 ounci?*. and at n tMnpomtUMi of IOC (!., U immcr 
ISO nuneeaof watnr whnm' t'mpnnitiim in 10° C. Attn thv lem[ 
hnvo bpcomo uiiifi>nn, Ibul of the cuoling wnl«r ia found to ke 
Whttt in the tpeeifir hpnt of thn iron ? 

Hew the wnight of tU* lieftled htriy. M, b 60, (lie toraperBtun T] 
100°, c U to be dtttcrmianrl : thr ti^mpcrnturo nf miitiire, *, it ^, 
W'-iffht of tlii; cooling water is 180, imd it« li^mpurature Iff*. 

_ (1 
«U (100-^22) 

889. CoTrectioDi. — Tbu -nteal cuntuniu;! the <»olinf[ water i*iuuill( 
L mniCI rylin^nr nf nhtrr or hmw, with thin |>iili(b«a] M^, tad ii np- 
porl^by some bftdly cuiiducliTig annn^'uictit. Il u obTtau* thai tUi 
vuMcl, which il oriirinnlly ot the tempcmtum of tho coolin^wMM', iiliin* 
it« incTCODO of lempc.rrttUT^, and In ancnrate «xperiinenl» thia muiil be ■!• 
lixwod for. Tlie decresiw of tempi-rature of tbo heated body 'v "|iul <" 
th« incTt^VD of lomppratiiiv nf the cooling watiir, Mid of t)ii< vemelin whick 
it in C(>iitaiiiL-<]. If tbi? wi^iubt of this lattPT hit m', and iti apadlic hfiii ■', 
it* tnnipRrnturc, likn that of the water, ia I : oonaequeotly tlie prariau 
•dilution becomet 

Mr(T — *) = m(e — () + «'#'(«— 0» 
from whinh, by obvious trnnsrormntioni^, 

r=!::^!n:^?>=^ = 0-1153. 

Oeuerally spt-aliing, thp vnliie, ni' i/, U put = j.; tlial la to My, a I* 
the wpight of wnl*r wliicb would abwirb the MTiie quantity nf h«it u tlw 
TOMiel, Thia is caid to be tht* rediircH value in water of lh« Towri, ot tbi 
vialer tquicalml. The expression accordingly becoiOM 

MTCT — 9) ■ 

In (tccumtn nxpnrimenU, it is neceeanry also to allow for tbo k(«l *b- 
wirb«d by Uie ^}a)n anil mercury of the tberoioiDHter, by intjodiiiiiag iau 
tbe equation thi-ir vnluea n<duccd on thi« prinriplc^ 

Inotdvr to allow for tb« loss ofbeat due to radiation, a pMlimioarjtl- 



* vnth ih« bod? irlioae «p«<iBc IimI u Mutibl, Ihe oaly 
bieh u M aMevuiii «pproxiuinicly tin* bctciuc of Utmprrature 
milrer. If iliis incr^'MO be Wf, fur enAiiipIn, itii) lenipvra- 
wsUc U roduMHl b\ b>ir tbii uumW— thst it Ui <<ny, C bnlow 
irature of Ibe «UiiMpfa«tv, and tho oX|)*riiiwnt i» thra carriitd ont 
iinarr manner. 

■leUiod of ooDipMMiitiaQ, Gist iotrodimil by Ruiufunl. tlic wotnr 
t BiimJi buat tton the atnlMphoro daring thi' lint purt of ihs 
tl «• U loM* by nuiMtion during tins Hecood ptin. 

tig. sa.'t. 

■n^ Bpi»KrntD« ror dotermlDlar apvctflo baata., — 

cntB Onr 'jf llift fiirtiifc •■■f ajiprirntm ""nd bj M. ItegliBult in 
• HpMifiG beau ity l\f niplhod of luixtiireo. 

I put is a watiir-balh. AA, of which Rr. StB reprewnW 
U coaniata of time oanceutric ci>iiipnniii«'nt* j in llio central 
k (mail ba«lirl of bmu «itv, c L-utitairiifi); frugni'riiU of Um 


as RUT 

^ MibilMw to be det«rmin«d. In the middle of whicfc la ] 
Bipl«r, T. The »pi!oiid compartment u bt«t«d by 
coming tliKxigh l)i« tubt>, r, Tnim a boiler, B. mid {iMnnf intaf 
T>h«« it in randiMtod. 'the thiH compartmiiit. tr, i> wi i^ tl 
hinder iVn- Iom ot hvtO. Th<i water buh, W, reiU mi i ell 
with duublo Hide*, KK, {artniofi n jickrt, vhtfh a kvpt Al 
wstnr in order Id ncliide the heat front AA.and fr[iniili*M 
Mintral (.■omjmrtmMit of tbo wBtnr b«th » clewed by a <lHnp«t 
<wa Ins opfni>ii Bt pli-iunir«, so tti«t the biwiWft, c, cjin Iw lowwi 
chNiiibf.>r K. 

On tho \i-n n( thu 6|{itm ii rrpmwmtnd a unmll nnd vtiry tlu( 
•)>1, 1), DusiiPDdM bv «Uk lhrviu]« on nsuiall carria^-, which CN 
oul of, uiinlu, Ihc cbiirabnr K. Thi.iVPMcl, which wervuMit 
onntaliM imtrr, in which ia itnm<3r»od n Oi<'rinr>nii-U>r, t. Am 
Diom«lOT nt (he aidu. ('. pvc» Uii! temptrmtun! of the ux. 

^^'hl!^ the tbennonicliT 'J' ihowi that tho titmpMatnn of ll| 
in tlie bath is slalionarv. xhc 4orvoD A l« nu*€<d, and tbe tcmqII 

[ jiiat below tho cpnirnl oam]mrttnDnt aftbc wa.t*T batL The- 
thnn wiiltdmwD, and ih-> baaltat e and )t» rnninnts arn lownn 
wat«r of the tcimI D, the thermoaiietn' T rviaunin); filsd ll 
Thn airnagii nnd thn twr) I> am tluni moTcd out, and thcwa 
until the tlivrmi:nnrl4.T ( buconiM alationary. Tho teiii|wrBla 
itidicnit'ii ii e. Thin temperature knows, tho reat at tbo uf 
nind<' in thn mannor dMcrlbed in Ml.98(l, can b*ing taken toi 
nefL"<Hiiry toiwclioin. 

In ili'ti'rmining thrnpocifieb^iatnf uibstanom — pIuwfthonM, 
— whir-h couhi not l>v hvatcd without cau«iug tbem to melt, 
some chiLotre which would inicrfvra with tbo accuraej' of 
HngHAiilt adopted an inver«a procem : h» eooW them down i 
rature conwdimihlT bi-low that oF the water in the caJariitMta 
olxcrved thn diminution in the lemporelnro of the latt«r, wbj 

. from ininiersiufr the cooled >tlhBtallt^c^ in it. 

To nicortnin the spcviflc lieat of bodiiu,«iich an potawdun^ 
DM of water w quite inapplicable, the det«nninatiou is madai 
liquid, »ucli ns fiirpontine or bpn*oU'. the •ppcifie heat ofwhtt 
:tOI. aCathaa of ooollac— Kqiinl weighiK of diffnrvnt bt 
apecitio beaU aiv dill*.- rent, vrilt OL'cupy difiprvnt timeti in cooll 
thn Munx nimiher of dn^pna. l>n1on^ and I'ntit baro applied' 
pie in deleririiuing the sp«dlic heats of bodies in tbefollowiof 
amall pnlinhod silver vcs!i>1 ii filled with Ibi gubitancD in a id 
fowder, and a therutonieter placed in the powder, whiL'h in pn 

' ThiavMvl u heated lo n certain tempenitur>s, and ii tben intr 
1 copper Toa«et, in which it fits hermetically. ThJa copper v< 




I tho MoMuil tMnpentura of mnliing- im, ami 
id which tlw rabrtBUM ukci in foiling; throngfa ft girFD nui^ 
ny from It," to Ftbv auiplfc Tbe timM which equal 
Smnt bodioi ic^nn for cooling thran^h the auD« nwgo of 
(m dinctlv as tlivtr tpeclAc heal& 

n* ptorod that with aalida thii molboi] dmn not prt tnul- 
U 1 it aamawi, which U not 4)iiit« tbe caae, thnt the ci>aJtn( 
• cfual, and thai all auliataiicai (lart wilh ihrif knkt to tb« 
ith (<q«al bcUilj. Tlia mrtlifid may, hnwoiw, be etnpl07«d 
in the tMurniiajiiiob at Iliv specilie heat of liquid*. 
Uo baM at lUtvtda.— The apodSe haat nf tiqiiitta raaj hi> 
ither bj th« method ol cuolina:. bv that of mixiunu, or b_v 
ta caiorinMtff. In Iba lattw cam iber uru contninril in a 
Mati, or a glaxa tnbtk which i* plamd in th« ooiiipsrtiumt 
and thaaxpeiiment then niada in the uaual mannrrr. 
aan Itan th« followinic Inbln thni vati-r nnd nil nf tiirpeDtiii<* 
gnafer spcci^c hot thna ihut, uf other luhitancni, and taoir 
n tlio BinlJiU. It in from it* (civat apratic hnat thfti wA(«r 
ag liKB in heing heated ■>r eooledi and that tar th« tarn* 
■n p iM atnw h ahaoria or gira out far mara haat lluin ntlmr 
lUa dmble pn)f«rtj is applied in th« hot wat«r Hp|iitr«luii, 
than pnwBtly ■p^'^ ■»>) it playi) a in<Mt imporlnut pnrt in 
of natuw. 

a ai^aeUe li«*la *f aattila aod U^ulda betwoan <J'' ana 
MM of ihn loaihod of nuxtniw and uf that nf cooling. M. 
I detennioMl the MpeciBe h«nU of a niimbur nf bodiPM. The 
la eaataina th« aumbcn obtained for thl^ bodioa niuall; met 

I fhttatk Specifle, 

ana linit*. Sabatancv. hMta. 

.... loooou Nickoi o-ioeoBJ 

... O-42SO0 Cobalt o-iooeaj 

ml charcoal »«n»6 Zinc O-OOfifiS I 

«l . . . 0-^[H Copper ,..-.,, O'OODlS 

OSOm* Braia OiXKlKl 

030187 SilrM 0-06701 

^^ . omei Tin U'W>e2.-t 

OISWO Antimony 006077 

0-14037 Murcun- 0-0333a 

0-191)89 Unld (Kmil\ 

o-ii;go nttittuiu o-o3»u 

0-11378 Bimnuth 0-03084 



Thes« BBmben repMMnt Ike mettn apedfic beat* hetwseD 0^ ul 1 
OiilonK still r«tit'H icuvBligi^unB Il«t«, 1iuwi<vlt. »howii tliat the I 
lluU iiiiTiiMii with the tcinpvMturiiL Thoaa of lh» dmIh^ for in 
we gT««l«r twtw«vD lUO' and 300° th&a betir«>«iii t«n> md lOO', i 
Mill grniter Wwccn fiOO* uul :iO(y. Thnt is to my, n inniilnr i 
hMt b rvquiml to ruM a boilr from aOC t« %'iO°, ibnu fcntn 100° I 
and iitiil moro than from tnra to 50*, J'or ■il»w, the mtan upMJie I 
l»tw«.i) 0° and IW 'v OWM, while betwwn (f ai»l 200^ a uC 
TUo apfaiGc h««t of pliiiiuum for nuv lemppmtum way bu «xj 
tho roroiaU 0OSS8 + 00000042 f, vhrrv / is ihn b^p^'ratiim : 
of w»i«r by Ui« fonniiU 1 + 0-00004 { ■+ 0-<NXKX)Oii fi. 

Th« incmwQ of apeeific hoat with the t«mporatuni U gTMtor M '■ 
•re neaivT tlusir fuiin^ point. Any action which IncrcaaM Um < 
and molwuUr agKrr^ntion of n bujy, diminishc* ita aprdtic hnit. 
vpvcilic bi-at of CAppor LH diiiiini«li<-<J hvita bfling liAfiiraeivd, buliii 
tb> oriinnal Tkluu afli-T tli« uli>Ih1 has bwn atpun hnlcd. 

The fipwiSc h«at of a liquiii inoriTiM-ji with ihn tfmpi'raluro mnclki 
rapidly lliui that of a aulid, Wat<<r ]», buwevpr, an exception ; it> c|i«rilir 
boat inciviuips Inu rnpidlv than doua that of solkla. 

X HubnlHuot> ill tie liquid uteM ha* n gr«iat^T specific bi-al than ^hra 
it in iiolid : thui, Divltnl tin has tbv apvdific bvat O*0ij:tT, while tktt •>' 
«oMlin i'ooly 00>%l)3:t. The opera lie brat of liquid broniinciiOUl. 
thai of solid lirumiiw bcin^^ 0-081. The iJlirt-rence iu the case ofvaltrif 
^«at<>r. Ita ii\nieitK bnnt ia 1, that of ifw, amnrding to IVmin,Vanf 
0-604. In tha ^aseuua alatu a body baa a liiulwr specific beat than ia^ 
liquid atnlc. 

Pou!U«t iiaed the fipeoifir lieat of platinum for ineaturing^ high itfR** 
of boat. Supposing 200 otinrcK of platiDuni lifuj br-Rii hoatod is atoiM* 
and liN'l then been plamd in 1,000 ounces uf wflt«r, Ui« tcmp^raOu* tf 
which it had rawed fwm Ui'toL'O". From thi-fonnukw* hate «=*». 
m = 1000 i e i* 20, and t i» l.l. The op^cific heat of platiaam i* IKOt. 
and we have, tbcrvfuru, from tho equation, 

Me{T — •) = in (<—<), 

-._m(»— + Mrt 7000 +lSi TISS ,nan, 
* Mi "= is*— =«fl = '"™^' 

It is found, however, that the apeeific heat of pUtinum at tampenlat** 
ofab'^ut 1000°i*0'0;t7.Hj if this value, tbniefore, be subalituted Ibr f ■> 
tho abuvu equation, 

T = "°^?=658"a 
7 '46 

By thin method, whtcli Kquirea gnat skill in ibe expatimtiiWT. 


1 lUlenniDpd a Mriei of higli («iiipenture«. He found, for ei- 
, itin trmiH-rntum of melting: iron to bn 1^00° to IttlXf C. 
. Dnlanv (ta4 PaUfs I»w.— A kuowledgi! of tli« BpFcifif bol ol 
ihu become iJ t^at imporUuico, in coiu>M[iicnc« nf Dntong and 
idiwoTCTj of tko niin«rl(Kble law, thai <Iih product cJ' tLe tprnfii- 
Tinj dciMnt into ila Btomte wmrIiI Li ■ coiuilnnt number, a law 
iwnj alM ba MUncUud hj mjiof tliat tir ijuri/lr hriiU of titnplt 
tiwt m v arM fy <w Ihtir atomic w^hit. Thtia, taking tlii- a tumiF weight 
wal^ iUipndflt; heal 0-11379, and tlii^priidurt :MMi; tltn aloniir 
btof nick?] LB ^-6, iU apecific k*«t OlOti.'), iirodiitt 3 204; th*- 
i wd^ht of hjdragm i« 1, ita apedfic htut 3*2, uisd thi! pmdurt U 3-2. 
all, who dvUrmined the apeoific heatH of n htiin miuiln-r of 
twitli irraatcan;, cuolirmcd Ihilomg and IVtit'ii Ibo, but he fDund 
I nntnber, inalrad of bnng conatant, a* Diilong and I'ntit had nip- 
, variu bFlwei-n 20Gafid3'4]. Tlii'BetiLrialic>iwiunydi^p(.-U(t [lartlyua 
t fiflculiT of nbuiaing tfin filemonta ^gaitn pum, and pniOy on tbc orroiu 
atal to (be deti?niiiiMtli>n» of tbe apvclfic beau, and of tbe equ!- 
Dul iba apedfio baits of liodirj rosy with the atnU- of ajfirrvf^- 
alao with th* liaiiu of the ifniiKTHiiirc at whioh tlipy are 
Soitie, auch aa potauiuiu, ha\'u bteii delcnuiuud at tumpe- 
very nwu' ihoir fuiing- [Kiinti ; olbm'*, likt platinum, at gn-n 
I fma tbetv poiuta. And, doi>bilc>B», lb« priuciiul reaauu of the 
ia tlui fact that tbo dcteriuinatiocs havu nut bvcn made 
■ identicKl pbvucal cciiidi lions, and at ti^inperatiirEa equaUy distant 
I ikf h4of point 
TlMMjuiialentaof lh« ^tementa repr«Mnt therxlatiro wrighlaof equal 
nmliar* nf •atnimi of tlieae bodiea, and the pruduct, pe, of th« spedSf 
kMt, r, into ibii njiiivaknt, />, ia tb« atmate tpKifie hnil, or ibn qiiantili' 
•f baal BaccMHin to raitv thi- tempi-ralun! of ibu itain^ nuiubcr i)f atomH 
\j OB* <[agT«« ; and Ihilong and Trtit'* law may be thus i-xpmucd ; tAr 
MUM faaMfaly of it'll u nttiM <o And an atom of aU limplr bodm to the 


Tbo atomic beat of a bod;, wbvn divided by ita ■pecillt- h«>nt, gives the 
a^aivalivt of a body, {trgnantt hu aroi propused to use tUia relation 
ataomna of d«l«reiiiiiii^ th« vquivatent, and it certainly i> of great 
MTVin in iladdlDg «u the equivnluut of a br)dy In c««v« where the 
ifciMiii al ralatUOM pmnit a cboiiw Ix^tirnrn two or nioni muiibiTa. 

In eaaquniiid bodto' the law al«<) prevajla ; the prndnct of tbn iipi>cific 
bat inlA tba eqaivolcnt in on almost conitant uiiuiber, which varitia, 
Wmt«r, with tba diflwBnt c!a«iie* of bwlion. Thus, for the chwa ol' 
adlMoif the (Tenoral fuimula Wi, ilia ll.SO, for lh« Muu|uioiid4«, tt'O*, 
n i* ST'lCi for the lulphidea, KH, it it 1S-&8: and for tha oarbooataa, 
ItOCf, ilUaiM. 




Tlw Iaw may be «xprMMJ in th«< foUowiag gmanl 
emnpataidi r^ t/u- name/omiHla, md of a Rimlar dh«iiiK«f <OMlMfa^ J 
pr« A ii< ^ <Aa nlonue vw^^ tnto Uv ^Mi/tc Am( ■« i* tmdati \ 
Thu incliutcn Dulon); uuJ i'l-tit'n bw u tt ptiiicuUr mm. 

SOS. BpvaUlv IM«t of oampaoad t»o«l«a.— In order lo dtJnt* I 
•fwcific luNit of iL iyim|x>uii(t ftum that of iu e!i>aMnU, M. W«tf]w I 
made thd foUowin)! h}-)Ki(li«Di : he MmiBiM that an oleawnt in i 
■nlu Miiubin&Liun lailii nlliM* to fonn a coiBpowndi boitf, Ktaia* it«( 
•peafio lieat, ao that if p, }/, ff', .... wpnMBBt Lbs atomic wd^tt I 
tli« denienla, aoil V tbM of the coiii|iiMwd j e, r*. i<', . - . . C, thai 
nupondinit spccilic beuiB. ivliili! !>,>',■■", . . . . are tbenambwaoft 
of ihsM iimple bodiM which inalw iip th« molacul* of the i 
tho felation obtaiiu : 

PC = i7«- + >ijf^ + •"p"c" + 

M. Wawlyn hru fuiind that tlie rwultn uhtuiut-d by calcvlatiaf , i 
Ibu lij-polh^ain, iho »pedfir. hMta of the lulphidca, iodid** and \ 
agi«« with KXpurlintMiIal n<«iilt«. 

•inft. BpoeUo iKat af Kaana. — The apt-ciGc hent of a ga* mf '| 
rcfrrr^ fithiir t« llml iit' wHtpr or to tiiM of air. In lb« fuaiatt i 
MpicscntB thu quantity of beat iieopnary to niiw a piren weight i 
gas thmu^h nnn drgroCjaacompiTrd with thi? hi^t iMionMnjy to i 
•an* wci){bt of water one dp|m«. In th» latter rane it Rfnaaottl 
quantity of hrnt nccnapary to raiw a ^vpn vciluinc oi tbo gaa threogbl 
degree, cuinpn'd willj the quantity nect'Wary for the auM tdnawi 
tTMb^ in tlii^ NimL' rnAnncr. 

De U Itoc.hp and llnrant dnicrminnd th« «p9cili«bMititofg<a<HiBr 
Miee to wnter by causinK' kiiuwu Tulumm of a (liven fnui amder i 
pnewrp, and At u Kivi-n tr mjicnilum, to puH thmiigh a ffaml ^laM I 
placed in wnler. From thv increaM- in Irmpentturu of thia watov i 
fnm tha other data, lliu ■jH>cilic beat wm ddonuincd by 
annlogOQ* to tliKt ^von iindpr tlie method of n)ixtaR«. The 
phyaJraitta hImi dclertniiied the epetriQc heata of dtflennt |i;a>«« i 
la that of air, by cnniparinK the f{iiBntitieii of hrat which nfual 
cf a )ti*en ifiw. «n<l of air at ihe same preMUiv and teinpoatim 
parted to «jual wci^hta of water. Subtoquonllf lo tbniw 
De la Itiv« Mid M(ir<;et bate applied llie uiethod of cooling t« the : 
detoriDiiiHiion ; And itill more recently Iteftnault ba* made a Hfiea < 
iaredigatinnH nn the calorific capacitiMof gates and vapours, inwhiebb 
kaa adopted, hut with niatiTiai improvement*, the method of IhkRedt'j 
wkt Bcrard. \\v hns thusobtuued tho following reMilta for the ■peeiCe 
bnata of the yuriuua ga£«s and vapuun, compwed fint with an i^iiii 




K ttikcD w unit^ 1 M<Kmdly 

witli ihtx of an 

aqiMl volt 

m httan, to ita own wcijrht ol 

wnlur taken 

M imtj. 

Spatilk. hsara. 





Air . . . 








tiyitogeo . , 






Kaoxidv of iulTD)fOo 



CorlMiiic oiide 



Carbonic aqid 



Ujdrocliluric acid 

0-1 tHG 





OtsfiaBtgw . 



Wtfcr . 



Etlwr . 






TupenUaa . 



B&aulpliid* of cubun 







iMaf ibew iictMiiiinB<iiiii» tb« gaam wtrni under a conatani pre»- 
tmiable TolunM;tbali(,tba gaaa* it wiu heaivil could eiptmd, 
h olM tba ipMJfic heat tmJrr vtmMunI prttmrt. Itut if the gna 
li^baalMl ia kept at ■ coiuutit roiunio, iu |mMaun>or vlwilic form 
■■rilj iacnantig, it baa a diflaMUt capacity fur beat ; this kltor 
uT ■• thn V^<' Aast trnder am4tant mlume. That Ilw iatter ia 
tk* funmr U ctiiIvdI fiom th« foUowint^ conaidcntiona. 
a givvB ((uaiilitf et pui to hat-e bad ita tvin|)iirBtiirp rained f, 
bn iifm iufn TMnainvd roiwlant, thl* incrvnM uf tciiipuritlure will 
■cmBipaiund by a oertaiD incmuc in Tolumn. }^iijipn«ing 
al 111* jraa ia ao eomptMNa) aa bi natorc it lo it« urifnual yuIuiiiv, 
lit at thin wonpwi ai on will be lo nusr tia Ii-iii{H'nitutc again to a 
CKtait, >ay t". Thtt gna will nvw bo in thu miuv couililioD m 
d Wn bfialrd. acid not been allowed loexjuud. lU-nci?, tlioaffiH 
rofbvat wbirli U nqinnMl tonisetbo tunipnnituni of a ^vcd 
tf gaa; f, while ibf pruwiiRi renuuna conalaut and tb« Tolume 
rill raiae the lenipemtuin t + f dT.grma if it in kt^t at a cooataiit 
bat Taii>bl« pRBBTO. The •pvcille heal, therefore, of a gua at 
I, c^ ia gicatcv Uian tho apodUc hcut under conalan 

tbajm to M>eh other oa e -i- f: (, tbatii '■-^^. 


ox BUT. 


It U not poadbU to detmainc bj direct neaiH lli« tfta&t kMi«(| 
undsr eoturtmit vnltune wiib «T«n an appro*ck to aasaney ; nd [ 
KJnvs betru it<?ti?nnuiwJ by •omo iniliivei iii«lliod, of vlticb th« i 
ciinto i* bucd na thn thnnrjr of tkn proptfp^tion of nund (90(!>. 
Uteit d«Wmiiiatiaaa niad^ un IbU baws givu tbft ounibaT WUl 

v»lu« of 5'. 

307. SatantliMttwfrdsioa.— BlMbirMt1i«nr«t«i>1iHrT*i 

iDjt the fniMjjn of ■ h^xly Uom the aolid to the liquid aUUe, « qi 

fawt disappews, u fftr lu thormoineuic effect* ue Mao^nwd, *»! i 

■ccardiDglf mid to Iih-uuii^ Utent. 

In one «iperiincnt hn *iMpond«d in a rnom kt the t«ntp«ntimi 

thin ({liua Owks, oueeiiutftiniugiraMr iil(P,aDdlheotbertk«MiMi 

tit ic« at 0°. At tho end of bolf an hour the t>iro[iemlure uf the w* 

riaen 4°, that the ice bdog unchaii^d, and it wa* 10} buanbffoiet 

hod mnlted and altmned tlic mine lempi.-rMtun-. S<m thv UnufnC 

tha room r»ninin''d ixin^tiutt, and it niiut bn concluded that both ' 

raotUTHd Ibi^ game atumunt of hvnt in thu Miu« tiiu«. Hence ill 

' miirh Kent w:« raqiiinsd to mflt tho iee and raiaoit to4°, a*i 

to riLioe till* winii' w.ii^'bt. of water through 4°. So that the 101*1 1 

of heat iiiipurleil Ui th^ ice n-n.i 31 x J = rM. and a* of this ' 

u*od in raising ihu temforatun-, tho rcTiuundor, 80, wm iisc4 ia i 

mcllinp Ihe ice. 

Ill) dbn d«^t«Tinined thia 1at«int heal \i;f iioni*niinf|- 110 pari* of 1 

0° in 1»5 {lurld of »vl«T at 87-7° C. He lhu« ubtained 'iM parta oft 

■I W-ff C Takins into nccniint ihn hnut rvoeiTRd by the ttswl iai 

the liquid waif placed, b^ obtainwl lb« numbar 70-44 a* lh« lal«iil 1 

liquidity of we. 

Wo Diay tbuB my : 

Walvr ul (1° = loc at 0* + Intent beat uf Itquf-factian. 

Thn motliiH! whirh Ittwk nilopt<id i> enirntially that which ii iw* 

for the detf riuirtKlioiL of liilvut healk of liquiiU ; it con«istjt in pli 

aubatnnrr undi-r examinntloii at a known tempcmtuii- to the ' 

Kliier liquid) of a oslorimnlirr, tha lemp«n)tiir«i of which i* iin 

melt UiD Hub<ttnne{' if St is aulid, luid tu HuUdify It if liquid, audi 

uniformity of lomptrutuiv ia ntAbliihi-d in the calorintclRr thi* 1 

ture h di'lerniined. Thu«, to take a aiiuple caae, euppoae it i> 

to detirrinillo the Intent hunt of liquidity cf ice. Let M be a 

weight of ice at xero, uid m a wfighl of water at f outlirinDl to in 

ice. Tho iee id iminer^ud in thr water, and &s budd aa it hu uwltej I 

Hilil tempcrntun, e", ia noted. The water, in cooling from I* bt ^,i 

pBJied with a quantity of heal, 7;i(( — e). If * bo the taU-nl hfil flf ' 

ieo. it abdorbn. iu liquefyiiijf, a quiintit5 of heal, Mj- ; but, beAdd ' 

the water wlucb it forma has riauD to iba lvnip«t«tim b", and U d« ■ 



fd • qnaolitj at Iwftt reprtMcnUd by MiL We thiw j^t Um 

ih ike Taliw of t is deduc«d. 

metliad, a»d avoidiii); all •outces of error, MM. J)(»uiu and De 
»y fomd tliftl Ui« b(«nt hMt of the liqaofAcUnn nf let i* 7fl'2ft ; 
fomat of Sm, in Uquefying, nhiorb* tlie qiuiicit^ of heat whicb 
mtiumrj to tum 79'3& pound* oi wfttor, 1% or, what ii tbv Mune 

pomd of water from wwo to 70'3S^ 

ftli«d ia tfaiu cMvDttally that of the method of mUturtu ; th« 
iBtiM nu; bv bmi), dwI tlie eame pivcautionii sati mjuinul in tho 
In delenniriiog the Uient b«a of liquiilil^r of mont eolida. tbe 
padfie bi>t> of th« anbMiuico ntqaim to bo takon iata Mxaiuit. 
MM, let M be tke weiirht of the water in lie ealoriraotor (tho 
mdvnta <rf th« eftlorinetcr and thennometcr mippoand to be iu- 
U the weight of the mibatance operated on ; ( iho ontpnal and 

temperatui« of ilie cnlorimctcr: T the orijrmnl li^uiperBliirv of 
IBM : € it* uMiltio^ (o: frMiing) point i (' iho spitdlicT brat oi' 
Boe in the tolid atato between lJi« 1«]npenttumi ff nnd « ; r H« 
■t in th« liquid etat« between the tcmpomtnrca T mid CT ; ai^tt 
b» kt«Bt hwai Knifht. 

xperifluot U tn*da on a inelt4>d niVtance wjiich giv^n out heat 
wteetWBOil eoUdiftee i( {it ia taken fur gnmtni tbat a bodv 
M much heat ia •alidifving na it nbaoib* in lii|iiofyiiiK). it U 
I lim quaatitj of heat nWrbvd hy ihi> calorimeter, m(t — I), ia 
it thne pacta: fint, tli« heat lovt bj the subatiinw in cooling' 
rd^nal t*nipe«atar* T to the inlidir^nK point Z : wiccindly, the 
n out in aoUdiScation L ; and thirdly, the hent it lows in tunlc- 
ito ialMifjing pcdnt C to tbu tcuiperaturc at the naler of the 
*t. Ilutia: 

t,= =i5^-<T-0 .^fr-e)C. 

who baa nude eereral reaeArche* on thiM enbjwt, ha* 
Ihe foilowisg Dnmbcn for the latent beota ot fuaion of tteviinil 




Biimulh 12M 

Sulphur 9-a7 

Lead 8'S7 ^ 

l-hoaphoruB fi«i 

D'Arcefaalloy .... *^^ 
MelCTIiy »«* 


MS m iiKAT. [m- 

Hmw Diuuben nfiCMiit ihs niiBibMr of d«^T«M tlnoogb *Uck ■ j 

L pound of water would hr nitd hj a pound of tbc body m epmtkmhl 

'fatriBftroui Ib^ liquid to th«kolid (taio; or, wbM i» iliesunelUw.C 

namber of ponnda of wmter that would beniwd t" C. bjr oaeoftbet 

in soUdiiyinfi- 

3S6l Ik«totfnUi*tl»B or the iBteat b«at »t TApaa**. — I 
we faaT4> wrn, in poiHtii); iolo the vtalc of rapour, abwitb a imj" i 
Mblfl quaollt}' «r h«At, wbicfa i* tenned lalftU Anaf ^ n^Mn-tiriilai. , 
detnnniaiD^ tb« beat absorbw) in liquids, it in waumed tW i 
liqaefjing, givM oat a* laiwh heat m it had abMitied la W o nA^ i 
TeH«d iaUt Tt^ur. 

Tho method cnploj^d i* MMmtiall}- th* waio m thai for 
tlw apedflc hft ol ga*M. Fig. 337 Mipt«««ata the appantai uwi ) 
M. Detprett. Tlia t^wut b prodncod tn a rrtort, C, wben iu i 
^«m U indloatod "by « tbenBomotair. It jitMe^ into t wonn iaunoiMd] 
. water, where it candenaet, irapaiticg' ita Inteat hoot to Aa i 

iag walor in the veteA E Ibi^ 
candensad tapour b calic<ud ■'] 
a vwHol, A, and ita wei|cl)i nf«^ I 
baa pawed throogli tht 
The thermaniemB tn B gife i 
cbanffe of tompnratora. 

IM U be tlM wvigkt «f ; 
condensed Tapour, T* ita 
rnturo on entering dte 
vrbk'h ia thai of iu boiliiq[| 
Mi'd X tfao latoni h«Bt of 1 
iiL-iL SLinilailf let m W] 
wcifbt of tha eondvnnig ' 
(coniprinag tbe weight 
Tcnel B and of tba 
mAm^lDwatcr^Ji-t r°be the t^mporatiini of tbew«Aer at the! 
and fP its lumptrnture At tb? *ud of tlie oipeiiment 

It in to tie cibii-rTed that, at tho cnmtucncoment of iha 
tbc coiideused vapoiir pMi««* out at tbe teniperaum f, whife at ' 
ooQclunon it< tciaperature fa e^; w« mar, bowvvor, aiwumG ibrt i 

neon Iprapernturp duriujr the (■xporimcnl ia * J' '. The raponr 

''•fter ita coudeiiwttiou ba« tbecvfore paited with a quaclity of b 

M (T— ^) Ci while tba heat ditongagod in liquefaction if nfi 

MDted by Mr. Tb« (luantit; of heat abnorbed by the cold wattr, t 

Fig, 267. 



m, uid the TOMil b m($—l), Tbitftfom, 

Mj+M (t —'-J-') e = m(»-l)i 

B wlucb J i* obtatiMd. M. DeepreU foiiuil tLut lh« Uii-ut hf nt of 
■MKu vaptwr ai 100^ U IMO ; tJiat i^ • pound of wntcr u 100° ab«orl« 
raponaiD)T w Bucb Imt u wnuld WM 5-10 |>i>iin(l» of waUrr tttcough 
It. B«^ga«illt favnd llw ntuaber S37, ud MiL Fain; nnd K!I>«nniviR 

U Ib tbo «*• of ILp Ul«nt IiMt of water we may wy, 
Sti-Atn ai 100^= Water U 100* + latent heat of gBMifieatioii. 

■•d ■Ubn-tDBOD'a caIortiu<it«r> The ■pi'krntiin (fig. 
t knihM a tvry dtltOAl^ in*An» of di'ITiiimin^ tliP enloriiic rnpaclM 
IflU*, kbort li«ata of eraporaUoD, and Ilie heat disengaged in rheini- 

1W lahidpal [«rt U ft ^)heri«Rl iron ree«n-«ir, A, full of merciirr, 


(•V tIEAT. 

wUck it holds about fiO ponndi, sad repnMDtiS iheT^forc. a To)a 
mtm (ban half « gftUon. On tlio loft tlwre an! two tubuliui^ i 
nhkh w«litt«i^ twoibeetiroD tuWoriMu^lo, pTnjf^np inio tbcid 
d1 the bulb. Each can bu fitted with • gUm tube Tor ounuiutng 1 
SUDn«xp<^niriiIndupiin. In moal mwii one mufflo uid one ftiM I 
eaoufrli ; ibi- twij am used rrhfa it u dMind to compare t]i« qnaatl 
liMt pmducixt iu tno dtffRciuit npmttumt. Iiifttbii>dT«ttical lulu 
then is ftlm a muflte, which can be uaed for del«raniinii|t cakriGc c 
by Regnanlt'a method (380), in which cue it u placed boteUh i 

The labuluin il cuntaiiu a >t«el piatan: m rod, tuned 
kiuidlf m, and which ie pruvided with ■ (crew thnod, tmumitt a i 

Fif. 300. 

t^^^flgdos 10 tbepirtnn ; but bj n pifculiw mtichiuiEsm, gifeeiti 
' '^W^Bbliaa. In the lust tubulum i^ a ^lasa bulK a, in wbkh it i 
capillary crlnu tubi>, ho, iliviilrd into portx of nqunl capacity. 

It will bt- st>(>D fruiu thU dMcriplion that the mercury calo 
nothing more thiui n thermuniL'tcc willi a vury large biilh aaj 
capillary eU-ai : it i» t)i>ir>>fore very c!><Iicnl«. Jl dilTen, ho«nver,j 
tbcrninmeler in Um iael that the ilivUiouH do not icdieaio the Km! 
of the mvircury In iho bulb, but thii nambor of thenual untie is 
it by the lubslaaces placed b niutllo. 

"Diia pndation ia ellucted as follows : — By working the 
niercuty ceo be nuide tt> «itop at niiy point of the lube, bo, at wb 
d««ir«d the ftraduBtiou slinuld eommt>ucv. HaTiag the*i phweJ i 
irou tube asmall quantity of mGrciicy which is not aflemrarda i 
thin glMi tuba, e, ia iiib&rt«4, vVwV \a^u^^ fixvd a^niitat the bu 



ttvnrj far * email w«dg* not nprcMoWd tn the flfcura. TL« 
ff thiu vljiuted, tbe poiat of a bulb tiib« (aoe %. SW) i« intro- 
lUiniKg wst«r, wkidi i* nii^i) la th« boiling point : tumioK 
an of die |iipetW, Own, w KpKaenMd oo n', n qunniit^r of tbi> 
n into tin* tMt tube. 

Kt which i» thus itaftatfi to the merturj initltM it «xpaud, ihr 
f mercurr in to ii lungdisiied by ■ number or ditiMnm, whioU 
nil *. If lh« waiar pourod into tha t«*t gliuu be w-'i|ihn!. »nd 
IwiUilii ba taknn wbi-u th« column, &», is stuliounTv, ibr )>n>- 
she wei|tht of tbn watrr into the nuiulwr of dojrn'i'* tliri>u^h 

ha* (kllcn iodinlm tbu nuiuber of tbenual iiititd irbicb tlji- 
tT« sp tn tho irDtini uppnriituii (ASH), UividioK !>>' " ■hi'> 
if thrnti*) nsiM, tli« qiiinjeot gjrps tliAHiimbfrr, a, of iffrmal 
iMfaading to ■ (angle divininD of tba tubu bu. 
tnniniwg tlw apedflc h««t of liiiuidx, ■ girpn weight, M, of tbo 
qOMittaa i* rmaed to the (i-iiipvr«tun* T, and U podrnd in tlin 

(.'■lling lh« apnciHc boat of the liquid C, its liiiul tvuipentunt 
ibe aumber of dirUious bj which tli* menjurinl coluiUD bo ho* 
I liaiv, 


SIe(.T— •) = na from which = 

mxif ivpf«*tnt«d round the apparntus iiru hiufrrd to a« to form n 
li ii lined with tOvr down or wadding to prevcot any Iqm cf 
< ia doaad at Uw top bj a boani whieL ia providud with n 
iMa abo llnad, which fit ovar the tuliulurm, d and a. A *mall 
iqf ftaaa whSch tlid«a akuig the Intt^r HDables iha diTiaioD* ou 

hampTaa. J What wdght of ice at mo mast b« nux«l with 

of WKlor at 30° in order bo cool tt to 6*f 

ba thn wnight of Im Tn-c wMw y ; in pnMiiigr tnaa the stale of ice 
f water at utra, it will absorb AOM tli«nurtl uoiti ; and in ordur 
t bum BOO to fi'r '^^' ibi-nnal unil< will be itRfdixl. Ili-nce tb« 
1 which Uabaorbt bt<uM-t-SM=^'>M. On lL<^otljt'r Liiuid. tlie 
» tip b; tli« water in coalici^rniai 2Cfto&', laiiKiSO — S)=1.V>. 


86M = 135 ; ftom wbicli, M = l-6l« pounds, 
\ml weight of MoaiB at 100^ is noawiiaiy to n^ iho lomptralurc 
swb of watvr (rom 14" to S^' ^ 

ha tlia weight of th« rtenni. Tiit lali-'ut heat of Uvmn Is (>40\ 
MMMttly p pouids of steam in condciinii)t into wntcr give up a 
of bnat, &4()p. Bad funn ;> puuuda uf wat«r at lOCr'. Dut the toiU' 
: mixtura i* 3S^, Mod thonfare/f givc» up a i'urthur ^uani^l^ 


ox DtCAT. 


of bnkt jD(I0a-.13)=e%v. for in thia ewe c i> unit}'. Tb«30S| 
waMrin bHUj^ bented front 14° to $2' ia>>nfbS(l«<»S— H>s«>t 

UCIp + aBp = Sru ; from vbicfa p = 6-16S poond*. 


gT&iir DtaiXKA. 

400. St«»Di •ntliiaa. — ^kiih fntHiw mv owduBW is wkldl 
force of <iqueau« T»piiur b uipd u motivn fatcv. In tha ordiiiaiT 
ilie altemnts rx|iiiu>ion Hii<I coudeuratloii of Btoani imparu to • 
■JtvniRUnK rRctiliiinnr mcitkin, vhicb is rhangiKl into «circubl 
■BtMia of vfirtoii» iiwc'linnica] itrr«ngein«ul«. 

Everr tlrnta vujiiw^ ooiMaU weatUUjr of two diatinct pu\»: 
pvatua in wliich ilic vnjKiiir i» prodiiMd, tai tbo an^iw 
■bill liwt lituvribi" ibi- fiircntir. 

4'!'l. ata«m bailor.— Tbi.- boiler U tlii> npparntiu in wbkk 
gecFrmt--ii. I'i^. J70 ifprc^cnts n cvlinilrionl boiler, Mlcb ai 

monly ufnd in Kmnpe. Hndwhieh, in thiicountrr, i* known mI 
toiler. Boilen) if ibiikind nrc^ UM>d for » Ilxfil ODjjUio; IbnawofI 
tivM and of stvani voxels ni'e verv dilTurvnt. 

It 1* a long wrought irun eylindpr, witli bnmiupkeriral nudm 
which IhnK an.' [i*i> scnaller rvllud^ra of th<^ Kami- mntirial, ant! onmmi 
n/atJDji; vritli th« boilpc ^ t«n tuW«. Unl; one of th««e ojlladM* 

mAx exoiKEs. 


A in the fi^re. Thoj in oilUd ii«al*n, v*A uo ^uile fall »{ 
iU» line boilar u naljr about lutlf AilL 

I^M bcatu* u lli« fim. Tb« mxike and bsMed air, aAa hat- 
MrinboNt Um lwater«Md the b(iU«r,Mcap» into t&aajUnoipb«t« 
gAgUgb chimney. 

^" ZiploMrfMR ofjigwr 970. 

• wliirJt enDdaeu thn (tram to tli« tabe, r, of tli« twbr fJUat 
p^w 371). 

c 'hj whieli tb» MMm paMM to a maaooiM^r ot pr m mn $mife, 
lie^N th» |!iraa*Bni of vapour in th« boiUr. 
1 pipe of thii bojlvr. 

r^r iMtIi*, no called beoaoae it RiT«* a whiitlit whua tbnc if 
ih vaiar in ilw builer, a drenmittaDM whicii migbl produM an 
Aa loDi? aa the lurel of th* water ia not too low fai iba boiler, 
V doe* not pas into the wbtitki, but if the lewl rinki bdow a 
|bu, ft Mnall Aoat, wbii^b U nut r«pni(«iit«d in tl)« ^giint, and 
M* tba bottom of Um wbittk, aink*, and the steani uscapM ; in 
It gnuaa agaioat tli* •df« of a natatlii^ piitu>, which ii mu in 

and prodncM ike aliaip Mund. This !<tpain whi»Tl» b ibe 
ird heqiMHtly cm Vailwa;* ; it u u-od a* a rij^al in lix^imntiTrji. 
<, to indicate ilia l«i'«I of Ilia water Iji tke boiler. It conHi«ta 
M^ 111 11 ^AM of atoao. paniallr imncraed in water, aa mgh 
Jh lyacv ropnMentod at left npen. Thia itcao, wkidi h lua- 

OM sftd of a tti<t«i, ia kept poised bv the l<ua of w«4g]it which 
I by iHtnarsiod in water, and by a wcajihl, ;>, nt the otbar mi 
vf, Aa loBf aa the watur ia at tho d«aited kelgbl, tbe leTer 
■buna ibfl float rvmain* li<>rti>uiUl, but itainkawbcD tbom ia 
wai4'r, and riata in Ihe ooDtrai^ dlrpclion wlian tbtn ia too 
i«idnl ii7 tbaan indKUioau, the (toiler can ngvlata tbe auppljr 

Mtdcal wronirlit iron Mttr. 
tfn, oppoaile ««n)i odiar. 

[bt wliick loada lint aafnijr Taliv. 
itMrpeiae of the float, 

^ f«AM> d«aeribtd und^r Papiin'e ditrntnr (818). 
~ktlr, OB aportUTB bv which thv boiler eta b* Mpaiiad and 

aotrta aetlon, or 'vratt'a snilBa. — In the ihtM* acting dmm 
I ateaca acta altnnalcly aburp and helimr tha piaton. It i* alto 
Tt tatffiiu. trom tu UliMnoiu la raatar. 



ox HUT. 

Wa AaB flnt (riv« a gvaerml idea of tU* enpiM, ud AaQ IteJ 
««cli part •epnntoU. On tha kit af tbe fig. :r71, U Uur cyln'' ' 
raodiiM tlm •fHn from ()■■ boikr. A ]iMt of iti ode u np 
■• heiag left open, aud a pteoOf P, cut b« Mcn whid M nioni| 
Mtoly Dp Uid down by tha piiwwif of tJi« Mewii abore «r 1 
pUUin. Br Ihr pisloD rod, A, tkla notion i* uaBamitiod to a I 
ktar, L, called the iMnn, wtiicli u •nppor1«d bj four (ton i 

Fig, !71- 

Tfae bmm tranimtta it> motion to a roimeptifts rod, I, woffchm on ■ (m1 
K, to which it iiuparl* a .contionoin rotntorf ntolion. The imuik I 
fij(«d to B horitontnl ihaft, which turus with il. «iid by iimmii of "W 
er endleM Iiandii. ihin thah ontji in motion vnrioiu nuekiara, Mck I 
R|HIIlliil9 framai, nnw milU, Iiilh«>, Sit. 

On tb<i left of tho rvlindnr i» n Tnivfl chi-it, wli«ie, by a 
which will preieulty be described, lh« ftteuii paaaot altonittaly i 



BU Xow, aflcf ita actioB oa either Gun of ib* piRUm 
for oihorwiM n ptHwiim would 1>« <ix«ri(<d in two 
OB*, uxl tb» pialMi mull) remun M ru>t. To i^fll-ct Uii*, 
I, after U luM BCtcdunwie tide uflhc pinUin, pANwa tnlok ve«<l, 
. ihe tmdtHMr, inm which cold wiit«r i» iDJeL-tod. It ia almcM 
^ eoodcoMd then, uiil MuiMquMillT, the pmrare rown in 
of tba cylindor which u in eommnnicstion with the GondeiiMr, 
kM« li now pivanm on ontj one ffK« of Ihe pUbm, jt eillM-r 

a «l Um condeRMr d«pHid« ujxm Wittf * law at rtponra (%0), 
n two VMMtU MMuauuickiintr with uarh othtir. fuid rantoininj; 
1 ■nfoia, km *t diffiacnt iMnpFmium, tbo Iciwoq U Ihv iwf»« 
•nd i« thii corTwqNMiiling to th« inijiperalutv of Ui« 

JktMr attint *[«am ttfflnt. 

i*eted wst«r in mptdlj beatnd by th<v condMiMtion of the iii«ni)i, 
I he coBBtAutly i«inew«d. Tbia U cffitcied by iut>iuia of two 
»•, M, i* caUmI the air ptmp, and pumps, from tbn nond'-nfmr, 
hd water wbicb it ccmlain«, and nlao tho air which wajt di»- 
tlw wator of tlie boihir. and which paw^a with th^ ntcnin int<i 
tder and oood^nwr; lb« othtn-, IC, iii caIW iIih fuUI HmtiT 
i force* cold wU«r tiwa a well, or ttwm a river, iuEo the run- 

t pwnp, Q. wUdi is called th«< /nrr/ ;nut^, utilises i|i« hmb'd 

git (niDi the cundt'DBCr into th« huiler. 
eouncrted with a parallel motion, and sarrbg tw tnuiic 
t Imam tbs npwaid and downward motitm of the pjRtnn. 
find to tbe oyUiid«T, or el«cwborn, and aupporttug the g^'dtng 
ilo* rod, C. 

Ua guiding ana directing thn jianJUl motion. 
I Roda fomavg at tho t'nd of tlie hvoxa a /larallrl tiHUion. to 
fixrd tbe piston md, and tho obji^ct of which i> to (ruidr tlio 
' tlua md ID a atislglit line. 
uf lb* OH* jmrnp, wbicb rtmovM from tbe condeiuer tbe air 
d water wbicb it eootaiiM. 

I of Ibe /ex' ptmp which forces into tbe boil«r through the 
be b(«ted waur pumped froni the condeDwr. 
[ ol tbe t«M waltr p^fip, which auppliee the cold «-ntcr necM' 

larfuyrW, which iranamila the motion of tb» bvuBtotherrauk. 
eb linpartf th« niotiaa of tbe lud la the hoHioutal i 
a 1 



I rf the futoa 10 iIk < 
M. Crfiada of ibe air pmti^ isi 



T. np» by which eohlw*t«rtn>wUie»wenoirrftt«fiM|S^ 
■iiti> Ibe eonilMwn. 

i:. l^p* bjr which tbesleaa IbM the c^UadcrpMM* into Oi 
nfur >ctiii)[ on th« puton. 

V. taiVH imn wh««l, called tlv^ irAni^ whkh, by ib ii 
to ngiil»l« Uw BotiuBreAiK^i&llv when ibe piatn u it tWay 
nf iu ooonc, and tba enuk. K, >t ito 4tadptmd». 

V. B«tit leT«r which tinpan* the notioa of tbe ceantnt^ i 
•Ude T*]re, h. 

7,. Bopfotric nui. 

n. Ap«niij« wbifh commnnicaUa boUi with lbs npfwrail 
nf th> cTlinili-r, oci^iirdinK to the pontkniof th»«lida nln^aod 
•tMua poMM inUi ihe (wndeuer thioagh ihe lulw C. 

Il Itod tiSDBniUlBg motion to th« tKdt takm, by which 
nal«1y admitted abav* and below th« plttoo. TU* will b* 
yrvalcr detail in th« next ttrtiule. 

t. Aperture by whirJi ■tnam nftdiM tli« vaUe cbmL 

d, litnl^jf bo*, in which ihs pjctoii md wuriu witbont 
tli« *tfam. 

■•. Errmlrir, flx«d t4i th« boritontal shaft, and rotating ia a 
whirJi the rod Z ia attacli«d. 

m- tlod which caiuicct« lb« ir,d of th^ alide valve h to ih* I 
Y, uul tu the eccentric 

Thv lower purl of Ih« ligure dcMii nnt (exactly repKBRnt I 
arran^itivnt of ifa<> puraps. Thn drawing ba» been nMnliflfd 
nun cJenrly to show how thMe pBrtN work, and tbmr qobdM 
fach other. 

403. 9lBtrlli«tl«B »f ttaa aivam. Se«e««r1e.~KijrUT« t 
,Mata the daliuli of ibu vake cheit nr iirniDi;i.'aii'iit fot the lAfri 




fnini tiie boilar pnoMi bj^ ■ yif«, e, tnlo ■ cut iroo 
rida tJ! tho ojlinder. 1b Ui« nidoa «i' Uia cjliiider th«Te are 
^ or ports, H, «, ud a, of whleh k commmiicatM by ui 
IbU vitk tlia nppnr part of th* c]rliail«r, and a with tho 
A atida, i, iri>rk« or«r ibe^ tliN« oriflOM. It is flzwl tu a 
1^ vliicb is joinieil at in. toa lugcr rod, «r, and iccatc* on 
dawiiwMnl caotMii frwn tlia bant lar«r, yoS, «iuch>>d to tliv 
. When ibe sUde b at Uh lop of iu oounr-, as nhuwii io 
I* ateaat pMN* thraujih n mio tfan Iciwvr part of th«cyltmlrr, 
cannot paw tbroiijjli the oritiue u, Tor it U <o\-«nid b; 

rvbiehUaboTA th«pUtoa pu««« tbrou^ u and ibrough 

An r, fnxn which it nnlen lh« condi^iuHr. Tbu puion i* then 
upvMnl*, and therefore Mc«nd«. 

1 ijide il at th« bolt-im of ita ctmiw, ih^ «t«im pnfM the 
tha apenuiB ■, sod paMM ffnin tho lowir part of ths tvlind<T 
Adiaar bjr n mid o. Tbe jriiituu I'uuaeqiwntiv dK^cDad*, and 
(pieia iHi (ov «*eh duplacement nf tha ■tidi*. 
ifd and downwanl motian of t^e alide i« fflbclod hr m(>'ui> of 
I ia a laicaUt pi«c«y K, ILxod tu the huriiontal ajuA. 

Vm. 2J3. 


tbU purpiMO in ('<imira]), and kteo for th« rapplf of wittpr to 
Tboj »t« pr«rfi>rm^ for thow pnrpn«iM ftom their ttpoiiUcilT, bst for <li 
mm Uiej bnvtf biMw fupifnuded bj tlio donbU actioB uifiiw. < 

Fig. 371 n>pr«Hfntj) a «nction. Tbe Iwflin, BB. b of wool,ii| 
wooden Hffiumln at eiwli tmi), to wbidb clirtiiii Hre Utacbed. Oh 
thow ctukia* w connected witb tiiv pitoo, tnd the i>Ui«>r with Ui» pa 


I Ilia [iiifil nf Ihn c^UndBr, A, la a voire cLeM, C. mU irhicti Mmoi 

I (nn ihr. boUer by Ui* tab« T, Th«<T« lud ilii^e vaIvm »i, », snil 

TuticBl rod. Tlt« rtlvm tn and opea upvonU, Uic ralre n 


I m maA o ai« opm, *a akowo in the ilrawiiig, ike aUtau pMHM 

I Um tube, T, oior Ut« ]hMoii, vbile the atcun, whicb in below, u 

into tho coodvDf^r thmu^rli >'>■) <"be M. Th« pinon therefore 

Tb* ?nd, cm wbkh «ra tlic vbItm m, n, ind o, ia ooeiwcti^ 

ki Wnt Levnr, iM, nMTtn;^ aa n joint e. Thin b?nt lnr«r clow* and 

ttbi taItok. For lilt* purpo«» lli«r« an two cau-hos, b tuul «, on a 

Lcoaiwctad tritfa tbo Wm, W iu«u» of which tha rod worhM 

llhf> end of tb« b*nt Irvor. From tbo amtngomunl of tlia valvw, 

Fk^wotMl in the dnvint^, t]i« pbtun ainka and camctt irith it thci 

IF, ^, cmaequantly, th« ealeh MrilMa ^aiiut th« l»r«r, and tnAkw 

|Ui at tba mm* tim M lh« lod rfmo, Ili« valrw nt aud u th«D ch^e, 

TW >;ioii with the boQvr m well aa with th« cood^Dser ia 

BU lid. xail the (team which baa made the ptnfou dnk posMS below 

Ik |iipF C. A* it pf taa r < oqnalty on Ixiili racus the pi«l«n wou]d 

■I mt, but it ti«M in oonaequence of ihi? tractioa of the weight 

It •«; Utile forco ia aiXBtmry for thia ; for thi> pump, the rod of which 

htd to tbe WKight Q, oolj requirM paw«T wh^n it« pjaton riwa. Whan 

piitoa r if at tbc lop oJ ita ooutmi, tho catch a attilEEa in litm sgunat 

ltt«r k, niMa tbe rod Jme, ibo emni ag»in pateea to the t«p of tba 

:, which BifMn deacvud*, NhI ao ou. 

Wl &o«eia»ottva«. — t otomo H v tagau*, or aimplr InoMnoCtm*, an 

co^iaaa wfatcb, mounted oa a caniage, pn>|H.>] thcnmUM by 

Ibelr motion to wheola. 

Tba pRailcl motion, the h«aiu, and tliH Qv wheel Ibnn do part of a 

i>«. Til" pHncipJ puU aro Iho framtwork, th« ^nt hax, the 

of tba boiler, the •luoA" '>dj-, thi^ jiCmiui c^i/indiir* with their Talves, 

Many «Ab/i, and \)\v frrd pump. 

flip fiamework ia of oak, aod rmta on tb« axW of thf wlieni*. Fl^. 

S7I nrprawDls tliv dri(*r of the kMxnnotira in the act of opeulu^ tlie 

nyiilalor TalFi>, I, pland hi tbe nppcr part of the ttram dome. In tho 

Ww part of ibia ia tba tinr box, from wbancM tho flanio and the pro- 

4wla of eombnatiaa paaa bito the atnolw box. V, and thvu iuto th« 

thbaasj. Q, aftvr baring pmrioiiudf ttarorwd IS& braaa Jire tuhtt which 

!■* ibnmirh thu bt Jler. The boiler, which conaacU the fire box wiib 

tt« amofca box, ia made nf troD) and ia cjlindricul. It ia os*cd with 

^ara of toabn(>wD5, which, bdag a bad cooduclnr, prOTonta it* coolinff 

loo opUly. Th« ataam pwaai from tbe buikr into two cyliudtre plocod 

Ka^v aide ot lb* aiBofca box. Then, bj maana of a atMm d>Mt 



OK »UT. 

tfnikr to ikat alrady AcKribed, it acta allcntttf )j on tbo |v" 'km ^ 
' tha fi rt nn, thv motioii of wkidi » tnamliud to ibe axle of u- 
iAnig wlw^s. Tbii wt«i«auBt ot tbe lUda valvn i» not ten n 1 
dmwiflg, iKOLtuB tt \m plucd undw Uw flwiB0 b«nrM>n th> 
^injliw Aftar kaiia^ act^ oa the piilooa Di>- iihinn U 
HumqA tlie UmI pipe, E, isto Ui« chtmiN)', that iwc w Mg] 

The BMlkm of Ibe [iJMaH k tnoiHitted t« tbo two lu;r* ' 
' iAmI* lijr two ecniBMttiig ndbs which, ^7 dimii* nf craukh i 
' (bMn roda with ih* uIm of iIm wheels. The altenuiiae 

tke alida ralte i* e9«etc<l bjr Beaoi of acccnlrica placatl on ibc i 

the Im8« wheelft. 
The liiiiin^ ot enpplj «( wai«r to the boiler ia obtainod br i 

of two pnMi|W placed usdar the fna*, asd moT«d by aeecBtries. 

pnnp eadc the waler from > neerroii placed oo tba totfar, 

• oiriafia attached to the locomotive fot entryiitg the necweity i 


EjfttMtMH t^jlgur* 374. 

A. Copper tube, into which auaoi pa w ee by ih« extiroutv I, i 
whicb, dividing «t tlio «th«r i>nd inta two branches eooTe?* lb* < 
to the two cfliiiden which «oiilalB the ptaWoa. 

B. IUad]e of th« Lever, bf which the motian ia TCToned. k ia 
■tction to n rod, C, irhtch oiiniuiuite*tea with the alMm cIlbiL 

0. Rod bj whicli t!ie moiiuo ia icTened. 
D. liownr part of ih« Urn bnx and a*b pan. 
El Eeeape jAyo for tbi- itenm aflvr acting on the paatma, 
T. Imei cTlindnr rnnutining a piuoa, I'. Tbore ti ana of duwt 

dd« of the euKJne. and tlie um in front !« wpKaenicd m bctng Wt j 
in order thai Ihc jiiiloa may be wvn. 

G. Rixl wiiioli opeM the rtynlaior Talre I, in oid«r lo allow thoi 
to pKu into tlie tulw A. In (be drawing th« driTer bold* b U* i 
llie lever which ninrM Ihia rtid. 

II, Cock for blowing oIFwat^r from the boiler. 

1. tto^ilHtnr trIvc, whirh ix opeoed and doand by bead, a» M Hj 
regulate tbe quentitj of Mvain pauiug into ihv cylinders. I 

K, 1^1^ rod ennnecting the bead of tb« piaton rod with the cnab HI 
of the drivinir whepl. 

L. Lnmp for um by nigbt. 

M. Crank, which trfuisiuita the motion of tbn piMon to thai 
the Urg* wheel, 

N. Coupling imn, by whirh the tend«T ia attached. 

(). Ftie door, by which coke It iniioduced. 



I, the rx] >>{ which u coaneeled with the rod K. 
faf whicb buUi atouu and uitokn mrnpi-. 

VrrA pij>*», throngli which the w«l?r in th« londur piw*(» tn 
» pump^ which wv BOt •howa in *b« drtwing. 



S nnanl (or tvmriTind oWtriKtiiMt on the nib. 
T, T. Sprine* mt which itiv mgJM raHa. 
V, U. Iron nil* fixnl in cliain om woodan itMpaK. 
V. FMmn of the Rinffiog box ol ibe eyUBd««. 
\, S. Criiiulrical boilrr, corercd witb maboguiT «4ar«f^ wUi 
Uia bad oaiidactiritT, hiodi^ the low of honl. Th« )ur«l </ i 
ujiurttwlow th««ib« A. la ike w&t«r &re tbe bibcnwi, I 
ttw hoioIr^ uid Bnaie p*M into tlie unuike boa. 

Y. Smokr box, in wkii?h tli« Or* liibM, «, lernunate. 

Z. Z. Km box, iMTeTHi bv H itome, into whicb llie Mmup [ 

a. RnNi Itibra, of wblrh tbcnn aro IS-V op^D U both tott, i 
ndutiim ai <Hk» Mid in the lire box. bdcI >i (be uthu in tbo t 
TbnM tab«* Inmamil to tbe WKtor tho biuit of dm lir«- 

U. T»<<hiNl Hfrniffni, [iWod on ili« Me of ib« fin boi, and in * 
UiB am oC ilie lever B work*. Wbon tfa* bandlo i« pwhad bmd 
palled back ■« tar •» it can fro, tbe fs^ne Ja in full tomti <a badvl 
^«r Tvap^cdvnly ; tba bl«nnediale Icetlt give rarioiM rale* at exfM| 
in backM-nnl aad fomxi moiMii, tbn niddln tooth being a dead pobil 

K. Ca»M owtaining qitiofs by wUcli ibe aafety valnat arc ngM 

g, SlgMa whiatla. 

t. Safntr «alT«a. I 

m, n. Sl«pe. j 

n. Olnia tube, showins the height of water in the boUtt. 

r, r. Ouidbg nxit, for keeping ih* laotioa of th« piitoo nia Unicht U 

(, f, UUiwinf^iff taps, for uae wb«n the pialoua am in motioa. 

r. Bod b_T wiiicb morion in mn*mittnj to the*e tap*. 

•ton. kaactloB maeUaaai a»ll|iyl«. — lu reattiai mnnk'aM M 
acta by n n'lu^tivi! forcii liko water in the hrdraulic tnunuqait (H 
lift idra of tbpw iiiiicliinea ii by ao in>-ati4 n«<w ; Hen of AkSMd 
^0 IsTeatnd tlia fuuntaiu which bean tia nanu^ deactibod tba fdBw 
B|ipnjatua. which i« kruiwn a* tba naelinn inachm«. 

It coniriiiti of a hullow uietallic Kplier^> irhidi rutato* an two jl 
(&g. 27G). At the (iiidx of a diameter ani two lubuliiree, piafcad h 
ally in opponto diretlions by orifliw* tbiuuiih which T«po«r MMJ 
AVater is inlrx)iir(<il iuto thi* nppnrnliu by hi-ntin^ il, aod lb«fi iSim 
It to cool in cold wat«v. If ibe apparatus be tb<<D h«aU>d to bniliaf^ 
rapouT diwngagnl itnparta to it u rotatory niotiun, which n dae t$ 
prcafUK of the vapour on the *ido oppnniin m ibal froik iriuet 

Numerous ntttinpt* havo b»en made to une this reaedra fbroa tt 
vapour on n Inrin' H'nlf- an a motive {•.•k<<, and endeaioure bate alwb 
tnada to cause tioam to act by inipulw by directing a jet of tIaaH 
the float boKid of a paddle wheel ; but in both caw* the atMS en 




I graftt an eflcet w u obuinod whi^ it acts ly expMukni 

^■f1««w kind* mf •MUM ensli>c*.^A tow pranare mt/mt u 
rtikb the wjuwiii nf thi- TA|t<>ur <i<ii>« mit much excevd no ktino- 

Pa Aijuk prrtmrf mj/iuf j« uDo In wliicli tli« juvnturu uC tbo 
jr cxrcixU tliiii atiuiunt cotundenibly. Low prcicurn on^ioM 
nj eamJmiiiu/ nojrnx*! in Otbfv wvids^ they gun«nUy liavti a 
^ whcR till! stvom bvcomH conrfeiiHd alUr bating acted on tba 
on tlie olhor hiwid, AkjiA jirnmtr* tmgmt* vk fnxjueiklly «'itliout u 
ir i Uw loooaiutivo U aa <-umtpI(i. 
««DiniuMoatioa b«twtpn ibn cylindiir and bnilrr n>.iii«ni npeo 

I motiioii of (tii; pUt<)n, tlie steam retiuns MienlUlly tha 

EBy ukd i* *aid P> act miihimt trpanatm : but if, br a 

nt of tba ilidc vnlvv, ihn neain omum 1a paw into 

hM Uia i^atOD ia at | or } of it* conrw, then tba rapour 

. u to «i_v, in rirtue of tU i-laatb fori'i.'. which !■ dua to 

tan. it atill acta (in thn piiton aiid rniiva it to finish 

icam a diMiactiou ia niade b«iwe*u exp&iiiliug' aud non' 


|lr«rk af KB ra|lB«. H0ra»-vow«r.— Tha wnrk of an angina 
bvd by ibn tnuan pmeuru un ibi- pintun x arva of thr- jiiston 
f tlK itroka. Ill Fnffiand thi" unit of work ia Xhn foot-poim^; 
I work patfonneil in raining a wi^i^thi of ana p^uod through a 

uffli, ua NiiHHini sou un-foniua u 

unit I* anvd, cMed the (AnW-ixijiriir, which 

formed iu runag 75 kilo^nmmes thraugfa ona tMtn in i 

equal to about 64:i fuol-|wu,ads per MMod. 


■nritCM OP niUT hvj> gold. 

400. BlArmit ■onroas of b*at. — Tli« folkuring i 
li«4t may hn iliBTJii^-iiit)i>'<i : i. the m^tlumital toitrem, comfrii 
lion, peri'iUiidii. Bud priiMun.' : iL the phgtieiU •oMroM— ibat 
TuliMion, iiirrHtrinl licnt, tli* ninWiilnr nctionji. tli« ch«ii^ o<i 
and vleclricLtv 1 iii. thv vhmnifol tonrett, ot va<\eiMiax caaAM 
man otpccinllj' combuition. 


41IX Sa»t dita ta fy)«Uaa. — Thn fricttno of two badi««,^ 
Uie Dlh^r, prudui'M hcut, whit'li Is ^■rtnlt-r tliL' greater (lie pn 
tlia mors rnpid tbu inatiiiii. lAir I'jinmpic, the axIcb of cutm| 
hj their fni^tion agitiiHt Ihi- l)u\''' '.ifv-^ii t>i?ci>»iH «>i Mrungly hca 
take fire. Hy rubbiii)/ top;tUcT two piec«* uf ico io a vaein 
lero. Sir II, Dtivy partially melted them. In boring a bni 
Rumford fuund that the heat deroloped lu the ootmn of 9f 

iiKrnAMCul MCKU or reat. 


of tW mrtnllic {uniclnt, irhicfa fiv off* bMl(d la Micb 
t tlul thoy tAk« 6rv iu llip nir. 

tiM dartMd on lixpcrimsnt hj which tbo (treat Ii«dI 

I bj friction U lUuMnHH') in a sinkb^ inimniT. A bmw tub-- 

B) about 4 UK'boa in Idigth and ) of na iiicii in tliaini-l«r, is fixed 

i irh«L hy tat»a* atm cofd pMsiiig ruuiul a luiti'li l&n^r one, 

lean barotMted with aof duind Tclodlr. The tube in tbiwe 

l«r water, and i* di^ird hy a oorli. In milling tii^ i'iptviin«Dt 

iMjmvMcd Wwctu a wuodco clnniji, wiiils the wheel in rotated 

I npiditj. Tbn watnr tvpidlf b«i:oiiK« tinntcd by thn Action, 

a^raiuTB aooai excMdiiig the boiling pciinl the cork is projected 

■if •prnral viuds hv the elaMJe fiim- of the atconi. 


¥\g. 3T6. 

. Xa«i «a« to prManr* Mitf yaroamom,— U a body be «» 
Ibal ila denutj u incnaaod, it» t^^mporatute tU''>i tu-cit^ing 
(fniiRie ifiiD)niili<a. Joule haa veiilitd this in the rmw of water 
Fail, which wetB espoMd In proMUtv* of ir> to 25 fltmixpherTii. 
> «f waiar at IS* C, Increaee of prt««iira cauaed lowering iif 
e, a ruult which afn^ca with the IacI that wnt«r contracta by 
I dda («inpnniti(T«. SJntilarly whi^ wniKhls nm tnid on meiollic 
b oTairad, and nWrbed when tliey are reuior^d. So in 
' tba MMlduDf of a DMtallic wiir is attoiidrd with a diminu- 

IpednrtioD of li««t by the compnuAJon of (ra*« ia easily shown 

' of the pnetmatk fringt (H^-. 377). ThU confiat* of n glau 

l^b ibidc (idM, tkMad hvnnaticnily by a bintber pialon. At tlia 

\ii lUa, Ihen ia a cavity In which a small piecv of tinder ia 


m andi] 

m koB wken the 

I b Awt^^ L wAMwH orpmIIt attiflMtdl I 

if lb M>:hK it bwBfl.T da* to Um < 

I Ik* |iMM. IiiWd «< tbe ttoder, outMS i 


Tte ttontiM «r tnrntn* prafaerf ); tW ] 
nfioMi ID cAm* tk* fiiiiiliiili 
,a<«MgtM«rfh ydBy laJoxygiM. 
I i» abo s aaac* af hMl. la Gii^ dwtaliami 
Amk «f inw b frtqwttdr MM at the BMMMOt of mfUtii 
WUbtartfc^ sMi woa tfadb wUefc m« uplodal bfik< 
IB bga tannt. A tnaU peoa of una 
■arbot. ThabaatuMianpljdu^ toani 
•f tha ■alawiha. ihat b, lo as iMnase in douit;, 

' aatia* uifBtwi to tbaoi ; far laad, whick do«l 
' hf fMBMilM, MTCMkalMa bacoaBM boated. 

ranicu aocacw. 

tke sin. 

(•«toU«Q.^-1!%e wMt iBt«ue <ir all aoom* ifj 

TW oaaw irf it> baat ia uaknaini; aooM bar« < 

1- as it^BiMd MaM expanaaetBg MBWiwa aroptioBs, vbilt otk 

ipcdcd it aa iiiiaynwiil iif lajwi acting cbemicaUj «(i«aik< 

lk« eoaiylM of a Ttdiaie baUvfj, a»d gtTinit rim to obetadl I 

vfeh ptulufv tigkt toA aolar )i«*l On both bvpoiliMai Hv^ 

■«■■• imT tb* Mu would ban a linh. 

DttkiBl atteapU ban b««a ntada to dot«niiuM the < 
aaaaatt]r Moiited br ibe ran. M. FouiUat, bjr naeaM ' 

rantcxL k>ckx» of heat. 


I pffrMiotiMtirr, luts eakuluad tbat it ibe total qouitil/ 
li Urn «Mll) rcc«i*«' frnn tlte ran in Um iviiu» of ■ ycu 
fed to tnclt ic«, it itodIiI be c«|MUa of n»«Itiai^ a lajtr 
[mud Urn i-Anb of 3fi ?ard« in Ibickneaa But bom Um 
ik tb« wrth (iiprm to the coUr iB^Mtka, and fmni ih* 
gek Mpnktea Ui» «arib boat tbe nin, thv quastilj- of keat 
vaith rwMToa can out; be fn i j ^F ia * ^ ^ ^' emitted 


that tlw aT«rag» amMiDt of beat ndlaUd In a 
h M9« ef ^Toond i» th« Latitude of Lcmdim in equal lo tbat 
fi W ptodocrd bj lb« (ixmbiution et idx^ taclu of omJ. 
traalrtal b«>c.~<)ur (ifobc- poMNaata ■ beat ptmliar to it, 
tiled tli<: It rrtiriiU krat. Tlia tampaMturo of tht (anb ^ra- 
fi«u the lurfiiM to a eauin dtiptb, ai whii-b it rFmahu 
i|ll aaaioiia. It u beoee concluded that tli« aolar bnat do#« 
jli baloir a ontain iat^mnl \*yvt, vbicli i» calM tli« luj/rr cf 
lyiiiB^iri : ita dopth bdow tbo earth's cxtcnnl larfacn tarief^ 
m diflereot parta ot tbs glob« ; at Parif it ia about 30 ;aidt, 
■pninre i> oonatant M 11-8* C. 

b« laycf of ciwMani tempmior*, the lAiitpi'iatiirc is obtetred 
t on the aT«n{rp 1° C. for erwrj W tttU Tkia increaK Laa 
M ID Bii&e* and nrtauan walla. According to thu, it » 
lOOO jaid*, the wntpeninM of a conwapondluf layvt would 
|1 at a d«^th of SO to DO mile* there would bo a twnpatMim 
n mt^ all BubataacM which »ii*i on iha Kuiface. Hot *pringa 
Mi coaflnn the exitlenoe of lliis centnl heat. 
ibjpotbea«a han ham propcaad to accotiat for the exi«ien<» of 
il bML That meat nanally adndlted hj pliv>iciat4 ii that tli* 
I (ri^nallf in a liquid alate in conscquciice of i!i« Iiigh Mm- 
M that hy ndiatloB tba aorfaee ha* graduallj aolidiJied, ao aa 
■abd mat. Tbo iblflnwaa of tliia cruat i» not boliovcd to be 
kV to BO niilra, aad iho interior i* probablr *till In a liquid 
httoclingmmt bv vety «low, in consequence of thu Luipcrfcct 
iltj at tiM cnuL Kor ihc ume rrui^D tlie ccntnU heat does 

Kaaae tba t«mp^raIuro of th^i iurfac« nior<< than ^ of a 
ica a waaa by •Iworptlaa and imblblUon. — Molocular 
Kncb at imbtUlioB, abaorption, capallarj nctionn, arv uoualljr 
tM bf ^MBgagenent of h*«L I'ouiUot found that wh^n«'T«r 
^|nn«d «n ■ ftudf divided solid, an bcrcaa« of lem^iefutuiB 
1 whkh variaa with the nature of llic tubstimtwa. With 
'ghiltiirTf. anch aa meUla, tho oxide*, tlic uuth*, th4 iocreasv 


r>ie nuT. 

it 1^ of ■ dtgiM ; but witli or^Mie MbaUMM, mdi M >po^ 
rooM, dried numbmiMi, ifac iacrwui) Tines fron I to 10 di 
Tbe Bhaorptkni of trwwt by aolid bodio* prnx-nti iht tim 
DJibOTcbcr fouod tlial when plutiiiiini, in tb<< Riio #Utr nf d 
M jtlNtiniim bWlt, i* placod in OXffr™, it ahmtb* nuuv 1 
ila vc4ume, and tluU llw gM is Umq b lueh B (Uta of 
iImi l«inp«TKtiui) to bigii, aa to )civ* ri** to inteiue comboiE 
jiltttiuum prwiuws iLe Mine «A«c(> A jet of hydrug«s i 
talfji tim. 

Tlie apparalua kiunm m JhAirriatr'* Z^imp d«>paiid« od 
of Saelj divided |>lMiBUtu. It cMuiita of two gUM *m 

TImi tint. A, ftta in the ]<f 
niiTBat of a tubiiliiNi which 
mMicallr. At the rxtnnntli 
luK thrte is a maM <tf liiu 
in dilute Milpbarie acid. Bj 
Adtiaii of ihe liac <n tha i 
drogm gM is ^nnntntcd, wU 
inu«>. forcM Ibi- liquid ont c 
into the rtoccl A, no that tht 
coulact irith ibe liquid. 1 
(hn uppprvnsvl i* rwurd to | 
nir ia proportion a» th« whu 
copper tube, li, fixnl is tk 
tdwl ^ tbero i« a Roiall ( 
ntod br An orifice: abore tU 
«[)onCT pUtimim in tb« cap* 
tnho H, >■ npcned. th» bfd 
and coming in cnnuct with I 
tin^im. Is ignited. 
M. l''avro, nhn hns rrct^ntl; riiunin»d Ibr qnwtton ot I 
j^aj^L-d when h gn» i« nbaorb^d hj dinrcoal, ba< fbuod th 
of be*l prcMiiiPt-d by the nbsflrption of n givrn wngbt 
•cid, 01 of prr-loxidn of nitrogen, greatly exoMrdg that v 
gaged in the liqiH?fm!tion uf the »ame weight of giu: fof 
tbo beat prodnciid by abxirption exceeds f ven the boat m 
dit«ogB|jM by llio Mlldificntion of the gaf. The bcBl pi 
absorption n( liieie gnjws cannot, thi>n<forc, be expbiinn 
that tbe ga« is liquefied, or erra solidified iu the pore* O 
it ii> probable that it ia due to that prodiicud by tbn liqui 
gw, and the h«at due to tbe imbibitioo uf lh« liqu id t» I 



nU^^MtMn and tiqtie/actiut; t!i« beM prodttosd by alM- 
wlU l« diaeuMed nsttor tlt« bcwl of EJHClridijF. 

cnxmcAt •ocHCH, 

|^M|^ aaBbfaaHaBa. eMn»a»tl*a. — Chdmic*] comU- 
WBBIt BMMBpK&ifi^ bv • n'ttaiii r1?i-aiicin uf l«iiip«ntU)v. 
M eon1i(BBtiaM tolie pirn.'* alowlv, u wh^n irmi oxidim in tbo 
Mt piodand i* hnpi'mptiblo ; but if Khi-j lake plncf rapidlj, 
iptfcnii^t of beitl b vrrj inUuw. TL« EDme quuiUt;r of hont 
Md ia bnih c*m*, but whoi nolTOd ■lovljr it ia ili«dpBt«d u 

iriiia i« (hfinieftl mmbinatioB kttt^cd with th» (rvnludon of 
Ibrrt. Id tlip c-nlinaijr combustion >n Uiiips, ttvi^, caadl«s, tfa« 
nl btdmgcn of Um coal or of the oil, etc., combine witli the 
tflkealT. Batmmbiutinndop«not n<v««iuiriljinvolTnlh« pTft- 
I njgca. If rilb«r powdered aiilinxtiiy or a fn);mHUl of pbo^ 
jbflattd In BTcud of dilorine, it unites witlicblotiiiOiprodudii^ 

I CMJhwtibbHi bum with flame. A Jtame {■ a gtm or rapciUT 
k a Uch iMiipenUura b)r mnibuiitbti. ll« ilium innliog pow«r 
^iftibe nature at the product f(inu«d. Tb«< prvsvueQ of a *vlid 
prbflMMinCHiMM the illumiualiti^- power. Tbe f!iun«i »f liT- 
BAgiit oxide, 'od alcobnl nrv pair, bcrnuao th«y onlj contain 
^^MUria of ootnbuattoiL. But the fluuicH c-f cuidlM, lamps, coal 
Hn IbA i]|umtn*lilif powrr. The; own tbia to tb« fiLct tlinl the 
Nifimue fcodueed dMOnpOM* nKdn of tlx.- ftm nitb I lie pro* 
N*' oAm, wliicb, not being perfrctiv bimed, bcconin ini-nnilM- 
P^lae. Coal gw^ when biimi in vu armu^i-iutDt by wbicb it 
P* Mi^Mta wipply oJ air, ia almo*t entire)}^ devoid of luminanty. 
t lune Hiaj b« made tumioou* hj placing it in plntinum 
The tRmpcraturv vf a flanie does not dvpciid uu it« 
H^fwwrr. A b}'dn:igrn llnitie, nbich ia the polcal oi nil liiuni'*, 

^<MaH*f«cMI 4nrlBC comlmaUoa. — Mliny phyaicUtu, mor6 
9 Uioitin, Rumfoid, Dulong, De«pT«tz, IleM, P avro and tJllbct^ 
*^ Atdiewi, hava inrettigntod tfau quantity of h«at disengaged 
^ ^t>£«« b cbsminl comlniuiUons. 

^l* ttpniniMta L«Toi^r uaed the Ice calorimrt^T atmiuly dn- 
k^inilwd uaed ■ calorimotff known bj bi> name, wliii'h con- 
P'^iilii copper enulater tiled with water. In thii canister 
F*>«m which pawM through tbe bottom of the box, and 
^t«t>* ia an InTOrtod tnoDal. Under thia fuuuel ia burnt tbe 

4M aCAT. 

neo rxpcrintBlcd upon. Thn poduet* of combwlM 

tliKnigli ibe worm, b«*t ilie WAtrt of the umituor. and tram I 
of it* tempctBlure tlM qiUDtttj ot b«at evolvod » calmli 
I>Mpc*U and Duloji^ hm9 toceemvvU nind)fl«d RumfoM'i 
by adluwinir tli« cowtMUtlco (o take jiUcv. not oabridn th« 
in a chamber of cnmbiwtiaa plarml in lb» liquid ita«>If: tht 
fiUMrr foe the combustion eoiiwd b>r a tub« ui tfae lom 
duusbrr, and ibo productH of combiwlian cMa|>ad bjr M 
Itlaced al the upper pnn and iwjj^(>sl in a aopentine fcna In 
Oiv liquid tu he lii-alnl. MM. FavK and fSlberuwon hai 
Uii« ralnrimvUT Ttrrr ^(ixnllj', not onlr br BToidlng or laUog 
■11 poaiibte fuurc-M uf Mror, bul br arrauging it for tb« 4l 
of di» baat eroUcd in other cbomienl actiaiM than Umm i 


Tb« cxjwriinenta of MM. FaTre and Siibonoann aro tbc ' 
worthy. a« bating boeo esMuisd irilh th« ^roateM cmc 
T«y dowly with tliow) of DuIudh'- Tkking as thermal ud 
aoKutaiy Uimiicthr tfmpnratuNof apound nf wnl«r lhrough> 
C«4iligi«d«i, the fiillovinjr table gfvee the thermal unita in i«a 
diseogaiiied by a poimd of each of &a aabateiqaa in bamiog k 

HplrDgen ^MfiOO Siilpbor 

Uamh gas IWOO Aotbiadto .... 

Olutiant gaa ISOOO Chanxwl . 

Uiloftiirpontiii* . . . 10060 Coal . . 

Olive oil fiSOO 

Ethar 90.% 

Coke 7000 

Wood, dry 4026 

\Vo.i.i, nioisl .... 3100 

Carbonii^ oiidu .... U400 

The psperimonts of iJulong', of Dtwpntx, and of n«M {W 
body ill burning alvsy* produces the Miue quantity of hMt 
l)iH tniae iv^j^e of uxidalion, whetJier it attwn* tbi« at 4 
rrnchni it nft«r pAiain)r through iiiKirtnediato MagM; HW 

woigiiT <'{ carbnn gir^ out the «iLUi(^ amounl of bvnt m hanm 
to carbcoiic add, lu if it wen: firal chiinged into carbonic (tuM 
this bnmc into carbonic add. 

417. siCaraat kind* «r be«Unc.— Ifnrfi'n^ is the art of 
domestic and ioduHtriHl jiiirposvH itiu ouurccs aif h«at whkb ■ 

Tallow . . . 
TKamond . . 
Abaolutc alcohol 
I'hMplicnis . . 
Iron .... 

KirrtiiKXT tiKM or beatixa. 


ll Mwraa of artificiiil h«t )■ th« combnitioiii of oobI, coke, 
d chariccML 

llkigiiiail flv* iciiid* of IiMiting, uconling U> tLe sppiiratus 
iting vilb m of«m ftn ; Snd, heating with au encIOBed tue, 
>« ; Std, Imting by hot air ; 4tb, healing b^ steam ; Rib, 
r cbciilatiaD of hot wai«r. 

pl»o— ■ — Fuv-placea are open hMrtbi built against a wall 
a^y, (lirough which tlic prnttuiitf of cnmbiucinn escape, 
inch ihny may be iuiprov-vd, llr»-placM *-ill aln-Hys remain 
parfact and ciwtl)- mode of hcattntti for Ihey ooly render 
Mr cent, of th* total h«at jieMud hy coal or cuke, and (I pi^r 
hy wood. Thij enonnoua lou of ttrnpmtuiv im»ej> from 
the current ft air itMMtUf for combiidtinD nlwayH aLrri<>s 

• qaaiitity of thi* hut pruduo-'d, which u ]ost in the atmo- 
Da it wax that Fiauhlin uud flr»-plRC«f> sbnuld be ndopt«d 

■ the anallcat quantity uf hcst waa to be ubtniucd from 
■tity of fiombustihlc. Xot«itb«tand^ng thfjr want r>f 
«rcT«r, iboy will alway* he prefCTml a» the bealthiait and 
lod* of heatiBg, on account of tho cheerful light which 
A the vvntOation which th«y enaure. 

CM •! Sr«-plmca«.— 1'be tlraagM of a Gre i* the upward 
chiniui-y fuiiN^ bylb« as- 
)dact>ci'coaibu»tJoDi when 
1 npid and continiioas the 
ad to dlntv well, 
tbt la casaed by ttin dilfc- 
B the t«iiipei«tur« of tb«< 
hit OB the ouUidn of the 
T la coiiaequ€«oe of this 
I gawou* ■ubnCancea which 
atj am ligbUir than tlie air 
, and cotuHqueetly eiiuill- 
i|OMibl«. Tfan weight of 
ll(w,CD, hg. ant, in the iMM^^f 

If lai« thaa that of thu ex- 

■ of air, AB, of tli« annDe 

• it a premum frnm t>i'- 
bt iluidfl which canted ;i< ^.,,, ..-., 
eHnhunion lo aiccml tbe 

' im ftDportidn aa the diOercnoe In weight of the two gtuuuiis 

Ota caiuMl by the diflerence in femp^Tatum of two commiini- 
KU matac* may be deinotulfatud by phicLng a candle near tba 



001 nur. 

Uf tod near tlw bottoa of tli« pwtiilly npenri door of si 
At the Utf, the flune will b« tun>«d frum the ruum tonnb tkat 
whik til* crattsijr oSbct will be poduoed wbm the randl* i> -li 
the gtouod. Tbete two effects lira ami<«d by Uih I'unvui ui . 
wluck iaMM bf th« top of IW door, while tko cold nir wh 
flotcn M tU« bMtom. 

In order to bavc « good dimuglil » clunuiisjr aaght to Htiif} tbi 

t Tha MtRtion of the chimney ought not to btt laiftrr thu ill 
to allvw BB exit for th« ptnduct* of cooiUution, otlturwios i 
ftaf^wJK^ catrenia an prodncMl in ibe ckiDuaer, wbicli tamt k w| 
It i* MlvMit*g«oiij to plico oD the top t4 the dimno; ft ' 
iLuniwertlMn tli« chimiMy, m that IhoiiaoJie may eoo^e vrilki 
nlodtf to Rsirt the Mlion of the wind. 

U. Th« chimn«7 tmght to bs taffidMitl}- hif[h, for u th* i 
cnuicd by the HioMt of the extenal om thv inienwl pce«>an, I 
C(<*fl ia gTvatifT in proportion m the column of 1i*>at«d Mr is kofK. 

iti. The cit^niAl airouffai to pas ioto the chanherwkhi 
npidity 10 oupplt thu wiuit* of the fir«i. In * bennslirallf dmll 
the eoiinbu!>tibltfs would not bum, or deaeendlng cwrenki 
(broi'd which would drive the nnoko into tli« loon. UmuD^ dt^ 
iu tatflcifnt qiinnlity b; lh« cToricef of the doon and wt j rffli w . 

ir. Tnu ciiuun«y8 Bho^UdIlotcl>mnllUlk1*t«,fiwif ooodnwit 
the other a dtarcnding current of sir i* prodoced ia the latter,* 
rie* imok^ with it. 

430. •»*•■. — Slom an Rppumlu^ for hMtiag with a drtatMi] 
pUml in llii> room lo he heated, eo that the hencndialu in did 
rgand tho store. At thu lower part is tho drwigbl ]>oi« btvM 
air Dec«8»iirT for combiislion enters. The producta of cumbuiMt 
br iiu^uiH of iron chinuii^y [lipm. This mode of haatin^uoofoft 
MononiiciJ, but it is by no mcAiiB ita bealthj as ihM by opn ( 
fbr the venlilaiiun Is wry bsd, mure eopwiallj wbotc, m in < 
stoToa arc fed from the ouisida of tho room. Thewatorailvl 
bad ini«ll, prohshly nriiiiiig front th«i decMnpontioa «t 
Hanee* in thf nir by their ooiitart with the heated aidei of ibi 
pipes; or priHibly, as JIvtIIIp and Trooat's recent waean^l 
show, from the difTuuuu uf tflLH-a throu}(b the bvatml tddMCf IH* 

Thohentio^ in vrry rapid with hlsrlcened in«tal stovi!i>.l>iiitli9* 
very rapidly. Stoie^i cou«lriicted uf pullsfacd eatthcawm, ' 
eominou on the Continent, lical mont slowly hut more pUaKOI^i' 
t«uin the hl^At lonirer. 

4SL Seattng by ateam.^ — Steam, in condittiunj, ^TMap"'' 
(Mat of Tapori»itiun, and this property bas been uatd ia btiii^' 



I ImildiRir*, hoUio<ii>ra, te. For Hut purpoM ■team is 
boilvrB ■imiUr tn Umm UMd tot tUnaa mgiDO, nnd \» tbeu 
ulkte in )Mp«* pliwwd in th« raoea to ho brntod. Tbe rapofir 
td in doing tu inipuu to ili« pIpM tb« laloit lic«t which 
i, and thiu bcHti tlw sutronndtii^ air. 
Mac *y b«c Mtr. — HMling bj bat air conalata Ib tiMtiiig 
• Idwct pert of a baUdtnjr, tram whence ii rixn to tlin higher 
ne of it« kcaeMd ivamtj, Th« apfiaraliia ia ammged u »• 

(bmt tabiMi. AB, unly ooe of whkb i» iihown in thn figiirv, 
I K btmacv. F, in thu collar. The air paM«« into ib« iub«a 

^^K Flit. SM. 

^Kiv and. A, wh<m it tiecoinea heat«<l, and riabg In Ih" 

^ba arrow* r(«rh<« tbr room, it, hj tb« hishor apntim. 

■irinuTcraHia la beli««M are pmiiidod with uoe or cooro nl 

Mmm, which aio pl«etd aa low in Ui« ronoi w pwaible. The 

t^bia ordijutrr dtiBMj. 

Iffantna an more pcnnoniimi than open fire-placea^ hut lh«y 

M1I17 owing 10 lb« want nf ii^ntilalion. 

iMtiac *y bM wkur.— Thii coDsista of a continiimifl circnUtioc 

< *birti having b««il b«aU>[l in a bnilcr, ri>H-« throiigh A aerien »r 

1* lien, afUr becorolo; cool, paoM^ imo tb« boilor again bv n 


'iBt KfKwnta an «pparata<i for heating n building of HTiral 


MeriM. Tbn boktii^ appajatut, wtikh k in tits aiOmr, 
dhiped boiler, m, with m intem*! flne, F. A iQBg pipe, U, \ 
nppnr put of the boilpr, and tdao in Uie naervoir, (j. pUnd I 
p«K of t)i« building u> Ixr boHietl. At t]i« top of Uiia i 
• uttVf rtXit, t, bj wliioh the pnaaun of tba vapour in ttei 
be f»pilat*d. 

Tb« boUur, tbe pipe M, and a poitioD of tli« Kserrou Q, 1 
irith water, a* it bccomev b«atc<l in the boili-r an aaccndiss i 

Fig. 181. 

hot watw riwa to thn rrnrrrnlr 4. while nt tho ranie 
ciinTni* of toldt-r nnd Jenser wfti*r pfl>w fwiii tlie lowor ■ 
•elToir tj into rewivcrs fi, rf./, (illi-d with wiitpr. The mttt I 
pnnanii Bffain ihntiiffh pipes into otlior roceivere, a, c, c, and i 
ntU'liiw the lowl^r pnrl of t)l« boil«r. 

I>unn); this cirruUtion th* liot watrr hut* lh<- pSpm nmj th 
which thus become ime water atovM. Th^ uumbi-r nnd tbn > 
of these piirtA ruiutily dctrnnincd frcin the axpttunettlal , 
(^nbic font of wAtor ia «iiilii.'lHnl to coBunniilcato the n* 
3S00 culiic f«el of tiJr. lu tbc interior of th« ncetTen, ^iJ 



ICMt-iron tube* whtch oHumivuirBli! inth tho outM^v by ] 
nadenieittb tho il<Kiring. Ttie air beooines li««I«d in 
I MiMrgBa Rt the upp«r ptirt of the nOMTiMa. 

ipal ftdvMita^ of tki* mode of bonting !« that of ^ving « 
wbicli U cooatMiI for a loop tiiii«; for the niist of water 
I dowlj. It i.i taucix a>«d in hatbnuicn, bnlhs, utiHcinl incxibit- 
(ooma, and gviierallf wherevwr a uuifurui Wuiptiaiur* is 

WTBCW or «oi;i>. 

r^r«>-ioB> Baitrc** or c«i«i.— Botiili^* itic cold cMued W the ] 

UhIv Irv'io till- tolid totbc liquid ■Ulr, of which wchuvet 
|n>U t* pmliicvd by Ilie«zpMia[oiiof )<iimi«, by radiation in g(<n«Ml, 

I «spM:iallv by noeturnal nidi«tiiu). 
lOold yr^dvewl by tbs eipaiuloa of ■>■••. — W(< hsiva B«cn, 
I A gsji i» coniprc«MMl, the t^mptrnlurp ri*-'s, Thi* n-veme of 
I tbe aue : wh«ii a gM in ntretiaci n nxluclioa nf lompt'Cntun) 
.Imhwiw * quaotitT of suuibh: hent iliMi|i]i«an whun thi' gae be- 
to a Ur^r Tnliim*. Thi« niaj be «bnwn by plnciii}; a 
Broom's ibi-niMiiiieti-r )iDd«t tin? rt-c^lver of an air pump, and 
at «4ich itrokr of tlm fUtaa the iii-i'dlc more* in the <Uiec- 
k alwaOfaoi reg^u Ita orifUial t«in>{M>nUiire whea air i* admitlod. 
nb^^ iiiT«Bt*d ■ Bucbiiielbr the mumfiKture of ico which di'peuJa 
IfUi pnipFrtr. The heat d«*aloprd by tbn c<iniprrii<ion iif nir in r«- 
9nA bv ■ current of eold «at«r -, the vi-e*«l coutaiiklog th« coiuprco^wl 
' Wic iiiUfnd in boinn, thn air i* aUow«d to cxpMid : in to doing it 
I the bdiu! so conuderably as to fracM water contained in TeMvIa 
I in tbo brine. It ii (taled that by thii meiuiaA tos of couU (uned 
B ateam edgiae bjr which tix« comprenion is efloctod) cas 
lafaM of keu 

OaM pr«4Meaa ttj DoeMnwI rndiaUos, — T>imnfr th« dnVj 

TWBivi'" fp'iu th-? "iiti mi'n.' h-.'til I.linii nuiinte* into *p(wo, 

> tiwpiBlare ri»aa. The nrrrwi ia the ciuw ituriu); ni^jht. The 

I tbe MTtli loefe by rediAlion is no longer conipimiuitnl for, and 

lly a fall of tfrnperalure takes plHiw. which is (.Tvatcr iiruonliii|; 

I Ay i* r1e«n>r, for (Jmiilii wnd towards tbn earth rnyx of {(neater 

itj iluB thoae whjeli (onie from the c«katJHl HpnceK. lu auue 

tit hte hMB (bund that riven have not ftoteo, the aky hnriag bpvn 

Ifrallhongh Uw UtennoaBeter has been for wvnrni deyg below— 4°; 

■il Mker Icee wrn) winter* the riven frvuxe whni thi- sky ia olenr. 

■te power eirrdna ■ great inllii'iiicd on the cold produced by 

i; the gnaicT il i* the gi«tt«f U the cold. 


ox BEAT. 

, In BenfEil, tha i»ctura«l cooling ia used to laasuEietariagiaB. 
flat tmmI* cootainiajr mtAr am jilncfid nn nnn.oondactiii|F 
aodi ta •Irsvf or dry Uavee. In coii»mjui-ncB of iti) ndiAlwo ik 
flT<cao«, «vea vrhec tho ttMnpornturi) cif tfan nir U lO' C. Tla 
netliod can Im applied in all caaea wiib a clear tkj. 

It WMkid that tli« Petuvianii, io order tu prnsurve tiwiiihoottcf | 
planu from fi«aiii)9, Itgbl great flr^s in their Dei^bbourliool.tkl 
of whidi, invdudng au utilkiftl cloud, Linden the cooling 

42'. Alnolvta xero of t«Dp0r«tiir«>. — A« a ^aa ia boalti^ 
its rolumo fi* <-*r.!i di-fc-rco ('fntitrnwU, it follown ibiit at a Ici 
373° C. lh« Tolame of any gaa nMMiired at a«n> la do«bM. 
nutnaor if tho tempentura of a given Toliune vt aera wm 
through —279^ the cnntntetioo would bo equal to tlw Tol^t 
tbe loluine would iiut exiaU 

At thin t»inpcmtum th« motian of thn Eao1i>cuI«a of ibri^ii* 
oaaiplet»tjr cease, aod the preaMue therabv occaaionod. la aUi 
babliit^, bat<3n mwhing tUs terapenture, gaam would nsdcit* 
cdiangtu I 

This pcoDt on the Centigrade scale ia oall«I tb>> aUelide vn if\ 
ptratwv; tba temporatum* mckonad from thin point ar<> railed A 
UmptraturM. They are ciMrly obtained by adding 273 i« the M 
tuK on thv Centigrade noale. ', 


■EcnAxicAL e<ivn\txsT or sbat. 

43f^. Ma«ba>tloal o<|alval«iil af hMtt. — If tlwi Tariona I 

the praduL'tion uf lit^til by iiiotu-n be riaminpd, it will be bmai tl 
all GwoD niDchnnirnl forn.- in cotuiuiii'd. Thui, in niUrin^ tm 1 
iigMnst eni'li nthnr, niotion ia appnrenUy dcatrojed by (rictioti ; Il4 
however, lout, but uppviin in lliu form of a inotian of the pwtklM^ 
body ; thn motion of tho taam I* trannfoTined into a motioB ( 

AtrD>n> if ■> ^>"^y ^'^ alluWHl to fnll t'niin ■ hnigfat, it attfliea agahi 
ground with a certain velnciiy. AcconJiog to older view* it* nat 
deatroyed, vm tn'ra is loat. Thi«, bowuver, inaottbecaae; the vial 
the body appears ta ns vita of it« molnculM. 

Ik the caae. too, of cli^nncal action, the nioat prnduetita n 
aouico of heat, it is nut diUicult to concnive that thetv ia tu 



1 of the dianmilar noloeiUea afabut Mch other; rh 
|Diw to Uis pcodwrtkm of btAt bjr tlia iaijiAct of mu«ea of 
■n aacb olh«r. 

•BBM, b(»t iii«}t l>a uuide to produoo mntion, u in th« ciae of 
Bginav tile propalMn of Bfaot from a giin. 
■ view HtU Xhtm it a ocauM'tiiru bi>twL>ea heat and modon 
■t wiUt in Um oldur writon^ Itucun fur Fjiampln; and I>ocke 
1 ia a v*Tj briak sgiUticoi of tlie tiwonsibi* piirta of tlw object, 
MM m na tbat aeiuattoD bam whence we dunomiattta tixo object 
t what in our wtnMtion n beat, in tbo object it nntbing but 
tMnfofd, in eiplitiuui^ bix ^i«at uxperiiu^Jt of tbv pruductjuu 
finetam, ww unable lu aangn an; other cnuv for the heat 
tan molioo ; and I>st_t, in the (aplanatiou of hi" Dxpcriiniint 
iea bf bictiMi in vacuo, expretaed ■imilu' virwa. Cumol, iu & 
t Maaoi «D§iM, pubUahed in ISS4, also indicated b conncciinn 

n, bowarcf, nrhicli bail bwn Mittod by inoUtod writcm, had 
inliuMica on tlw pragrwi of ticiautili<: ijivetti^lloii, aud it is 

UMS that the modem thnorica m«f bo *nid to have bad tlieir 
I that year T>r. Maj^ a pbyudan Ln Heilbronn, formaDy 
there csUta a canneBtian between beat and wurlc : aud hv it 
Snt intrnducod iutn td^Dm ilia axproaaioa ' nurhaakai tqui~ 
Inrf.' Ha/er alao gavu a method by which this K|uivaleDt 
llculalcd ; tlM particular miulta, hownvcr, nm of no raliir, aa 
I, tboogh eonvct in phiici[iti-, i« founded on ii)c»rr«ct datA. 
ne 7«ar, too, Colding of ('openba^t^ui pubUihed exv*'r>'i'*'<ita 
lnct»on of baat \rj frii:ti<in, from whtr.h \\« cnnrludfld that iho 
if boat ira* ptopurtioiul to the mcchaiitra] energy cipvuded. 
kt MBM tiiao n* Maj-er, but quito ind'^jmndcntly of him, JauJc 
I •aatiea of oxp^^imeatal luiMti^tion* on the Klation betwnen 
mk. TlwHe tiiM drew the attoition of waentifio men to the 
i w«ra admiit«<l a« a proof that tbo traniformation of heat 
loieal coerKT, or of uiechauical cu^nO' ''^^^ Itest, alwaya ukm 
iafaito numerical ratio. 

■alljr ta Majrurau-lJuuli'.MTora] pb;sii-istDbf IheirthnoRtical 
nMtal inwrti(fitioii« haw MOtribiittd \ti Mlatlilinh tb« iiicicba- 
7 of h«al, iuuii«ily, in lhi» coiintrv. Sir W. 'I'bomaim aiid Itoo- 
latHanj, Hrijnliolts, Claiudua, aud Iluluuinun ; and in France, 

Uariog ars aonte of tlie ooal Important aud tadsfactorj of 
p i ti ia wiU. 

r TMmI, B <(ig. 381), waa proTided with a bniM paddle-wbfnl 
> dotted linaa), which could be made to total* about a 



mtauoncjj. avnv^LDn or rut. 

r Mriw ot tacpg ri i D— ti, tk« air ia k nccinr wm *mm^ 
I of ft fiKoe puHp, bath Map t iiwi wwJ ia * kaows «n^ a< 
rUa known tempenUvre. AfttrSOO Mainarf Aafiblf. ifa«hM>, 
rnamitnl which ihe waivr had oisfd, TUi 

lof tWiiraBd(olhabictei«rihBpirtM. T«< 
' mAoMKi^ tkc •xpoHMBt WM BBda ndw ■&■ I 

tba ranint ops. The nr ww bm c u w yfL ^. mJ 30V 
I tt the piMm JfwiopJ C ihmaal laaiM. H/aea C— C i* tha 

iMpvadadio prodDciny th» hOTt b« W, «« W*«-— ^ ftr Oa 

riftbe nwduunlfiqnhalHt, E. BriU*i 

\ ■uiMbcr wUch JomI* adof*^ far ifc« ■• 
1 ■ah ufi Uw C«aiign^ ok t> 13B0 1 
Male it ia 77S fiMt^pMnak. Thia : 

iHlnriiV ia Um naibad whnfc IC^«r MBflBHMi ii 
IcqaiYalaBiofbrat. It ia uli« wiih •■fltt 
tt^alall'a wnrii ■» ileal, irhiiL while (trietlT Uknraif Hmv^ 
tewnsclcdllw data. 
: at fappaae Uiat a iiilMgahi v«Hd witk • Hatka af a 
f waralni at 0° a cubic Idm «f idr aadar th* aadtaijt 
and Utt aa (vppoae ihaS it fa cadttMd ky a 

I BOW that iba eahie foot of air ia kakd aalil te i 
Cnm tha otwBriwrt of wcfMaow of afa-wwhaaw thai thaa m 
at 373° C. TV pa in doabfiaf ila ruhmt will ter* iaaM4 
k|iim timii(h a Caot to W«hl: It will h«« UM tfa . 
I HuiMgli tlua dMtanoe. Bat the atmu 
tJaimtadpumUrt 15 x IM = 2W|iMii B^ • oMe Iba* 
I doubliiur it* Tolime h«*Bft«da««a^efSM0ya«a4ad*Dmk 
l«f afoot. 
rabic foot of air at wen ■mifim l-» gaaoas Hid iba ifteilt 
r ail wid>!t crootani ppsim, that n, wkoi it on ^fiMd CMalf , O 
Iwith tbat of n af aal watghl of aMar, fa fttM i ao thtf iba 
r of bMl which wiU imb t-tt ohm of A thra^ 379> will 
■>(KI4x l-jngQ-aiea. of water tiMioa|*tb»w»a»HanL««apii 
m. v^wai^r raiaad tluongh Z73°faafBd to6-S9fMHdaof «a<» 
Ithnorfi I* C. 
I ia, tba qvaatitv of haal wUrb wiD doabk tbe ««bnaB «< a eabic 
I «« rii. aad m H iUag wiU lift 2M0 poaadi tbren^ ■ hti^ erf a CMt, 
h G-W Ihnnal uaita. 

■ > 

«i nuT. 

Xnw in l^ abote cue tbe gaa hu ben htMled nnilci oi 
»<ii«, tbftt in, when it couU upMid tn^j. It, bowwrtr, i 
b«M»d mder coBttaDt roluiur, tta BpecUe haU wooU Iwra t 
tin Mio I : 1-4U (39S), m Uuu tte qiiMit% of b«U nf 
tkcM ctrcuawtaocw M mae ti» leuptntare of • cubic todt 

bo 5-SB X ^ = 3-74. Pfductiag tbia from S-iS, tbe <fifl 

MfnacMta Ibe might of waWr wbicfa would ksn been nk 
tbe oiM« of b«M inpulod tn tbc ur wbon it could niptod t 
thit «icMa Kb* bom (onmmMd in the worii of niaiajr 21t)0 po4 
a foot. Diridiu^ tbi> br lAu «<? bam 1%3. Ilcncc tbc heal 
raiaa • pouod of walac ikrougb 1° C wiU nia* a ir«gkt <tf 1] 
a hctgbt of ■ tonA : a numericaLl ralua of the niecfaaaital af 
bMlagraaUif ucloaalju can bariqwctod with tbat which Jn 
na lbs OMMt oeitaui at U* Miptriiuvaul twulta. 

Ila Inr of iba raUtkn of haat to ■Mchankat eno^y maT tb 
B«at mtd Mt fA— » i « i muryy 4tr* tm ^ i i tj fy cmnrtAU ■■ tmditti 
^pnAutitm, aWfwdHoa* ty ab rf£«^ppa*m>»o«^ m<tAaiitalm 

A. Tarietj uf esperiMcuta maT in Uka iauuui«r be addawd I 
wbenerer hwt (tiiiM]ip<'nn work in jiroduoad. For axanpli^ li 
voir inunenod iu wuu-r ilie air bo eonptaated to ibe «xteot « 
■pbcrNu ; Duppoiini; ihnt now, wlicti tbe compriaaiJ air faai m 
tenpi-ratuivul'ih'- walvr, it be allowad to act upon a ptatoal 
weight, tbc waght is niawL At Um aaane time the wktn heet 
abowbg that a certiUD quantity of beat bad diaafppand ia pn 
mMhuuiciil vtUtrt o{ niaiiig the wrifcht. 

Joule ploi.'ctl in a calorisictor two equal eofqwr rmnrrotr^ 
be mnuMi«d bj a lube. One of theae ooutaitwd aii at 2j i 
thn iitbrr wu (Uibauirtcd. When tbej^ we«« ooBnected, tfag 
equilibrium under a pn«»iii«of llatraoaplianai bulaaibepi 
ing had drino no work, there wna no altwation in tawifaniM 
Itowever, th« second r^M^nnir wa* full of water, tbe aif iD 
oUigtd to cxpol it Bjid thus perform work, ami tKe tempM 
Mriag (■> in ab*orptirin of hmt. 

For further iufuruialiuu the ><tU(l«nt of ibia aubject !• (tfcq 
IMDdad to rMd I'rflrr'Mnr TvodaH* Jteat at « Mod* of Mv^ 
the phiMuiiieaa of heat ar» throughout explained in acoM 
nodan vif^wn. .K condeiued, tliouigh eontpUk and ajrauaa 
of the dynamii^iO theory of hv ni i> met wiili in Piofteiot FdM 
on ' Ueat,' in Wnlto' IHctiiaary of Chemitlrg. 


lox, TKixjcirr, iSD istkxsitt or uenr 

Ua off URbt. — />hvit is th« agent which, bj iu ftcUon on 
lt«a io na tli« Matatiun of Tialuu. That p«rt of phpicN 
Ub Um propaitin of light t* knoim h opric*. 
•xplain Ui« arigin of lie^ht, varioiia hvfolhewa bare Wn 
t ImportMit of whteli un the tmifion or cot^iucuJid' tliool^', 

MM* tlworir H i* BMuttiPiI Ihitt lumuioua bodica emit, in kU 
iBipoadentbU (ubiil«nc«, vhinh cc>iiiii»u of moIeculM of an 
M of tcBui^' : tbvte uv pnipnpited ia right linn with u 
■ velocity. I'Mtctintio^ inki tbn e}r» tb»7 AcC on the Tetina, 
• tlie MnMtion which eonstituli^s Tision. 
UMarj Uisocy, *ll bodiw, an yrvll nt tli« (v.1o*tial <<pn/f«, 
•a eitfeaieJj Mbtle elnstic mediiiin, whieh h cidlt'd the 
tthr. Tie LnmiDoiiit}:' of a body is due to an inliniiiUy 
(jr notion of it« moleciiW, vhirh, irbcn commtinicnled lu 
ftopagnted ia >U diivctious ■□ tliv fumi uf vpliuricnl whvc!i, 
tmtoty DKitioa, bxin)! tliiu trimiiiiitW in th« mlinn, rallt 
■Mion of riuoa. The vibralionit of Ibv «<tber tuki.- pliu'v uut 
ina of tfas wave, but in a plmiu ut ri^ht iuik1i-i to it. Thn 
lUed the ftwRftwraoi ribrations. An idea of i)i«He may be 
hahinff ■ rope at one end. The Tibnitiuiin, or Io nnd fm 
a( the iMrttelM of tli« mpc, am at ligbt iuihIi'ii tn thn toiiinh 
twt tb« onward motiun of tliu WAve'a fbnn ia in the direction 
hof tho tnfn. 

Mm Ifceucy the |1td|)1^ob of li^ht is «ffi»cti>d by a motion 
lofpwticlw of light thrown out fruoi tliu luniinoiu body, ui 
ilchainJ from a gun : on the undnlntory theory there u no 
of Uio paitidea thomiM.-]Tira, but only uf ihi^ Mate of 
wat coMnnuoiratcd by tho Iaujiiiou4 body; it ia n 

■t <*c]i sncowBite rutntioD, wid Uiia i 
nttHtnntw of tha c.thn. 

Tlie funiUiiieutiLl iiniidpltwoftheuudulAturr tlieor; w«ni, 
Iliijghetiii, and lubiirqunitty by Kiiler. Tbct cmiivian tlieai| 
owtog to N«wl(iu'ft powrrful Hupprjrt, WM fur lun)f tha prav» 
craod. Tko imdulntory tlmur; was ti/Aoptcd and udrockUd ! 
abfwed how « Ut^ iiuinb«r of optical pli(<ouaii^na, partkali 
dUEnctioii, vi-rv to bv Explnitwd Ly tlinl thi'cry. i^ubse^iwUlj'l 
indepeniii-ntly of, Yoiuiff. Frwmel ohowed tliat th» phmoiiMi 
friftian, luid aim tbutv of poUriiuliaa. ani oxplU'abli! oa tiie W 
which, linco his time, hn* biwn gnnemll)' aceeptml. 

Tb<^ aiidulatiii-v tlieorv n'>t ot>ly ^xplaina t)i« pbuBoueiiftj 
it K^vi^aU an inlimntp cunnoction belnvtm tbaw phenoino 
heat ; il ahom, also^ how completely antloftni* tbe ] 
UB to thoan (if sound, ivgud boin^ bad to (lie dtllbiciMKa i 
which tliMM two clasM* of phenomena t«hr< plac4^ 

i:vx KnmtBaos, tHUtapBrant, mmalaoenl, ftnd oj 
LmnmiHit b<xties are thov which nmil ]i|iht, such nc the iioiTl 
bodies. 7i-nn</inrrnt oriAiijnAiiHniu lK>di«i tra tlnfM wliich r«adl 
litcht, and thmuj^h which otijoetji eiui be iliatintiuiidHMl ; wt 
pulinhed glnw^ are of this Idnd. Tranthu*tit bodi»ii trxetniit 
obji.'ctj cnuii'^l bv d iat tiitfutiibed through Ifaeiii ; gjound ^I.ia«.n 
«lc., beli^g to this cIdu. Opaifwi badtiw An not trnnuiiil 
•mplc. wtii>d, iDet«li>, etc. No bodivs are (jull4 •>pHquH ; lb 
or \e^ tmnstucent whm cut in nuliictontlT thin laaro*. 

Foucault has rocently *hown that wlir-n th^objnctirlilMj 

il ^d 


«f Uabt In B baBBOKeseoiis niM^lam. — ^A mc 
HTipaoe or ■ubaUnn' nhi'-li li^bl chii trMv<-riH',:>iii.-li lu » vttcuua, 
W, gUi^ etc. A mmliain u Miid U> be homof^tKOim when it* 
llfompwitiini and diutait; mn the «iun<> in all jurlD. 
vy Aiiiw jWu aM* KHdivna I^Af it pn^m^atttt m a rij/ht Uw. For, 
I^M body ii placud in tbo rit;ht line which join* the tju 
I Innuiwna body, tkfl lifrht is inierropud. Thi< light which 
Ko a dai4t rouai by a mnall ii|>L-rtiiru, Iumtm a lumiuous trace, 

I tUU« from tlw light falling oa tho panida* a(up«»l«d in 

tfc ai ff ita dinctkin on nentin^ itn object which it cannot 
I, trwbm it paMM from oim medinni to ani>iber. ThMe phono- 

II ba fitacribed under thv Uertdi r^trrtiVn and rF^mnfKwi. 
IfcXlnw. p*aiin>I>T«. — Whf.n litrht fiJIn tijioq an i>iinqun boity, 
t pMMtmto iah> Um) apuiM imnwdiatoly b«liiud li, uud this dfiiivi- 
11m «!«&•«•. 

Wriitif tba extent and the olispe uf shadow p^ljecl•^! by n biKlv, 
I ••■ tn be diatinguiabad : that ia which ihi- lumiu'iiiJi m>ur.i; ia a 

and tlial in which it t« a bodj of nny ^ivnn -'xl^nt. 

i-Mjr, Uri S (tig. !fri3) \k the luiuinoun [loiuL. uud M a *plieric(tl 

Fig. 2(13. 

idi caniwa tbe sbaduw. Il on biliniiuly long iilmifht Une, SG, 
■d tlw •|ibi-n< M tAngfintiilU', alw^yn pHiwing ihroujih thn point 
Im will product! a rvuical turlitii!, wliivL, hoyouil tliu sphere, 
I ikat portion of ipaea which ia in ihoduw buoi thnt wliti-h i* 
led. In the prewni eaat, on placing b«hinil the <>pii<)iio bcxly h 
Hi. Um limit of Um ahnduw, 110. will bu thirply d>^liu<^ Tbi* 
nwiBxvt, usually lh« cm»>, for luutinoua bodim liavc olwaya a cur- 
Mitndv, and nre not nienjy luniiuouy piiuta. 
Ih tliat tbi> lumtnoua and illiiminatrd Iiodiei ara two nphcrca. SL 
|'(fif. d&l). If an infuiitt! uLniglit Imu, A(i, rii'^tf-* l«ii|^>riiially 
kplMIva. always rutting; the linn of tbc cnntn^n in tliv point A, ll 
Put* • conical BurTftM wiili tliis point for n Kiimniit, and which 
^iarf tbe qtlifTi: MN a peifectly dark upacr, MOIIM. If asncund 

39« on LMtrr. [*H- 

riitbt UmsLD. wlucli cnl« Iks line of «Mtt« in B. marea tancuAiilT 
li> tlie two ftpbnriM^ ao m to ptoduoa » new cumicftl sarfac*, Bt)C, it 
br Mcu ibst h11 the apMo outside this furTum n illuminfttcd, but l^ 
pan between Uie two eaniMl Mir&aM U nelUwrqaih) dark DOTiiuiteil 
8i> tl>nt if a M:rui>R, PQ, M plMMd b^ilkd tha ofMqii* bod J, tbe p««iaa<Od 
of the •cnvii b <]iul« in the shadow, whLl«tli*iTM»«frrecciT«Bli(lAbMj 
Miuio pMtB of tli« lunuBOu* bodj, and not ^m other*. It b btiglAr 

tbn tbft true thadotr, tad not fo bright m Ih* mnt ol tba MtMO( lai & 
it tOOOldinglf ealltd the ptmniAra. 

Sbadowa aueh fW thuae nn*. grom^rifal tiaAmv : phytieal 4«lMn. t 
thoM tUcIi kk rrallj' aeeo, arv b; no me«nx*n nharplj dvflned. A crr< 
I quAOtllv iif li^lit piwi« into tb* nhadiw, evuo whitn tint «oiirr- ■' 
S|tht U n iuer« poiul, tiiuS conveniely lb" »hiido« ini3ui>nf*B lb» illuuiu- 
ate.1 part. Thin plienomsnon, which will be aft«fward» ilMCittM, i* 
knowu by tlie namit of iliffrarlion. 

434. XnM(«* |>r»iltt«e41 by bib«]I apertarea. — When laviMKl 
nj*, whirh piuu iniiJ B dnrk nhambrr tkioHgh a *mall aptrtitrt, OM rn*t™i 

Fig. 385. 

upon a imtnn, thny Conn ima^ at extnrnal objcctA Tbwe inUigM 
inverted : tlivii nhnpt< \n filwa)-^ ihM of tlie axUrtBal ntijeeM) awl ii '■' 
dependvQt of tht> •hnpe of the Bp«rturp. 

Th« inrerxmn of tbe images sriMw from th4 Eact tliM Iba lanlM* 
rnja pruceeiling from Mteronl objecM, and penetnting Ibm li* 



OOM DM Kimthvt in pMiing th« apottaN, ■■ ■hown in &gr i 

Dtfnnag bi • mraiglii Uae, tli« nj» from tlie h!i^«T {mltm 

KTMa at ike Iwwm puts, aad iavemd;, IhcMc which nimo 

I lomf parts Hwet tbo hi^h^rpaiia of ilioKtixiD. I!i>ac« ihe in- 

Ttbi >Biag«. In tbu anicls aimfra oiaeara, it will be ^'H^u huw 

lillkMiandpFiscimaitof thaitnii|{«i**niincraMod by maaiu of lennM. 

r to ili«w ibat the aliftpa of Ui» ima^ la indepuDilviit of Aat 

■pwtwv, whan tlui lall^ i* Mfliaonti; ■mall. Mid the KnwR 

^■daquta Ataaeat Inufine a UiaDgvlar aperturo, O (fig. 2rt0), 

I the door nf a darii chamber, utd let oft bi? a acn-'eu uu which 

tbo iniagv of a I1mi*(>, AR A dUcrxv^nC {wocil frani fiatk 

tlia flamr peiKtntn lliniugli the npvrture, *iid foffiDa on the 

< triangular iniagv tv»iiibiing tho n)>»rl»rr. Itut tlio unioo of 

< pvtial uDigrea iwinIum* a total' iina^ of tii« Hjne foonn m 
DIM* ob)<c1. Fnr if we cnnfciTc that aii icltnlta ttraiglit 

Fig. 3W. 

ruanil the aperlum, with thn coodilion lliat it Is alwayi 
to ibo lumiooiu ol>toct, AB, auU tbnt thu a|H.>rtura U vi-nr 
ika atia^hl lia« deKribcm two connn, the npi'ji of wliicb is [h« 
, wbtla <nB of th« btMo* in Uiv luminoiu oblMl, and the other 
a)f}«et on the hctvcd — thnt i*, the iiiinfrn. llcni^ If the 
ta ptrpoadicular to tli« right lino joining itii? n^iitru nr tb» 
and tb« tpntro of the tuuiiuuui bodjr, tho imnf,-o in limiinr to 
dj, ImI If ibe Knwn ia obliqun tbn imago ia eloiigatr>il in the 
of it* oblkiuitj. This is whiil is Ht^^u in the vhadow pro- 
ind iij foliage; lh<i laminmui mra puuing thrDUKh the Iwvi's 
■tice im^t^ ot iiui »uii, wliii'h tire ellbvr ruiiiid or rlUptirnli 
Moling a* th* groaod it pcrpvuiliculnr ur obliqiii! to lli« solar ravx, 
d tUi i* Ou «aa« whaiarvr bo tho nlinp" of tlto aperture tbmugh 
Whihi light pa*MA 

iU. TalecItT af tlvbt, — Light mnvr* -nith >ucb a velncilj that 
|lbMriaCB of the outh lliere ix, to ordiunr; ohitn nation, no appn." 
inleraJ botwoon th« occurrcocD of any lumiuoiu plienomunoa 


Of LKiirr. 


und tti p«r<?»ptina br the cjre. And •ocordingly, thU vsloeit; n» M' I 
iIcutjiSumI hy mowu of wtroDOuucal ubwrruiou. Riiiner, • 
MtmnnmRr. in Itf75, flnt d^ducud tlic rclociif of ligtil tnm en i 
radon of tha eclipMs of Juiriur'a but MtcUits. 

Jui^itcr i* It plnniit, round which four Mtellite* r«rolve w tkt : 
|4oM KUiid Ui« enrth. TbU llr« MWllire, Iv (fig. St*'), tatftrt < 
-that la, pamat iuto Japiter'ii HUwlaw— «t e^ual bfi 
ilmo, which are 4S II 3fl ID. .Ill «. Wliili^ thi' Mrlh hmtm in thM j 
of ito nrUt, oi, neateat Jupiter, iu diaUtniri! from Uitt plaaet i 
materially alter, and tho inlfTTBln botwtca two nicnciriT* occuln 
nf th<; Mt«11it<i tuv •ppmxiniat«l_v (ho xtine ; hut lu propoftiua a 
earth uiovFA awar in iln retoluCiuii niitiid tlia mm, S, the in 
bflwA'-n two occullAiioD» iucruMiM, aud wheu. at lh» and of lix ma 
the earth baa jutwed &uni tho pnrition T to tlw paaidaa T a UaJ 

tvtaidBtioii of )Q m. 36 a. is oWrvvJ betw«n) ili« tiian at vUA Ai 
pbeDomanon is seen and (hat at whidt it i« cali-aUiMl to tafc* |1mk 
BmI wheu Iho t-nrtli wm in tho podilion T, thf fun'o lighl irdfrt^ 
from the Mt<^llitc V, hnd to tnivont« th4 dlatanoe ET, tciuU in tk 
second puirition the Ughi had to travene tli« diolniw ET. Ml| 
diiitnnec cxi^cetla the lirst hy tho qunniity TT, for from the pP^I 
dittancH of the mlnllito F., the rsy* ET and ET' may h^ cun 
par*llel. Coi)*rqaeiilly. li^ht rcquirai 10 m. 30 >. to travel the i 
TT' of the t'.-rrcitrinl orbit, or twice the distance of the earth fron i 
■on. which givp4 for il» fslot-ity 100,000 mihw in a aroond. 

The Dtiin nanrciit thu rnrth are «epMat«d (Vcm it by at laart 'JO 
tiinni the distftiioe of the mu. CminMjUL'ntty, the li^tit irhidl thtrl 
required 3\ yenrn to rcnch ui. Thoui ntiu* which are only viJb 
Micnns of the telcwopo, Rn> poatlbly at such a distance that : 
years would be reijuiied for their light to n-itch our planetBiy 
They mifiht have bi'i<n eitingulsbed for yean without our knmring iL 

•130. Toaeanlt'a ap^arfttna far deUrmlalac Ui« Talsallip af I 
U(M> — NotwilUstaJiiliny tin- [irojigioiis I'elotitj' of U^;lit, M. Koucaali 



liadcteimuungitcxperiiaonully b,v thoAicI of ad Sn^nious 
baaed on tke lue of Ui« rutsciii)^ uiinor, whicli hut bMn 
Ifc^Ur. WluaUrtone in nennniii!; tiii^ rrtL-iiiir of vl«ctric)ty. 
|k« daacriptim of Uiia apparaiufi, a kn^iirlcilgv of tiiv ptiucipal 
Um oi niuTora And of Iiuumi* w prpsuppcnect. tlgur* SW 
tW principd paHii of M. FoucaultV Ri7iuig*m«(it. Ttie 
•b«tler, K. of « dkrk diaaiber is perfurnttM) by a «quftr« 
. baUnd whidi • platiaum wire, o, ia aUntchrd Tcrticnlly. A 
Bfbt tvi1«tfW finni the out«id« upon a uiinur vntem 
bj Um Bquara apurtuni, meets the ptntiiium wirr, and 
•n aehroniBtic Ictv, I., wilb s lon^ I'ocii*, pl«wd at ii 
thn platiniuu witv Ibm than double tint priiieipnl fiicil 

f,B. -^«". 

Fie. 289. 

The ima^ of the platinum wint, ni'jir« or !c«i masniliud, 
fatti be toraied ou the axix of iliti Iniu); but thu luDiinoua 
■nog txavcncd tbe leuii, uitpiiigeti on a pluiie niirrur. m, 
wttk gtmt Telocitj; it in Mflccii^d ftnai tliii, and fomui in 

■Biaptt of tbe platinum wir«, wlitcli 1^ di9]>Uevd with an 
Ttlociij douhU) that of the mirrar.* Thiit imogt' is rvllected 

tr» mirror, M, whom conllv of c^iirvatiiri.' enindiln* with thn 
i&m nf tlie mirror m, and with ita ceuira of flj^re. The 

> thii^ Irt mm (Hg. WO) be tbe rotating mlrrot.O ■ llxril objtrt plu«t in 
I Rmalnc lu UDaga M l^. Wlien themimt coinvn into llif pnniiuii h'h'. 
th farmad at O". Bat the arc ft'm equnlj the aro On, anil Iliv nrr (l"n' 
ttnUiB'! bmec the att> OO*, OO". an rmpvrlivvly ili>iiM>< tlm am dm, 
, lij- MblncUon, 111* an tytT it iloublt tliv ate h«', ut Hit anniiUi 
I la dwlik that of the numi. 


OM uoht. 


pancit NdMted &nin tlw miiKir M ntanw upon itnll^ iitffj 
Odd) Ui« minor nn, tnT«»M Um luna b Moond line, and M 
of tbe platinutii wim, which nppMM en tlio win iUcU nI 
loiiTW oi tiinia Blowlf, I 

Id ordur tc ih« Mb auigo without hidiiiK the pencil vbU 
the itpsrturo K, a mirror o( uiinlTcred glMi, V, with fmi 
placed betwevu lli« hu» and thu win, and U incliu«l u tl 

Ot«d Mjni Inll upoa a poworful ^n^ace, P. 
he apparatiu b^ng amnged, If tiu mmr m ia at TM. t 
mwiiiijt M i* reflected to tn, and from tlu«M nhttDi aloa) 
putii, tilt it m««la the g:1*M plat« \' in a, aud Itatn^ putitl 
formn at if— the distance m/ \niag equal tn ob— aa iiiag« i 
which llio cyn in enabled In obirrvn bj maaoa at thn VJt 
ibe mlmw, IzutWad of W&g fljied, b movbg tlowlj roiwi-t 
at right aimrlei to tho plana af the paper — tlurc will be no Mi 
in the poMltuQ of tho mlrrcr m duriug the brief iaierval a 
ItRhl trnvnli fiMDi ni to M nitd bark ajtaui, but the itnage w^ 
diiiap[ii>iir aud ri^apiwur. If nuir the velocity of an ia incteaiil 
nf 30 tum« p<ir Hvnnd. thi: intcrTnl between tlie diMppcaa 
appcanmc" in to »linrl that iha JinpnMNon oa the ere U pi{ 
the imupa appears pcrft«ctly nlndy. I 

IjLRtly, if ifan mirror tum* with miffincRt rolflrity, j 
apprddnble i-haQ^> iu it* poeitiuii during tlie time which tl 
in mahinR the doubk juuiney from ui la M, and ttom H 
retiim ray, after ita reflaclion fram thn mirrM m, takoa t]i<> 
■ad tamt* it* imatre at ■'; thai iti, the image h*s undol 
deviation, M. Spf-Akiiij; pmdacty, tlicrr ia a dorintioo a* 
mirror tumi, en^n tilowly, but it ia OdIt ap|H«nable wh*a it' 
a cnrtain mnK'nitiiiln, which ia tho caau wli«o tho velocity a 
aulIIcioiiEly ngii^l, <ir t!)i> distance Mm tufficivnlly gK*t, tat 
nweaaarily inc^n-'uetfo with the time which the lij^ht Ijikoi in 
ita owii pRt.b. 

Id M. Foiicftult'a expiriiment Ibe distanoe Mm waaoolj U 
tlie mirror rotntvd with a Telocity of UOO to 800 turn* 
doTiatinim of /^ to j\ nf a mlltiiiieler were obtainml. 

If Mm = ^ Lm =r, oL^ r, and repruMotingby nthe ml 
in a ancond, by 3 thn absolute d^vinlion £, and bj 
light, M, Foucflult arrived m the f'jrmula 

t u+n 

from which the velocity of li^ht ia calculated at ISS, 

In cbia spparatua liiu'ds can be exp«rimeDt«d upon. Foi 


the ml 






liwt kajT, ADil liUwl wltli iU«ttUiMl imter, !■ placed 

[ nunnr ui, and > ixiDCar* nurmr M', identical witli 

naou: njrs niflMI«d b^ tbe T-ilnliag niiirnf, in 

aT«T*c tlie column of wator, Alt, twiou Man 

But ilie nriura nj then WoniM tvfli-ctt^d nt ir, nnil 

I i i the dctiktUm il cnntequenllj gniiter for rny> wliich 

' tbui for thorn which bun pmund through ur alanv, 

r of Ugkt in Ua> ui wtil«r tbAO in tit. 

t ivpatant put <if thMc cipsrimmt*. For it b«d Item 

II; IliM OB iha undiiUtory tbeov; th« velocity of li^ht 

I the man hifrblj pefraating mediiiiii, wbils th* very 

ooBteqnance ai thn omiadon theory. II«aoe 

' be ngttded aa a crucial t«at oi Uie validly of tha 

•b H. Fuu>»ult uMi to tuni the tnimt irith threat 
of ■ wnall atciMii turbine. bcrmtij{ b tott i>f nunniblance 

1, like thai iiMlnuaeni, giving a liighor tiouud an iho 

nfnd ; in fitct. it i> by the pitt:li of (hii nolo that the 
KatkiD i« d'>I>>rmin<=Hl. 

•r M. ruMBf— Id 1849 U. Fueau meHsund 
titjr of light, by ft*c«rtMning Hie tiin« tt look to travel 

HoBlniailr* and back agab. The ^pamtux ciuplun,'«l 
il, oapaliln of brinfi tumc:d more or la* quickly, and 

itooold beeiaclK aHi-rtaioed. Tli«t««th wrm made 

Mun* width ee tbe iDtvrraL* li rt w«ea thrcn. The 
lUocd at SureMM*, a penni of parallel rayk wur iniD»- 

I iotcrra] belwcvo two t<«tb toamirTDrplncednlMout- 

icil, dirwtfd by a properly mranpHl ayilein of tnhn* and 
CI tliB wluwt Aa luDK ** tbu apparaiua wu> at nist the 
UClly tliTOMfh tbo aamo intocvnl a* that lhR>u|[h which 

Bat when tlie wheel wa« turned MdEdently faoi, a 
10 take tbe pUn- at au iulcnal, biiiI tltn my was inter- 
iug th« wbrvl to turn more rapidly, it ti'ap]><>iuv4 whpn 

MB the ni-xt two Iwth bad lakuu tho pUc« of tb« 

le inatant of the ratnm of tiia ptoicil. 

'tween tbe iwu ttatloo* waa 28,3^ ft By moui^ of 

I by tbia diatance, by tba dunoniiaiu of tho wb<wl, ita 
Ion, c«c., H. Ftaaau found iha ralocity of tiicht to b« 
' Moond, a raaultaKTVMDjf with that giren by tatruuonii- 

doaely as can be expected ina detnnninniion of thiskiod. 

«ba Intanaltr af lictit. -Thu inlmtily of illuniinittion 

ligiit tvticive-i OQ lilt: unit of aurfnco ; it ia subject to 


on LIQHT. 


I. T%r Mr«ud^ tf ittMiBMtiM «( n fiam turfte* « iMf^r ■< 

n. Til- ittlmtir) of iOiauimalitm iMt* i* nMntW oUip^ • pfj 
tiemal la lie cntiiu of Ikr an^ mUoA fAa Aunmow njf* "^ aA 
■onnsf to Uit Mumimatnl tm-far*. 

In uffdnr to d«faaiutr«ta ibo fim law, iH there be twocimkrKN 
Ul> tad AD (fift. 290), oa« pUwl M it c«rttiit dwlMiM frm it^ 
MMUM Lf Md the otlitf r U double tlii* dbuuce, and Inl « anl S h* 
■KM of tlie Iwo scneaa. If a tni tha total qtuntil; of lig^l •U 
niaitted by the aouTm in th« dtr«cti<ui i>f the tximi* Al.B, tiie inlfl* 
the lighi on Ih« hotmiu CU, Uutt u, the •quantity vhidi falb « ik* 

of iiurfac«, i* " , and Ui« bluiBitj ca Uie acnwti AB i» V Xow.ii 

trUoglea AU) and CU) an rimilar, the dianeter of AB ■ A 
Uiat of CD; and a* tlw aurfacot uf circles an a* tlw ifKi 
ih«4r diamelon, tbe tuj&ce 6 i* lour tima* a, cotucijuieatty the at 

"[ t« one-founh of 5. 

1*11^, -mo. 

The Mme law mnr abra bi' dumoDstraMd by m 
apparatua rcprMviititd in fi^runi W2. It in niativ by Min|i 
■hadowa of an opiuiue lud oaat upon a glaiu plato, in oac caw hv ih 
of a aingle raiiillo, and in umthiT by that at four caodlei^ all 
double tha dUlnuie uf tbe tint. In bnth cmcw iho »had<>w* . 
sauii! btennlty. 

Fi^m •JH'l ihowa ibat it is ovriag to tho divarfenoe of 
nty4 «milt(<d froni tho nitme murer- tbal l)jv iuU^niiy of light iri 
a* the xjiuLK uf tb^ dli4aiicc- Thu illumiuBtiDoi of a ««r&ce | 
beam of paralUl liimin»u> rnyn in thr saiiia at all rlirtaiifa i 
iu a Tapuuiii. for iu air aorl in othnr tnuiipamot niodia the i 
light dwrnim in eotuM-queuce uf aluorptiou, but far inne« ahw^ 
tbu square uf tbe <iii!tAiic«>. 

Tbe wcind Inv of iniemity (MmMponda to the law which w 
found to prevail for heat; it may be tbooMtically dedac<ed w k 


nrrmsirr of light. 


W), be • pencil of pantUpl nv« Uling: oUiqnalr oti * 
B. Hid l»t «>• bf tha oornial to ihU eur&M>. If S ia Uu> 
tha pneil. a tbe total qunnlily ot li^t which full* on tho 
I, ml 1 tk*t whirh {Mm on llie unit of fiirran (tlMt U, tb<> 

t DlaBtiutUD), wa bave I = " . But m S u eaiiy tho pn- 

AB gn a pluw perpifniliculu to ih» pencil, we know (tom 

fig. SOI. 


n that 8 = AB cm a, IVoin wbidi XB = ~-^- . ThU talue 
' ^ coas 

tin tbe Bbora fijnntioB. gives I^^ cos a, a r>nuuln wltjcti 

:« tbe law of tha coci&o, for a« aandSnKCcaiaUntqusniitwa, 
tianat to eoaa. 

t4 tbe co>in« applieo b1m> to mvH emitted obliquelv by a 
udace i tlMt it, Ibe tav^ an l«u uit«n»v in pruportiun m tbef 

Fig. -J02. 

ndiued m i1m> ■urfaiM> wbieh rmita them. In tlih K«pccl lUcy 
to the Ibiid law of tbe ioteniitj of radiant heat. 
iM««teMra> — A p/iotiimr<rr la BQ appamtti* for ut^anirin^ thi? 
Iraritira of Ugfat- 

ii plietomtttr. Thiaeondstaof a^ronnd glnm ecrotin, in fronlof 
tud Ml cpaqtie rod (fig. 292) ; tbe lighla lu be coiiipuod— for 



DOS, a lanp mi t miuUi— nr^ |i1iu»d at a csrtnn jkbani 
^OMumw that «Mih pmjiKU on tbe (rr«en a shadow «f Ik* i 
•badflWB thus proj«cl«d ue at first of miMjunl intcitritT, kitt 
tk« poNtian or tiM lamp, it ma; be m plamd ibat the is 
two ahndowa b tho same. Then, buicii tb« abadciw throm \>fi 
\i illiiRimittDd by the caiullo, and tli«t ihrowa by tb« caod)* iii 
by tbe Uinp, Ihp iUitntinaiioD of lli« scnvD duo to Back ligUii 
Tii« intonntini nf tho lira ligbU, ihnt in, thv illumiDfl 

vruuld ^ive M i^qiial dutaaoM. atv thnu dirvctly proportio 

of thoii dislaiiCTa from tile abadom; tliat U to mj, that if t 
tUree tiniPi the distance cf the candle, its Ulualnatiag 
timea aa ^rt'nl. 

For if i and i' an lh« int^ailiM of tlia lamp and the 
unit of disianoe, and J and <f tlivir distancM trvmi th« 
follows, finm thv tint law of ihn intvnritj of li^hi, thai th* in 

the lamp at thu diittaiioe il 'iM \^ and Uiat nf tbe candle 

tdutance if. Od tha 


•cmen lliaae two inlcouiiet an eqa 
rhich WM to be pmred. 

I I' „ 

Jl> = d^ ""? = rf^' 

Bant^t phat'imiitr. 'n* lien h ^reiuM> spiit iainadeonaplMftj 
pnpar, tho put nppi^arri traii!>litcfnt. If ih<- piipnr bo ilti 
light plao4td in front, tin? w^nt appvan diirkiT tLHQ tbe i 
il, on tbe coutrHrr, it lie iUumiimtiid front bohind, the up 
on n dark ground. If the greaecd part and tin? rcxt appear i 
thu iiiUuslly of illumliiatioD oii batbsidcn ii tbe Mini.'. Buna 
mrlcr di!pnnd# on an npplii-alinn rif ilii« principl*. A ciKO 
iund<^ on A paper Krtx-ii b}' uiiwna uf h (Dltitiao uf spermaceti I 
behind t)ii> b plufed a lif^ht of a certain iiitrnnty, irhich 
ctandard ; in tbia cunntry it 18 usually a wax candlr of known i 
The light tu be t«<l«d ia then moved in a riglit lin« tn nuchi 
rfiont of tho dinp!n«Ain, that there ia no diffenace in ' 
the graued part and the rust of the •crpen. By ni««sQni 
of tbe lights from the teivna, their rvlatiTo iUnminating 
d«du«>d from what has betnu pivTtuiuly taid. 

Dy ibia hind of detenniiiBtinn great accuracy cannot be att 
Mpucially when the li(fht« to l)o cuiupand aro of difTexeilt 
for iuntnncv, boing velluw, and the other of a blniah tinfc 
the del«RaLnntiuii of the relative bri^'btneM is ijidte \ 

WkteUtmitf ithotirniKtrr. Tho principal part of ihia^ _ 
>»l bead, P (lijr, W3), iixed on tlio edg« of a difc, vcbUA ; 
n, o, working in a latj^c tuutbvd wheel. Tbe wbeel fila] 
dricaJ copper box, wliict tt \ie\4 va oao \u«A, is^cJ* Ow 



: tuna s enlnl uiH. tbp motioii of vhioli !* trunKntitted 
, to th» pimoo o. In tliii nnT thn liittrr tamii on iUfilf. and 
imc reTolTM round tli9 circamfetetice vf tbe box ; Uie bend 
lubU notiuii, aod oanaaqtutnttj deMxribca a citrro in tba 


Fig. 194. 

1 aad N be tb» twn li^hta wh««o intonMtiio aro to be com- 
kotcmettr u j^ni^d between Uiem and npidlj' rutDlnd. I'ho 
la prndnOMl by the roflection nf th« light nn ihn tno oppT- 
tw bMd g:iv» riM to twu lumiuoiw bauclM. arruu^Kd tu rnpii" 
. SBI. If one of ihnm » morfl brilliiuit thnn the oliier, 
itKr^jia boni ibo light M, tot iiuUnce, the iiutrumont in 
vr the other li^t unti] tfa« two bandii .rxhihit th«' Muie 
Tli^ disUnce of tbe photMU«t«r from ««ch of thi^ two lighu 
taanffid, Uidj btenntiM are proportionnl to the (qiiitrM of 

H u; 

Hf tb« reSeettan »r llctit. — Wben s lomiiiuiu mr ment* 
Aea, It U ndoctrd nccnrdiiig to lli« fiilioiting two 1fiw«, 
< 1hit« M«a, «I«U prevail for heal : — 
if «jf rvgScefwM u <fna/ fo Mr on^b o/* mrwfMtt. 
n'ltiif and lA* r^/keirtl my urr Au(A lii fAe M»i< fifiMfe, wAicA 
tar (o iA< r^/lnHiijf mrfae*. 

I «• h*re uatd in the Mma Mm» u ia articl« 367, and aewd 

C TliM two Uw« may 1m demcinRtnt«d by the ftppnrntiu 
in fi[f- 2ftj. It* of n ffnuliUktod e\ir\r in a »ertii-iil 
braw iJi>1<>i aiore round the ciivunireitmM ; on one of tltnu 
Ke i>f icniuud gla«^ P, and on the other uii«ptu\ueftcie«i\,^, 
« ot whkh it M muMl! ttf^rtatv, Fii«d to t^e \ftttet i 


urLKcnoic OP uonr. hibhobs. 


then is alio ■ mirror, M, which otn be moK or 1m ia 
alw*^ r^iwioa in a pUne perpradictilar to the pLuw if tb« , 
circle. I^aily, tberc U a ■innll polithrd mcUllic tBirrot, m, jS^^ I 
lonUJI}- in tlw nstrn of lh« tittle. 

In making the ezpniaMb' 
dl of «oIar light, $, ia 
iiiipii]^ im tb« minor M>< 
■HI ini^Uard thut th« iclclli'' 
]wiw« Ihrough the opoM*! 
Mid (Will OQ ibocMMnaf All 
•n. Thf luodaow pcocfl I 
p«rii!Dcai aMeinil 
dirm-tion mP. which ii : 
bv movinf; F until «b ia 
•pvTtim i* foiinil in it* G(«tn.l 
nnmbfT of dt^t'nvs conpiiMdif 
arc AN u tiirit rv«il off, aadl 
wi)« thai in AF, ihfae bFing 
it follows thM thv oiiiik li i 
lion, AirtP, i# ijquil to thean^ 
incidellfP, AniM. 

Tlin Mtiv.!!"! i«w follow* foal 
ijg. jij;. *rr»ngpnicut of thr 

platuf of ih* rars Mm ud ml 
pw*ll«l to the plane of (he gnidiiat«d cirt'l«, and co<M«c|DatitlT, | 
dicularto the mirror m. 

Sevfil proof. Tlic law of ibe letlectioa of li^hl vuj alao be doMi 

"w bOoBiii^ pxpi-rimrnt, »Wch is tniAceplibl* of RivBlor 
■■* Ifau Jim (kwribni lii the eealn of a drclc, 
■?li filMd in a vmicd pruition, thvrti in a imidl trlwcopi' 
■ *fiHFptnU>] 10 ibe linbi fit a suiubl>^ ilinUnce iWre U 
flrfiKKUiT, wbieh furma n p^rfbclly hoiiMntol pluiu mirror. 
nlirMtr of ths fint or iincoiid msfcnitiide h ricwed tliroiigh 
|>blbc lUnMtioii AB. anil tlm Iclenciip'? is tlirn inclinrd k> iu 
feinf, AU, Mminf! from tli* ttnr afior bninii rrDrrtnil fr-iiii 
IfoWvof liie aiFrvury. lu ibis uay ih^ Iwo Hiijiln foroieJ 
EAmI da. with ibi: horiz^intal All. are fiiUQil lo be c-qunl. 
(1 m^ mmI; b* nlwiwn tbat ibe soj:l» of iiiriiioni*. Iv'lll''., i* 
■q^of Rflediini. KL>A. For if Dl^ in thi^ iioncnl lu th.^ 
W BNnuitT, il U pvrpnndiuiilnr tn All, uid AlU), Alll') arc 
ICU* of liw pqiul angiln EAII. IiAH ; lb«f«r<^ ,\.F,U, ADK 
Nt iho two rxy*, Al^ and UK', may ba coniidcmi paralk-l iu 
of th! grvat dl-tanve of I be etar, and lli^r(^i>T>' ili<- iiii^ln> 
EAH«a«|«al,fortbD7an- nlirmale anKWi.aiid, cuuM^queuilv, 
^^^•qiMltaUiDRngli- tvDA. 

juvuxmox or uuiir irti>»x PLtsK nvKfACta. 

B^ IiMf ••, — Xirron Br« boiliw vritb polifibed i-iirfniw>, 
^R-flvFiiua nbjnrta |n«»«nlnd to ifavm. Thir ptncc nl nUii'li 
ir ia tbrir (uiiu^. Accordinz to ilielr shnp*, niiniir* nro 
•, tvtrvx*, Mwrnr, ifihn-irel. pnrahotk. rvnitnl. \c. 

Vtg. as;. 
, of imaK«a "W pl»na tBirr*«.— The dou-miination 
■iiu .J iuinjn-- ^■*"iv.■s itwlf into iuvecupaling l1i» 
, of pcnul*. And fir*!, tlic tas^ of a .iiiple point. A, 
lUK! inimir, MS (fiB- LTHJni. will U- I'-'n-i.lcfwL Any 
__ from »bi« pant on ibn mimir. U rdUctwl in tb« din*. 
a»K Ite aogle of wfl*cti<.u, lUtO, i-qual to Ibo angle of inct- 

«|twlbAN; U«t u, tb>t Hiy M^, XET 
bMo^ nAected, thai iTw pmlongition 1>«low ih« i 
cii]«r. An, in the poial a, wliifh ia al Ibv snmi; diaUawvl 
a* tbn poiDt A. This iipplins aliui tn tlio coo" M* anv otl 
point A, AC, for Msniplv. Fruui thb lb« important i 
■hat all njn from l)i« point A, rrHivtrd (roni tbn mir 
jttrtiuH, (An mm* tUmiion at %f liey Aotf nO pr^nrAd fi 
ajD ia (Ivceivdl, and tea tlio pobt A at a, m if it wers ' 
' m. II»n<w in plane mirror* lit imajft of mjr poM i* , 
DiaTW at a Jidanft t^val la that of Iht film point, 4md i 
tar lit faii/rom tliit point en Ihr mirror. 

It i» nifuiifiisl llial the ima^ of any ubject will b» j 
»lructbg according to thin rule tho imnfc* of each of it* ] 
of tboM vbicb are siifflcit'tit lo d^ifrnuine il« tittm. Fig 
thn imaftn, eb, nf any ()bj(ii.-t, Aii, U fomieil. 

It fullowH Trom tbu rouDiniciion lliat in plane mir 
the tame lite at Ihr ohjcrl, for if tbe trapiMiiun AS01> bj 
iiapiium IKJoA, lhn,T arc neeD toooinHda.andtlMobj* 

A further cotasequcnM bom th« above conatni«tiMi 
Rurror* tlir inuifre i« symmetrical in r»f«nnm to ilie 

4*1. Virtual and ra*! Imacas, — Thrn* kit two i 
i(Sl»Clion of rut x r'/fl-.-ot-jd by uiiiT>.>n, ncci>nlm^' asth«] 
•re «onrerii<iit or ilirf rarnt. In thr finrt nw tin ; 
iue«t. but if Ibny aro viippoMd to be pr^^iticed da lli» 
mirror thrir prulmt^ittionii coincide in tbc nmo point, i 

RErucnox ttr ucnr. 411 

"*fiwiMjfce «xpn«crd by raring that r»al iniofftf ^ 

Wl^fflid^ra^til*mttfev',«Hd virtual inoffrt Otott fm-mtd hjf 


M^IMi Imf*" tmwmitA br ftu» mirror*. — MetAllie mirroi 
**■ kM m nieetinfr nrfiu:*^ <m\y triv<r oat imofrp: it Ud 
'■■^in^ Uwr pr« liw to Mvet«) iiiiHg''-'. > lii< 1i are Nwditr 
t*W Id imitge of * otndle ii looknl 

i ht« w,a4tbwt • vccjrilirtiDCl oop ; 
IMknaa wnnl otbcm, whout ini cn- 
('■DfiKitaBa until lJi«,v ilitiapp<«r. 
I^Hmm UM* bocn tbo louldn^ g1 au 
MMie(ii(ig(Ui£u«t. lyhcD ibe ntvii 
■ H*l A *Mt tbe flnt •urfitra. a put 
Mallmwui ima^ a, nrilin pniiit 
•fntap&o of tbe m; AE, reflet'ied 
■Aeti IW olliw pwt pM*ci> into tha '' '8" ''^^* 

' it nAectod tA e, (nm the Ujr«T of mvtkl which rovera iho 
■Antf th« glan.Mid rMcblngthovvoin th«iUrt<otionini.Rira 
{H*. lUaiaiageisdirtantfroaitbfillretb}' doable the ibidtneM 
Ik h i* BOfc iDtenae, Waiutt uiuial rrfl<-cls butt«r lliiui |.'tnM. 
■i to ibe otbw itnuffo* il wtU bo iptnArknd, thni whriu'Tnr light 
JMd Ireai dim meilitioi tn uothef, for tiirluiai, fruui elua Ic 
■■* «f Ibt niT* ^t tbrouKh, thn mnaiml^r uv rrflrchKl al tbi 
lUtkboamU tbo twi meili*. ConM^ni-nlly whou lb•^ pFui-il(^j 
tan C^ ■U*tnpt> (o le«v« tbe gltu* at d, triMt t-f tlic mT* rom- 
fM ialo till) air, but tonm ».n U'^vel^ M il, uiid cdnliuiie 
»tfam. TbM> nk affaili KfleoUid br the tDctnllii.- lurfw'r', iicd 
UiBig« of A ; »ft«r thii n'flncti<qi iliej' mimn to MN, whtiii 
■p tad tvndcr tbv tbUd iinii)^ i inblr, but Home uv lyiiiii rv 
ttJB iIh* grlwi*, "id in • rimilv manner givn risn to a fourtli, 
M^fB, ifaorebj completing thu eeria* above deKiibiil. It ia 
faiM tb« abure «xpl«nMti<m that rnch imagr uiiist Iip much 
M tha one p(«e*ding it, and roni^iicnllv ofA mom tlian n 
Aruo tiidbU — ordiiuiKly nut niore tliaii <.-iphl ur trn in all 
ItltipltoilJ of iBia^n* U objecticinablp in iib*nn>lii>nii, and, 
\j. ■atillii nrirruT* arv preferable In opticnl it»tnini>riil>. 
Mtpl* *■!■>»■ ttna tw« plaiM ■ttrrorai— When au ubjrot 
belwcro two plane mimmv which fntm an anitie with norh 
m right or acute, InMgva of the objeet ara formed. th« number 
Wliiaia with ibe inclinatinn of th<^ airror*. If ther are at 
M lo nub ntbor, tbre* imaireA are (ee<D, arran^fd an rrpmcnlc^d 
S. Tbe raja OC tad 01) Irom tba point 0, after > *ingl« 


tas Licnr. 


ba thai 

lebciinn, givo Hu< on« m itdifte 0', UhI the «tbei 
the nv OA, wliicb lioa nndoTgone tvo nfleciiow M A i 
thiH ima^, fy". When Ui* kngl« of lli« iiiirron U 80^ 
proiluctxl, and aeven if il iii'Mi''. Tbe DumW oruiuvMi 
t-mva in pmponioD lu thp nnirlfi duniiiUlitis And nlieii h' 

wlirai tile miiTVira om ftati 
of iDiafrm i« thearetMiUf 
iniilti|>lidty ariatn (hwi it 

I^^WH^G^H >>"r of reflectjou* bom ow 

|n|BUn^^H Tbe JnMdMMiBr, ioren 
l""*^^'C^^^B Kirmtter, ilcjimdii 0*1 Uih 
rJJnnd mimW- ll onntiri 
wlik-li aits thiw mirrun n 
r-nn riid nf tliD tlibf it> cIm 
;iru<iiid ^lata, and tbo ol 
pmiiiiiHl trilli an sptiTTMr 

l"'S- «"». guia, pJccM of colouml g 

at aw oncl )H:iwt>«n the ground g'lftM and aiioth«v ^Is 
inak'ing ihmujtU th«(ipe«urc, lliti otiiorend twlng bdd toi 
ihv olijecls Hijd tht'ir iiii*iwn am fevn ttnnnp^ in bpaiitil 
foniii : bv liiming the tulit- ut i-ndl<«« vnrivtv of tttfw »bii 

44(i, ZiT«fnIar r«fl*etlati. — Tlie rrllM^tion from 1 
]M)I1»Lih1 biKiii^n, til-- liin-B of wliicli liavo jurt b*«n ataU 
frgulur at tprculor rrflectiuH : but llie quniltilv thtu n6ei 
ibe incidnnt li){hl. Tht- li^hi incldi^iit on an npaijue 
wpiimtes iutu tlint- purta : ona is ntii'Ol^d K^:ululj, mioi 
ibnt i*, in all dirertiona; wliilv n third u eititi|riii<iU«d, 
ihp rvflKliu); bodv. If ligbt fidb od a tTMwpuvnt bod; 
IMntion i» trnnamitted with rpirubuity. 

The u-rv-tfiilMrl)' ivflerK'd llifbl iarsllod (Mttfrrrf&jrvU: | 
ninkea bodici viMbhi. Tbe ligrbt which 'a ivfl>wt«<l reg 
irive ae tha image of thn rvlli-rtinit nurfacc, Iviit tbai of 
whidi th<! b^-ht proceeds. If, for exompl*, » Mtlnr IfMni 
ft w<iil-iM)li»hoil mirmr in a da-tk tooni, the mow pfrfvrr 
n^fli-ctL-d th<- leNft viBibl« is lb« mirmr in the dlffermt fW 
The <nv dop« not porpi-ire tlie iiQti((;u of the mirror, but tl 
If Ibi- refliftin)t power of ihr mirror bf dimini»h*d bj *pi 
light piiwdur, iho jmlnr iina^-p beeitaie* feebler, rtnd the t 
froinall parts of thq room. I'ltrfoctly smootli poliibod wt 
if aneh llwre wtc. woiiM V- inriMble. 

447. X)iMnatt7 «f rwfleoietf Uglit. — Tb« intcutity od 


■ ** ' ^! bovMM wilb tbn dogron of polish. Mid with tlit 
V^ll^madimxnf. For bsUucv, iTa slirctof white poprr hv 

■ OMeicindlo, and b« looked at very nbliqui-lT, an Jmi^ of thr 
'■^ IjnBrctioD, vhich t* n'.'t the ca*e if tlie «« n<cciva lev 

'■taaljraf tbo rcfl«ctioo Tana* with diffeii^nt bodiws eT«n wIwd 
^tf |nU and iLa angle of incidence an* itie eamr. It alio 
■U Ibe natnie of Uie niRliuin wbicb tho my ia traTcndnf hvlotv 
(rniaclMa. Polished gUm imiiH-nwd la vator )n«ee a gmi p«» 
ikclinjt ponr. 

uvucnox or i.inur vkom ctbvkd ctrxrACM. 

Iffe«n«al mlrrvra.— It haa been alr«adj *tal«d (441) that iIihk 
•I Uoda ot ciirred minora ; tboM moat Gnquedtly employed arv 
aad pMtbolic mirrnos. 

m/ Mutw« are tbow wboae cunstUK l« that oS a pphvr- : thtii 
lay t« luppoaid to be forrocd hy thn rernlulion of on arc SIX 
•hout the railiiw CA, which uniiee lh« middle of tho mc loiht* 
Uia cncle ot which it in a part. Accordin; a* tho redpclion 

• friMi Uv mtaraal or thv exiomal facv of tb* mirror it i* Mid 
OTv or cOKnr. C. tlie vonlre of tho hollow iph^n, of which the 
m* (■n. t» called the centrr of rurnrfurr cff gromrtrienl crvSrf : 

A la tha <«Dire ot the Hgure. Tlie iutinit« right line, AL, 
Nca tbnntfh A and 0, b tho principal luii of the mirmr : any 
wUcfc ttMpI? paiwr* thruutih tho contreC, and not through l]i« 
ammmmJarif aiii. Tho an^'Ie UCN, formed by joining tfar 
B axtnRiitiiai of the mirror, ti the aptriurr. \ /inVt^i/ or 
r i te w la any eMIioB made bv a plaDU through ii« priucijinl 
tfttAmj! of miiTcira tbooe tinea atono wilt b« conodered which 
IHW pnneipal Mction. 

wry of th« rofloction of light from oumd mirror* ■■ Mtily 
xm llio law* of Kflivtion from plnno minor*, by connderinK 
t of the foroMr as made up of an infinitude or eitreiiivly iniall 
latk, which are ila tiemailf. The somiiil to thu eurrud nurfaoe 
1 poiai is the perpendicular to Lbt< cj.>iT«<[)nnding eiemimt> ot, 

• mm* thinf, to iu correipundin^ taiigunt plHut>. It la shown 
tj that is spberts all lb« nnnnitli prm* through ttia centre of 
.« that the normal may readily be drawn to any point of a 

r«aa cf * aplMrtcsI voDcavo mirror. — In a curved wirr)r 
i* a foiat in which Iho reflected cuys meet or tend to meet if 
iMMt backwanh ot forwarlt* ; them mar cither bo a rml /onw 


4U ^^^^ 0.1 uoHT, ^^^^Ti'TM I 

Raai /mw.— W« shall nnt oondder the cue in wbick iW '^fS^v4 
TST* MW psmllol to tlie princip*! uU, which pmnppeM ^'u^HM 
lumiuotu bodjb U mn inftDitc duUuu; l«t QD (Of.VOtkl ^^^L^ 

From the h/potbens th»t eurvint mimm an mrnpntml ''■>*^^^^Bti 
itiHntUily amiitl pUne fllenunita, thii nj noiilil (m tedetteJ "^^^Wrf 
•lument correspiMidioii to tlic point ]), aocMinlinif to tbolnratf A'^^Ha 
flm-tiaa rrom plane niirrun (-IIO) ; thitt i«, thai CU Wing tk *'*^^H 
til* point iif tnddrncp. D, ibe iiDirI>^ if tefl«eilon, CDK, it njitlil^^^H 

Mgleof iociJ^oAp, ODC, and in to the Mmn plant. It Miowt {Nnd^^f 
that tlin {iiHQt F. wlit<r« tlti- r»llit<Tts(l nj cut* the prinripal utt, dinhv^^ 
the radiu8 of curvnturr, AC. vi'rv DMrif Into two H|aal partA- Fm ^^M 
Ilia lriiuif(l« PFC, thetnglo DCi'it equal t« tbnanKl<?ClXI.rM'ihi?»H 
alternate and appasitD *ni;W; likewjw the »»gU CDF m «<pul (a tteHj 
■ngle CDO, frnm the lnw« of iwBectian; tfaomfim th« anit)* FlK'tlJI 
equal to th« Bn)rle FC1>, nnd th^ (ddw FC und FD an eijual m y^^B 
opptMiifi to <v]uitl nnifkD. Now (besmaUor the are, Al>, th« inow il^^H 
dnea DF vqutX AF; nnd wb«o tli« arriiotily a nnall Bnmbaraf d^^^H 
tbu ritrht liniiD AF mid FC ma; In.- taken aa appnutinatrly Mi)ud,ai^^H 
pniot F inaT V tfthi-n an the middle nf M\ So lontr m the ■;ett^^^| 
the mirror does iiot i^xfettd S (o 10 de^fnvt, any other mj. Hit, wiU^^H 
^nSecti^D [utu voiy nuiirty throiitrli thn paint F. Ilenc, when A fi^^| 
nf rava paralli^l to Ui>.>n%is fatlH »ii a conuaTe tnirrar, ibe nm Mm^^M 
nftor r«fl«ction in th" aiiini^ pntnl, wbirh in at an nqual diHure (hH^^^| 
(«nti« of curvHliire aiid fmrn the mimir. This p"tnl b nalled^^H 
prmcipa! focia ni thr mirror, iind tbu dhtonceAF U thn /iruicyrfJ^^B 
Jlltllnit. W^t 

MX rtTi parallnl to tho ui* meet in the point F : and eonrendjI^H 
liiniiniHta ohj<>c( he plnred at F. thn t*y» nmittad bj thb object wHlt^^| 
rellBCiion taku tliL> dirootiimii DO, BH. parallel to the prisdpal axitt^^l 
in thin naw th>> nni^Irii of incidoni^e and rellorlian have chang^ fM^| 
but tliMV uniflf-^ *lwftv" reniftin eqnal. ^^M 

Thr rnrr- \n nnw tn he oanKidun^d in irbiuh the raya are •mltlod b<^^H 
lununouA noinl, L (Hs. 801), nlaccil in the prinripal sxia, faitt ■! <nH 

*'J uiucnox or Lioat rnoii cchtkd in-itrAcrs. J15 

■■••*« tlef«re awt pknlWI, b*il divMgwnt. The aiiel" I'K<;. 
■*»tafart ny LK fomw wiih the DormaL KC, b (nalW tluui 
V>SKf^«)ucli ibe ny SK parallv] to tlie uw forms wJlh Uic 
'■'■4 iAl, aoiiM(|nMiUy, tlin anifk of K!l*ciian comMpoDdinir to 
T U, BUM b* MBiIlor Uiiw tliu u)!{Ie CKF, com»p'iitilmf( u> ilit^ 
*■ Aai, Ifarrfflni, tbe nr LK wilt mewt tlie kiU oAcr nil1i.fti»n 
ihj W f n nw th* CMItw>, C, md tbn pricciiMi Toimih, >'. S.i litti^- 
^IWtdTlke nitror duM iiut oimiril a suiatl iiiunber nf degmeik, 
I B^ hta Uui point 1. will inU-Twct nfter reflectioii in tbe 
Ah faint la e&U«<l Ui» niH/n^f focat, in order t« la^icutti 
unka bstwwin tlie poinU L umI /. TkcM points are ncipniml 
r, that It; if Uie lansiiiiMU point won CmiBA!m<J to f. iu con- 
voaU Imi at L, /K being the incidant and KL the rclleLiml 

F« 301. 

■dating tlM figure 301 it wiU bo smd tbnl fthra the objpct, U 
it neat to' ot r^ianvad bom tb« ctntn, C, iu ooiijutrutv iociu 
« or kokIwi in a awTWpaodiBg maniwr, for tbe Bnglei of 
and nSeedoD incM«n nr decnaaa tog9lh«r. 
H^gact L coincide wtlb tbe ecnln C. tbe an^le of im-idenue \* 
as tbt^ au^le of retlecticin muni be the hbrii', tlio rnj ia ri'llcntc'I 
nd Uie (oDiui eoinridee nilfa tbe object. Wh«u tbe liitiiiiioii* 
Wweea tbe cvstri?, C, and tbe priticipol focui, tbe ciiojiijnite 
tnm k oa th«< «tlt«r iidn of th« csntro, and U furlb^ from the 
iMding aa the luiiiiiioua pnial la nvanr tbe priiK-ipHl fucus. H 
iMt point coiocidai with the prim tpal fociM, the reilccled my*. 
tlU to ibn axi«, will ui>l itiHft, Htid tbere ia, couaeqiivntlr, no 

ytMWfc— Then ia, lavtlv, thfr caM in which the object ia pluovd 
raoi tbe principal fucun and the inim>r \,^^. ^>i). An; my, 
(ad front tbe point [.i, mnkRi with tha normul CM, au anuria of 

LMC, frraater ibui FMC ; tli-.- iui|eI« of n?f!>H-lion miut bv 
■B CUR, aaJ tbcrebni tba rvlbcK.'d rn}, ME, diT<-rtt«* 

m^», AK. Till* ia a]»o tliu cajio with nil run fniui tliv 
■d banoa tbaae rajra do ciut intumect, aud, cuii««(iu<intl;, funu 

Hi ON LKUir. ^4 

' no conjiiiratii fueiu; bat if tbojr mw «0BeMv»d bt be pinkngcd 
iMbft Md« nf ihe HiirTOr ihMr pralmmtiMs wilt intenRCt in ika i 
nnt, ( on tlip niia, nad Ui« «]re eapmeacca tbe wine JnipiiiiAinl 
B)r» vnni «imtlnl fmm tfan point, I. Hnire it nrftHiJ/iKtu h Egmell 
analojcoiia to Uiun fonitpd by plaup mirror* 1 443) 

In nil llumt COM* it u aMii thai ihn pinition of ibe principal 
niHlwi, wbilc ihnt aF iIm- Foujavxte fool and of Uw vinunl tMl 

Ft|t. 303L 

Thr prineipaf and tic eoiytiyatt fori air ahmji* tut llie mtnr •li'r i 
mirror at th« oh^tet, wbil« tAr tirtiul fotiu i» o/myi an tir tfAir . 
tie rnimtr. 

Ilitlif no liw luminniM point hw nlirtt* been mippuanl to h: - ' 
the priEii-ip&l Hxis iwit, aiid tlim tbu fm-iu ii formi^ na itii> . 
the fBi>o in whirl) tlin lumiti»iiii point ia hiumo im n aeciii 
(Hit. :iO-t), by nppl;i'iiig ta ihimuis (he suae rauoiiingu i.> 

I it will lie Men tbat iitv focus of the poitil Ii ia fohncil nl 
an die M'coEiijiirv ■\iii. nnd tliAt ari-onltim t<i thu di«laiici! at Ibf 
thn fiiriJn mill W irii)n-r principnl, o'lrij u^«t"N fit virtniil. 

■J'W. r«el or eoBves mirrara.— In c:jivc\ mirrocs Uiere an 

Pig. .-tOi. 

foci. L«C SI, TK . . . (Hk. aot), b« nj% punik) U 
"lirtadpiil axis of n eonvox niiimr. Ttiw« ht^ afinr reHeMkm, tab I 
.iivpTgin^ liiirctimis IM, KH, vbkb, wbt-n conliniwd, nwet in a point,! 
wbicb i« iho prinajml iiVfw.i/ /o(a« of tho miiroj. Ify niMn* "f " 

oEn-ccTiov or liobt fkoii cl-rved surfaces- 


CKF, it najr be ikvwa in the Muns mannor m with coneaT* 
ikii Hi* point V i» iiipronniBt^f tke nolddle of lli- ruUua of 

iftad'nl Inminoma tay>, inatod of being pMitlUI 10 l1i« «!•, 

bom > point, L, «ilu«t»il on th« axid at a Biiit« lUatnncr. it i* nt 

tlial B 1 irIiuU fociu iriH be fcirmod brtw«on th* principn] teiw, 

iktlttR Of tk« prtttiolp*! fdotM.— In tba appllc'tioiw 
*(• mod cmtux mirMn it b otXta nacowu^ to know tlio rmliii* of 
TKid is lantainuwtt to ftiuling lh« prinvipnl fiiciw: fur being 
mt thr QUiidle of the mdiuji, it in umply necuiHarT t(i (ituiblii Ili« 


(14* rocna with a eoiMfivo mirror, it ii i-xpmoci to thu wxa'» 
iu principal axin in p«nill<>l \o Xb^ni, knil then with n miiaII 
fpnami ^Im the poini in M>u)iht at wliich the iinafi« i> furaipil 
fnxuM h)t«Daty: tlti* t«th«princi^focti». Tbamdiimnf ih>' 
dnalik thia iltatwK*. 

viRor in mitv«x it U nOTiiml wilh pgipor, but two mnnll portion*, 
, mn IcA oxpoM^d at equal diMtac:!!!! Iroa the Mrnlre fit tbt* Sgurx 
B th» Mine principnl xrctinn t'lig. 30(i>. A •crrfm, .MN, in tbt 

Fig. aiM. 

[ iiiiicli iaan opsiing Isxftfr tlinn CLuiliBt«ui}L'lir,i.i pliirvU before 
r. If a pencil i>f aolarrafi, Bll.S'l. [uimllrl to thn nxln, full on ihf 
' l!;tbt is rttdected al 11 and I, on the parta where th« mirror 
, and fomut on tbo Krven tw>i brillinnt imairni at A oiul i. 
: ibw *ervcD .MS, nsartr to or farth«r front the niirtur. a p'vii- 
I at witicb the ilistancv A« in tloub]« tiint uf HI. Thr disljinn! 
iIm aneon to ilie mirrnr, th«n nqiinU thi> priu(?ipa) Cv-ni 
yor thn aiv, I L\l, iloM not lenaibly ilitrvr bom iu cliucd, uid 

llhn tnanfflM Fill and FW are similar, '"=|'';^, but III ift half 

1 thenfbre ako V\ u thn half of FU, and tbercforo Alt ia 
^AP. Fnnber, Fa it the principal focal diataace; for tb* njs 


o» twirr. 

^H mi ^ an pamll«l Ui ibe axM: MMequenlly bIm twin iW 
AD equal* tbeiwliui o£ curTklutv aribn ntrmr. 

i^'i. rormstlea «( lmkc«« tB ewB«aT» >DliTara.~Hitkttta 
becD *uppo>^ liial iho tuniinuiu ur i11umiiiiit«l objprt placed IB 
thn mirmr w** nlmplv a point; bnt ii thw i>b}«c*l»MBcen*Jn 
w« iiui cniici-ive k suGundBnr bxIb drawn tbroogli oach of in 
ikuaatrrim of n>itl or rinunl foci could bo dutcnninnl, th* ocJlKtaBI 
whjcli coui^iM* tlie i<&H|ra of tka objtet. lij Ilia lud of the ocntmrtia 
which hRve mutmI fur dc4««iBuiniK tlui foci, vs shall ioTraniiit ll 
}Kuiiii<in and nu^itiidc of thoM iiiiBff** in coocBve anil is wm 

Jlntlima^. — \V« ilmll lint tiike tile OMS in whkb thfl BlijMliiN 
«BV», and ili« otij«ct AH <tiu. :)>»l. in on ihn i>llu'r iiMl«irfthfl ciatn. ' 


nlit«in tJi" ini«g« or iho focn* of Bny [wiot, A. n Mwnndarv nxlt. AE. 
drawu friim thU puiiit. luid tliea dniwiiijc fr^mi tl»r iKdnt A >n r 
Mv, All, tbi? ncirniiil lo this |iMnt<'ltiiitAlipn,afltlili«BnKl<»<'JTrlWili 
alia, i* madn tt\nai Co tlie iui)rl« of Inridt-uf*. AIW. Thv poiiita,«t« 
the ii^fli*c(ed raj-ruuihe MdMuUiT B«i«, AE, ■« ilie et^uipic foca 
th« pniiit A, boi-niiMi oierf Minn rav dmwu tnmi (Jiis punt 
thnoigh with n. Siiiiilarlj' if B •Nnntluj nxlr, BI, Iw ^wb h 
liie pi>iiit II, tli« ray" rmm tlii* [H>ini lucnt ultr rrll4>etioii ia i, mKM 
thi) (Hinjiigntn fi riia of li And at the ilua^ii of all tbv poinu •/ 1 
ubjwt Biv I'onunl lietwFenaiind A, «tiiillMrci>nip]i>l<'iiiiMKeorAJl. Fni 
wlint hnx bi^eii iiiid about foci (441*) it tip{"'ani Uint iJuu tm^uw 
•Birrtn/, ttnaUn- limn thr vfiject. lard plaen/ fipf iKm lltr <yn/iv o/ 
om/ M* principal ffnit. Thin imaif oiaj ha wi:>n in lira wMn ; bv tUk 
Ui« oyti in thi) i^nntiniintiiiii iif the rt'>liH:I«l raja, aod th«ii it is Bo ai" 
unBfr« wbich ia muu : or iba nyt ok col[(?ct«id on s MTvcn, on <4ick 
iinimv uppnan to bo dnpintpd. 

II' [ll(^ luniinotM or illuminated object in pU<t*d at ot^ bc(*MB 
jiriiKUpal fuctu mid ihc cQiitri', it* i]iiaKi> i> furiuMl at AR It MllnB 
reol bnt iiivuHnd iidagi- ; it i« grentir ibin tho object, toiJ M* 
'Ac obj'fti, ah, M ntartr IJu/acm. 

KL-imx xit uaar na* rt-Rvtn svnrxcti. 


i« plarvd in the prindpdil Tocui itadf, ua itanft >■ pr»- 
ea Ike nvf Bmiltnl from «tch jiotiit fonu nfti-r r«H<«tiun 
rMfmcliiolf pnraltnl to tlie seMrndory Hsia, whkh Ih 
the pcdat fnMii wbich th»j uv eoiiitv>l |441M, ui'l limt* 
Ibri niir imatn* u* fiimird. 
all iwinlB of Ibe iib]f.-l, A It, M« ahnrs lli* prinei|MiI ixi* (ig. 

^^ fOT. 

^^BMlin)! Ibn pnwxling cnoitiuotiaii, il ia l«*di)y iCGn th«t the 
HHp u1y«;l li fi>fiiMKl At ni. 

»MMiy. — The owo reniainB in vhich llie objwl in pliuvil 
ttwi fTJudpitl focuD u»l thi- mimw. I<ct Aft tw Ihii <>bji>i-i 

h lki'undMtniviiJUri«fl«c(i»uUik«tliHilii'<^-tiiiU9 DI aijil KH. 

t ]mlnn](atioa« ftinii'it tinuid iniofK. •>■ of Ui« piint A, on ibi: 

i .^. 30K. 

17 axil. ifiiiuUrlr, an hii^^ of D Ir fonued Mt A. roiw>s|iicntU- 
mm at ui tb« ioMi^ of Alt. Thu imafft u niliinl, rrrti, unit 

wfcat haa bean lUtod it in tnoi tknt accorJiiig lo th« (li>lftiii*M ,>■' 
g( eosAVB mimn praducn two kiii<)* of imn^rM, or uoiie nt nil ; 
n DoticM this hj pUcing biniwlf Iwfure u miioivi- inimir. At a 
£rtaiK« )mi ■««■ an ima«« of himiwlf ioTrrlvd bii<j unitilleT; th» 
nrf i»age : at a ku dUtauro (hn imngn bviyiiUM pfinfuanl itnd 
wbw bu ia Bl llw fociM ; aliU nntrer tho iioiign appt-ani amrt, 
il ia a Tirtual iii>^«. 
VWwaUsB vf l^ia<*« in ««nTei oilrron. — L«t AB(fi?. !)0n). 

4SU OK LlflllT. [*'^l 

Im m olqed iitnced before k nimr at *nv fivm diauoce, AV taiKi 
tn taoonduir bxu*, muJ it CoUuhts fn>ui wrut luu bcvn akcMlT •tttrfJ 
ih«t all tfco n;a bom A *ro diTcimat alW nOMikin, lal ibi iWl 
prolon^iOiMW pOM tkroU|i;h a poiat a, wluch b the vlrMl imu;- ^tk f 
point A- SLmilaJly tiw my* from It tana a Ttrtiul tau^oi iliallftj 
poiot A. The ey« wliirL naJTM Uie divergitnl nva, DK K\, . . 
leai in tib Bn inufn of All lipncv, wliatcrrr the poMtiim c( «a t 

Inifoic ■ I'onvcx Diirror, lie iuiagr uatwagi airltial, Trrct,tmJmMft 

K4. TvrmuUa tw •pberteal miTrvrs.—Tlie reUlIia Vt«m i 
(Nwiiion of an >il>ji^( and ihui •>r itn imBKr in •pli«riul muRni 
rxpiMsnl b;' H T^ry umple forniiilt. In tlie cnf« oif concamnimnl 
It b<! ltd nuiiuRof ciirvMtu«,|)tJie(lwtaitor l>.\'irtlM-«))ii>cl, L t^3 

Fig. SllX 

Mid p' tho diiitniir<< /A if ihn imAge frnm thi> iiiirr<>r. In lk« 
liM/, 1U« iii>niinl MC' divjticis Ui« Migle LMt in two eqnJ [Vt^i 
from gcnniQtry it fallims thnt tlio two KgrnnnU, Iin, CJ^ m l»f 

>ith«r «■ the twn ndcia cnntainiii){ the angle, that i* ~1- ^^1 '' 

L7 X LM = t'l. X lit. 

U the arc, AM, doM uot excMd k or degrve*, llie lisn liL 
nra n)ipriixuufllt-ly equal to AI> and A^ tliAt i^ to j> and f". 
Fiirthor, C/ = CA - A/ = B -/, 

nnd ttino t'L ^ AL - AC = p - R. 

Thew valiiM tubslttulinl in the prKcdin^' eqiiaiiona gira 

R;, - 11''=pp' - B;i'. 

KixccTtoK or LiGiit rncni cl'rved surfacim. 420 

trbkb tianfNMiug nnJ ivdiicinf we hai« 

Up^lip:=-2pp (I) 

ktmf of thU «(|iiatian be bII divuled hy jqv'it. wc obtain 

>i=s '« 

iittl ronti irf (bo c^uotloii. 

'^-./-u .■■•(«) 

tlio dbuncfl of tbit tiaitgc from thr mirror, in urms of iLe 

ol ibe objr«t, osd if thr nwliiu of cnrvntiirw, 

M ww IPB »t tbm fSTBiiilM r«r Boifrvn. — W<i chnll now 111- 

I die (liflbtcnt ralucB al p', Ki;>wiliag lu tbe vplu«s cf ;> iii tli<! 


I ibc ol>jnrt be pbtord lit an iiiiiuite ilintancv 011 lb« axiv, hi 

Itbr Uicidrnl ra,v> ■'■^ pnnlli!!. To obtMn thu vatuu of p' 
tike bacliua ^-^^ iuubI Ik iliv)d«d by /i, whiol) giiVH 

- b »'(0, atiil w» liave ;•'=.; tlwl Is. the image is 

n tlia principd fociu, M ounbt to bo tb« cue, for tbc incidcuit 
pandl^l In tile «xk 

tV object upptiMrbe* naamr live mittor, p ducrciwcii, nnd lU 
■dnator uf IW fdmula 1-1) (liminUhee, (haTalm of /j' ion^BiwAi 
Ml; ibii nua^ apprdacbi^i tlie oenUv at tUe Miaip tima u ibf 
Mtll U kl«nt)-B bctweeu tbe princiiml faciw and the centro, fur 

|i^u> lt,w*h«»e ^j^>Jand< K. 

I^B ibn object coincidea witb thi.' cwtilrc, p ^ R, aud, COn«c< 
if* = It, that i^ lh« iinag* coincide wiiU tbo objert. 
rban the lumin'Xui object U bvlweeu tlie cetitn nnil llic 
I InCM, p < II, and bi>nc« fron) the forniida (4), p" > R, ibnt io, 
p k fomicd on tbe olh«i (iSd« of th« ceiitn.'. Wben the object 

ifocui, p = , wbich ^Wrtp' = =s », that In, the imiif:o i> 

inita dtftance, for tbo reflected rara are pamllol to tbe axia. 
Mj, U Ui« object i* h#Hreen the priuoipnl focua and tb" 

we get p < -^ ; p' ■* ibnn nngatira, becauiw tba di-mjinlnator 



of tlie fonimla (4) in nn|t«tiTe. Tlienfon, Uia ^mUw* ^ U 

ttmxt th» inuK^ ai'M h- c^I^hImmI on Um axu in m dtneUM 

p. Tttv iaiage in tben virtiisl, wid U on lli« adwr Mo «f ib n 

Making ^ negMiir« ill lli« fomul* (S) it beciiBM — ;= ^ 

^ /I K 

fonn it nnmpmhRiiiii dl c-Min) ofTtrtiul imii)^ in coowa 

In the cajm of cnovi-x uiircor* Um inM|!« i« iilv*^* tirtal 

kuil R Mrt-aftba namn si^, mdmUmi inw^Mwl diecentreanc 

riJc of tb<^ iiiinv^, wliilu ttta «tij«ct Uriiig aa thm oppcMto nit, 

coutfW}' eifni ; hctiiw iii the foniiula (2) tra f[et 

1 _i_s 

/ ^ Te ■ • 

M thn fiirninU for convex luirrortk It may »Uo Iw foaad dins 
i-Kui^ ^e-iuietrical cuauid(>nitiiina as tliOM wbich have ted to ill 
11') for e^nrnve mirror*. 

It muM b« ubwrtnd that Urn fT'^cediug fumuto ari> mt 
tnw, iuaMniii^li a« thiny dnpi^d upon tlui hj~patlia«u tliat tW 
and (M (69. 410), am i-iiuul to LA and A'; altboiigb tlii« ii 
wrordiintniehM without limit with tlie aaj^n MCA; and wliaa 
(|iM not oKi'fiPil a r^w iefffif*, lli« anor i« *<> inuill that it maj 
tiee, be ni:-i.-l«-iwl. 

U6L e&l«al*il«B »r Um mavalindfl or lmaf«a. — By 
lAbnvn fnrmulie tho mngiiiludH vt an ipaagis uiay hv ciikiiU(*d, 
^dtatanra of the nhjiv^t, iti mairnitude, and ths radios of A* 
Far if 111) be th« otijoct (lig. 311), U tta lma«e. 

i1i*liuic<t KA, Bud ihn rudiui A(' be tmawn, As can be cat 
lUPftua of rnrmuU [H) of artiele -144. Ao liuown, oC can b* 
Itiit *a Ihe IrUiifiV* IK'D and tlCb ar« limilar, tiMiir baan ■ 
awi in til"- ]iTiip(irliuii I1I : III) = Cn : f'K, ■» 

IjiiiikiIi or tba iuiD)^ : li-iipth of the objact 
= diottuii^c from imn^ to rantro : dietnnr^ from iLe objact 
457, Spheiieal abarratlon. CauaUoa.— ln thefnn^- 
t)w foci and iiuHjfO* 0/ ipbiirical iniriMn, it liaa already 

Rtrticrmx nr lmht frou cuRtKH sunrACCs. 


itrttrtrd ttyn Only |Mn lliroojrii a *iiu:Iepoiat wln^alheBperturF 
Uirrar d>mt nm r.xtred B or 10 <t«;r'^nii (441)). Wilh « Iniywi' 
, ifc* nj* rell«rti-d niwr lli^ vi^r^ iii»et llii! axjh ii>-iir«r tiiv 
itm lh«BB whicli uv rv'tlBMcd M ■ sninll dlsliuic^i! frvua tho ninfrh- 
1 ef lbs mitryi r-f ihn nilrrar. Ilvniv nriu-t n nniit n( prvi'iuiiD 
iai^M. lahich in i-alled ipitrieet atrtTation bv rrllui'tiuri, tu ili*- 
<lt Iran tkn f^tricml ■berTatii>n hj ntfrertiuit, irhich ooMin in 

nillDciHl r*5 rata tbn aun imit to it tfiir- 31^)i »nil tli«r piiuita 
I Toim in «pae«i ■ curv«i •m&M, wbicii i* allud tlic vmulie 



Fig. 113. 

T1i« CBiTit KM iqiraiiuib ons of rh« bnuicli'ui of s »«vtioii 
made by lh« plMiH of tli^ pnper. VVh«n ili« li);lil of u 
<Mfl*rt«)l fram Um tmidc of n rup iir lambler, it iipction nf ihn 
Urijue can b« ma bv p«rtlv filling tlia cup or lambliT with 

IppUeBdvns ot nlrrara. — Tbn a^ttcationii at plnno iDiinira 
tfat •conMn* u« w«iU known. MJnon m« al«i> fnuiuviitJj- iiwd 
a) aiifMfMUw for anDdii^ li^ht in » cvrbun diKclinn. The tolur 
ddJv bewai in a cmwtiiM dinrction b^ making the itiirr<>riiiot«- 
■Biut Im*f a iiMliau which cciiupm«tM for tha cnntiinial 
I iJui diiwlinn of thn ntn'i ra^n pmduonl by Ihn iippHrnnt lijiinial 
# ilia ton. Tkid rMull i* obtnlin^ bjr mciiiu uf « clook-wurk 

whirb Uhi niirxir ia lixnl, imd wlucJi caiMu* it to fatlnn tlv 
tlM nn. Tlii* •pf«rativi i* called lh« Miait/ii. Th«i r«llci?;tiiiti 
■ alH> kird til siouura the ftO|;lM of crrat*]* hv monjiit of Ilic 
nil known m r^Urtmg yoniomttfrt. 

m apWieal mimm bk Mm) otivn nf>«d. Thfy "re ii|ipbed fur 
Of nmTwn, a« in a iihsTioff niirnir. 'I'tK.-y linvit Iwrn c-mploTn) 
o^ninonv aod arc Mill ubtil in t^leiicopi>«. ThnyAlD<) Mrve hh 
, fnr oonrofing tight to ipvi^ dbtancoi, hy pliu-lug a luiniuuiin 

1 ikeb' principal fociu. For tliia purpouc, hnwnvi'-r, pnniliolic 

i«ratooll« nalrtwra.— /VoAo/tc mirrors KK cuiicate iiiirron. 


ox LmttT. 

tjffhiMB MrfihM is gi^noMted by llwKTolutiovflf theuvoftj 
'-Kboot ill uU, AX (iig. 3l3>. 

It hM ban •Inady autni tliat in i^Wrkd mitrcm 
to ibfl uii coBTcqps only apiiroxioiatelr to the 
recipmralljr when « Miuce of liRlit i* pl»mi in Ui« 

the«« niiiTorm. lh« ' 

Parabolic minon 
thi* ftrfcct ; Uwy 
to (yiutruct, Iratm 
rvHivion. It U a 
prjjfrty of a 
tifitt Urn VH, 
focM F. to MJ 
currr, nod tiM li: 
I» the «xia AP, 
■nglM Willi Um 
thLii pojat. CODaeqi 
prunUiit to the ■<!■ oIVt n'docliou iu tli« fociu nf ihe 
ivi-iprocdUy, when a »oiirre of li^ht h plmysl in tlie 

iiicidriit im thi! mirror, 01* 
fMjalli;! lo t1i0 axu. The 
lenda to mainlaiQ its Ibi 
imttt didiuKv, for it tiM 
iJiiil it ia tbu dimrinace uf Um 
myi wliich ptintipiiUy weakaM 
Mty or%bt. 

It ia fexn thia propa rty thai 
iiiim-n an iwad in caniage 
[Iii> Ihiu)m ;>la«wl in fnmt of 
nillwaT irainf. Tli«M KdMlon 
iiierlr usi^d for Itghthoaip*, but 
ri'pliicnil by IfHtic-ulaT gl«»w«. 

Whrni two •<]ual parabolie 

(-lit by a plnne pofimndkcnlaf 

|iituiT>)r ibroiigb Uie foL-us, and 

united at their rntnaectian*, aai 

figum 314, » that ibeu fan 

ayirtFin of rptlHct'>r# ia i>btain«d willi vihtth a taag\B lamp illi 

twti direclioii* iit nncc. Thi* nrmnifcnicnt i« umd in 11^ 




mnht BEratrnotr. ucsnB. 


«rr«ft«et(»n. — Rffraiiiim U tliu ilvHortiuii wlibh 

■ «ipn4(ion! in p»Miug ubUqut.-]}' front (m« nu'diiini i(> 
from air into mter. W* mj ablijKtfy, bcFniuo if 

«7 i» peqwMdkialar u ilie siufan- m-pMaUng ifaii two miiilie. 

ctnj, and MDtinnn ila four^ in a right line. 

trmf bMntr i*|)i'«Miit«il by 801%. St 9), llip rffmrln! rai/ 

m Oil wliicb Uiiht Uk« in llio nvrrnil moditim : iinil <if tlip 

Md Ifi'll, n-htch Umm m* Wu 

Al), at ritflil antla to liin sur- 

pcntM llio twii iniTilin, thit fir^l 

p/^ iWiidnMv, luiil lbs titlwr tbp 
diim. Aoeonlinir ii» ibnrcrrncU'l 
W or <levi>t»« frma lli« normnl, 
idtnai M Miid to bo niaiN! or Ii-v 
i^pHtujf IkaD tiin fit*n. 
|U wUeb (nib .10 a reftMling *''8- *!*■ 

Mt ttinipl>t«l;r pun intn it; oii(<piuti«inRi>clcd*oilaatttn«d, 
' peoetiMifl* iuio ili« niedlum. 

low* tkat 111* diitelion »( rvrntftion drpcndi on the rvlnliir 
At in tlie two iiMidis. On iliv iinduUt'irv tlii^nry lh« motv 
K niidimn u tlul in irfaldi llie velocity uf pro|)Kg)ition ia 

UImiI m«dla, micti aa>\tt\A», orditury yUua, tIi«luiiMnoiu 
I ; but in ootain crvit^lllwd bodira, oiich m Iculand 
, tke iiMad«nl nv givix riac to two ivfrai:1«d rHV* Thr 
U oalla) dauUe ivfnMvin, *nd iHU bu diMiuted In 
koofc. Wa shkll h^ra UmI exclii*ivoly witk w^ 

F«4nti« r«rr«ati«n. — Whan » InnunoM* mr is ntfncw^ 
p« mnhiim liitn uiotbvr of a difTdivnt refrnciivo povrvr 
I pratail : — 

r litr aUipulf tf (Ao innilfiU roy, fir ralio n'hirh Uie Bur of 
]fUktitrt (o Om tilt ofllu imir'c of itfntUiun, it nuiAml for 
Mdtia, M M/M* inU diff'rmtt mttUa. 

ItdW aa<f (Ar rr/tiuial ray uw i'm fV jtnniir planK IcAick I4 
!• tV mr/cMV w^roCin; fAf firo mtdia. 

an Ditairftt lairt, aiii] art) d«int)n*trat<'d liir lli« 



M Ltaer. 

t'ig. 31 C. 

mmt MppuMtiM M tW uwd for the laws of nflection lUO). IWj 
niiTcv is Uie eeatn of tli« gnultutcil drrln m rppliiMil bf i < 

dries! gl>MT««KlUM<i6l 
to Mch « tiniiHit llul tM 1 
«Mctlj> the height o( ^ • 
{6g. »1«». If lU mimr, ' 
tbvo ao iacliiMd, tku » i 
mv. MO, ia dindfld tionll^ 
iHfikti*. il ia TtJtmnti m 
iatu th« water, liitt it 
iriihnut tvhnctkm, 
iU dltwtiuD L> at ri|rlil OflMl 
t)i« enrvixi sdoi <iJ' ih» tMi^ !■ 
atd«r t» obaervd tha okmm (TU* 
nrfmcted n»y it b leectnd « i 
wenta, P. which ia iMmd miQ ik-i 
iiiM)(« or tlic apattuR n ifo MM 
If ia fofmgd in iucantm. laiH 
pultiooa uf the Mnoot K Hd 1 
ihfl nnm of Uw Mi)(ln« of ■dtal 
aud r«ilV*eticin an uiimmiJ 1 
m i-aiM of two jrndt aUd ruin bpI^ 
Mv Hr} lu Ui bu alwa}-a horiiuntal, and heiiM parptiidieiiLir tu tbt <'~ 
mi-tnr AD. 

On T<-fuli(ii^ off lh(> biigthii ot the mdm of tlia aiigl>^ UOA md 
in Uiv iical« 1 uid K, tlie numlwni an^ touod to lary wilb ilia | 
Iff thn wnutiiA, but ili<'lr ratio is ranntont : that i«, if the •ineef in 
Woiii<» Iwiiit ur tliree tiniua ■• Itrgv, tli« Biii« of rt-fimotiafi incHMnl 
tfaa Hiiiie ratio, viiinh damooatratei t)i« lti«t law. Hib 
ri>1lrf>B fruni tli<i arMOKviueiit of th4 apparaliw, tor tli» pUiin of 
irnuluntvd limb is porpcndicalni to the autfaoe of tbn U^sid ia iW woi 
cjUci'irii'Ml vwwij. I 

462. XDdoa ar reft«aUra.— Tli« nlio Iwtwtwn tlw nnet of th> 4 
rii'lnnl and tvlnictt d iiii^le ia calli^d iniiru of rrfraetim or rtfrmtim mm 
It vario with the media; fui exMiplia, fti>iu air lo water il b }, andbM 
air to glwi* it is |, \| 

If (be uiedin are uonaidered in an inv^Tan ntimt, tiMt V, if %ht faM 
from wntrr ui air, or trom glaM to air, it follows thi- nna 4Mur»*. bat b 
a ctiutrarj diruL'tioii, PO becoiiiiiitc tho iucidnnt, and (J.U tba ' 
ray. (.'oniii^iiu«ntly, ibi' indu* of rvlroL-tiuD in ruvcraed ; from ' 
air it ia ibHii ^, and fmin t^Uju In sir {. 

-lAt. avoots pt-odnaBd by reOwctioo.— In mnaMitMam at t 
badJM iminQivi'd in a mndium mon biyblr rcfrsctiag tkwi air < 



I of Utw Bwdiutn, but Uiey appMr lo b« mom diaunt if 
I rafraotiag nMdiuin. Ix't I. (K^. 917} bu an objwt Jni- 
IBUi of mtar. In p««iiig ihi^mx intn air the rsva LA. I.U 
^ftoiB Uie Bormal to the [lobl i>( icjciiienufl. fttiil aiuuitic ttin 
,C\ W> ■ . . tliR jiralovgalianaofwliirh mtrnu^rt nppTnximniitly 
I V, phtoJ nn the parpvlkdinular I.'K. Tbe nyt< i^neiviiiic 
ma tliv cAj>cl L at 1.'. Tlii^ K'™^' ll'" oliltquit}' of tli« nya 
. . ibn hii;fa<* (bu object tf poMM. 
tbtt Mili« rvMOk that » uick plunfml obliquely into watei 
It (Sjr. SiB), tbo 1iMm-»h1 port apiiFa-intr rabed. 



t'lg. a IB, 

ka nflect of rrtnelion itatv Am viidbk to lu OTon whrn t)*T 
llw horiioi). For m tli«< )Mer» '>r the fttniMpherv arv dvUMt 
on M tho; are Dearer the raiih, luid w ibn rofroi^tiTn^pawvT of 
BUM with ita dMuitjr (4TS), it foliou-a thnt on enlcring ilie 
I the luuinoua nya become bnut, nn sten in tbe ti^>. SIH, 

■ run* bttfoiTn r<>acbiiii( the eyn, an that wn urn th» *inr at S' 
famgval of tliia CUTTft inKload of at S. Iii our vliinste t]i« 

e ftJncttoti dooa dm raiM the atan wbno an ibn bnrixnn mnro 

HTnBMtlva. Crliloal utKle>— When a luiiiiiioua ray- 

■ me naediam bio another which ia Icm rrfrn(!tiu|(, m from 
«lr, it baa beea (md thai the mtiiU nf incidoixw i* gr^al^t llinu 
tt roftanCkiR. Ileoee, trhnn U({ht !• pnypafiuti'd in n miuu of 
1 S U O {Ag. 3*20), tlinf* i* alwnyx a valufi of the migh of in- 
>B, neb tbat tlie angle of n>fra(-ii(<D, AOR, is a rij^iit anf^Io, 
MB iIm T«Aiictod ny cmcrK™ pRmlU'l to the autfiu-a of tho 

At^ 90H, i* callud the crilieal migle. hccauae fiir any (ircalrr 
Iflh* inddeat ray rantiot iiiiii>t;k<, but tindnrnomi an internal 
(rUeb ia called totiJ rrjhetiim, hftinii* (lie incident li)ibt ts 
Wud. FraiB wvWr to air the criti<--al ani^lo ia 48' ^C/ ; from 


09t ua«T. 

The onvmaM of Uib intenal relWrtwn ni*y l«e uWntd ^. 
foHowing wiMciaiwit- An olijuvt. A, it pUond bufm a ^Ihb 
vilb WHIM (Hg. 321); tbe mirfkm at the Ui|iud u Umi looU 

t'^. m. 

K>|c. 321. 

•bovn In tke titit^, wi an imRpn of tlie nljnd A isfMn ii a, 
by tho r«y« wflecUil «i m, in tlir ordiiuir inauunr or ■ minor. 

W/i. BClrkvo.'ThR miViij^e is no optical iUu.iion by which inl 
imiijtvi or ilulnnl oUJMU ar« ai^a la if bek>w tli^ |rn»ind nr 
aUuwphprr. ThU plionomfncin ii of nioal freqacnt oeauTenr* 
climBtrs. aud liiorv Mpei'lslly on the wndy pUanii of Hgypt. The 
there hiu olUn thi; Mpml uf a tmnquil lak«, <u) which mv Tt4ki t- 
Hud the aulfUUQdLng vflUgV*. Tlic phcnamcDon hu long boca 


Fig. S33. 

but Hoigc, who ftccoinpMii«d NnpolMn'* wxpnliiiMt to Eg^pt, ra A 
Ant t> ^ivi> An i-xplonatiou of it. 

It it B phc>ni)iii«nan of n'.frocti'M, wbidi rcaolu from tb« iMfM^I 
<l<fiiuty of the ditlWaot Inyfn of the ait when thuy m UfViM If J 



ilb ihs bmUnl loil. Tlw iBMt 6enm btjttn mv lh44i the Inw^M, 

uu ray from an el4>f ftted «1^ecl, A (H^. STi), tnvenN laren 

tan gndiullj Imm nfinctiiiK: for, lu will be ohawn pn^mtly 

. iWw tocUait power t>r a rw diiainuiies wiUi iMweed d^iiriti . 

■ceimliD^lT inc w ww fraon one Utpi Iu tbi- otiicr. 

. ibiF (TJiirjil an^lff, b«niiid wbic^b, inti'mnl nH*c- 

U ntneUav (4(H|. Th« niv tlien rue*. M aeen iu tlic 

< a *«nMi of MMCunvn rofnu^tiunii, bnt in • dirortinit 

, far ll iMw paMM th^Mlglt lay«r« xchicb tm (rnidtialK 

Till' luminoiiii r*T ihrti T«*eh(« tbi- aye nilli thr huiw 

)if U Wl proct-edMl fmiuii pnJnl b«hiTtbe gmiinij, nni) li^'iice 

Vcrlnl iaMfre c^ UiP okji^i^t, jiml an if It bad IxtKn ivflpcled al 

"la 'Itr •Hrfn'N'ora trni>qnil laki'. 

- MFP intafrm in llw nir of ib-^ sfioreo ol' of disUtul 
111 . ii> thi- MiiM caUBc a> thi- niiro^ri-, but in n Fotitrnn 

L, mly aocmriog wIm'Ii llie 1«mp«nilitr€ uf iW »ir i* Rbovc tfaiil 
•(fiwtlwn tbo Lnfrrior lavenof tbv atiucuphmu»detuK-r, uwiu|t 
«oaUaet wlUi tb» Rurfaof of ihv watar. 


Madia wlib parallel faces.— ^^'h<D Iif;lit travaiw* a medium 

mlli'l facu. titt' riiir,\irut ii>}> an- pantlM to llit- JDoldeut rajn. 

N itf. :i'J:'-f tw a k-l>w pUli? «ritli psTaUcl focM, Ut K.\ b« th» 

■nd Dil Iha ometj^iTOl tsy, land r tli« anulo* of ineideoM and 

»l the cuiraDm of lb» i*J. and. la^llv. ■' mid r' iht? nmr 

•( ii> ein«4Keooo. At A thf 

t &tal relraclion, tin- 

"■" ' m'2). At n 
Bill r ^ ' 

irfradcd ft aevoBd tifu«, and ili'- 

b tlMO *^'. Bill w^ hav^ 
aiu K 

it A* index of ivfraciion or flu*'- 

tile reciprocal of iu rrriai-tidri 

t|»{|l«M; hanoe 

•bijP _ rin >• Kig. S23- 

■iu r^ un I 

llu! two norniaU, All and W,. air parallel, tlic an^l<'* r nnd T 

, a* htoBg all'-niat« iDt>'n'>r aii^lpH. A* tbi- iiiiiii«'rat<iri' iii IIjp 

iquatk<n an equal, tile duuouiiiiiilon mu*t 1h- nln equal : ibu 

dwr'aDdiMV tbenlora oqiiaUaiid hi-ar-p UIl la iinrnllrl t<> SA. 

-In optica • pritM is auj^ Irtuieparenl uii'ttiuiu I'uiiipribrd 

rwUi^ it 


ox LicnT. 

betwt«ii tvro pUnc Tmm incbood to mA otlitr. Tbt 
Ihenf two fnrw i* tli«> #i^ of tli« prisia, and lliclr ii 
rvfnirliug nng]e. Ever; ivctiao (irrpcndiciilar to the rifi* 
principal §<Ttien. 

Tb» pmms u«#d (or eipfMVDFUtit are gcotnll; rit^t 
of gloM. M ahown ia th« Sg. S34, and thnt principal Mdiifl 
■agl* (fig. 334). In tliia »M;lioa t)i« paint A is calWd tbi 
th* prim, uid tiie ri)(ht liiw, BC, i* called tba i«M 
iMTe raTeiviici) to th* triangk AiK-, mm) not tA l>i» prbm. 


Vis, SIl- 

WLnn tbe Uwi «r nfi^ 

408. Pkllt of rKT* IB prUm*. 
kininn, the pounpr of nivB in ■ pri»m M rtMidUv drlennincd. til 
n liiumuus pint (lift- ^^) '" tli« tuam pluw m tlio prindpd m 
AH(', of a priam. Aiid let <ll> bi' an iDriilnnt rn_T. Thii nr i* nf 
at D, and appronchni ■!■« aoniiul. U^-hum it pawei inxti a mom 1 
rolnutmp m«liuiD. At K it nptimaet* a arcnod Mfmetlin. bm i 
il«viaivR fmni the nnniial. for it paww into air, whicli ii U» nit 
ihtm kIbsb. Th« li):hi ii tfau* re(i«ct«d twioo in tba gaina djfaMi 
tliMl tkr ray u d^tvUd tiiivorJt th» h«M, and cooMqaentlj Ilia aj* 
ivc«i>'i«» thfi mniTifnit my, KH, Bee» llip i)b}r«t O ai O* ; ibat h, 
ii-m Ihroiii/K a iirimn a/ipi-ar dj^rtttd tuirar^ tb ncminiit. T)u-m]|)e' 
wliiuh thn incidi'dt nixl umvr^eut rays form witb oaehotbr/, tiipriM 
deviuliuu of li^lit rniund by tbe priEini,Bud ia cAlIpd th* im^^dH 

iWida* this, ubJK-Is Mvn through a primn appear in all tba e 
of tbe raiubow ) ihii pbi-uumeiion will b« diwcribod aoAta Uia in 

4*t9, OondlUona of aneryeoo* la priaiaa.— In 01110 tia 
luiniuou* nirii t*fn«tKi aX thu titut fiu'i- of ■ pmm may omei^e bo 
(wcond, it t» nuwssury tlmt Uie rptmclive nngl,. of ||)« priam ba Im 
tnic« th^i crititnl angli: of tbv substtuice of wbicb tbe prifoi ia aao\ 
Vat if LI (li^. !^3tl) bt> tho rny incidunt on tlut fint fac«, IR ike IcA 
lav, I'l and I'K the DurmiitH, tb«< ray IK cad otily pmerfrv fin 
second face whi-ii tho inddi-rl aafU, W.V, i> low Iban th* critNal 
{tm). But n* tb« incidtul an|c]« LIN iDcr(i»M«, lh« angla BIf 

WalBP Smi 

TRAKMiiitMOH or Lictirr. 


Fut. 33«. 

I IBP diaii&islw*- lli^cr, •rroHmtr an the di^^ctiaal 
I In beoome panllvl wiih ll>e C*ce AD, dn«« thin ihv Ieii4 ' 
M At ivcaad fan^ 

■ Mnr iMTkllcl to AB. tbe »n^l«< r I* tlien equal to the niilictt 
tb« pcian, b««a*w it 
ujnnn Ttlae. Fur- 
fa trlMgls IPG. i* 
■f**; but Dm «ik'«' 

m pwpi u JicnUr, ofi^l 
I = r + ('i iborv- 
,^l ^i", for in this 

[lann>,if A =:3ior 
ybU lure f =: fnr 
^pBn the nj would 
Rr Iht Mwond Tam. 
nmlrTira int^niaJ r^ll^otion. anil would »merg« M A third files, 

wunld be mocfa mom th* cam with rAva wbr«c- inriiltiiit 
w tb«a lilX, bMMum wt< bare almad<r oem that ■' cnniinuiitly 
Tbns tn lh*r eaae in which tlic n.-fnic:tiiiK mf\r »( & {irixni h 
»t t* irTr«t''r, nn IuibJooi)* i»y could pi" ihnniifli the fncta of 

ritiMl anffla of gloM ia 41° -Uf, twic« this ntifiie. in Uhm than 
SOtdinKij, nbjwl* fMUiot bv «««(■ throiiifh n glan> privni whnw 
ngW ia a njr''' *"?'*■ A« thncriliciilnnffloof watrr ib'IS^H.V, 
p>B IhliKigh a hollow refUmjfiilM priiut fonnpd nt thrw (flaw 
flM with water. 

Mom a to ba ftT««lM' than / nod Isaa than SI, then of t*j» in- 
I nne williin tbe ani^te NIB will t^nirrgc from AC, other* 
Mn^ nor will any timnrgc that are inridrnt within the iaig\e 
maippoM* A lo lisvi- any maifnitiido Immi t)isn I, all ran tn> 

wbUa tho anRlr NIB will rnirriip froin AC, u aluo will 
M* tneuUnt wlihln tbo ititnU N'L\. 
■I— ««vl*tloia.— When a pcndl of lolar lifilit pauM* 

■ apftan. A, in 1h« rid« of a dark chambor (fig. :J37), the 
mi J Bt t ad In a alntiifht linn, AC. on a diitaut kti-vii. Ttiit it 
^tila b« int«rpcard bctwi-nn thr npnKiim a^d thr norrt^. th(> 
•«lM»d toward* the baae of tho prium, and Ihv linage Is pro' 
I, at aome diataneo Irnai th« pnint (*. If th« priini b« tiiriLt>d, 
I inridant angle dwwnMuf, the luminous di»o apprnapho* ilie 
p to a MTtaio pocilion, B, from which it reverts lu ita ofifiinal 
m when tli« fTum ia potatvd in the Mtno direction. Ilenca 



tlicn is ■ dui iaiiuo. EBf. K-h? iKhd aiiy uilii3. It atr )» 
in«tlwn«licail; tlint tliU Miimmuiui deriati<iM uW fkut vbia ife 
uf iaddnmw nad <^ «aieigeiic« are «qual. 
Th* uigl* of niainivin ilnTUliuB umt be cnlcnlNtoct wlua Ih 

lic-viation is letwl, ■> tU« iinyla uf HutrrigVDCv K ii eqiwl t« lb» i 
HUglp t (69. 3i^). r mtiiit 3 •". ftiil it tiiu ViMn fbnim abitn 
A = r ^ •" ; cawMiucnd;, 

A = LV ... 
ir lbs miniiuuni an(:li' nf ilrriKtion V'lll. Im- eiUlifl i/, thU 
■■xieriur to Um tiionglo I il K. <n> iMwJiij obuin lb*- t^iioiiijd 

wbcnce (1 = ^— A 

whioli iprM the HttirlH if, wbiv ■and A am Icnom. 
From tli« forniuln' 1 1 1 nnil |:^) a thin) mav br ntitniaul. 

111 cnkiilaUi thf iiidpK nf rclWlion nf e )tnftiii. wlica itn irfrvliatti 
nnd ibe uiiuiiiiiiiti tluvinttim ur kDOwn. Tlir indn.x of nfnniro, 
lh« rnlio of tbf Mnes uf tb<^ iui^I«'« «f iiicideuce and rtimeucai I 

M ^ . ; rr^lacins' • and r frnm their taIum in ibo mbami mm 
{I) nod (2),w« g«t 


471. XeaaturoiBcnt or tbe iMttu sr r«lra«tl«n In «« 

iiK-niiji of ilip prL-i7fiding fonnulji (.1) tbe refruMivc iiidn t^ a >olij 
calciilBt-il wlmii the Kiifjlf* ,\ buJ d nn^,-n. 

In ardor to cli?t*Tniiiie ilie mgU' A. ibe uulwIuiM i* cut in tin | 
nf H tpi&njpilnr prism, oud the niwle mi-wiiivd bv niMiu of a gaakm 


in tbe following atumet; « my LI enuttcd 
[ Std) ia recwit'cil on the priini, which I" turned 
iha mininiiim d«vi«tion EDL'. By lueiuut nf m 
Mt*d ciraUl, the nnjrlc KDL ii mad olT, which th« 
Im with thn MT 1)1/, t:on)ia^ direct)^ rruio the 
« Kn;(I<> of niluimuiii d<±viaii'iii. u<imiinK thnt ths 

two rmy», I.I nnd I/I>, or- upproxiiniit^Iy 
» tli«n onlv auvd tu bo tiubstilutcci in thv tijuiilinn 

V> NeirtoB. Under niEmj circum»[Mic<eii it ouiont 
tDcn. whi-n th•^ n-'ftacliTP iailcx of a niorf drop of 
1 IbU cw, ui^ mny b^ mnde of a tuschud duu (o 
penda uo Uw dvlertniaitiQii uf thit criticnl angle of 

n AT tba In4«« vr refrttoilsD or uqoia*. — M. 

irtOa's LBOthoii to di'Uriiiiniin; iiiv ^1fr«^■tiv^.■ indpx 

pvpow a oyUndncnt 
'7A in. in diun*ler, i* 

prim, FQ (Bg. 32tt), 
S ti> th4< fiict of color- 
I dosed l)j two platM 
Milted on tho ridn of 
n iottodaoed thtnitfih 
pertiifv. It. The re- 
t minimum deviniioii 
a til* carity having 
r raioM an iDtroducud into the funutila (3), vrlucb 

Fig. >-'U. 

W Af tb» iBdax at r*flw«tl«n of wmavm. — A 

MM Caanrfi'd O'l lliat nf X*i«lrm liiLi b'-cri ili'i'ist'd by 

Tbn nppnratuB wliicli thr'y nau crinaiits nf a glaat 

\eA at it* two rjitn>niitiRii. nnd cluni-J by irloMplatM^ 

I at U-P. Tltii tiib« la ojnDoctud with a bulljar, )I, 



on LtGirr. 

1ft wliich there it a eiphon banxMUir, and irilh • *to|nock b; 

which ihn appantiietu h c 
f^ and diriereat gWM btnlilH 

hATin; exhwnrted tiM labt A 
light, SA, ia tnuintiitu4,«ti 
awmy titmi Uw nonuJ iIun( 
r-iftt tha fine iaddcso^M 
IttlmuKli an angle T-r* it 
Th««B tm) deviatiuiLj kii 
th« total deruitioQ d it r- 
In the caM of * minimim 
i^r' and r ^ i', wh*ni» i 
illioei'+i'=A (469). Th» 

vacuum tn air, which it «<id 

tuu thMcCire tha rnloe ^ 

nn I 

Fig.SSO. nenr^ In order to M 

Aactire iiuImi from naut 
which in the ahaolaU ituiftr, ot prinf^tal iWrt, it ia ainply 
know the refracting itn^n A, and tli« angle of niintniuin dni 

To obtain ibe »bAoltil« index ot enr other gao, nfter barii 
a riK^uum, tliia gaa Li iulrudui^ud ; the auglen A and J hariai 
»iirad, tbo above foniiiiln giiM thn iaicx at tvfmctitin froa 
Uividbfi the index of rufrai'tiuu from Taeuum to ^r by th« I 
fiaction from the^u laair, wnobtiuntho index of lo&actioall 
to the ga*, that iai ita alKoluti? index. 

By meniu of this nppajatui lliot and Amgo hnrc (bond t 
f^aelire indices of ga»c« are Terr «mal1 aa compared with ibo 
and liquids, and that fur the BHini- gnuj the nfredtBt povw u | 
tothp denaity : iDi'nning hv thn m^nrtiTri action of anibttaim 
of ita refrnctivu iude» lets unity, that ia^ n*— i. The «6ac 
dJHdod by the density, oir 


ia called the ahtaluli! rrfircttv* pmcer. 

Table of the lAtoliiU iuJinu ofr^rattiam. 


Kiulphido of eaibon 
Ic«lAud spar, ofdiaaiy 



to 2-rr> 

I'hosiphurus S-224 

Sulphur 2-11& 




Almdial -i. l-n74 

I-4M AJbimwii 1-atM) 

. 1-67K ElW 1-368 

. 1-UO CnrilaUiDi) Icn* . . . . 1-384 

. I-B48 Vitiwus 1-339 

. 1-«S Aciuwiu „ . . , . 1'337 

. 1-600 Wnter 1-S38 

. 1-470 loe 1-SlO 

B^ntetit* m d i eM o/ffa$m. 


Otrboiuc actd . 
Byilroditoric acid . 
Nimiii» oiido . 
8iilp)iur6us acid 
OlcIiMit gtut . , 
Cblotine • . . 



tat klaOa «r !•■■•■.—£«»» an tmi8|Mn<nt m^a, 
Iba cWTNturo of their niifnci's, bnrc the property of 
MiifWHf N)-* vhich traTOTW' theiu eitlior la cnnvor^p or 
Uccnling to thdr ourvature tliey sru cilluT Kplii.-rinftl, 
Uptieal, or pukbolic. Tboto unnj in optim an nlwaya 
tjr mm luiuUj' mftdtt eithw of ■town ylati, which L» free 
tljlimt jfltM, which containa lend, utd i* man: refractive 

Itloii of i(ib«Tica] Hurfnoc]!, i-ithcr with each other ur with 
, fiT«* riM to Enx kinds of l«nses, seclion^ of tchirh arc 


Fig. 331. 

flp. Ml i foiii *w fonned by two gphorical surfaCM, and 
^d a ff berical nurfac*. 

amra, B in a jBlmuMWniw, C is ft ami-nyiiip lymcafo- 
4aMt eoitw;*, E !■ a plano-foiumet, and F ii a dirrrginy 



tmmao-emnmi: Th leW C I« alio called the eam n rf u g 
tli« \rai V th« tUcrrgiitg Muwunu. 

The tint thnu, vrliieh a» ikicker at tbe «en(n tbu ttl Ac 
tommryktg ; the otfa«««, wbicli an thiniMr in ilio nuiba, m 
In the fimt itroup, tlin doiiMo nmv«i lena only bmiI W 
in tlieaeciNiil tbn double eoiieaT«,u the propcTtica of tatktftlHe 
apply to all tboao at tbo atxtve f[Tnap. 

In Uiweairb<M« two Hiirraopg are uphMical thecmtreofotlbw 
aro nallod fln* * !-** o^ nirfature, and tbo ri^bt tUio wlucb pMn 
tlirM two CMitiv8 i« the prmriptil axil. la a ptaDO-coocavt k 
convex Una, the principnl haib is tbc pflrpondteular lot UUmi 
of the «ph«ical fitca on tho pluio fucp. 

Ju onlei t'> com[iaRi tbe pulli of a luminoiu ray ia a Imb 
in n priim, thu mok: bypothesu U miulo a* fitfouned Minm (' 
i*, lb« surfacua of theat leyaaa an anppowd lu be fumwdt'ni 
mnall piano aurfacM or eleownla ; the nwmitl nt aiit p«nt b 
IwrpfindiculAr to tbn plana of thn eoimpniidii^ clenMiI. 11 n ■ 
metrioal principlf^ that all the norauda lo tbe aaaie apberkataubit 
through ita centra. Cta the above hypothwia ire can ainja 
two plaoe Mirfuma at the poinia of iondence and voasisijniM, vUA 
inclinad to cac.h other, aod tbiu produce thn nHbrt nf a pfum. 
tbia vomparison, the Ihna lenaoi, A, II, and C, inav he oHBpv"' * 
■nocetaiou of prbina having llictr Rummila oiitwardi, and the Iibm' 
E, and F, to a KTica haviuj^ their aunimit* inward* i bom lUt*< 
that tho finl nii^hi to condense tlie raje. and the Utt«r to dUptW 
for wo have already sei^n that when a laminoua nsj travanta i 
ia deflectvd Tr>wanla lhi> hniw (■I'l^). 

•176. r«el In donBte eoa*«m lenatta. — Tbo focna of a IM 
p(Unt wlii-m the ivfrDctnd rari, or Ibnir prolon^uljon^ niML 
convex leu»ea have the same kind of foci as concarn ninvn: 
roal fori and virtucd foci. 

Rfid fact. We shall fit«t conaidM- the case iu wbkJi the laaW 
raya nhi^h fall on the lens an panllel to ita prinHpa] axu. at Ami ' 
the Utr. 8.13. In thi« caw^, but incident ray. LB, b »^\U»tVt ' 
noniinl of the point of iuddeiK*, B, and in tlivrrfniiK baat it •• 
point of flninijwneii, 1>, ia twice refmdod towardi ibo ui^ wlocfa i' ' 
■t P. Aa all nji paralkl to the axis ar« refracted in the mm >a> 
it can be ibown hy cnlcuklion that tbey aU paM very naHh 
the point 1'', HI) Inn^ a* thn an-, \iV., does not ex<:eed W 10 I? 
point is fnltud the priniipal /vthi, and the diatanoe FA i* the 
/opol diaani'f. It la coiiaUuit in the aamo Imis, but rariu whh 
of curvature and the index of rffittction. In ordinary tnues, 
of crown glau, and In whiob thu radii of the two aarCacca an 


I ffiaoMl Ineiu CMiicidu leij clowly witii tlio centra of 

F-s. m, 

r^ofwder the e»ae in which Urn luminoiu nbjnct in out- 
focxwi. but to a«*T Uial all incidtut roy^ form o dJvur- 
I •faowD In B^. 333. Tb« luminouM point being at L, by 
Ht pkth oT ft divftrgikgr ntj, 1>D, with ihM of n ray, SI], 

Fig. J33. 

[to 111* «sU, tb« Ibnner ia found to malHi irith tho nonnal an 
, ■Rstri' tboA iha mgle SBn ; conix^quunllj, nSivr Imwiain); 
lib ny euU tbo uia at « point, /, which in mnro di^trutl ihui 
, F. A< *U raya IVom ibe point L intersect &ppnMi* 

Fig. 334. 

[h tfa> unM> point A thin InlCar i* the (wy>^# /««** of the pnint 
I baa tho ^nw meaning hem as in the c«ae» of mirrorB, and 



MiitKsHM tli« rplUion dxiMlnj betwoen t)i« two poinb L ttH,^ 
is of uich B nature, tbnt if ths tuminoua point U moral b^Ait 

pttltUH tu L. 

Acconliag aa the <ibj«cl coaiM near lh« |4>ii»m, Uie a»«^u«< 
«fn«T}^Qt ray* daccea*M, nnd tfao (aciu 'bccocoM mure duUM: ' 
ot^oct L coiadde* with the principal focoa, tba cimtgnit nn i 
atb«T ride an pnrallel to tliu axuy and tbere it do liwua, ot, vU 1 
MUM th'uifr, It i* iafliutHy dirtant. Aa tlio rt6Bc«d rs;a an ] 
tlita caw, tha intendty of tit^ht oalj iecmum alowhr, lurf aaB()lj 
cou illumiuate ^TMt distancM. II in men-)r luerrtaxj to {Ira 'df 
forii* nf n dciubte Duncave lens, as aUown in (Ig. 33i. 

rirlual /em'. A ilnablc eoavrx Iniu him a vittual Gxw^ ' 
luuiiacmii objwt is placed betwenn the Uat and tbe praidpll ' 
ahoim in fij;. 335. In thU cak the inoidenl rava make witk tKe i 

Fig. 33i. 

^Atur BU^Ic* than thoo made hj tk*' ran Ft fmiB ilic 
hcincR, whiiii tim fiirm-ir raj» t'ni*'rp>, they mme Iknlivr bom 
ihflu lilt- Intlvr. uiid funii a diverjriug peuc'il, JiK, GM. 
cnnnat proUui'ti a rciil roriin, but ihnir pmloii).'atii)a« btvtawl 
point / ou tha axi«, and thit pi^t ia tliu tirtuni foctu of th* 

J7IX roM 1b donbl* oonvave lenB«a. — In douUn con«atv im 
there are only liriuiil iVioi, wlmt.Tvi-r the ilUtance of tlte obJMt. 

I'V- ;i:ni. 

91 hd uiv pencil of my<i parallel to tbn axu (Sg. 336), ant iff^ 
reb-OiCUd at thu poiul ot \nd&mtm,\,w& aaf^MactiM ttw nonuil 



Alt aS mmr^mek it u r«fncUtl, but divurgtu from the normal, 
bil It la twice re&iict«d io a diroetiaa wbicli movM it fiuni 
CO*. A» tbo Mno tiling telcee place for every other nij, 
ll ftXknn Uial Uie raya. atlcr tnrerdnj tho Ufa*, form a divtirg- 
1, QD, MN. llcuc* tkon i* no fmI focus, but the prolong*- 
lieae rajra cot van •Dotbet Id a pobt F, which 14 Uic piiutapal 

Ma bx wUcb ite nja proceed from a point, L (%. S97), od 
t b fiNwd bj IIm aame oonatruetian that a rirtual foou* i* 
t, wliicb u b«twe««i tlie principal focus aud the lou. 
■patl^Matal determliiatloB «f tbo prlaelp*! foooa «f 
Todatetmias tbo prinvipalfocusof ihrj- 
1 to tlie aon'a nyu ao tbat tlicjr arc pantUel to iia axii. The 
ponril baing rocdrvd on a groumt glut «cr««ii, thu point to 
nja oonnti^ {a readUj aecn ; it ia the principal focua. 
doitUit ooBeara \ea», tbe Crtee. *A (fig. 938>, ia oorenHl with an 
e, audi aa bmpblaek, tiro aoukl] aperturav « aod i, being 


■^ Fig. JSB. 

B Hnui principal atction, and at an o<}iial di8t«nc(> from tbo 
Mdl of anl«r li^t b then reo«ired on Ibo other late, aud iho 
, wlndi Kcdvea the emer^nt rayn, i* moTpd ncnmr to or 
in the iena, antil .\ and B, the >pot« of llj^ht rrom the tniall 
m lad h, are dlvtanl from ench othnr h^ tirico <ii. The diitaoce 

Kul to tbr focal diitaucti FD, becauu tlie triatigl«e Vab and 
U eeatre. aeeeiMtarr luda. — In eveiy lent there lit a 
he optical ct-tre, shjoh in aituated on the Axi», and which 
IM |T^ thai any lumluout ray paeaiag through it cxpvrienrRi 
tdaristiott, that ia, that the eroergnit ray L« pardlul to the 
tj. Tbe MiataBoe of thia ptunt may bn dinnonnmti'd in (he 
I1IIIHI : lict two parallel radii of ctirvsttira, CA and C'A' 
ba drmwu to the two lurfncc* of n doublu convux \vn». Aa 
lane elRiiiMita of tbe li-na A and A' are pnralkl, n* hrxaf pt^r- 
tiro panlM ri/tht Jinm, it will bo gruntod t\ittil X\v« 




OK LravT. 


Bftacted nv, KA, A'K', U pTOp^aUd in * Biadinm with panllftl 
{enc«, a rav vhic-lt narh«a \ M mefe mi ineUBatfon, that lAcr . 
tion it toliM the diruetiuu A^V, will pmarfi piii«ll«<) ta tu Am i~ 
(•UWj i the point 0,Kt vrhich the li^t Unv cuts tb^ uu, b 
tha optical oeatra. The poaiiioa of tbi* point may ho dttemiacl I 
th« CM* in whiah tb« curvature of thi> two CtMa ia the Min«, >Uehi 
the u*uiil (xmdition, by oWning that the trintiKle* COA aud Ct)A'i 
equal, and tbenfora thai 0C=OC'wfairii gives tbf point 0. Ud>*t 
vatuica am unequal, the triontrlci <'()A aud C"OA'rrB Maular, and « 
CO or CO niav h« foiiiul, aad tlwrafore alao tha pdai Q. 

In 4aubl« ciuicaTA or eoncam^oonvax loaaea, tha optioal enm . 
I be (ktcnuiued bv iha tame oousiniction. In lenwa with • plana 
Ithia point in at the intenectinn o( the axin br the carved fae^. 

Kig. WB. 

V'li. SMI. rijrht line, 1']" (li;r. 3J0), which pataea Uiiaufrh tbu .^riul 
centre wiihoiti pn>*in^ Ihrnngh tbo crairm of ciimtaroi ia a tKm ii if\ 
tuts. Ftvjui the' [iiiijK<ny nf ibe optioal centrv, eivri' atraoiitrj 

nta a lumiooun rcctiliuoar ray pawng thrau^ thia point, tel 
^ftom th« »%hi ibickiiMM of the Iraaea, it majbe aaavoM)! that i 
paaiintt thruutfh the optical centra arc in a rijjht liae, that ii, that 
aniAll dcivintian may ha n«igl«cl«d which n^ expeHeooe in inv 
a medium with parallel (itoea (fig, 333). 

So lon^ a* the wcondnry ax« (inly ninko a nnall an^le with th» \ 
dpal axL>,all thai hwi bilhertd been said abuut the principal axifbi 
cable to Uirra: that It, that nya emitted fmm a point, I' (lifr.340),Ml 
aecondarr axia, PI", iiouly converge to a ceriaiit point of ihi* u)*, fj^ 
end flu'ordiiJtr H" the dulaiice froui the poiut P to Ui« lona ia gnattrl 
1(TM than tho principal foonl dittancn, thn inffan thus forawd wtU ht( 
ju^te ur virtual. Thi» principle ia the fuundatfuQ of what ruUom aiti | 
the formfttion of iningoi. 

470. roraatlon of l^wc«a is donMe ooarea Mnaa*.— In haal 
na wull aa ui luiirurs the image or an object is the colloelion ot ihekt 
of itaaovernl poinl»; hence the imagvn fumifhvd by laDM* an nal If 
virtual b the same cnae aa the foci, and tbelr oowtructian nmohta inV , 

LCKSLS. 441 

n KrieB of poiato, tu wu tbe cam with miirers 

Kaalimagt. Let AB (ft(r-$U) b« piw«J boyimrl thi<: principal Tocur. 
MOOBilarT Kda, Ao, ba dmwn from tbo uuUiile puiut, A, uiy nj, 
finin tUa pobl, will be Iwioa rarrnctiwl at C nnd 1), luid both limcn 
m MiiM> diiwtioa, spjoMochmfj ihr nrt-imdnTv nxix, wliioh it cut* M ii. 
t mioA hat bMO nid ia Uie l*'*t poraRTapb, tbo athvi nyi ttora the 
t A will intifWWCl in ihc purat o, which U iiccunlinglT the lyin- 
l> (oeiu (if ili« poini A. If the Mcondary miii be tliAwn fruui tbi' 
I B, it orill b« MMfl, in lik# iMiuivr, that the r*v< from tbu point 
M« Lb tba point A, anil w tbn pi>iiita betweeu A and B havu thMr 
■wan « uul i, ft noJ bdt mtvrW image of AB nill bi: fomiod kt 

cit^r la WW thia htiafe, U oaaj be rtcoiTml tm a whit« XKca, <m 
:b jl trill W dspicted, or the «j« nuT be placed la Ihe path of thu 

t:g. 3*1. 

li;, tf • ( were tlio Imntniiui or illiiminAtviil chicct which 

, tta imafTC irnulil be fonnud at AB. Twu cuwi-qiieocM 

' tlw l]l«ory of optical inMrumRnln follow finni thin : that, 

I affnrtf, m«h ■> tvn/ Uirfr raw, U at a mfficimt diit-ou.ii from a 

■ lau, (A* rtal aiul iapated imaffr whkh in oUaiiinl of it it trrif 

lAi- prmcipai femt, but $opieu-hiil farthtr from the lent 

I if ; 'ind, if * trry niuiU olgtet be plactd tuar Me prinvipol fori*, 

I btfof H, tkr iiuHjt irAiri t* formal iial tt ^-nal diitaiter, it i* 

llAot u> propoHioii at Ihe lA/ect m Hrarfr Ih* priitnpat 

il M*«* the ohj«ct and the 'aaa^v hnrn ihc *iinii! pMporiiou ti- 

I CKnh tbu len*. 

> pititdpleii an) oxpciriiii«ntallj conlirmcd b,v receiviug on n 

^faHfe of a UgtaUd candle, pUced *uccMNvely at various 

I a d«nbla eoavex Icna. 

yiitmd image. Tlwra \» another caw in whidi the objvct, AB 

.84j), iapUonl btitirren the Ivni and its priucipalfociu. If nwicon- 

j Bxia, Ma, be dmwn from the point A, orery ray, AC, sftet hnving 




ox uoar. 

be«n twlca reAactod on omerRiii)!, lUverftm ttom tbU ui*, 
oint A ia at • iem dutance lh«n ibe pdncipftl focal dintaum (tTS>.l 
J, continoud ta an opftoritc diiwtioo, will cut Ui« axit Oa. b tli«| 
, whkh in tbe Hriual foctu nf tbo point A. Tnong- tbe i 
r tba point II, it will bt> Tuund, in tka mm« luannHT, tbit tto 

tV ZVi. 

Tocui of tbU polnl \» formvA at ft. Then U, tbiuvfarc, an iim(W 
nl u6. 7*ui i« n rirtual imofft, it it tnti, om? Imytr (*«■ (if o^W 

The tnagaitjiDfi powiT U groatcr bi proportiiin ai the l^aw ii niw* «^ 
VBS, and the ohjiwt noantr tlia principal fociM. W« ■hall prwanllf ** 
how iliF mAgt^tfiag pnwtf maj bo calculated bv meoiu of ibl fao^ 
ivUrin^r to UniMa (608). Doutite eonrc* Imi***, iwod in thia ■»*" • 
miifiiiifyiiix elAiuhui, Mu (!atl*d tlmpU mier«Kafea. 

4^. r«rmatloa of Iniksaa In AoubM ««aMT* Uaaaar- I^>M 
roncnvd Ionics, tike convux miiroo, onlj give virtual ima^M^ ^m"* 
tliv di'lHiion of the object. 
Imk AB (B^. 343) be an object placed in iWint nf nurJi a tai UA* 

(MODdary axielw drawn (i^\ 
pi'int A, mil rajnsAC, AI,i 
this point are twice 
thii MMu dinxtioit, 
from tlia nzt» AO ; to 
htv, nediing tli« en 
DE and GH.snppoaM 
pTuc««d from lite jpcial 
ilii'ir ptnluiiinitioai ewltl 
noiidnrv aili AO, in th* ' 
In lili« mannPT, dnwto^i i 
dorr axu boDi ihi^ poJat 

Fig. 3*3. 

rayn from lliin point form a pcndl of ^v*irgt*it rara, the 
whicli, prolnnjiud, iiil^rwcl in 6. Ilnnof tlw «ye •*« at •( ti 
iniBtK of \ 1!, tckich ii alrca;i> rrwt miil tmaUer Wloa (Ae t^Mct. 



ML Bpbarleal BbarratlvD. C«nitle»> — Id the lli«ory of the foci, 
|«f the ittugtv* (nnii«l lif diSbtcat kindii nf tjilieriral k'Dst's. it liu 
■ihtlboria maHun«d, titat iii« raya ei»iu«<l fnim a iiiii;;la point iutvmect 
faiba Tvlwmctioa in a >iii)flu poiat. Thi* U nrtunlly tlio e»» with k 
HwboM ajHRan, tliat ii, tht iaig\e ohuiaei by juUiiui; the txIgM t3 
» peincdiMl fiwaa. doM bm «xoeed lO" or V2''. 

WiwR« tlia apartiUE U UTfptt, th« rm^ irhich tnverM th« ku» ni-at 
( adg« an* Rfraclml to a pomt oiwivr Uie Uiu thui the mr* which pai* 
■t ifan oxU. TbE phdMUBiKni that jnvjdaced i* siuned ^Aei-icil ah/r- 
im iy rrfntclitiH ; it ia Mialogoiu to tbo apfaerloal sbemtiun pruducml 
f wHwitiuit. Tbn lambioua raribec* fanned bjr tbo inleiwoctioii of thn 
Amu4 n^ U« l«nn«d emdic* iy rffVdc^Mui. 

^«io>l MhrfTBtiuu ia prvjudidal to the shorpnem »nd di-liaitiiin uf 
• iawf*. 1/ k ground gUai •cnoD bo plnc«d oKActly in th«< focua of ■ 
Mt, ilw bngti of BB objoci will be Bluiipl? dunned in the c«utru, hut 
^'^^rt il tiw odfrea: luiil, tier ttrm, if thu hamo in nhnrp at the cdtro, 
h «ill b« iwliitiiKrt in tbn contn. Thin defect is very obJMtioiinhJv, 
■iHpKullT to l«iiM« nwd for photo^ruphy. It ix luiciinlly ubtiaud 
If fkebf Ulbre the Iodm* dinphnfmi) prciridod with » cenlrat ftpenrnv 

Fig. m. 

Ikadi ddmit* tlMt raj« pwinp near lb« centre, but cuts olT those which 
IWd^ tb««d^««. Alw by ronibtiunK two Icnscaof KuitAbk-currBluit!, 
1u rphaiicml ■faiTralion nmy b* iliutroypd. 
I&i: VotvbU* r«UtlBK t« Ito nfc — In all I«>iwes, the Klalion 
Mtw«fB the ilUtAOCM nT the ima^ and obj*ct> th« mdii nf I'lirvnlurp, uid 
k i^Ktiva iad«s, may be Hpisiwd hy a fotuuk. la th« cnnj uf m 
ImU* unvex lecw I'll I' bn a lununotu point, ritiuvte on the bxU fig. 
lU, Ut FI b> Ml incMcot ray, IK ita dii«ction within thn Iphk, EP' the 
jMipiii ray, ao that V u the oanjutpitc focus of 1'. Further, let 01 
iri TK ba tbe acnoaU to thf> point* of inridoncn iind nmor^ncf. uid 
PA be pit Minal to «, EPA' = A ECA' = 7, ICA = i. Nil' = i, 
Hl> «s r, IBO = «". X'EP' = r". 

! tlw angle I ii Uw cxtMriur angle of the triangle PIC, and iha 



Ingle r* the nterior sngk of tbe nUngle CEP', tb«nto^ i = '^ 

pnd r' ^ 7 -^ 0, nbcBoe 

i+.'mo + jg +> + 1 . . . 
Bnt Kt tke pouQt I, no i = n ma r, aad at tbn jkiuit E, *ia r" i 
<4(Q), n bdng tbe tvfnctit* index of tli* kos. Ninr ir tbe Vt i 
only a tmiitn QuiaW of de^trvc*, tliMc ria«t om^ b« «(ifi«iil«iW « | 

[potlJoD*] to tbe anglM i^ r, ■', and r', vlieac^ bi tb« ihm I 

^nuqrnrplKM the aincs bv tliMC antilM, which givn* t'^ HrMdr': 

Lftom which f + r* = n [r -i- ■'). Fnithpr, bpMiMe the iwn trita^I 
and COC hare a cuBiiiioa equal aagi«. O, thurpf >ro r + ^ = i + M 
vhichi + f' = a |.Y-f ■)■ latrodudng thia vttlw btu th»f^iiite( 


l«i(T+a>=a+M-T+8,ftiomwhich<ii-l)fr+l) = .A^ . . . 

[ Let CA' bo danotad by R. C'A by R', PA by p. and PA' 1 
Thoo with centM P and radios PA dcBCtibe the arc Aif, and «itb i 
P" sod radiu* fA' d«acriba thn ait: An. Now wIihb aa tn^le bI 
centn of a circle snbtMida a cartain aic of iho dmunliinnoe:, d» \ 
tinnt of tha ok divided by the ndiut moamn* liw mglBi < 

, _Arf„A.( -„A'n -A'K .,_AI 

Tbcrdbn! bj tuhttttutioii iu (3) 


Now ^CH (ho ibioktMW of Ihe Ims la Terr «nnll, and th« a■^Ile >^ 

■nnall, A<f. A!, A'E, and A'n, dilToT bat littic from oainddcsl unflii 

line*, and era tli«n<fE>re lenKUy n|uaL Hcneu Uw aboMtitiuo 

I beooiue* 

Thu is the formala for duublu convex leoaea ; if p be = «, w« b*i« 
}>' being iLe principal TocaI diiftAOoe. If tfai«bempni«aBtedbj/««^ 

<-'>(r4-)=) ■ - . ■ -^ 

from which thn value of/ in eiu<Uy d<i]iii^d. Conaiderud in ivftnwc H 
foTTUuU (4), the formula (3) Msumea the fom 

. . . V^r • • 1 

which i* that in which it la lujallj employed. K lit-B the ■■■■nJk 
virtual, ji* changes its sign, and forniuin ( 9) (ahas (lie fnnn ^| 

L i" /*'/"'' ' 

otsnmoK or Lionr. 445 

tie «ui«T« bauM, fi" asd / reUin the Mme lifB, but ihat of p 
H tho fonxinl* (A) baoonwa Ibea 

P P' "/ 
(T) any be obtained bj the iwrae ntHooings a« tlie otber. 


caAPTER n'. 

l)«ooipo altloB •! wlUM llBlit> S*lkr ■iniiiliiiw, — Ttu pbc* 

lit i^Mtioii is by no niMm ao nia{il« «• w* havo hitlxirto iu>- 
iaU> lighl, or tlist whicb nnehm us from the sun, pauM 
BKdlani Into aiK>lhi6r, it it Jteeuipetal mlo teotral kind* o^ Uifitt, 
ta whick Ibn nanw oiMptmuH i* piTim. 
(o ahow Uurt white light ia decoanpoaed by rofraction, a pcndt 
lifbt, SA (Gk- 334), ia alkiwad to paw thmuKk a iimall api-rturc 
VindaK ahun«r of • dark diaiiibar. Thi« pencil t<<iida Ui form a 

Fig. J»4. 

. «akNtrttiw image cT tb« mn at K ; but if a flint glniia prism 
id hcritantaUy be InletpoMd In ita pataa^, ihit beam, ori <'iufT)i- 
B iht ptMni, beoomea refracted towaidn ita bnw, and produces 
biMt tcpma a vitrucal band, «oloured tn all th9 tint* of tbo 
r, wbidi y ealtad the tolar tptrlnna. In tliti spvclruiu there 
Mlitjr, an Inlluity nf difrer»nt tint*, which imiKirvcfitibty in«Tfre 
!b other, bvt it ia ciutouai; to diBiiugruisb wren priucipal (mIoui*. 


ox LMurr. 

Tktta MK m«U,mJijf», Uue, fnrn, yOow, arvHfe, nJ; ihljmi 
In tliii order ia tbe fpMCTuin, th« tiolat baiim ilw moat iwfi« n M n| 
the rod Uie least ■>. Tliej do bm tU ooeupf an «i|m] axMA t 
apectnun, viaht luria^ xhe gMalaat «xUMt, aul taaaga lb I 

With tmuptrval prumu of difTsKtit aulMMOM, or witk 
prianu filled with variooi liquid*, upcctn are olMabwd 
nme ooloun, ami in tke aane otdcr ; but wbcu xh» denMiai { 
ia the Mae, Uw longtli o( tbe apectnim Tuiea wttli the i 
wluck Um priMS b Bade. The aofria of aipantiMi of twn i 
(nj in tli« rc!d and tite *ii^) pndoMd br a prian i> cbUmI lb i 
Mon. and (!>•■ raiin o[ tlii* angle la the meda denaiion of tb ' 
is uallml the t^ptniw ^MMMT. Thit ratio i> ooKftanl Tcu- lh« 
Manoe an long a« the tafracting aagl* of tb* pnan in miBlL Pfl 
AmatiNW of die two nn are proportl<««l ta tbe nltme^af; ta^f 
£flanBM and ikeir mean ran in Ike aania nmmar, a 
ratio of tbair difiarenoa lo Uiair HMWi iAoonatant Tat^Mffii^t 
0013, (or cronra-gbuB it ia (H)M6^ or tfaa dupoMTv powir of I 
ilnoM doable that of aatmflMt. 

Tbe apectra which bib ftMrneil br ailiflcUl %Itt» tanJ; i 
tba colour* fit thu loiai npnctram ; hot th«ir mkiur* an bund inil 
Hpcctrum, and in the aaue order. TliMr ivlative inteuitf ii alaii 
tied. TbeahadaofcolonrwhielipradoininntaainthttflMiBiatdWWiW^ 
alK) in tli« «pactnu)i ; yellow, nd, and gTMO tbuMO pioJaoa ipds ■ ' 
which the dAninaut tiat i« yellow, i«d, or graea. 

In order to producn a oolaf apaetruin in wludi thir aavtn prin^aA 
ai« diatinctl; afcn, the aperture hy whkh light «Bl«ra ooght as* to it 
mure than a few millinMitor* in diamotor, and if tiia ntfrocttnft nf)> >' 
tha primi, aa ia iuoiaUj thf> aiee, is W, iko ktmhi oa vfaidi the ifecva 
ia cftught luiut be fi or (t jmnla (liMaiit. 

Fig. Slfl. 

484. Tba e«loBrs of tB« ■pcetram sre almplo. aad aDa^aal^ 
refnuiclble. — If ooe of ili>> roloim of the tpectnua b« liolaled bjV* 
t*rwT>tiiig thi> oxhvn bv meaus of b ■:rMii, B, a* Aawa in tg. M^ 
and if tbe light thus iiiurcept«d be allowed to paa* through a "*'' 



, B, a nfncUon wfU b« otueiTcd. but the light reraains luicliRiiged: 
, tliir boMfft neriffd Ml (be tcn'cn H in vinlet if l]i*> vjolM p^ocal 
I altowt^ to pMS, blue If th« Wao yvnvU. and no im. llrae« the 
laf t&D »pt«tniBi an ample: that is, they cannot fanber be «3e- 
I bjr tL» prum. 
r, lli« eotoun of lb« •pectnim un uniM^uaUj mfranpibln ; tliat 
1 diflnrant rvftactiTi? indioM^ The i>loti^at«d rha'pe uf Uie 
I would be mffirWat to proro the un^qunl mfmnKiliilit;' of tbi> 
eaJmus, for it i« daw tbkt tbd Ti<>1et, which i» nioai dvQeobd 
Um b«ae of the prtanii ia bUo moat ivfmn^-ibii-, nnd tbnt red 
liilMat dnfl«ctodiii I«Mt rofniBgiblo. Hut thi^ nm^qiinl nfmngi- 
at dntp\e ootoun Eoaj be aliowu by uumuroun t^xpvrinieuU, of 
I th* twn foHnwing may bo addncnd : 

nanuw Mri[M of coloured pitpi^r, one rvd and tin- other rinlet, 

, ckkH 111 vtcfa other an a abcet of black fvpvr. On lotikiii),' 

I ilittngli a iMinn, tliiiT an kmii to be un«qually displaced. ih« 

to • Isaa fxUrnt than the riolet; hencu tbe i«d rays arv Ir-ia 

tkaa the vi»li!t. 

cancliuloo niay be drawn fnNii Xewlcn'a experiment 
iBiMfMid pmnuL On n pritm, A (fi;;. 3*7), m ■ horiinotal poHlJOD, 

, The Maw 

Fig. SIT. i 

of wliite Ugbt, S, U Kcelved, which, if it had mMely trat cn^ 

t, A, would fom tba Kpnctrum, rv, on ■ diirtMit Krvcn. But if 

print, U^ be placed in a ivriioiJ iirisjiiijii behind the lirft, in 

DM tliat tfa* refracted p>>iii.U piuwj tlitouKh it. the tipe^tnim 

__ d*i«et«d toward* lh« h»M^ of t)i« vortical prinni, but iusuiad 

« lift I It I il in a dir«:tiua parallel to ilAolf, aa would be the cM^ 

oilonfl ot the »p«ctriuu were equally refracted, it ia obllijuely 



nfractsd in ifce tfnctlM Kv*, provtu;; iliAt fron red lo noMtkc 
an non uid isore mfiangtUe. 

Tb««e ^iflunat ncptrttBontt «favw UiU tbo nfractim indn lUfcl 
diffittwat ootouni OTta mya wkkb arc ta pE>«P|rtiuii 
htivH not the hbis nfnctir* iadas. In tlui rad b«iM], (or In 
mjii «t the extremity of Om Bpecinim tat ta« nftacktd t&n i 
si« n«*i«r tlM ora&go tom. In cilwiliiing indicM oT ! 
it ia uMul lo take m ifae bdes of ■ aubiuiioe tlitt nti 
]paUow m; in ■ ptifln faraiad of tliat aulMtBooc. 

4Sfi. SaooiBp«alti»B ar wbit* uvbb— Not mcr«1v ou wtiH 1 
b* naolvi-tl ictn Iti^hts i>r vnnmiB coloiuw, Imt by cotabisiofr tiia i 
pntdk aapuatod bjr tbs |in»in. trbiia lt(pht can be wfoiiimd. 
mar be eSK(e4 In Tmcioin wava : 

Fir- 3t». 

lig. 3Ao. 

i. If the fpfL'trum pnxIucMl br one prian be. aHowcd 
a ■ncoiid prinn of the iadhi lUKinnal, and tba HamA 
lli<^ Qrvt, but toT«rt»d, aa abown in 6g. SSO, th* Uttar nrnnitol 
iliflvreut culuurs of lb-.' ■pcctram, aod U isaMS ibai tba enoq^ 
K, wbicJi i* pnrnllcl lo the peni-tl, S. U cotowhiMi. 
ii. If ib« vpooUuiu fall* upon a dnubia caavex lena (ig. 

wliile imat^ oT thd *un will bi 
□n a whitn acnao plaool in tW ka 
tba l«iu ; a gUaa ^<tlM filled villi i 
pfodiieni tbo (ante rflircl a« tlioba 

iii. \Mi«-n <li« fipedTUin &II1 1 
i-onearo mintv a wbito inuga b I 
»n a Hcre<<n of gT»«nd gtaaa plan^ ill 
focm (6g. 351). 
ir. Light nutj be teoain|MHi 
of a jHvtlv experiiuent, wliich oamiiia in rBCtiixiug tbe 
^onta of ihn Hprclrutn on H!v«n amall (tlas* mirrors vilb plan* ' 
Ud wUoh can be «n inclined tn >11 poaitioaa that tbe rtAeeted lti1><*'T 
ba tninamiltril in anv pvcn direction (fig. 36S). When tbeae wBtM 
ate auilablj' nrranget), thn mvca rvfleoWd pancib ma; bo oauard !■> "^ ' 
<m the coiling in luch u manner ai to forot aaraa dUtinct ibmip^-R^ 

tig. 361. 



m ufiiiT. 

Uie c<i]oun oT 111* spvetouiu. Tliajr praeaed froog Hk emat u ti 
cumfnroiic«, and tfaeir rvktim iltBHtuiaiw «id tinU mt nA w V 
»enl fltv ffwetnt (fig. 353). n'bM this due u nr^dlj kM^ 
racdivei liiiMiltaiteaiBlT lbs trnptuston of the m*hi cobob ■! 
dim apfttn wliiU <f ^ 3&1), or at all ttttati ef a p tr ji A ib l fci 
Mloun wUcb MTM H cannot ba airaagcd «xacUy in (Jkiwi ~ 
or of the urns lintu as tt'isfl of tbe •peotram. 

4^ WewtMi** Umoit •' (k* ttoapoaltloa vf Uc>» •** 
e«]«ar at ti«4laa. — N«irtuii wan U>o linrt la ileeDiiiipcH sUn 
the prism, ajid to rooompoM iu Ftobi tho raiioiM MfcnwM 
we hftT« deKHb«d be coucluded Uiat white ligkt «>• net 
but fcnaiod of aeruD Ligfata nneqiiallT refrangible whickbeoflrf 
or jirwrnttw %hU. It it owing to tbeit difl^naoe fai w&MpHBji 
tbov become nparated id Unveniiig tba priaoi. 

On this tbaoi; UkUm hIm dacompom Ught hft%taAm,wi 
culuur ilupeadH o«i tbeir t«flee(iii); power Tor the dijbmt 
Thiim which rirtlort all coloure in tbn pr>>p<irtioa tn whlrli fbf 
thfl apectruui are wliiU; those which reflect Dane are blKt. 
them two limita tll<^Tc are iatioite tint*, acconjiiig to llw g wfw 
extent to which budi«s reRect aome coloun, and abutbolbn 
bodiot hnro no coloun of tbam*ctt-a*, but arc colound bjibi 
Ught which th«i}' reflect. In fact, if in a dark room Ihe ■!> 
anocManvofy UlumtnAied by e«ch of the Mtoum of the ifaeinA 
haa DO apedal ooloiir ; it appean T«d, orange, gr«fln, eui, wmliol, 
potation in wlikb it in placed. The colour of bodi«« alas niitf 
nature of tb« Yifthl. 'I'hii ii the cuw with tha light of g**, nlCJi 
in which yellow predominaUit, and which oonuuunicotea iLiiliiit 
oljcctii which it illuininntcii. 

4S7. OomvlemeataiT voimira. — If in wliito Ught any 
auppKaaud, h tiiixtuiu of tlii.- KUiainder ii called the 
e^our, for it I* th<^ cokiur m-nlnd to cotnpl«t« the sumIm* '' 
light. A luixturv of blue and yellow proiiucoi a jn'nw, and, .... 
giecn U tlin ramplnmnnlAry cnliiur to nrd. In iik4' maniiM a vnf^ 

nd and yi-llow produces ormff*, which ia eoinpli'meDtur UhlM 


laily JQcliifo in thr coraplenicntoiy colour to ydiuir, and ytIlo«iA 9 
to riiili-r 

488. Koiaoc'neaiii ligtat. — Tli« ll^bt miiltetl fromlumiMC**'*^ 
U onTnr (juilu purn. In optical rrMinarchns it i« fn^qncntlr of fN^ 
porl&uce Vy pmcutu homaj/mmHU or monocAroauriie light. CoO»**^ 
in the tlanio of n Hua»n'« lamp nivoan yellow of Btvot puiity. P^* 
light, ordinary li^hi i« tritusmittod through gUaa cotour^ wtli wb^ 
of copper, which abmrbs uppirly nil the ray* exceptiBg the i»d. *■ 
pure blue is obtained by trAn^inilling oidiuai; light thnxi^ii *■ ° 


1 ddee, owiuiuitg an Numaiuaad Mlation of f ulphnto 

•rtiM ■moiiHWi — 6««jde« iU lanitiioiu propettiw, 
to [ndaoc caloriGo and oh^oniotl f>SkiCM. 

It nffeim tivm tiw eiperiiiivnta of Ftaunhufi-r 
tba li^t in tlio jeUmr part of the upectrum luu 
ity, and tbu in the liaict tbo l«Mt 
, ll was long known tlial ihc i-arioiu part« of tbo 
hi tfa«r <nlcrific cffoct*. Ltalio found t]iat a thgrtno- 
IHerant paita of llie op«clnira iiidl<at«d a higher t«m- 
inTed from Tiobt towanU rtd. Ucnchel fixed thu 
I7 of Um licatins' cffocia j nst ouwido tba red { Bemd 
flaeheck aho«vd tliat tfauoe difll»vnt i-lfecta dopeitd on 
with a jirum of watrr the gr«atoat calorific ciToct 
lotv; wiili uue of HJcuhul it 1.1 iatb«onuig«-;tJlow; 
gla«it iain thn middlR of thn rrd. 
•Dd lenaes nf rick sitlt, Hiid b^ availing him- 
of tbv tiiiTnio-i'li'ctric appnnttiu, Itfnt made 
of the calariDc pro|M'rIieB of the thermal spoo- 
led, a« wB haw Kcn, to Uiu confinnation and exten- 

Id nameroiia phenonwna light acts aa a dieoiical 
ehloride of nlvnr Uadcoiia under the inflncnca n( 
jifaoaphoraa b«coniea opaqaey vegetable colourini; 
aod dilorinc gaaei^ when mixttd, comlunc ilowly 
^ih cxpIo«T« violence when exposed to direct 
action difF«T» in diffL-mnt iiurtH of the Bpfcirum. 
whrni diloridn of *ilv«t wiu placed in thn violet, the 
mergirtii: than fn any otlier part. WuUiuton uhserved 
KModad bcjrand tho riatot. and concluded tlutt, bcAidna 
here am aomo bridblfi aud mare highly refrangible 
Iw chamical or otHmc raja. 

M dliaraacia in the action of Uie difforvnt raja. Moaac 
fng on an iodiaed rilTcr pUt«, nod eipuNed it to iho 
Hon liad COnWHOCed, and then placpd it aadnr a riolet 
liL AAec a few ininules picture wtut »tt<i) nith great 
I wiinn placi'd umler a mi or rollow glaw it roquirrd a 
UkI waa very iadittiui^t. When, however, tbe iodiand 
brt exp-Mod in a cjunum obacura to blue litrbt for two 
itiMm brought uiide* a red or yellow glww, an image 
Imt not vrbcn |daocd under a grevn glaas. It appcnn 
iMiou of a oMtain Telocity which oould c<>mmonce aii 
olbeta which niu devoid of the properly of 



coaunendHg, but earn oanttnno ud eompluto an Mtion «te4K*t 
BM^onel, wlio diio>»'«rod th«w prnpertMa in luiniiioiN n7*,<<M| 
fnnacr ArnMy Ff*, B°<1 tli« laller miditmrnf or fl^i^iionfM * 
Thf. phoKptxwQgnni'! ra;s for in*Unc«, bavs tba pro]^}' a( i 
eerUin oltjvct* wlf-lauiiiiuut iu ilie (Urk nftcc ib^ hav« toft ■ 
fot Kama tiaio to th* light. Hmi|imrI found that tlu 
■p«ciniin extMid«d from indigo lo bxjroDd tite vioteL 

4i)0. B«A llBM of lb* aifirMM. Tha oaloun oT tbt mI*1 
ttniu lUf DOC contiBiioua. FnrMTcral gnulo* nt ntaaphHiXj I 
wantliij;, and Lu cuUBequeaoe, tbroughoul thu wbole utnnt tl At I 
ttiiin, there am a trmai nninbcr of vaty narrow dulc liaM. To4 
tb«m,a panol of «oIm nf» ta admitted into a darkened tomh, 1 
naiToir •lit. At a (UrtaiicD <jt three or faor yaidi^ we look at I 
thtna^ti a primn of B'mt glaA^ which must b« v«rf ftw frm im^l 
cara to hold iu vdgv paralk-l to tlie iilit We Hun iJbmnt%l 
nnmber of rerj dolicnic dork line* panUol to tlia odgw of tbf | 
at Twy uoequnl iatenuU. 

Tho rsiitcni^o of thn duk linoi ww fint obanrffd bv Wo 
1802; but Pratmhriri^r, a colebrated oplLdaii at Hiiakh. finti 
Itave a dcUikd dcicripUoa of thmi. Frauobafcr mapped tba fiM^I 
indicatMl tlte most o1)\'i<iiis of ihi'ni by the lettMa A, a, B, C, IV^I 
F, O, M ; they an> therufore ^-ui-rnlly known as KrMinbofar'ii lioM. 

Th*i dark line A (nee fig. I. of thn or>ii>iir»d pl«l*'), !• at Ibe i 
nnd it in thu midillp of tha nd ray ; C, Ht the buundarj- of the ni I 
oranga t*; ; I) i> in thn ornnKo ray ; (I, in the gnvn ; F, in lb* 1 
0, In the indigo; H, iu the riulut. Thuv not ccrlAtn othor 
dark linci, ouch «t a La tho rod, and b 'm fhi> gresa. In ibo cam of ■ 
light tho ponitionii of ibo dark linM are fixed a&d delinite; on ibbl 
count lhi<y ar« u»»d for ubtnining an exact detrraiination nf the 1 
index (471) of ench co1<iur; for «xamplo, tbe refra«ti<r« iadn I 
the Mue ray i», strictly ii)H?HkLu)^, UiAt of the dark lino F. In the tptdl 
of artiticnBl liKhta, and of tho utarx, tha n'UtiTd piimti<)iMi of tbedaAIil| 
nrcchnngi'd. In the elMtrii^ liffht the dark liuen aro replaced by) 
lincK, In colouml Hamm, tlint io U< my, flnme* in whii'b cedais i 
pal sub«tAnw« uiiii«rg<> «vHporatii>iJ, the dark tinM arc rtiplaocd by \ 
brilliant lium of Uf^ht, which diller for diiTorcnt RubrtaocM. L'iilFil 
the dark linM, wini* am conatant in poeilioo and dlntinctnoM, Mck I 
Fraunhofer'a line*, but vouie of lht> fevbter linen are nen or not i 
to the huittht of the sun abovu the hommi, luid tbe state of tb* i 
sphere. The lixud lines are due to the sun ; ibn variable lisM i 
tixouf^ht by >omu to be due tn the ab>orpIioD of the air, and an aMM 
bgly pnilrni Mmoepheric or Ifliaric IJnea. 

fVauuhofpT ojuuied in the i^iectnira mon tbna 600diirk Iin«^ dM>4 
ICM diiitinct, diitribulod irregularly iram the extKBoe hmI to I' ' 



IlRwi(«r Mimted SOOOi Dy Aiidnp lbs Hf^uted rajv to 
""fcMrwljr tloaa^ Wranl uialyMii^ jiriimui, not mnrrJj- ha» the 
tf 3D00 dark line* been wKwrUineil, but MTrral whicb bad been 
■q^to fcaT» bwB tbowD tu be duuble. 

• IppUaMlvas Af rrsaBhofot^ Ua»«. — Suhti^iitntly to Fnun- 

• MiCMt pbTNci't* sIik)>«I th" dnrk Iiiiv« of the (pcctrum, 1q 1833 
Bmch*] muuii-d tbat bv T«Ut4)i*in!.' nulntAiirfts in r llnn>« % vnj 
llni Mi ii lUlbrdfd nf drt«rtiDg certnia In^riHtiiaitii by th? caloura 
IfMt to Mnaiu of tb« dnrk UiiiM at Ibe ipuclnno : and Fox Talboi 
I HBt t i H ii optical aaalfn* m probnbly tho mo*l dcticftt« niFuii nf 
If mamtt portioiu of « aulituuice. To Kirdiholf and ituninn, 

b reall; Jac tbu merit nf baxin^ on th« obnnrvation of Ihe lines 
ifKliiiin a luctboi) of analjr^ The; uccrtuiiei! UiHl ibe MltB 
melal, wbcu intrwltifcit into a flaoio, alwaf* juodun: Unm 
d ia cnlauT utd prvitioD, but difTer^nt in colmir, |>oeltlan, or nuin- 
4iAf(n( matab, and Unally ttat an i-xuccdingljr ttanll qunntity of 
MdEeaa to diadoMi it*Mtiiit«nrv. Ilenre hMaiiwn a new method 
rs*, known by tbe baidi- ottpeetr'd amalt/tu. 
U p» nu mm t a y ». — Tbe naiun of upoctmiKopn bu boen given to 

ui emplnjcd \iy Klrrbboflf and Budivii for the itudy of tlie 

One of tbe Carmii ot thi* njipnratua ae modi&cd by ItIM, 

Onundeau it repreMnted in Sg. S-Vi. It i» (imposed of tbiea 

nioaitr«d cm a connnion fool, and whose axtui oonvcrfie toWKTdi> 

P, of fliot-glnfA. The lelneoope A is tbe oal; one which c&ii 

Ifca |iiiiBi It u fixnl in any rKinirpd puiilioa by a ohun]»Dg 

I, tim aenw bead, »i, i« oKd ui AiiSi thn poaitinn of the ey«- 

p> tlut a clear image of the opecrttuui may be oblftiued.urr in other 

to /ten* the cye-I»GCet The kkw brad n u used to chongr the 

loB of th« txit, 

cplain the a«e ot the tcleKoppii B nuit C, we must refer to fig. 
IA AowH the paMS^e of the ti^hc ihrmigh Ihn npparxlus. Tbe 
Itled by tbe flame (I UI oo llie leiu n, slid Hre cniued to euovergo 
iDt, k, which 19 thi> jirinripal fortu of n m'cond 1eD>, c. ('onw^ucnlly 
Kil. on learin^- Ibi- telewope. It. ia fomw<d of piimltel rnvH. Tbln 
Mitrnthopriim f*. On IraTio}; thupriam, thelijrht in decora [xiMid, 
tbb Rtate fn]l« ou the lens x. Ily iht^ hnt x, a raal aod reierwJ 
if tbi» •prc-tnira in fonai^ at *. This iiunfre h seen by the obmirvrr 
p a KBgnifylag glaM nbicb fnmii' ni w' a virtual image of the 

magnified about ei^fbt tiiueti. 

fcriaionpe C eertco to mcuun; the relntini diitancee uf the line* of 

dnm. For thin purpoM there is plnced at m a mietvinieter 

ado 9S equal parliL Tbi- niiersnietcr i> funned thus:— A aenle 

nlDinieleiB h dtiided with great euctueai into 26 equiU 



o«c uB>r. 

pul». A phAtap«phic neg*t!v«on gfaMof tiu* Milebtital 
to 1& miUiiuewn. Tlio ncg^tiTa U laliea bMMU* tkn ik* i 

li^hi on K dnrk trrouod. The »cal« is lliM pliMd at M a 
focua of ibe leo4 e, conHequeutly, when ihe »c«l* b Ugkt»d I 

F, tlie ntya eniltied from it leave ths l«n* « in {iiii*I1«l pcncib; 



Ft. SST. 

g nflaetod ftom * face of tbe priam, pMMa tliroiiK>> 'b" I<ns 

• poAcUf diatiact inuig* of the ttrictomoler ot i. Uivn-bf 

t niMiM of nwouring oxictly th« raUlive diKlance* of tha 


iMtriotBlc«»p«0(£g.SSS)uAiniulied with aevemluljuiit- 
r: of Ui«MiKljiHtiUiefocaii;<i displitcn> the micrometer 
on ot the Bpectnua Utorally ; r MUea or lowur* the micro- 

it don b^ giving different iucliutioiu to the Ulwcnpe. 

ig wkeret^ tKe Ugbt <if 

■l«a the t«l«M<opa B, 

I nanvw yertkd »1U, 

opcatd mon oc Un by 
e*Mib)e piece a to 
noede bj mcana of tbn 
SKy Wh«n far pur- 
puuon two tpcctn tan 
waad maaitaitooa^j, 
Li over (be upp«r p&rt 

uuU priiBi vbim re- 
U b OV. Rars from 
baww, H, full At light 
t &M of tb« prum, lfa«]r 

Don total leflectioo oo » Kcond fu«, and leave tkn |iri«ta hy 
p, and in a direetica at right angle* to that faci-. B_v IbiH 

paaa bilo the t«leaeDpe ia a direction pnnUrl lo it* axifi, 
mj itfne mixti^ irith tli« rayv wbivli proceed from the 
t, O. Ccoatqwrnlly thn two puncils of m,ri tmvcMo the 
. 8S6), and tona two huriiontal vpectrn which are viewed 
tly ihioogb tha trJoaeopo A. In thu Uuiil'ii (! uid II am 
Ki^ t, t". Thew wire* bare beoo dipped beforoband into 
(h* Mlta of tho BMtela on which uiiHTiini-nt in to he madu ; 
ajMMaalioD of theao aalta tli« iii«<CalD modify the trutnuttted 
ra dae to definite Uu«a. 

M ftmaa JI and G Li a j«t of (ndinary gv. Thr nppnratui 
A Iha gM ia auppUed \» known aa a £utt»tn'f bunttr. The 
noagb tho hollow Mem k {Hg. SGfi). At the lowi^r part of 

a latnal <iritic« to admit air to aupport tho conibiietion of 
tia «ri£«e can be mora ot leM cloaed by a auiall dinphrajfrn 
a a reguUtnr. If we allow ■ moderate amount of air to enter, 
■ with a luiniiMua flamey and the Unee are ob«cured. Itut if 
. riaady curmnt of air antsra^ tho carbon ia rapidly oxidiand, 
tea iu bri^-hiiieat, aad buma with a pale blue light, but with 
•M. Ia thia *tat« it no longer yields a apeclrum. If, how- 



ox UOBT. 

OTW, ft metallk udt b inttodiiMd either In • Mlid iMeetiB* 
Mluiioo, tbe «|M>ctruiB of tb« nwAal mokn it« appMniKt, ad m 
wUta for utwervBtioD. 

4m. ■cparlm«B(B wHb tlM •9a«tr*ae«»a.— Tlw Cotoml 
t)i« be^niiitiK' thnvs («rt«iii apMrtrA obuirrnd bf OMani if A* 
»fope. t'ig. I. r u preat a tt the tolu vpoctnui. 

Fig. II. kIkiwii tlw apaetnun of poMMum. It ■« eostiniiMu^ 
eoniaioB all th« coloun of the mIht spMrtrtim ; BiotMN* it ■• 
two brilliiuit linr*, one in the ntrriun ml. corrtapavdiiigto 
dark liu^ A, iK« otb«T in the estntiw vk>1el. 

Fig. III. ii)uimthes{i«otrumvfKdinm. Tlita RpfCtnmeoolnM 
kH, omngv, grm-a, bliwi, nor Tlolvt* It )■ nuukwl by a nn 
yt-llow my in vmctly the »tm« poRlkm u Fraunhorer't d«k fii« 
*U metal* Mdiam u that whicli pontMia tho pmaU-sl ifiMlnl 
In fact, it bM bc«ii aacerlititit^ ihut one two hundred niiUi>atliif 
of Hodai* unougb to cause tbe appcuanor of tba roilow baaif 
ConMqiieotly ll ia V4in' dilficiiU Ii> avnid tbe appeatssce <t tbb 
very little diut fcnltt^rrd in lht> apartoicnt t» caoagh topntall 
(ircumatnnce which Ahows how abuDdaatlj aodmiH it Katlritd 
out nature. 

Fig«. IV. Ritd V. iihow thn Rprctra «( nrtium and ritbiiKmm, 
ruvcrpil by M.U. DunwD and KitvhIiutI by meaa* of tpMMl 
Thf> fomiitr in diiilinituiihRd by two blu« lino*, the latter I17 
britliant r^d liD<-* and by iwu ]»u intvuAe violrt tliie*. A tUdi) 
iAaHiam, hn* bwii diicorRNd by the onroe method hf lit. 
Ki^rland, nnd liidi<p«[iil<>iilly by H. lAiny in Franco. TballiiOi 
nict'-riw-d by a (liriglc ^n.111 Vine. 

Btill mfltv n-cputly ICii-htnr and ItMcb hare diwovrrrd a an 
aMocUtcd^^'itb tine, aiid which ihuy call udiinn fexn • couplrtf 
trri*tic line) which il r>irm> in tba tn>li|(n. 

Th» ^xtrvino dclicAcy of llii^ 8[)«ctTUiii reactioiu, and tb* 
which thi^y niv prodiici'd, cnnntitntA them ■ mnM raluaUo I 
quaiilit«tivn analysis of the nlkalig and alludine earth*, ll ia 
place a *niall portiun of tiii* subatance under cxaminadoa no 
wire n* rfpniieDied in ^g. ^7, and compATethe tpeelnna ibw 
with the charts tii which Ihe positiona of tfac linea pradood If 
vaiiou* niPtala are laid down. 

^'ith utlif-r iiKftnhi the prmluctlon of their »p«otntB) is morr 
nxpecially in the riu>i>ufsomi>nfthcnr compound*. Tlia hnit cf« 
buruerixiii'iuliicieni To vnporiip tiie Tiiftala. and a niore Iniea** 
mu*t be ujwl. This i» ullfcti-'d by takinff electric aparki brtw* 
conalflting of thn metal whose •pi^ctriini la rvijulrad, and lh« alfCU*! 
arenoatoouveuk-nlly ubtaiuedbyiueiuiHof Kulimlrorf' • eofl. l**' 
the metals may be broiiglit within th* inhere oJ'apectruin al 



B «t(Hli«l thU lbs rlianrlcr nt thr iip«irtruui ctinni-pii with 
In*; Ihiu cU'Hiiln <4 lithiuin in ilia ttame of a Hunwn'i 
•tjngle iBtoRM Ibu ; tn k liolbtr IIiudc^, u tJint af h.« drojciMi, it 
fidnaal onnin lin>; whiln in lh« oxyhjclrni^ii jet or the 
hixmi brilliant bl«e btiad MniF« out in nddilion. HometiniM 
io* to Uin appennoKv or new lin» an iii(T<>nw> in ti;iii|H'mtiin* 
I* AmmIi whk-h <>xi*t into a niimlwr of liui' liim. whiili ju 
we aotv aixl in KORMt )«w rnfruii^bln Umui th« bRDda from 
m fanuod. It mar bn aiippoiwd rliot lli« (flowing vitpoiir 
< Iw Uiapantun oomIsis of tb? oxide or tcme difficu]ll,r 
■kl, wlienaa wl tbe (mormouily high trmpomttii« of ibo 
w y onndg »r« decontpowii, aud ihe tru* brifcht Uimb of the 

n «rf Itrn ffUM MD obtfuncid by taking the electriu afmrk 
I libM of a apMiki ronDlnic-tinn. pruvidi-d with ulmTtro<]<^ of 
IfllMwitli the^winqUPMinn in a ntntn of ){T«alsiIeriualioD : 
be pMoed Utrou^b li_vdm;.'en, tb<- light einiltcd in hrighl 
ipcctran omnalji of one brifihl md, can KTrrn. and nnf blur- 
fa nhrofen lb* *|>ark ix pnrph^ nud thfi rpctrum T^r; cooi* 
Uw electric 4i*el>ai^ Ukvaphiw thruujfh ■cvtiipoiind gMor 
ftttn arc tlwiM of thn nlvmentarj MostitiirnM of tbp pu. 
'•t Tuv int»iiw tHnpemtum cbemical Gunibiuation «a« tai- 
orrgrai and fardmiiMi, chlnrinR and Ibn mptala, could CO- 
pante form, allhoii^h mocbanii-HlI}' luiird with each other 
aaallon of Ula dttrkUntw of tbo aolar aportnus. — It hax 
MMi that inrandoiorat fodiiim va{K>ur g-iviu h biight jellow 
iting to the darli tinl^ D of thn solnr spH'triim. Kirchholt 
ibM Ui* briUiaatKuhlpmdu<;ri bj- incnn^flsc>>iit liinf jiaiueii 
DM colowcd hy awliHia in ibe uaual iitiuiuer, h apectniin i* 
tbicb ta a diirli linu toinciding with tbo dark line II of th(^ 
n ; what would ham bmn • bright veJIow linu LecomM a 
■bn formed on th» bat-kirroiind of thn liino light, hy 
riarfUr manniir thA lini*ili^t to travi<rii« vapours of putu- 
i, rtrontiitni, cU., ibe bright Itoea whii'h Iher wnuld hnvn 
fouad ii> b" eonvertcd into dark tinea, 
thin that tli« vapour of sodium has th« power of ahiorbins 
nr nAanirilMiitT m tbtU wkii^h it rmita. And thr nunc i» 
ifMcaafpotaMium, btrinm.otrnntium, Ptr, Tbi» alixirptivr 
UBiaanaan wolaM pbenomeDou. Thew cul»tiuiee> nhnrn 
1^ witb lh« *a|HMtr of nitmn* ncid, which nrcwNlrr found 
I bUowioft propi'itr : when a tnb« filled with thin vupciur in 
'|ath nf ibn liphi rilher of the ran or uf a pi* Hnmo, and 
itHfiuntI/ d«conipo*cd ^^J a prinu, a tpcriniin is produciil 


a» uom. 

wfaiebiifuU uf d«rii1bee; And MilUr tlioirtd Out iodiMial) 
Tspnar pnNiucod aoologmu eflecla. 

ll<.-Dci> tlie<iri^<f Ui«kbi>v«pbenoiiHiuiau,d(MMl«ahAii 
bj the >Kliiiia tapour ot njs of th« ttuns kiBd, that i^tf All 
fru^bilitv, M ibow which it hiw itMU tli« pawur of i 
rBTB it nlloirra ti> [inM uiu.-bfmg«>l, but thMe It either taullfMi 
]mrt DuppifMc*. Thui tlio pniticulnr line* is tha ■ p c etraB I 
tiiew mvs would conTWge ue illiiDiiiuit«d only bj t^ Mif 1 
aodiiun Hnrae, and ■ceordSngly Mppi.'Br ilark by con t nwt «ilb ' 
poKiiHwof llw *p«ct;nni vhieh no-'m Mght 6oid tha powMl 

By i«pLKiii(COincofth«flsm<«,fl oril (fiy. 367), byanyc^Mlvl 
i»flect«d fivni n helio«tai, KlKhliofT M»itaiiwd by dbett i 
that tbi! bright Un« which diaraclvrisi- iron oomapcmd Ki4iA| 
the M^ar epoctnim. HoalaofoDnd thoMUMtobat&Dca*imllil 
■uigneriuni, c&lcluni, uickel, end womb other melala. 

Prom tliHr> obwrrniicaw w« may draw important ooBclurionHJih^ 
to the oouRtitiition c( tho nun. SiiK« th« wUr aptcmuB bal 
where nodium, irou, etc., gite brigfat oou*, it i* probable thiti 
Mtlid, fa mora pri>bably liquid, body of thn *iui, wkkli thien ■ 
lifrht, th<M>.> oxIhU » vii))on>u» enrelopo which, Uhe ik 
in the cxpntinimc diucribn] aboro, abeorb* cortuo nya, i 
which th(< envelope Itwlf eiaiia. ilence lh<Ne ftaU of lhi< 
whirh, but tor this aheiwptiaa, would bavu bt«n iUuMiinaUd 1 
pitrticiilnr raya, appear feaUy InmiiKiuii in cnmpwiaao wil^ l' 
pa^t^ unce they are Uluidnetml only by the li^-bl 
tile envelope, and nut by thu lolnr nuclouv; aod «« *n> il I 
timn led to concluilo thai in ihU vapour there exiat Uie I 
injji. etc. 

Iliit^uiuid Millor have applied ■pactntmciialynBlottei 
ofthv- hftRTpnly bodJee. The ipeeU* of the hkkm and 
Mghi i» ri^llwted from tbo aiiti, (five the fame liDeiaatbaMrf| 
'I'ho ipiTtrn of thi? flxi>d »tnre coiiEiunt however) deric liiieedt< 
tb<j ai'lnr liiii'B, and from uns nnothor. Thu ted »t»r Alilph*raii (f* . 
corrujpiindinji with i>odiiim,i»ngnMiuin,<-«lciuin, iron, bidniuth. toll*" 
nntiniMiiy, and iiii>n:urv. In tbe >pvctrum of the uruig^tini^ 
a Oriunin lliu Utiuii of ma^ciiiuin, Rndjiim. cAlciiim, nnd biiouill* 
iihwirviid. The brilliant white el»t Siriua ff^v<» Bvidonct otliel*^ 
oftiodiuiii, uiugui-sium, hydro^n, and iron. It vodld tkiu iff^^ 
thwp H.xckI fUirs, whilediflVring from one another b the matWf'^ " 
ihey are cflnipiM^d, are constructed on tbo Mme gcnoial pita '**^^ 
lIuK)|<i» biiB»bierved n striking difleieucein tlie speetnof IW^^' 
where tbtiy can at all he oWrrwl, ihny are found to oumlrt pi^? 
bright Linea, like the ipectrn (,{ the lulled gMMf IMtcad ef t*" 


ncyiAEscExee. 499 

I aad atan euuiMing of « brighi tiri''iin<3 inlMMcUd bjr 
It k luoMe probabl* Uttt the nebula' an.- miuaiu of Rowing 
lot ootinal^ blca ibe mu muI »t«n, ol > pbototphoni sur- 

glMOlU UlnMpbCK- 

I— — w . Prio ft wig Stokes Las niftdf thu rcmnrhaUo dii- 
Ddtr ccrUin dMumdaiiM* the ny* o( light are ca[<«ble of 
diaj^v uf refraagiUlitj. Th« dlMovetj- ontriiuiivd iu tba 
MMMDoiMB iibMTTcd bv StT J. Henvbcl, that ccrtun Kilutiom 
at lijr inUBauttt«d Uglit appear colouri«M, but when TMwed 
fbt ywiMwt a Uuiih appirnrana!. Stake* hw loaati tbat thia 
ld> he talhjbiorticrurr., U cb«nict«rutic of A large cliua of 

ia bnt mod whnn a Mlntinn of inilpbalA of qiuiuac, 
k noogli with parallel «i<Ju«, in placvd ia dilfvNDl poutioa* 
fUdfaxL. No chanfcn u obaervod in tho upper put of tbe 
I froa about the middle of the lioea G and 11 (frontiapieoa) 
oca bqrond the cxtreoie nii)m of the riolut, mjs of a beaa- 
coliMr an weo to proceed. Thete UiriMbla nllnt-vioWt ra;* 
tUthU vbm the (pactrum t* allowed to bll on paper Sm- 
ith a tolBlkw of innMu (a ■iib«t<u)M> extracted from bnni 
I akohoHe aolntiaR ol rttamoniura. or a plati' uf canaiy glaM 
lomad b^ Ksans of unuiiiin). ThJo cUnngn nriiw from a 
1 liuL lefran^biliiv of ihooe rays outaide the vkdet, which 
' loo ndnuigihlo to afftct the eyTL. 

to abaotb anaaj of these tuoi« refrangible nvK which ii> 
rtj to tiM MUlu cit»nt with qunrtx. When prinnu and 
■d of plates of qiutrti are tiwd, a !>pertriim msy be olilained 
is Ifce lina H, is double iho Imglb of ibr risible >pectrum. 
m thus Bwd« visible dark line* may be soon like iborc in 

WBfaa tuKV he obsorTod vitbont th* nas of a prtam. When 
b a dark roooi Is closed by ni«aiis of a pieoe of blut> glata, 
t itaUmrcd to fnll npim a pli«i! of tatxniy gltui*, it inalsuitly 
JMiBOna from ihe emission of the allei«d rnyn. 
■M It ia the Tiotct and ultra-violot rayi which undergo au 
' NAngibiltty, but the pLenomenon is not conilned to tbrm. 
<f BaddeT in alum givi;* yellow aikd Tiulut light from about 
kkjood tberiokl: an alcoholksoliitionof chlnrophyllcgiTM 
V dw Hm B to the Uinlt of the sptTctrani. In these cases 
^kspum, and the Uuerays oxp<iri>'i>c» tliniiDutJonof roftan- 
■duap neiret proJuMS mortr hifthlj refrangible rq)s. 
htc a^t give* a verr rcmnrkalilc ■pectniiii. With quart! 
^*^ oblaineiil a speclnnii «u or Wght timos a* long as the 


liTinple mlonn (484), and i* oaUed etrotnatif abtmtim. 

For, M UwM Diiiy bo compMvd to a teriM of jaimat 
miBll fncM. Bod uiiik-d at IhoU W««, tliey nnt only R 
abu deconipoMF it like n jirinn. On Hccount of tlib di)pa 
Unaee have really a dUtiiici foirui foi tmeh oolour. In m 
r<ir nuRiplc, Ihe red ra.r*, which arc tkn IcaM H<A«DpU(| 
at « point r on th« Axi« of th» lens (B;. 368). vbila tlw ^ 
lur mori rtiran^Me, cundd* 
)-ii]it r. The fici oT Uw onag 
blup, and mdifri) arr bctwtvn li 
i-hn>niAli(' «l>rmilioii t> aiOK pe 
point at whi<'h tli« rave atv O 
frwu lh« axi* ; for tli«n th« ilnj 
Fig. 35M, f„ra the dispornoD uv ioOMM 

497. AohromatWtt.— By coiubioiiig p tiw na wludi hi 
rnctiDK iuip1<--i i4ttr).iuid amfortiwd at miWancoaof m 
piiwi?ni J 4A'i t, while ii>(iit rmv 1» r«>fnu-t«d wiiboitt being 
taiiie r«aull is flltiuDcd by comhiuing Icnaoa of dilmal 
curvaiurunf whic-h am HiitAbljeombinod. The unagMC 
through nnch l«n«Af do not oppear tolnured, md thejp 
callud achramalic XimKot ; aekromatum being th« iMm tf] 
noiniinnn of tJie rofmction of liichi vnthoitt d«oompMilio 
By obwnuiK the pkonuuienuji uf thit dispcnion of adj 
water, of ml nf turpentine, and of crown-Klam, N«i*KiOia 


thU ttmlt, lot two priniiH. BFC nad CUV, bn JMii«d luiij 

iMBtnt; dlrectioa, w ibown in tig. SflO. I^t us Hupptwu. in 

I tlwt l>odi ptunu uv of the »aiu« niatcrisl, but tliat ih« 

I of the McoDd, CDF, in Ioib thu tlw rafnctjiig angle at 

[tike nra priMu will pmducc tlii> muim afTact m a lingle prUni. 

1 » W my, tl)«t whit* liglil wLicU tnTenpn it will not only be 

bal alao dMNiinpoMil. If, on th<- rontTuri-. tli" firnt jiriam, IJCF, 


)Wt-jlitv, and tlw Ollwr cf l&nt-glaas, th<? dinpenion ntt^fhl )m 
witboal ilmtroTUiit tha nfractinn. l-'nr hi flitii-glnu in miiic 
fhu crown, and bh tli? dingi^rxiuii priKlitovd br h prisiu diini- 
it> PEfnctiofr angle (48.1), it folI»wi that by tuitably trawniti|t 
Mgln of tba Hint-glaMi prinni, C.Fl), m contpnivd witli Ih« 
of tlwt crowB-flaM priinii, BOP, the diHpcnire powvr of 
■■f b* aquaUMd ; and u, fmin llu<ir pnoition, ihii diupcnioii 
b ft oontnuy dlrorttoR, it i« neutnillMKl, that ia, tli< unwigtut 
\ «n puallcl, and thi-rcrocv irire wfail* lijcht, N«Tartlidiwv 
rfllMaNiitnl m?Faiul CPD, wh)<-h la oiiit^le for tlwt paralluUmi 
4 Up Hid »iol«t nrr, i» iiol ra for the intamxHliatc tnvn, bikI. 
■■ll*. ml; twn of tbe ray* nf tW ■p^ctJiim i-nn Ihi •• ciiiu- 
■'iktirhtnaiAtisniUnot quit« (wrfvi-t. To obtaiu iwrfucl nchru- 
WMlprMWi wvuM be nvcnaouy <if unoi|Uiillj diapannrcnintariiil*, 
<(|fa* of wkicii wnro luitaUf ramblned. 

'■hdica ii iiot d«atruyMl at the snine timE aa tht- di'iH-rsiori ; (liiil 
l?hlfpai if Um refrartinji pownr of a liody vnri<«l io the: «iunt- 
' «> 1^NTMT« power, wiiicli U not the taw*, Ci>iiM-qii>'iitly the 
f *•>, to, ii nii< cssctlj parallel to the iaddunt ray, aud there is 
"• *ilboui appnvinUe decom pod lion. 

"^uicUnwM am miide of two leusu at uneqnnUy dlapn^ive ica* 
*•'•• A, tl tlint-jUu*, in a diivrfiini; eoncaTo-Ponvfi (fin, iWfl) ; 
'■ Hrf (rown-glau, it double tiuuvox, and one of jt« fsi'»« runv 
''''"M* with tlie cimnavo faro cjf thu lirirt. .^ with pri"ia«, 
^■l *mU be IMOOMftry to nbUiiii perfect (whroinfttiflm ; but fiw 
^"'Vnti two >re mtliviunt, their cunature beiu){ auuli M to 
*™ t*i» iad ofan^ r»y«. 


mr Licirr. 

amuL iJt*THriis."ew. 

IBS. Vkfl iUtorent klnOa of opUoal liutrvnMBU.— Ri 
•jofMvrf MMInmtaif u auiint any cooibiiiAttun of Ii7in«i,cit ofle 
mirrora. 0|>tical nutnuuMiii) ma; bo dwid«d ioM three diiwt i 
ing M the eikle tbey u« iaUjided to niwiret, vii.:.^ Mia 
which HTii dMignctl t^i nbtaiq n Migoifiod UMge ot taj obJKt nb 
(Umeiuloug tn loo ftmnll to admit uf Ita beinir wen dbibctl* ^1 
calwd cr«. ti. 'J'rlrta>pf», by which rory <lwtut objtcu, wUl 
oeleatial or toirentiiftl, mny b« oWrrod. lU. /wKmi tnto 
to pcojuct un n KrB«u k miiipufied ur Uimiolabed uMge of auj i 
which can thonfay bo tithiir depctod or randand nabbtoac 
fpeotaton ; »uch a« iho mmcni JiR»ifa, tb* nHMrw o(*nra, j 
AfifMiriatHi, tht maffic IsuUnt, thv unlar mkrom t ipnt iitt plufoti^tnc ^ 
an^, etc. Thu two funuer cImm) jield rirlual inugw, the 1mI.< 
tho «icoption (if tliD camtra ttKiia, yidd loal iiur^. 



4IH>. m* BliBpla Bkloreaeopa. — The nmple tnirrota'p* or < 
fftoM IB invtwl)' a euuvux leii» of short total Ivntrth, brmuanaufwUd 
lonk at ol^oeta plncml between thu tc^ji luid ita prinriftal fociu. Lei 
<Q^.301) bi- tlii- iilijoi'i til lit! riliservctl {ilnred Wwit-o the 

fiii. Ml. 

principnl focii*, F. l>raw the «ecandafj bxm AO aud BO, aadl 
A and II nya parallvl tr> tho axU of tho Lpim FO. Now tha« i 
■piutaaf out of tho lenfi, tend to •poaa t)irouKh tUu fwrand principal 
F', oiHiaeqiunitly tlii^ am ditvrHcat with refonmca U diaarmiidi^ 

i] laCROsoopEs. ^^^^ 403 

tiunfnn, sbcn pivdaeed, will cut Ihcne v[«s in A' uid B' re«peclirel,v. 
I |cinU ue ibe nitnol foci of A and B r«*peciiviily. The leD« 
I fooduMs at A'tf ta enat and magni&Ml Tirttutl imago of tho 
pMiUaa mi niagiiltud« of tliEs image depend on tbe di>t«)iee of 
><iiitt bam ika foctui. TIiu«, if AG in movrd tn at neatur tha lenfi, 
az«a will contain a grratai' saglo, nod the image will he 
at ifV, aod nil] be tuucb uuallor, and Duorer tlie eyv. On the 
laod, iJr tb» tAjtct ia naond OiRlior trcaa th« Ira*, tlie tingle 
ih« •ccondsij UM ia diminidwdt and thdr (nteneciion n-itli the 
t:iiin of tlra nAMted ra^ taking; plnco brjiind A1)', the tmn^ i^ 
binhcr ban lli« lena, and i« Ini^r. 
» dn^e mictaaeope Wli cbronutic abemUion aud ii|)liurioiil 

Fii[. 3H2. 


atiea burecae witli the degree of mafpnilimtiini. Wn have nlmadjF 

iliat tiM fonncr tan be ct>rrected by uclng acliiwinalic I'-n»e» 

. ti/7h anii the l*ller by iming dinpbm^UB vrbtch nllnw the piusn^' of 

I ray* iNiij a* arc UL-arly pural!«l to the nils the iiphericnl aberration 

F Af tkne ran being ixiarty iniMiudbb. 

[•^^Kneal abvrratlui