experiments on the production of dephlogisticated air from water with various substances. in a...

Experiments on the Production of Dephlogisticated Air from Water with Various Substances.In a Letter from Sir Benjamin Thompson, Knt. F. R. S. to Sir Joseph Banks, Bart. P. R. S.Author(s): Benjamin ThompsonSource: Philosophical Transactions of the Royal Society of London, Vol. 77 (1787), pp. 84-124Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/106716 .

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3

. .

Th)m}??1<} IVa* iS R. S X Sz LJoIiph 33anks} 347*tx P . g

Read Feb. t 5} l 787*

X E A R S I R} MtlNtthe 8tptx t7 It86*

ARlOUS oplaions havitlg bee entertaitwed with re@ed: to vEwe origin of the dephlog;Ilicated airs produced by expoX

ling healthy vegetables in water to the a&;on of t:he Iinsss raysa according to the n:<hod of Dr INGENHOUS%; and not izeing lnyIElf thoroughly Iitisfied wich any of the theories propoSd} I made -the illowitlg experiments with a view to throwing bme new light upon that IV%ed:t.

Having bund that raw filk polSeis a power of ateraEitg Katld feparatit3g air from water in great abundarsce} when expoid iLl it tO the a-dion of lighta lt occurred to me > examine the -properties ofuthis air anA to colltider mom attatively tEwe c;> >^cumRances attending its pmduAions thinkillg that this might Apoffibly le;d to fome irther diIkoveries relative to the pmZ EduEion of the air yleldesl ly water under otEwer ctrcumRan>s * And though my icceC ill tMi inquiries has avt been equal >

my withes} yers asfill tlae cgr+i of my miarches I have di£: covered ime fids +whl-ch I take tv 1)e new and as I have con Wirmed other 3e1ffae klowna by a variety of new tsperb

tnents>.



Sir BzNJzXs 5SobxPsosts Bxp:rUew?Zsg Sc tS znents9 I flatter luyIelf that yotlVwill llot thiali atl accoullt of ny labours upon this fubjed} altogether ulliLltereRitg;*

:13efore I enter upon the cletail rf tny experimetlts it avill be neceIlary to p-r-emiSe, tllat I {laall itl gei:leral conl5ne xllyfelf merely to the EclERs as thcy appears wlthout applying them to the coxlSll*nativtl or efutatiotl of the tlieories of others, and witlsout eaterSg iato aty fpeculative enquiries relative to thelr lelazore caufGs G and ill dciScritDitig tl-we diSaretit appearatlces I Daall Lnake uteA of tiae lnoR ftirllilinz tertnsv ThusX in fpealiilzg of th<: air ps-tDe1 Z>\- d ttpuzo ey>tzoXJllg 1aNV l3:J1£ ill w<lL-er to tl-le aEtiell

c:3f^ li.l-lt$ I f1Rwl1 for Seti Xacs rtletlt;Oll it as lti-j; viplded by t:lle i11( D otit1 I San11 totnetlLz:les f)Cak of tile air furnlfhed by ex

pfs)I]T]g si&tatefg '\lAi), t]aS pleviOuny turted greetlX itl the funs &7-$7 as bezzg i;ntnediately produced by; tEat vater, though it is probableS thcll t1-av greeva maZZer ads a very importatlt part in the produAion of th;s air itl the one cafe alld in the other. But

t)R,.\r it ads is tlOt svell aCcertaitled; alad I had in gelleral mucl 372ttlel CC)llfille tnt7felf to a fituple alld ever] atl utaleartledv de gCUiptiOil of a2S) than by etldeavourillg to give tnore precife defitwitiotlsS at firftS to invola7e mySelf ill all ttle difficulties sv-lich would <wttetld accoullting for ph2tlorntua, svhofe cauSes are ILJut very ita-lpertcAly ktlowrn. '

Yotl nvillX tllerefo e9 taot be furpl^ifed if vou fould tome tin:es filld tne fpeaking of appealwances ill the fatne matatler as a -perCoxl w3uld rnelltion thetll svho faw thenz for the fiX R tile a-l-d zvlacz did llOt ktlosv that others had dilcovered tl<m lhefo1weX aild I<ow they had eLlcleavoured to accotlllt fior t6at>tm. I take care that the zEahs fllall be faithfully deSclibed9 axld l flatw ter nafelf you will llot thulk then the lefs interGfRiag on account of ti--}eir beillg ulladorlled But I haIlell to gisre yon ;ti cCVgltlt of my expe^imelltsv



fir W3EsAXs Tuoz:PsosS BdberS¢Sa

B8ern-eax M t

LTy fiX^ll o\3C<R was to colleE a fuffitient qtlatltity of t-11e azz {elparated trenl water by fl+k todetelmilae its goodt-1eSs bv the t-ei5c or laitrous airX and tO tlliS etld havitlg filled with clear 43rit1 uate* a ,lete of taX17 svhite and very trarafparetlt blafs 4k lEac1)es itl dtaluetetn svith a cjriitld*icral tleck + of atl iRch iIl dit<1&tt14) ttt] 200ut z itlches lotagX I illtrOduced iLlto

it o graitls of ratwsr f11k which had lzeetl previouny wafhed ia u7aterS iw Qrder to free it of air a and itlvel^ting the globe uIlder waw ter and placillg its lleck in a glafs jarS cotwrainitlg a guantitv cf the fanze svater with whicla the gloSe was fillelly I expofed itX sxl rny window to the adion (uf tIle funs rays? and prepared nySelf to esarnine the progrefs of the getleratioll or produEtio

of the air. The globe had ilot beetl expofed tetl mitlwtes to the adion of

the fin's ray$ whetl I diCcovered atl itlfinite nuLnber of ex ceedlIngly finall air-blbbles} which bXan to nlake tE<eir apw pearance upon the furfice of the {ilk; alld thei 1)u13bles cone titluirlg to itcreare itl ilumberS arad itl {izeX at the end of about two hours the fllkS appearitlg to be irltirely covered with themS tore to the upper pilrt of the gIobe

TheSe bubbles g;oing olz to increaSe in fizeS and running into each other at letlgth begarl to detach themSelves ffom the filky and to form a colledion of air at the upper part of the globe t but the nzearure of my eudlotmeter beirlg rather large it was not till after the globe had been expoIEd in the full near four days that a fufficie]t quantit of air was colleEted to make the experimerlt with llitrous air in order to aScertain its goodnefs by that ttilO

X EXaving;



os the aOa/*QX + D@hicZed Aasr ty

Having at length colleded a ifflcient quatltity of this atz br that purpote I caref;lly removed it So£n tIle globe and

mixitlg wtitla X aweafure of lt 3 meaires of nitrous airn they wez reduced to 1>24 meaftlresy utllich IEewss that it was adually RphlXgedv*r alld tlwat of a confld¢rable degree of putit

COLnlnOt] alr tried at the Ianze tirne, I tneafiure of it with X naeafilre of nitrous air were reduced to I jo8 meafule

I-:Iavi)g agill expoRel tlle glol3e with ttwe Ii{re water atad fIk ltl tny willdexvS sv1Atre t1R-e S1t1 Ihotle tEle greate{t part of ttwe (lay at the end of tIaree dtlys I llad colleEted ;> 3 cubic itlctles of air5 wIlicha proved wirla llitrous air giave ta+3SIsX8>

that is to fayS X meafure of this airs adkedk 3 rneaires of itrous alr) wele reduced to ItI8 meafure A iall vvax taper whicil had beetl juft blowll outX a Iinall

part otaly of the wick retnailling reGh0t upon beirlg plunged 111to a phial filled witll this airS im:nediatelytook fireS and lJurnt svitll a very bright alld eniarged flame

The water iLl the globe appeared to have laR fomet-lwing of its tranbal ency and had chatlged its colour to a very fiit<t greenit) ca0 tlAving St the fatne time acquired the odour or fragrance proper to raw filk.

Tllis experincellt I rereated Ibvera1 tirnes with fEeth water -(letaisitlg the me f1lk) and always with nearly the {ame re fults witll this difEelXelce} however that when th& in Ihoti-e very briglat tlIe quantity of air produced was n-ot only gtseaters

IDut its quality likewiIi sz7as much fiperior to tllat yTelded wheti t11e ft1la5s rays were more it>7 or when they svere frequelltly i-wtercepted by sSying clouds. -sThe air howeverl was always rlot ouly tnuch better than cJimmon air but better than the air in gelleral produced by the Seffi leaves of plarsts expofed in Wtel t0 the funs rays itl the experiments of Dr INGENZ

HoUsg. S



88 - Xt BENJANIN rISOMPSON s 8Xp6telW8gS

;XevSzX atad utldel the circlltnftances t1Ae tmoRe £1voul<able lt was fo good tlatt X tzlea{ilre of it required 4 tneafures of 3:litrous airi to faturate it and 3 6S tneafures of the two airs u7ere de-

illooyedg or p¢os7ed s?ill n;trous air it gave w+47Z=

wllich I believet is better tIat1 aIly air thae }ans yet bee

producel io tl1e expeilwlClWts wtth vegetaI TesX t1>1nt zntthod I tlave tCre atItoptcd of utlllg aIgebrat chaw

ra2ets iI] IlOt]Dg tEle lefu3t of ttat txperitlwetlts 1made to deterZ

naine the geed1)el$ of ail* though 1lot 03i21 nzatt1ematical7 iS

verr coisvenient > and ir that teafol Iflzall conltitltue towtnake

Xlft Of ita ja repreSents the air whicll is proved; S rultrous air s

arld the tlumbers svlzictl are JQitwed to tisefe letters ffiew the quantities or the taurnSer oiS meafures9 of the diSlbetlt airx naade uSe of itl the eXpefitnetat The other rlurnbel which fl:ands alotweX or without ally letter attactled to it9 Ot) the other

{ide of the equationS thows tlle volumeg or tile tulraber of

meafures and parts of a mea.ire to s-fhich the two airs are

reduced after they are tnixed. I thall fornetirnes add a fourth

numberg Ihe 7ing the quantity of vlle two ail48 deRoyed) as this

naore i-mtnediately ihesvs the goodlleis of the air wlaich is

proveu tRllus in the experitnetlt lail metltiotledX I meaIBre of the

air proved mised with 4 meaires of nitro-us air utere reduced

to T35 meafure} collfequelltly 3S65 meaires of the two airs

were defiroyed 9 for it is T + 4= 5 Iv35 = 3,65> and the reilt of this tria1 I Ihould write thuss + 4n _ I 9352 or 3S65.

0r fbr Llill greater cczllvellience itl pradice, as this laI} nutn ber 3X,65 or 3 16-QaF ihew5 more immediately the goodIaeX of tlle air itl qutfiiot as I have jull vbServedS lJy fuppo{illg; with DrX INXEN*uouSz the nzeafure of the &udiometer to be divided

anto aOO tgttAl partsX it will be Oo + Asor _ J57 atld 6SX

exprelEl]g



oa Sttue Pfo0jSffi*at of s DephlogdiGat@d =X0 89

txpreSlng the volutne of tile twvo airs deRroyedX will i3ecotne a

who]e nu1nber. But, in0ead of svriting too++Oon= t3Sg &Ck I fihall coa<*

tinue to wrtte x+An_ )35 and nzall expreLs rlze lall number (3Gs) as a whole rlUmber notwithftanding 9 and I Ihall fomex tilnes (followitzg the exarnple of Vr. IssN-uotrsz) write tt nurulDer onlyX ils notillg the goodnefs of any air 111 queiLtion

I worlld ju{} obServe, with refpeEt to the procefs of proving the gocedtlefs of atly kitld of airg by the teiR of nitrous air,, that I £nix th@ two airs itz a pEsialx about a inch irl dia£neter atld 4 inches longX putttag the air to be proved illtO the phral firR, a1ad thetl itltroducitlg the nitrous air, one tneafurx after ano wtller tlll the volume of the two airs after the dimitzLutioll has take1l place, atnounts to more than one meafureX atld is leSs than tisn meafurese

ImulediateSy afier-the ltstroduAior3 Qf eacll nzeafure--of ni- strous air, I give the phial a couple of akes; after which I Iulier it to Rand at reR, while I prepare another meafure of nitrous air, which commonly takes up about zo feconds.

The meafure of the eudiomerer being ldlled witl] air9 I fuffer it to remain quiet ullder water lS fecoIlds, or while I catl leifurely count 3o, ln order that thfe air may have titme to acquire the

temperature of the water itl the trough, and that tlle water ill the nzeafure may have time to run down from the {ides of the glafs-tube; atld in filUttiIlg the {lider I take care to britlg- it to

be exadcly evetl with the IStlrface of tlle water in the troughB Similar precautions are likewife rtade urC of ill tneafuring the volume of the two airs in the tube of the eudiotneter9 aRer they have beetl mixed and dimilsiihed ill the phial

In order that I nay know wherl I have added xlitrous ar eIlough to the air iIl the phial, fo that the vo]umel of t11e tV\rO

vOL LXWIIe N airs



4Wo B te sJ ̂ M t s re 0Ntross B#ft t$a8as §G

Sl1^S Sty SIBOUllt t0 I meaf*ure and may not be greater thane X x<acafures, there are t-svo marks upola the phialX made with the pOillt Of a diatuotld the otle ffiewitlg X lmeaive of 1ny euldio- tneter tile oth-er fiesvirg; Z rlieafures.

The tube of: my eudiotneter is half at1 inch in diameter inw teraully and I meaifure occupies 34 illches in length upon its atid the tneai;1re itWelf is made of a pitWe of the lime tube Both the oile and the other are grouncl with fine emery on the iIlfides itl ordelX to take off tile palith of the glaIB atld by that meatls ficilitate the runlling dowrl of the water whiclu miglt otherwife hang ill drops upon the inEde of the tube upon the

* . *

lNtrOE LUO10S Ot air The tlitrous air was alsvays fireSh made and of the fime-

material58 t;So fine copper urire di{Iolved in fmokitag Iiirits of slitre diluted with 5 times its volume of water, antl all poS- ble attentioll was paid to every other circumRance that could

-

contrlbute to the accuracy ot the experlments

I have thought it lleceII)ry to mentioIl tti-ei particulars on

account of the great difference in the apparent goodneIs of any kind of air proved by the teA of nitrous air which arifes frotu the diSrence of the circumfEances under which the experi xnerlts ate made

.. .

But to return to tny experitnents upon the air produced upon expofing; {ill in water to the adioIl of the fian's xays

Experxwent Nb z

Finding that the quantzy and the quality of the air produced depencledS in a ;reat tneafure, upon the iLutenfity of th-e light by hich the water and tile fiik were illuminated7 I was de rous of feeing whether by depriving them intirely of all light they would not at the fame tinue be deprisred of the posver of

furnlffiig



ox tbe Paz2aAia f DVhbggrvied Hir g X

fiXrnin-g alrQ To akertaln this fi& I took a glot3e A5 fimi lar to that rnade uSe of in the iregoing experlmetlt and having filled it with fi*eth Epring waters I itltroduced into it 30 graitls of raw {ilk and pIacing it with lts cyllnTl-ical neck itlverted in a jar filled with the fame water, I covered the whole with a large iIlverted earthen velRel7 and expoid ity b coverecl upS fbr Ibveral (lays in tny witldow by the Iide oiS another globe 93 containing a like quantity of \v8ter 2nd filk, srilicLa 1 leR naked atld confequently expoSed to tlle diredl: rclys vf the Xtl

- The refult of this experitrletlt svas that rlae water atld IRlk in the globe expofed to the fUtl$ rays irlli«ed Air iS great abundallce as in the experinzetlt beforementioned d svhile tEatv iIl the glol3e covered up it< darl<tleI)3, produced onty a itX very incontiderable air-bubbles, svhicll remaitled attached to the

iilk

xperzment Nt 3.

tro IEe lf lleat would lwot facilitate the produAion of air xn the globe iEelteled finotn the light I I1OW removed it frotn the wvindow alld placed it near a German Rove where I kept it

f F HR;NHEttrss tisertnorneter ir nzore thatl- z-4 l<ours, but tllis was all to no purpoWe. The air ptcz dllced svas fo exceedingly Snall in quantityf ti<at It could zeither be proved9 nor lmeairedg tl}ere being oally a fiv (lerached air bubbles9 svllicll llad colleded tiwcmSelves tlear tlae top eJf ttie globe.

lnhe medium Tweat of the svater in the glole expofEd in tIae fullss rays at tlae time sv1aen it irrliShed air ila tlle gleate} abundarlce} \VdS AbQUP SOO FAHRE:NIXEXT. IT WAS imetigwes as high as 6t; but air svas frequently produced ill coiltideraDle quatltities svhels the heat did tlot exceed 6)° atld 7O°.

N z E9X>e



59 2ENJAMIN THMPSON'S vxl9¢rttetgs

Experxment N° 4*

FX.l+(2ling by the laft experlment (NQ 3.) that heat alone:^ W';t9tOlt>t l.igllt. \\ralS NOt fUffiCieilt to enizble Iilk in water to pro-

ducz airS I vvas defitous Qf fe*elt]g the eEfUA of light withou0t l}eat upO11 the1n. To tlais etldS I took the > globe l3 - withi its contet;ltsX atld plungirzg it itlto a misture of ice atld: water blougllt: it: to the temperattlle Qf about 50° F. and taking 1t 0Wt 0t- tiliS misture and expofing it immediately in the fun's rays (which were very piercing at the time) I enter- tai;ned it itl this temperature above two hours lJy the occaflonalr application of cloths, s7et itl ice urater, to the lower part of ttl@ globe

Notwithfltanding this degree of cold, a colaf1deralDle quantlt- of alr was produtced s though it was) tlOt fUrtlilhEd iR r(3 greatt abundaace as when the globe was fuSerect to become hQot in the funs raJrs.

Having tllus aScertailled the great effed of the- fun's rays is the produdion of the air furniffied UpOI} expofing filk in water to their iI<fluetlcey tny next attemipt was- to determine whether this aroSe from any peculiar quality in the fun5s light > o-r whether ptber light would r<ot produce the fatne effeEt \Vith1 a view to aScertaining this polnts zvhicIl I conctivedt to beq of rery great importancex I made the following intereRing espez

4

rPnent

Experiment Nt- 3 Hav1tlg renloved all the air from the globe iBy and having

fiupplied its place Witl-l a quantity of fFeXh water fo as to reilder it qulte fu117 t repla£ed it illverted in its jarX and removin$ it into a dark roomS furrounded- it wsth- 6 lalxps with reflC&orsX

t1



oa tF7e Prodazor of DeSJplogacvted Sr p3 alldA 6 waxwcandles placed at diffErelat diilances fiom e 3 to 6 lches from it, and Io didpoIed as to thItO\ t;e glweateR quan tity of light po1:51ble upon tEle filk itl the \\taterv taking care at the farne time that the svater thould t<(zt $CqUit a greater fleat than that of about 90 F5*

Things had 11Qt renzained itu this fituation above io £ninutesX when I plainly diScovered the airwbubbles begillniing to rnake their appearallce upon the furfice of the filk; and at the ersd of 6 hours, there was colledked at the upper part of the globe a quantity of air fufiicient to make a proof of its goodtleIi with nitrousalr; atldX uponttrial, Ihadthepleafuretotlds thatit oas dephloto,Jtic4zed, and of fuch a degree of purityg that; ts meafure of it with 3 mearures of nltrous air occupied no more X

tilan >68 meafure. I afterwards expofed, to-the fam>e ligh-tg in fmall irlverted;-

g;lafs jarsS filled with water a frenl-gathered healthy leaf of *e peach tree9 and a Retn of the pea plandc-with -3 leaves upon it ; and botha thefe vegetablestfurnifheclE air in the falu>$ mannetr as they are knowil to furtwiffi it when expoSed utlder IilniElar^ arcumlEances7 to the aAion of the fiunS clired rayss but itl lefae

gualltities7 which I attribute to¢the g;teater itlt:etlfilty of thek fun's light above that of my lamps.

The experiment with the {ilk andA water I repeate feveral timesS alwaysiwlth nearly the Iame refult-O The qualltitJr of air furniIhed sras fometit2-es a lttl:le greater and fortimes a litZ tle leEs ; butsit svas always ;n much greater abundance thars that furnifhed by- an equal quantity of water and filk expofed to the fame heatX but excluded from the light; and I have reabtl tc) thinkX it was of a tnuch; fuptrior quality, though tlle qtlantity of tElat produced bils thedark was to > ia11 to- be ibmitted +e

a,y proorg

t e TheXi.



94 Sit BENJAMtN tHOMPSONtS Estenmexts X Thefe experitnents appear to me to 1Ze of fo lutuch lmporZ

;tance, tllat I could wilh they might be repeated9 atld varieds n fuch a manler as thoroughly to eItablith tlle fzad:s relatilre to

the i[ubje&t ill quef:ion. For my partX I woup jlnoR readily undertake the inveIligation of the matter; but being etnployed n anotllev purfuit (the CONtillUAtiOll of my Experiments upotw

Eleat), and, lJelides<this, much of lny time being takell up by the duties of my -nlllita;ry employtmentg I have taot leii::ureg at prefient for fuch an underea]<irlg.

Perhaps it may be proved by iture experirlaeilt, tlaat tl}-e matter of ligllt is a conRituent part of what is called pure or deplllogtRlcated air; if Sce, may- we aot vetlttlre to coilclude with Ni. SCH:RESE tTlat the lighz, as well as the he.lt, pro duced by flataweX and in general allSburning bodies, aliSesleSy frorn the decompotition of tlais air, -?.nd not from the phlo- g;iIion or itadamlual)le principle of the body whicil lis burtlt ? There are many phtlolnena whtch svould feem to 3>ufiify tlls

* * :

opllllon. i .

zBut to proceed in the accoutlt of my e7cperiments.he operation of inverting the glolzes utlder water, and placing ther-lz in the jurs, atld of difplac;tlg and replacing them upo< removing the a1r ploducec3, tbeitag atteladed witll fome incon veniencesX I had recourfe to allother method of difpofing of the apparatus, tnuch more flmple and mo colls7ellieat. 1 1le gloles beiag filled were laid UpOIl a fmall piece of deal board9 vwith their llecks illclined at atl angle of abou-t zo° above t11@

P1aIze of the horizota, and filpported ill this pofitiotl by a per perldicular fork of rwood, fixed to the end of the t30ard, as repreSellted l)y the figl: re, (See lnab.V.3 The part of the bf3ardX tlpON whicll the under part of the globe repofed, was hollowed a

little, to prevent tI<e -G;lolze firortl rollilS;; orS whwat 1 foun-d IBO1'



on the Prodio7 OJr Dephlogxf afeX S;r X

teore fafe alad convetlietlt, a flxlal] ritags 01 }zoop, of Coft woodS was llailecl down UpOll tl]t board ill thvlt part.

13y ttliS arrat:)E;elnetlt tlle jars were fpared aIad the eIaci of tlle tleck of the globe beillg eafy to be cotne at9 by introducing a svire: or, what I comtlaoraly made ute of in prefereIacej, a

fmiall glafs tlll)e, iIltO the g;lobef the air hanging; attached to tlle filk can at ?@11 tilues be fepclrated from it n whicla is often neceIl farys ill order to deterttlitle vaith greater; precifi1otl tlle quatltity of air furniihed in aIzy givell time.

The air produced naturally rifes to that part of the gl:obe o?hich is tlppermoll, wllere it colleAs in a body, driving out aa equal voltzme of water; whichv to prevellt its running about9 Inay le colleded, by placing a proper veXcl under the mouth or end of the neck of t1le globe, to receive ite

The rnethod of removillg the air from the globe ts to ell Ekiaown to requil^e a defcriptioll I svould heaweve-r obServeX that ita doing it care Ihould lte taken, that the wclter itl whick the globe is immerfed be gite clean, and of the fanwe kirld with that in the glolDe, othSerwiiVe that wllich etlters the globe, tow replace the air removeda, might derange rlae ¢xperiment.

Having pros7ided mySelf s07itEl a nutuber of globes of dif- fieretlt fizes, all fitted with boards or Itands to fupport theme i:}w the rnallner abovoe ttefcrilteds I proceedced in the- cotlrSe of myf experimel-ts astfollosvsD

Finding that ^aw filk? tspoWed- ir> water to the aEiotR¢of light, cauSes-the water to yield pure air itl Ib great abulldanceg I was defilrous of finclirag out whetller this at-oSe frotn any peculiar quality poSeSed by rlle f1lk; or svhether other bodies lnight not be made to produce the fame effeEt: to thls end, has;llg provided 6 giol)es) each about 4 inches ill diameter9 andi; haviIlg filled them with freth ipril)g*^sater9 I itatloduced into

then



<6 9 BENJAMIN tHOMPSON S Experzzenes them the followingfubllances, and expofed them all,, atithe fatne time, to tlle ad-ion of the fUllsS rays.

Intthe globe l!i° 1. 41 put tS:grains of Ihe@5s wool;

No 20-tv1 5 grains of rEider dosvnX N 3. _ I5 grains of the Sue fur sof a Rut

;-fian hare Nt-4* 4 I5 grains of cortotz, wool9 No 5. - lS grain-svof litatX or the ravel;gs

of fil-le litlen, N°-6. - I5 graitls of Ilurnan hairs tlieIe

XbRarzeesteitlg all well waffied, atad beizg tlloroughly frd of air, by being wet before they svere put itwro the ilobtes

The-refults of -theSe experirnellts svere as follows.

Experizet W° 6. The globe Nt t. whicll contailled the {lz-eepXs woo] kdid 1lot

begin to furnilSi air in any cotsfiderable qualltity till the third day of its being expoSedL to the adtion Nof Bthe fun's rays 2 and fefireral days of cloudy weather in-tervenizgX I did not remove the air till the eighth day, when I ;*colle<ded Ig cubic inch9 whichg proved with nitrous airfl egave Ia + 3n = I238, or s72

*r. S degrees. The virool at no time furniShed imore than one-thlrd part o-fE

the air, which an equal.quantit of fiIk would have furniShed arlder the fame circumfiance

The water was very faintly tinged of a gree-ruiffi hue

Experiment N° ,. The water in the globe N° 2 Witll the Eider down9 begat

almoIt immediately to furni{h air:, and contirlued to yield it dUtiIa the whole tinle of the experimelltt nearIy in as large

quaxltlties



sn the Prtglsan of I3ephlog/?icated S*r p7 quatltlties as tEle water with filk had done ill the former expe- ritnelts and ntarls7 of -the fame qualitwy. I + CUbiC illCIleS 05

thls air9 ftlrnifted tlle eightll day fiom the begil}nitlg of the exgerirrletlt, or the thord t:3f furlthiI:le5 proved svith Ilitrous air

gave l a + 3n = [,349 ot^ z 6 6 degrecs of purity. 'I>}e svater s^ras faitltly tinged of a grcetainlX yellozzi{h caRv,

atld the ffider dowtz, svlaerl examitled attetltively9 appeared to lJe covered with a greetlifh nime

Ezperimest N° 80

Tlle glolze NTO VVitll the hare9s fur (wlaich svas white) fute

ninaed tllore air tllan the theepss wool, but 1lot fO mtlch as the Eider dovvn. After four days of fullIhilae, I colleded z cubic ilacTwes of tllis air, svlliclaS proved witll nittous air gaveV

+ 3t= 1v447 or 2562 The srater llad acqtlired a very faint yellovv1 hue; but it

didl 1lot appear to Xlave 1o1l much of its tranrparerlcy, or to be difpofed to depoflt alay fedimellt.

The air prod-uced itl vllis experiment lmade its appearallce itl a

diSeretwt mallner frotn that furIziffied in thoSe preceding it, the air-lDubbles svhicll appeared upon tile furface of the fur being at coni1deral)le diRatlces from each other, ancl growing to an ullcommon f1ze before tlley detaclled thetnfelves to riCe to the fulface of tlze water.

Azperimez! N° 9. trEle g^iobe Nt 4. ss7ith COttOtl svool furLlffied a conflderable

quantity of air svhich appealed to be better thall that fuln;ed by a1]y of the five other globes. 63roved with llitrous air, it turne(l out IB+3n Iv07, 0f 293 > and, what was particulars ttle water did not apapear to leave alteled its c.Olour irs the leaItX or to have lofl: ally tlling of its tranfparency.

Vo LXXVII. O Exp



S;r BEPFJAMIN THOMPSON s E¢perimgntw

Experkmenf N° IOe

T11e glolJe N° 50 svith tavelings of litlen was very tarc3y iil furIlilhing air, alld produced but a fmall quantity, at the eVnd of a fortniglatX hosvever, Io collehed about 2 cubic itlches, which3, proved svith nitrousaIr, gave Ia+3n-I,SI, Ot' 249. > The (zir appeared to have v-ery little difpotitioli to fix itWelf t(3

the flrface af ellis fubNalace. It sras very feldom that tilere vere ail-bubbles ellough attraEed to it to caufe t to rife to the

ftltfce of tile waterS and the few bubbles wvhich occafiloncllly made tlleir appearallce very foon difappeared upon the dinaillu-- tiOll of the light and heat aS the fun. In ffiort? it appearedy

that there is 1)t1t a very feeble attra;Etion between this ftlbIlarlDce aIld the particIes of air) at leall when they are dilqolved n vater. Whether this arbSes from the fuperior affinity of the isub{l:ance to svaterv or not, I svill not pretend to decide; but it appears to be probablev as thet-e is fo firong an attradiotl be tweeIl vater aX^ad linen, or flax, which is appareI<t from the ar7idity nvith which a piece of dry linetl drinks up that fluid, and becoines Wet9 evetl to a collfiderable diRallce, svhetl ont end of it only its placed in it.

You will recolleR that I here cortfider the Separatiotl of the air from srater as a fmple operatior; and that I do not take lIltO the account the puriScation, or rather the generatioll, of this alrv Tllough there is great reafon to conclude,, that thei:s twto operations are very nearly conneded s yets to firnplify myr inguirlesS ][ IhallX in the firft place, conI;der tlle appearances as they preSented themSelves to my iElafes. It will be eafy after- t-wards to draw awy concluEions from the refults of the experiments which a careful examillatiotl and comparxfosw of the various phtnomena will jullifyt

Expez



t the Prod?W2;ox of DephlogSicved Sir 199

ExperimenZ ND° I te

The globe N° 6. with human hair, filrntEed Ilill lefs axr than

lthat ssrith ravelings of litletl in the 1aR mentioned experiment;

^buts notsrithRatlding the fmallnefs of the qualltity, it was con

flderably fuperior in quality to atmofpheric air, fiora proved witlt

itrous airs lt gave Ia + 2n X,459 or X 55 ; whereas commot

air, proved at the times gave Iaf In_1,08, or 9Zr

Experimenx N° I 3e

To aScertailo the relative goodtlefs of the air furnithed by the

water ill theSe experimeruts, and of .that produced by expofing;

dEreXh healthy vegetables in watelr to the a-diote of the funss Ilghts accordillg to the meth(3d of Dr. INGEN-HQUSZ, I colled:ted a

fmall quantity of air from a Rem of a pea platlt, which hadi

four healthy leaves UpOIl it, and foutld it to be much inferior to

that furl}ilhed in the experirnents nwith fllk, and the various

other fubltances I made u-fe o£ Proved with rlitrouS air it gaYe

Ta + zn-I ,0s, or I 9s X

AI1 iIltire plant of houSewort, of a nzaderate fze, expoSed

LI1 I 2 ounces af svater 7 hours, to the adion of the fun s raysy at a time when the weather xvas renzarkably fiIle9 and very hot, furlli(hed about w of a cubic inch c3f air, which was fe 1NUCS worfie than comnaon air, that I meafure of it9 svith I tneafure of ni-trous alrX occupied I-S36 rneafure-s; or it -was -Iaf In! ,36, or 64. But I lay llO kind of Ilrefs upon tlle refult of this experimeIlt, as it is more thall probableX that tIle badnefs of the air arore from the roots of the plallts; for frorn the leaYes

alone I have frequently fitlce obtained air3 wlwich appeared to

113e coIlfiderably better thall common/airF t , Frotn



X OD SF ElENJ AMIN - THORIPSOPQ s EXPr/^SS-S Frorn the leaYes Qf the PeaCT\tRee I OE)ained aN air Bth;ChY

PrOVed With nitrOUs airS gt\?e 14+28 tf33) OJ; I68 ; bUt I did I+Ot thiI}1R iX 11eCeXY O TBUIt;P1Y TheSe eXPerimCStS PAr- tiCU1arlY aS I)r INGEN-ROUSZ And A4rJ SENNEBIER have given us the refults of i tnany of theirs UpOtl the fime fuWe& of the accuracy of which thele is no roon lefE to cloubt I {hal>l

l

therefbre coIateat nzy{elf wth re3fbrring to the refults of rlleir experimelats

With a vle;v to derermtuing9 svith g;l4eater pl*eciI;on tlat quatlt tity arld the quality of the ail produced ty a given qualltity of water atld iE;lka expofed for a glVC£1 time to the a&iotl of the Xass rays I lnade the foilowing exper11nellt-.

Expe3*mdnt NB r3. A gIobe of fi^tleS clear, wrhite g;3a alzout 8T:< inciles ln

diamerery alld Cotltaitlilg; zg6 cubic ;lcEles beiIag filled w;th fi-effi @ illg vvater aild 3o graias of raw fi:lk, was expoSed itl tny wlIldow three daysS ti%. the totli 3t1] and t4th of May laItS tlleSe days being ir the nzoR part cold atld cloudy witTl i1ze}rt iX3telvals of Xlllhitle Air produced g> cllbc iuches; quality

xa 37Z iI6tS or z3g.

WIay I5* This air beilgg remeved} arld lts place fupplied wit-h fi*Cfh wratcry the globe expofed 1ll ttle fu< rllis day froul nine oclocld ir] the tr>Orrsiag till f;ve oXclock ln-the aRertaoonS the weather beitlg vely fiXle, yielcledy SaT6,, cul)ic inches of air9

which pre3veci with nitrous tlitl gave tv + +a = X 74 or Ja6* The heat cf rlae water in rlle globe duling tIze experitnent, was hom 70° to 98° 1F The water had now loR conlideralbly o£ l t J tra<@arency, and had aXutned a Tight greelwlth hue

May 6. The alr filrIlithed yeRerday belilg rernovedS tlie rw * ^ s * * ¢ w r > r w , . s e g O )C St}lL:e6 I 011S (: y dUrXIE;11X hQUS OX TUI)1 ]1I1eN 9 CUD1C-

* s

i3 ANCLeS



os te ProduAion of DephAogi/tcated Air. IwfOt,

aches of airs which proved wi{:h nitrorls air5 gaYe Ia + 4n = Iv44 or 3)6¢ }

3Hay I7* Tlle globe itaiEbed this dayS during 3 hours of finShirle 6 cubic inches of air of a very trninetlt quality t

. | * r t * *

tor provet t wta ztrous alra t gave a+4X S35> or f

3t5* May Is This daay cold atld cloudy; nct more t1!aan

}aours lilnlhillea aisr plceduced 4 of a cubic illch; 6palitsr a++S-I556s or 344* May 9. ttI1e giobe appeariLzg I1OW tO 5t quite exhauRed of

airS {hewitag no figts of furtlithitlg atly additin3na1 quantityfl though expoWed to the adcRoll of a very brlgIlt; in) I removed the globe firom tlae sstindoswa andl placed it by the iRde of a

German Itovey wllere irt %7aS Iltpt warm to Ioo° F. SomA -to

otclock in the naortlitlg till 5 oeclock it tile aRerrl<t}ons By this means I olJtaitled X of a cubic illth of air whlcT proved

* * s wXt lltrousalrS gave z+48=I74 tr336. Not beillg able to obtain any more air Som the giobe I nowt

* w

put an ttlc # to t Lle experlmell.t.

The qUantiTiCS t1d qUISIiZiCS Of The AiS firniEed UPOR ThO- - Diffrent daYS >7ere as fUlLIQWS :

. .

QSlantitys - %ality rtIpou the t zth) 3t Sth} and IAth of May 93 cubsc inches To4 + 3n = I>6 T >+ OR 239

1 5ti ' 8 a f +8 = T 9 74> or 326 X Sth - 9 ta + 47a-fI +42 or 30 z7th - 6 - waNat-sn35> 0t36a 8th * -3- a.+48= T56> or- 344 9th -+ sa + +a-I7+> or 3M6

_ s _ __

TotaL quantrty 334Mean quality ia + +e = I 847 or 3 r6 * e . *

. .

^As itl this exper;metwt the air firtliiTled eacil dC was retnoved at niglit, azn1 tIae plaCet < tccupied XI1 the gloUe XppltedX wid

* - het



xoz > BENJAMIN tNOMPSONsS Experitnes * i

freSh vrater I was defirous of feeing what variation it would occaIion itl the refult of the experiment, iZf; illRead of removw irlg the a;ir from time to time, I fuffered it to remain in the globe till the etld of the experimellt . to this end I made

Experiment N° I 4* i ][t1 which the globe being filled wsth freS water, and the

filk uSed in the IaR experiment (being fir£E well wanled)>g the whole was expoSed four d-ays to the adion of the fUn's rays9

the weather being remarkably Ene, and very hot Upon re movitlg the air produced, I fourlci it amounted to 3OtIz cubic

itlches; and its quality, proved with nitrous air,, was 1v + 3n 0=I,02, orzg8,

I fiould 11ave continued the experiment fir fome days longel-Qs, as the globe did IlOt appear to be exhauRed; but-the quantity of air already colleSted ill the globe was fo great vllat it becaxne very difficult to relmove it without runtling the lifk of lofiXag a part of its or of letting tlle air of tlle atmofEehere erlter tlae globe, eitller of svhich *vould of coutSe have fpoiled thz expe- ^-riment. FO1G fatety therefores atld that I might 1lot by an acci- de1lt lofe the trouble I had already had with itX I put an end to tlle experimetlt at the end of the fourth dayO

The water had loft of its tranfparency, alld had a:cquired a

greeIlilh caIt, as in the lall experiment; and iIl both thefe experimel-lts J obServed, that a conIRderable quantity of whitSh yellowiffi earth wa5 precipitated by tlle water which, falling ta the b-ottotn of the globe, attached itSelf to the glaSs in fuch a

matlner that it svas with difficulty that i:t could be removed Iflhefe were general appearances, alad took place in all cafes iIl

a greater or lefs degreeX Fhere a conflderable quantity of pure air was fepariated from water by the influerlce of light.

Expe



ss the ProdSxoa o:¢ I)epXZoSic;X:ed Sir 10s

hXperitsenZ N I S The fllk made uSe of in the laR esp-erinrent having been

flXequently uSed in the fio1egoig experimentsS I was defirous of Reing tlle efEeA o;f nzakitlg uSe of freth flk; and alfo of vary- ing the pioportion letweetl the quatltity Otc filli the quatatity of water, and the fize of the globe, acrordixngly9 at 6 osclock P.M. UpOLl the I3th of June, I filled a Sall globeS about 3: i2lches in diameters or (to afcertai£l its fize more exadly) svhich coI<tained julE zo cubic ilaches vvith freth fpring svater and- I7 grain$ of raw filk, woutld in a fil3gle thread, rhich had xlever been put itlto NvaterX or othersviSe ufed7 fince it carn-e out of the hands of the filk-vviI<der.

At the end of four daysS zVt%. the 4th} 5t1z I 6th, and lr7th of June, thES globe had only furtliffied 4 of a culac itlch of air, which? proved with tlitrous airS gave Id+--I-S-1S329

or 68; co21fequently vas much wolfe thatl cotnm?n ail. Upon tlze I 8tll, it began to produce good air, and duritlg fix

hours of funIlsine it furnified 1<lo50 cubic illclesX zvhich> proved witll nitrous air, gave la + 3n = I, I J s or 285-* :

The two following days (vi=. the Igth and zotll of June) t furniShed I<5o7<> cubic inch of air, w7hich proved ritil ni-

trous air, gave Ia+ 3n_ I ,37, =263; after-whichit totally ceafed to yield air, though expofed for I4everal days in the full7s ts1yS.

Total quantity of air produced zT6070 cubic inches7 tnean quality ta 3n= I,465 or-2s4.

By this experilnent it appears, that raw i:llk when uSed fg tlle I5rft time does nc:t immediately;dii:ioSethewatertoyieldl pure air; on the contrary tbat lt phlog*1fli£ates the air yielded



zo4 Sgr 13E NJA MIN 1"HOMPSONS Xsperx7XS

by water to a veryrcorlfderabledegree; a£udthisIaftersvards :found to be the caSe with fwWral other fu!)Ratlces

Though the qualitsys at a lrsediuIn of tTie air firazfhed in tizis experimellt svas xlot quite v -geod as that fdrn1Ibell ill tlle

tX7o experir<actats laa elltiOlltd (iSiSs No t3. and N° t4Q.) yt

tts quatltitv in propOrtiOrl to ttle cluaJatity of svater made uSe of wtas great:-er thatl in eitlaer of thezl l it atmoual:ed to fome thing raoretharl oneeghth of the volunze of the svater

Oif all the lubRarlces I had hitherto made uSe oiS itl theS ext?eritnents rasv folk- had ftlrtliShed tile greateLt quatltity of ptlre air t or, to expre{W myilf tnore properly, laad cauled the water to furniffi the greateIt quantity; but it appeared to me very probable, tllat feme ctller bodv tnight be f;ourud that: poiRed this property itu a Rill greaeer degree tE1at1 t:ill. Turat itl8; this tnatter itl my luiild it occurred to tuts to make the expelitazetlt svitll the IillEy} or rather corton-likeS iSubRance produced by a certaitl Ipecies of the Poplartree Pcpslus nigrv very common itl ttliS country and which I believe grovvs itl Englatld I recolled:'ced that examinirlg iwt fome time tefbreX svith a differellt view (that of ftetug if it nwight not lJe snade uiSe of with advarwtage, as (1 ful)ilitu-t:e br Eider down) atld endeavouring to render it very dry by expofing it in a chitt plate over a chafirlg-diffi of hot embersS when it had acquired a certain degree of 11eat Iinall palcels of it quitted the plate of thetv osvt1 accord} aad .nautlted up to the top of the room.

This convinced me of the tirne t1Qt ouly of its extreme finenefs btlt a1{S of the Illoilg attradell svhich fubSilis lJe- tvreen it atld the t)articles of air; atad it now occurred to rne that tlhefe qualities I10t Ol*!.ly reIldEr it peculiarly proper as a

liabRitute of Eider doternJ for collfillillg heat but likewild are properties



>>ox fXa Poos&a4t f DEba/eX S;r ZOs

qrepertles tf a11 totll^ers $11e moR next«r)*; b ts tupPlying the tplace of I*llk in tlat produ&;otl of atrf by cxpetitl8; it in svater

to the aS:ioxl of vLae it1sS rays. I t!*lerem 1oR ao ame a

>s.-3makilg tile fallosvtlageermet<ts

EReeroment;19° x6* TIle great gloMel *(contents 296 cubic tnched) l5atlg filled

with fieSh I}ring waterS and t2e grains of poplar cotton} v}pon the evenillg of the gth of June anxl lJting the usst daB -$he tothL of Jtllle apoitl to the futl about four hours) upoa the tnorning t3f tIae litll tlae aw proutlced was rettoved arld -<*;Xts quatltity was ftud to be X * cub-ic itl-ch Its quality was very bads tz;Z. ta 4_ t' !t $65s or 35 degrees only better thaa >thoroughly phlogtfiicated airO

{3pon the Ilth t2tt) and 3th I -cu}i-c H1Gh of a-ironly . .

was producedS and tIlis appeared to be as bad as poltllJle; fzX

q?roved with Llitrnes airX it gave IB + I,8 2 or o.

Uporl the *th a w air- lzubbles ouly were - fiArtl;{he^; louX -not&vithRanding theI:e utlfavourabl& ap?earances I Rill cotlti enued the experimenti atacI >tny patience svas amply rewarded t

{ir the ruext dayS the I 5thb the I;II1 bez-ng very poweril anal the weather-very hot, tlat water changtag fuddetlly to a greenith -colour, lzegan all at otltce to give good air¢tll great abundanceb

ln the courSe of the day tOisot> cub<w itac-hes strere produced}

which proved wid nitrous air gave 14 e 3n r>43 or z57*

June 1-6thJ a very warm clear day The globe expoIEd in the futw fkorn 8 oclock in the mornillg till 5 o9clocli in the afternoolz firrsiffied x4<oo cubic itlches of air, whichX proared with nitrous air gave a; + 3n- X ,345 or a66

w3u V0ts LXXVIIo



6 g1/ Bv-4-g Nr; agOD?iS,2S43NqlS EJ4t>/gg48

*.]t]1C t tt?Rg cloTXa.y) n Xth lt<tet Va1S of X}zl:;lixlew T le g;Sobe svt1 a1-1Ott ; hours X1X1 gClc 7-i9,,4o- cubic il>hes of ai;+> o£ a verf ClMiijlCtlt QtlAlitV i)t4ts I4t 48- tv49s Of 36t3*

ti:the rta;ter 7k2.aVit.g by degrees Oft its tra!Xu@aretzey< atl-2Ci 11aV

X8 acquxred a dtep gz^tetA colout > it bt^olie up tla1s dsly atwd de po(ited a gleee) fedinentX after vI-lich it recovel^ed its trsui)aS etlCsXrX atld b>cat>ie aXtmoR eol0urlefs. IF CO1ltit1uC(I2 nOt\vit StalAdit}gS to furtta (diV it) COtRildercllUld qtlAlltititSo

tt11)> ] Sth) I;Cltig expA<3 t.n the ftlt< s ravs f;rotu 8 o cloclS ^S] the tucrtai-ag till z osctock ;il t-lEe afteraoon (Wtatt1 th£: lleaw retls became crverca-a) tlle glolDe yielded 615-070 ctzbic il<clles Of

airv ss->hicll }&roved twitll ntrous air gave 1a+4n. vg449 or- 3560

JIle tIze t tl-< atlct zotl Thefe tsvo days the gIobe fu£rtliShed xlo tmore tahalkl ;> IoXo cub-ic ilaches of ail^ whicil, proved with

aitrous arw p;ave iv + Dn I gc62 or zg4; after which it ceaSed

totally to furtliffi (liZ4 aIad t-he colour of the vater changed to a

Micad yello&vi(h C:aR5 an&l the cott3n affiumed the fatne huc. The *-fiellowlng are the quantities and qualities of the different

parcels of (1tr irtwilred sa the couSe of thts tsperimentX

Qlalltlty QIlalityO

IJpon the xot:h of Jun I4 cube inclies IB In In65> or 35

llt) T2t, and I3th I I4+In2> or Q lAth O _ _ ___" ;5t5 *" °1402¢ La+3nI<> or 257 :t6th x+4 sa+3X=T,34q or 266-- 7th 7X3c4ws Xa+48_ I740 0 36 .8th 6It-00 4+48la44a or 356

gth arld 2oth - 53sIo3iS > Ta+38 I,067 or 294 6f; , D 4! pl _-^ F

tT4281 SutA:ttlt.S 444. Mean quality ia + 3n = I ,23a or z7y

w>_. __o

Thsi



ppt 2 ¢ § Deth¢P-7Zed Xrx to7

vefuIt; the total qvlatwrity -of alr produced beiolg Ai3t- cubic inclles, -and its qualityr9 at a n=zHiutal I44-38I,36, OU 74

To aScertain rlle relative fit-enefs of tllis poplar cottong alat tthe threcld of rasv filk as Epun lty t46le wormo itl o-rder to mke an eItitnate of tlae ftlrface of the<-folllzerX I examinecl tE<e toth at the falme tirme utlcler atl excellerlt microScoye wher tlie diatneter of the cottollv ̂ th¢;Rt is to fayv Qf a fltlgletllreacRor .fbre of i.t, apJpeared to lDe laot more rthatl l<alf as g;reat as th& diameter of the Illk, cotlKequelltly its dint-rlerer was not more tAlan 36t s part of atl itlch; for I hclve thewllS tn a wformer letter, that the dial<zeter of a thread of filli, as I}ull by tlle torin, is ollly s<,2,'zF of aw inch. The fpecific gravity of tlle cotton I foutad to be very nearly

equal to that of svaterS collfequerltly it is zo tllat of filk as xooo to 1734 its furface, therefore is to the furface of aI: equal wei ,ht of raw filk in the icompound propor;tion of < to I s

asld of I734 to IOOD; that is to y, as 3468 to IOOOo

NowS as the furface of 30 graitls of raw vIllk amoutlts to $76 fquare illchesS the furFface of 3o grais of poplar cottot muR amount to 65 fquare itlchesX which gives 55 Sqtlare inches of fuarface for each grain lrl weight; colafequetly the furface of the COttOtl tnade ure of in the foregoing experitnent (19° t6I) did 1lot arnoutlt to lefs tlzan 660s fquare inclles (for 120 grainsX the weigllt o-f the COttOll, mElltipliCd 5 55, gives 4600); an enormous furfaceindeed for a bodyX whoSefiolgd conzents did nc)t alnount to quite half a cubic incll.

sFrom he1lce it appears evidently that the quatltities of air irnithed by water, ill the experimetlts witl] raw filk, atld with poplar COttOIl X were neither in proportioll - to the quantities of theSe fubItatlces made uSe ofs nor to the quarltities of their

P 2 furfaces



tc8 S;r BE;Am IN.T7oMPS<XNtS t;eZiSeS#S.

(ufiCCie a Appttll-S iikewife from the txvo 1aA tsperirmetiltW that tEle^ aii vshCh is furniflled lIl the begitlaitlg of tile experi wnentX tv svi1e1w tiwe water is firIt tspofidt to the adtion of t1ze 4s'tpS rays) is tCst1Rwer b good nor in b great abundance $:

aSerwardsS at: a tnore advatlced period 2 andithat tt totallyzceaIEsoiW to le p-aduced aficr a certaiil tlme.

To aScei*taitl9r sXV*oth greater p,*eciElotaX the qualities of the all- irnii:lled at: difiretlt periocts of tEle experimetltS or rather the y3eriod wllen tlRe 6vater begir$ to give g;ood air; alict alSo to^$>

derertnltze tle relative qatltities and quallties of the airs pro+ Eluced in tlle expertlmetwts svith rav {il,* and ill thofe with^/= POP1Xt COttOIlx I mJad the 1IQWi*t1S eXPEriMeI1tS

Eeerzme7xf DJ° I7.

A globe abot: 4t inchesV zn diatneter containing ;^uR 46+ cubic illcl-esS lzeilag filled in the evenil^ag svith frelh fprirlg waw ter alld 3o grains of raw lilk whscll had beeD previotl{ly wathed thorotlglllv to See it of air and the remains of brmer^ experirnetltsy alld ldtilag expoNed the next day in my window9 the weather being cold atld cloudy svith not more tlaan X hour^ of funlhule, W of a cublc illch of air was producedf sYhich> proved witil llitrous aira gave Id+3X1986 or X4.

The two fbllowtlg days the weather beirlg cliear ted modeZ ntely warmS 34 cubic itlches oi6 air were produced which>

proued with nitrous air gave v + 3n X X X 4 or z6*

BxperxmettN:° 8.

The gIobe haviIlg been agaitl filled wii freXh rpring wateri arld the farne filk which hd fierved in the laR esper mentfi afier X I<;ghtss and T day of about 4* hours fuh it hadt brnillhed X T cubic ixlch of air whoIb quality was I a + Xn =

I^X3 Q^ ;9Zo T



- sn tSe iPro^it of Dz9catedSir* xcge TIe two followilog daysa the weather beilog very fine9 ;t

irllidled 31*i-3o cubic inches-of airX whichfi provecl^vzith witrouso air, gave Id + 48 =ws! v5$> or 3+2*.

Epergineazt N° X gX;

lthe globe beng agaill filled with freITl waters> atld tll-e farne hElk ssrell wathedS arsd being expofed 2 days in the fun9 it gave xlto cubic inches of airn wEliclzy provied withiinitrous air gave

v + 38 I gb7 or 233te

Evenmer P

A like gIalzee with freth water atld an equal- quantity of jpoplar COttOtl BThich ha.d been uIed in forme-r experimerlts teitlg expoSed at the fame times gaxTe 2T5-o3<>-- cubicsitz£hes of airX whofe quality was x+3n Iszo or z8O*

Experiment N° n-t.

A fmall globe, eoutents 2O*cubic inchest- with; X 7 grans d

taw filk9 expoRd at the fame time, gave I cubic lnch d airs, which tured QUt la+38--I,37 or %63*

Experincent No 22*

A large globe cotltainitlg- 296 cubic lnchesS lveng filledU avith freffi wbater arld a ftnall qualtity of conferva rxvalarzsR andsexpofed at the fame time with the three globes above-mene

tiotwedS gave culzic inch o;f air which9 proved-with ni

trous air7 gave 1a 2r -IS76 or T24.

The water itl this experiment was changed to a brown co- lours owing, as I conceivedX to the too great heat the <aerva

* . P acqtllrec 1ll t ze lune TheSe expcriments were mad- betweetl-l ! the - ad arld tIle stla--

s

tS JulF.,



fir<BJ A-MIN tHOMiPStEi s -E2/-}WeX-/s

I:Experzzent Co 235

Surprifed at the ftnallnefs of the quantity, and tIae il-ferior- qvlality, of the4air produced ill the laft experiment9 I was in- (-luced to repeat it; >accorldingly the globe beillg agaitl filled with srater atld a quatltity of ire« con,%2rsUd riCulariS (>l fmall hatldful), eatld balog expofed to the adion of tllc furl's rays during 3 fine days, I3l-3T40 cubic inches of air were producedX, whicll, proved with rsitrous air, gave Ia+^n-I,54 or 246

At the clld of the experimerst the water appeared<to;be verv Ritltly ftitzged .cf a greetliffi callv

The tv^ro followirlg expetiments we-re luude upen the 20th and 2Ifi of AuguRo

*Experimen lN° 24.

A glo1)e9 about 42kluches in diameter (cotltetzts 46 CU5iC

iruches) leitlg SlkedQwit3:1 freh fp-ri:rlg water- atid +3s gralrl-s of <a<aw fllk which had been uSed itl manydpreceding experimentss alld beitlg expofed to the ad'ciotl of the fun?s rays t%JO days, i a11 about 8 hours of futlihine, the weather being cloudy great part of Xthe time IT6 0 cuoic inch of air was producedS -whichX proved with rlitrous aira gave I4+3n-IR96? 0£

,20,+.

FE sperz°ment N° zSo

At^>the fame time an equal globe, cortairling freffi br:lllg graver, and about- 1 5 graitls of poplar cotton (which had lilie wiSe been ufed in former experiments) produced 1<5o80 cubic zuch of aor, which;, proved with nitrous air>t gave Ia+3n-

6s;X>4O7 °Z 26OS,

Thc



& /t6 Pt^sA2iat nf DMhZvved XrO * >

Tl<e wtater itl both tllefi experimetlts had acquired a fAil<t. greeniSh cafl but tlze colour df that with the cotton was tather the deepeft

Upoll eXatnilwitlg this wat-er u-tlder a naicroCcope I fbutld it contailed a great aumber of atainalcules exceeditagly l;maIt, and of nenr3y sz1 round figursz lLlwat writh the Iill cotwt-ainect t1ae faXe kttzA o;E alhinnalcules likesviSe bvt notz im m g;rear> abutadltlcz I Tw1ever failed to fitlul them in¢every caCe in;> sxhich<< the water uSed ita an experitnetlt lad acquired a gSeeniffi hue sWe

atld fiXom their prefience alo-rleX I tlainbk lt Inore thatz probabIe> tlwat the CeIou1 of the srater Z7Z theX at¢: arofe n aIt caiZ* I have fpent a great deal o:f time in olJiet^vitlg themS

alld have tnade many experlmerlts upon their lprodud:ion <l but as 1[ laave not yet lJeetl able to tisi rny ow-n tulud> witS rebeA to the part they atit nl the operation of pUStiIlg the aic ill water I lWall IlOt add to tbe length of this letteta by givXg an account of my enqtliries and obServations rebeAing themt

I was ye-t by no mealls fatisfied with rebed to the part which the filk alad other bodiesa expefel in water i¢s- the fbre goitlg expefimeIlts9 aFted n the purifying or dephlogilticating oDf the air protleced

I:)r. PRIESTLEY haslo;zg fince &kovereda tha-tmany alllSmat

arld st-egel:able ilRances putreng or rather diIlolving} tIt

water ita tl:ae I;ltl Caui tll-t water to yield lage -quantittes o£ dephlogiEicated airX but I eould hardly concei^7e-at thc Small quatltity of filk which was uSed ill my experitmentsg and: which had beetl con0aul:ly in watr br more than threeX months atld had fo often been wathed anjd tveni beiled itt water thoulzl yet retain a power of commurlicatirlg any thillgt to the large quantities of freSh water in which it was icceS bely placedl ;; at 1¢aR Xhing in ifficient quanttties to unpreg

azat



abutztlaetCe of ail wlaich rlaezy pr*OdvlCed It..,:W.as,;.11 more diEcult to account :ir-the,purlfiCation d

<t11e air lli stsiAw cXl erirnents with weel and fur, atu2 hum>atl hair : tiptCiSlLiyR.*:RS t-zOlM& eS- thenlS experimellts th$ \vater tlad 1aXt

>itltibly clhqlzg-ect clt3t}-> mSor dld --it appeart to have loft any t11A;Xwg olE its t*at3:Ipav-S;lcyQ t.. :)tiS'tf@ iN thei CfieS9 > the quatl tities v£ air p>redWubedazver-e very final-l 2 but yet itS euality ura$ better thatli ttat -tV cterlawon ait> atld co-tlflderably- fuperior to that of the air txifii£a; S in the water previous to its bettlg expofed to tht-taftiotz of t-lle futlSs llghlto it't'ns "lort' it was dephlo g;fl:icated in the -experitnetltS lJut -the nser in wvhich tla;s was dotat is very diffiwlt toXaiertain

Witla a--vieur to throwing fome nesv igllt->upon¢tElis irltrllcat iInJed: I made 11-¢ fUllQwltigbeXPerime11tsO

Eqerirten! -P z68 Cotjcluding-u that if S;lk atld other bodies9; uS 1Z1 the fore

go;tlg experiments adually did not corltribtlte anjr thiIlg CO

Iidered a$ cllymtcxll I:ubRallces,- i+tEle protefs of the produdio of pure air yielded ly swater ; lttltS if; onL tlle contra they advedelrlewly as a mehanical aiel i-n the rton of the air frotn -the Kwater by afforditag>a* wavenieDt fur-ice f;or the ait

to attach itfclf to t11. tlus tcafe7 t<avysotner body} harring a

large i:urfice, D atdt attra£titlg ai-> ln wa;ter, might be made uSe of inltead of<2 lillcbf;E*the<-ex>pexime1wt, atld pure air would be irIlithed itho-u«gthe body £b made u.fie of {hollld be totally illcapable of commutlicating any tbtgtg whvtever to the water

fToraficer£aill this iEt waShirlg tile great gl-obe (containing zv6- cOubic7tinches) perfedly clean and filling it witTl fiefls liritlg, wa-ter, - I itroducedi illto it a quantty <3f the fine flexible

a thread



¢AZ Z?e pr&2lDS of 13ethfag0X¢ated Al't t 1 3 tlzread of glaSs, conzmonly called jpan gIRpSs fuch as is nfed for makillg bruffies for clearlitzg jevrelsX arld for ulakitlg a kitld of artificial feather :Erequently fold by the Jeuv pedlars This rpu1l glaSs is IlO other than cotumon glaSs drawn outX when hotf illtO 2S exceeditlg f1ne thread; wl-wich threadn itl confe quence of its extretne fiLrweneSsX retaitls its flexibility afier it llas grovvll cold

I luade choice of tllis ftllbllallce not; only Qll account of its great furiFaces but alSo orl account of the Ilrotwgr ateraAioIl svhich s linown to fubfiR betxvectl glags atlc air7 nawd the stnpoffibili of its comlnuIlicatiIg any twiilg to vlle svate**

The refult of the expelztnellt srasX t=>lat the globe ttitag ex pofed itl the fUT1) air-bubbles begall ZIIXOR 911z1nediRPe1Y to lmake thelr appearance UpOll tl]C furface of the fpun glafsf atld itl +

hours a7070 of a cubic incll of air svas -ColleAed, wl-lichs proved witll nitrous air5 gave x4+nt7X4 or SSX after4 orhich, tlot a fing1e air-bubble lllore z0ras pt<3tIuced thougil the globe-was expoSed a svllole wteek in the svilldov9 during whictt time there were feveral very war1n9 fitle? Iullnlilly days

This experimetlt lllenvs evidetltly that fomethillg more is wawtillg to the produAiol] o;f pire air l)y svater9 tspoSed in tfflhe fun, than merely a furfa-ce to which the air diflolv£d in the zvater CAll attach itfelf7 itl order to its making its eSca>e

The air irnifhed ill this experimetlt svas doultleS-s merely- that vith wlaich the water iflUiIlg from the earth sras overo charged atld wllicll would hav-e made its e-fcape firotn the svater had the svater inftead of being expofcd svith the rpult glaEs in tlle full beetl fimply lefE br fome time expoSed to the free air of the atmofphere

It appears tllat this air llaturally exiflaing itw fpring waterf inRead of t3eing dephlogitiiCated? is fomethiIlg worfe thaa

AT0l, LVIID q colnmon'



I X 4 Sr BENJAMIN THOMPSONSS Experimeyats commoll air; atld this agirees 7zith the obIervatiotls of IDrt PR1ESTLEY and feelms to JtlIlify llis OpilliOIl with refped ta tlle catlX of the irtility of lands xvathed ly sntaters iflililag fiorn5 the earth.

Jf the abos7e experimetlt ffiesvs t11at Iornethirlg is wanted to be mixed with waters itl order to enable it to yield pure Air9

when expoNed to tile adtion of the fiItlS light9 tlle following i11esv tI1at this Xgtt;g vvhatever st tmay beS is frequelltly to IJe f8tl7wd tt1 the ntater itfblf; Itl its 1latural flateO

SXsrSe2t M 27- A largc jar t?f cItar svhite gla cotataiIling 455 cubic inches7

beillg svaffied very clean9 was filled with :ffe+h fprirlg vv^aterX arld inverted irl a glafh bafon of the fame allel placed in tlat- Iniddle of the gardell of tlae Evledt)rss Palace, svhere it was lefit expofed to the weather >8 days.

DAt the fime time arlother like jar was filled vith water takena :ftom a potld in the garden in which many aquatic P1au1:S Were grOW1Ilg and was expofel in the fame place, arld durillg the fame period. This water had a very faint greerliffi caR The polld from which it svas taken is fed ly a large rivern (the Ifar) which rutls by the tOW11.

The Second day after theSe waters had>been gexpoSed i:r^tlic iMu* I oI)ferved that a frnall quantitv of a;r had colle&ed itWelf at tile upper part of each of the jarsX

The third fourth2 and fifithidaysy ie pond waterfilrtliShed- a}r in pretty large quantities; and it went on to yeld it wit:hout intermiE1ol> wtletl tlle I;nl IhOnt UpOIl its till the fourteenth day,, when it Seemed to be nearly exhauRed. I continued the experimexlt, hewver till the twcntyeighth dayj though durirlg

thc



or xie Prodv8xsn of DethloXZd Air. X X S tlle laR fortlligllt the quarltity of air in tlle Jar did not appear to be fenfibly ilaclXeafed.

The blZitl; svater durilag the SrI} five or fix days9 ful*ntthed very little air a and it was 1wot till the foilrteetlttl day that itS L>egilw>>to yield it tl ay eonISderable qunnt/ities From tllis tltne it sstent- 011 to filRLli« it tlaough it very I1ONVIJVS till ffiout the tsfireiltyfccond ^Ay7 SVllt11 it ceafed appeatialg to be quite exlRlauRecl

Upotl the twetltyelghth day I l*emoved the ail4S fiotN ttle jArSs when I fotllld heir quantities and qualities to be as fbllows:

Qzantity QllalitySF AlrfalrlllAled by tt fpriUg \Nitter I4 C51t iCt'S IS+24-I>62§ or 3$

.

by t:he pOIlCt water 3 I -t - t 413 4 = I >482 or 25%

Ngether the colour of the fprillg vaterf 1lor that of the polld vvaterS appeared to be feIaElbly changed fi but both the orle alld tlae other of thefe svaters had depoElted a confiderable quanX tity of earth svhich vvas fbutld adlaering to the rEaces of vlle g]aSs baforls ill hich tle jars svere itlverted.

As thefi lJaSotas vere ratiler deepa atid as they wvere veC thik ill glafsS atid col<Seqlatatly llot very tratafparttitS thei-t bottoms, here the fedilmlent of the water ss7as colle&ed} urere iol a g;reat rnea\fure, olaScured or deprived of tlat direEt rays of the fU1a. Sube&itag that tlais circumRatlce might have had foLue efi& b as to havre h1tldered the water fi*om furtliSaing Co nuch air as otherwifb it rnigilt have yieldedy to fitisfty tnhylElf rerpeding this matter :1 repeated the experireetlt9 di@Hlug the apparatus ill fiuch a manneb that the fediment of the wateb which attached itSelf to the bottom of tlLle veXel iIl which the jar svas invertedX had the advanta;e of beillg perEed:tly illuX minatede

Q 2 - wF



S;r ENJAMIN THOMPSON+5 Exp-erxmerts

ExperMent ° Z80

1to A large cylindrical jar, of rery Ene tranfprent glaSsg a inches ill diameterX an-d IX i^nches high, filled svith fpring water, I taverted a colaical gla;fs j.arX 94 inches ill diameter at^- the bottonn atld CO2ailling 344 cubic inc-hes, filled with t1le famewater; a:tld expo;Sed the whole zI daysy itl a windovv frontiIlg tlae fouth.

The quaI-tity of air produced amounted to 40 cubic itlches >

and its qualityX proved by the teIt of 1zitrous air9 gave ta + -I,87 OZ 2J ^*_

The water iIl thiS exp-eriment irlliSaed very littk air till the ;feventh day 9 but after that time) 11avltlg afiumed a faitat gleexlif caN7 aild a fille greerwiSh Ilimy fedilnerlt (the green arrer of

3Dr. RIESTLEY) bPgttl:-tlH]g t0 be fortned- upon the botto-m o£ tI<eiarX it began to y-icid air in abulldancb, and continued to furninl it ill pCtty large quatltities till abotzg the tightecllth dayg when it appeared to be exllauRed.

Why the water fhoiuld tuil-n green it<-l this experimentX aI1d. IlOt itl tlle laIl, I know I10t 9 UlllefS it was iIl COtlretUenCE of the ]arge fvurface of vater ill tIle cyllIldlSical ja-r, which svas ex poSed to tI-<e air irl this experiment, or ill cotlfequence of the iUIlsS ]ltliNg direEly un the bottotn of the vedel where t11C- ieditnent svas formed.

In the fiorlmer experinzent the baSota :tl wh=ela ffie jar vas- i)verted was but jtl:R bi-g enough to adtnit tlle jar ; atld as- rl:e jar \vAs cyliladricalS thP fu;rface of the water expoid to the atzlo FlAphe^eS in t;he lDaSonX swas- but v-ery fmall X alld the baSotlk being- very thi£k7 alid fotlmed of glafi wllich? thoughd of the white LIt}(1 was of an infier:or quality7 and very imperfedly tratfpa reilt, as I have already obferssedX tbwe bottotn of tla: bafon

7 zvhere



sx the ProduSion of Dep?logieottgd Sir : tI'7'

vhele tle fedilulellt sras- brmed, was lJut rery imp!eriEtly illuminated.

I intellded to hwave repeated thefe experiments with57ariations,> a;nd to have made feveral otllers svhich I had proje&ed, and which I thought mi:ght liave thrown Come irther lIgh-t upon thI0sdwon-

derfill proceSs of the produEioll o£ the pure air yielded by water 9 but a Ivries of uIl!favourable wea.ther p>UittiIlg a A0p to my elaqui- ries alld my tirne having; heell muchA taken up fince vith;other avocation$, 1: have llitherto been prevented frorn pUttiIlg my de< figtas itl execUtiotl; atldt the lneaSotl proper for thefe expertments is 110Xv fo h1 ads?ancedn that I do not thillk it will be iIl my poxver to recotntmence them ti-ll the nes-t year.l Ill the meaw tiLB& t0 fulfil lny prolllife to youS I fend yx this aCCOUllt 05

tlae progtefs I have already made in thefe refearclles; and whew I Ihall find leifure to purfue the matter further, I Ibalt not fail to aCgUa1nt yo11 svith the refult of rtzy etlquiriesO

10 llav-e-the hotlour to be7 &cof

P- 43: S T Ss Co R I Ps To t3tNC;E writitag ttle aT)ove, anr itlterval of fine wteatherX arzdV

a mez:zeLlt of leifurea hXave givell me atl- opportullity of m-akitlg;* aS few nOre txperimetltsb of svhich I have thought it right: tof giVrO OU a Ov2-t accou+t.

A>iad IL trsuR l)egitl by acquainting you, that having Ilever leen thorougllSy fiatisfiecl svith refpeSc to the origin of the de- phtobiRicateeS air prodAuced upon expof<ng SeSh: vegerabIes- il< water to tlae aAion of t-he funZs rays9 accordiIlg t3 the mettaod of DJ7e iNGEN-HOUSZs tny doubts with refipe& to the OpitliOtl

tleraLly eLltestaired of its;beiIlg;eiaborateXiil theveICels of thei {?latlW



X X 8 Sk BE NJAMIN tHOMPSON S Ev¢ins; platltS ila{tead of lJeing removed were rather cotafirtned by tl<o *efult of rlle experitnents of which I have given an SCCOUtlt iR

the foregoing letter; arld hovrever difbofed I svas to adopt t1we . .

Iveautiful tlatorft oiS tlle purificatiotl of the atlnofpbere by the vegetat)Te liillgdotm7 l zVas 1aot sxtillitag ta adrntt a fiE srrlwicIt lans l>eezw brougllt i] fupport oc ty tx11 it Ould .Ippear to Lue to llave l)een de=uo lEJated Ly the naoR deciElve expPt4ilmetlts.

tI>l^It rl}e fiefll leaves of certailt vegerabsS expofed itz svater to the acAIOtl vf a-lle 101*lss rays cauSe a celtaitl qualltity of pEllC Silo tO bn ptodvaced, is a iR whieh has been put beyowd a11 doulDt; but it -does 1lot appear to me to be by arly rneans-fio ciearly provcda t9-ant ttElis a;: is 44 vzfah0r48dGitz the p1ant by the ; Iourers cf vegetatlotl §)v44 phIogiticated or fiXecl air belXzg 4 tirDt abITtived or inllibed by tise plat<t as fbodn ancl tlle deplllot

Sc giLitca-ed air beltlg rteSed ias a11 excretnetlt: for beIides t11bt nl;lwyother flbRatCes) alsd +Xtl wlicla <o elaboratiotlX (3r CirCulatiotl cal:l poIEIlJly lJe lufj?eAecl to take place caufb tlle svatel^ i< uthCIl they a*e txpoSed to the 22IOn of ligIat to yield ;depblobifiicated air as well as plants and evetl itl mucil g-reater quat<tities atld of a nzore eminent qualityv the circutnItalces of tile Ieaves of a regetal31e wllich accuRonaed to grosv ill airs are fiparated SotnQits Retn) atad cotfitled in utaterX are b un- natura19 tjllat I callnot corlceive, that they ca1< perform -tiSe fatne fun&;olls in fuc13 difEerent fitalatiowsF

Anollg £nally fads ssrSich have l;een brought ill fupportzof the received opirlio;n of the el4Iorios of the aiL ill tle veITels of the pIants ill the experi1nellts in queItiotl there is one upon s^rhzich great ItreIi has been laill9 svhich I thinkS requires fur

y . .

tilel exaluluatzoiit

The fielh healthy leaves of veget:ables SeparaterI im the plant atld expoIRed itl water to the ad3;ion of the fun's rayss

s appear



an be ProdSion ef -DephGogHicafed Air. I I q

appear, 1:y all ttle experiments whiCll lAave llitherto tJeell male,

> furnith air 5nX for o} t^ne after a day or tsro, the

teaves- changitag cole3urS cenSi to yield air * and this has beetw conceived to arite Sorn tlle powters of vegetarlon belng de firoyed ; orS lIl otller sverdse o the (leath of the platlt t ank1 fronz lleLlce it has been itaferred with; fotne degree of plantibilitys xZot oly tlzat tE> leaves aAually retained tlacir vegetative poslvers fUr fonze tirne aRer they svere feparated fitorn their Xck, btltt tleat it was ill collieqtletwce of-tlAe exertion of theSe posversX that the a-irS yelled iLl tild experitmentS was produced

But I haxre burwd, tI<at though the leaves, expoIEtl itl Nvatext

X the aftioll of lightS a&tIally do ceaIk tQ furtliSl air) aker a

certain time yet that they reg;ain ttlis power after a Ihort itX

terval vlwetl they f;erlwifli (or zather caui the water to irniffi3 more and better air tlaan at firIl svhich catl hardSy be accourztetl br upoll the :ippofition that the air ;s elSr4avd ill ¢ ttlc v&ffiCls+s of the pIanN

werkSSit Nb zg* A gio-be*, tltaillsug 4G CU5iG inches filledywlth Senl fprillg

water and two peach leaves was expofid in the witldow to the aV?cion of the ftluss raysa iO- days licceElvely (the Freather

being in getle-ral Ene)>- when the bllowing appearances took: . .place.

The xft and zd ds> a !certain quastity >of- a-tr uras produced about as much as in brtner;like eweximents The 3d day very little was produced > and the 4th day norle at alls thes glo})e to al! wpearaLlce being qu;te exhauRed Cot:tinuing the experimetlt IlosveverS upon the 5th day, tliewater llavirlg acquired a fhint gxeniffi hue, air was aga;n produced pretty plentiilly makang in <vce gpwn the 9cv f he l¢ases av the>rg of vir

bgwtX>+



a:o > 22NJAMIN rHoMPSQNS Eeermen Agbbles, as vt zbe 3eginagng of the aperX7Ane8Z; at the elld of the 6th day tEle air was removed, atld it was found to amount to

tr§o40 of g .tUbiC inch) its gality being z3z degreesX QR Id + 3e > 6$ ._-X *

UpOt) the 76 day 9w or f a cuSc inch of air was produced of

:97degrees! or tq3n=to3; arld During the 8ths th, and Ioth days t- cuSic itucil vS

*$1r of 3Cy clegrees (or I4+48-In93) svas furIli£ned) aRe3#

which an enc! s0ras put to the experiment. Teal guantiv3T of air produced 3X o90 cubic illaCt+leS s nleal:}

quality 29T degrees or t+3X= I og¢ Fitlding that leaves which svere dead nr in whch all the

powers of vegetation were evidently deRroyedf contitlued not svithRandilzg to iparate air firom water, an-d t1Zat ln fo g;rea.t xbuttdance< ][ was defirous of Ideing the eSe& of exfing f;*eM healthy ldaves itl water svhich I knew to lbe previouDy faturated wtith atlt1 (liSpoSed to yield dephlogifiicatect air I collceivedf that if the plants tspod in svater adually imbibed fixed or

3?hlogiRicatect air as fioodX and aRer digeRing it 44 diikharged is the dephlogiRicateid air as an excrement ;' itl t1lat ca 2$

+here is rse illAallce of atly plantS or animals being able to

nourifll-;tSelf wlth its ossrn ewrement the l-eaves expofid ia water -fturatil with dephloFllicated air} itwIleatl of imbibiilg and elalJoratlug;t would immediately die

The expeaments which T made to akertai1w-thls fie alld +wl¢wicl wsithout -any cotnment I a11 IBbmit to your>cotaft deranot xvereawfollosvs.

iExperiazent Nt 3O

Having provided a quantity of wa-ter} whlichS 1)y lJeing ex qpoRd with a iw greeil leaves 1n the ftln had acqusd a

greel1tth caRa azd whicla I fiund was dibolbd to yield dephloZ g;iQticated



oa; he pxdudson f D@XlgHivvteX Atrw X Z X

gHtlcated air in great abundance9 I filled a gRo5e} contaitwitzg 46 cubic itlches with this water atld pUttiIlg to it tWO

healthy peach leavesy expoSed the glole in the futl upon the 7th of September7 frorn I l O'CIQCk ill the SotNing till 2 o(lock ;n the afterrloot3 (3 hours) when <7 of a cubic iach of ar zras ptoduceds whichSprovedwitl-l nitrousalrX gave Id+34 iJ2y

or z48 degrees. A lile globe svith fre{h fpring water atld tsvo peach leavess

expofed at the Same timeS fUlrni{lhed ouly 9 of a culzic inch of air which on accoutlt of the fmallefi of its vquantity I cIId not futzmit to tlle tell of nitrotPs air

Experweat Nb 3 r *

Septernl)er S. Very fille clear weather, but rather cold for vlae feafon. tlhree equa1 glolJes A, B, alld CS cotltainillg tach 46 ctlbic itaches} were filled as foilowis alld expofUd in vlle in Dom 9 osclock ill the awortling till half XtR hour paR 4 itR

the afternoollS s5then theay were foutld to have prodvlced air as utlder mentioned.

The globe AS filled with waterS which, bzv beitlg previouny expoSed in the full for feveral days with potatoes cut itl tI1ztw fiicesX Ilad turtled green fiJrnithed w9w Of a cubic itlch of air of a degrees or Id + 38-I tO I . N. B. This waters beim it was put ilato- the globe, was liraitleed througll twa tEwick2lreSes of very fine Irii linelw.

The globe B filled vith the fime greenL potatoo water (Rraitled as before) to svhich svere added four middlzngZfized peach leavesS fbrlli{hed 22 cubic inches of air of 32s degreesX or Ia+4s-I880e

The globe C filled with fFeth fpring ss7ater with fbur peach leaves iDurniffied 50:Lo of a cubic illch of air of X 5 X deg;rees or wllicl pron7ed with nitrous airs gave Id+2n= x,4g.

\ot. LXXVI1. R lno



I 2 2 SiF B E nJ AM I N tHOMPSON S Experimes To afcertain the quantities and qualities of the airs remain-

iat, in the difEcretlt waters uSed iLl tlliS expetitrentX puttixlg the ,lobes feparately over a chafingdiffi of live coals and naaking the water lDoil7 taking care to hold tE1e glol)e itl fuckL an 5;n- clirled pOfiltiOll SS that tlae ail feparated from the water lmight t3e colleEted in the ulppet part of the globeX the airs produc.ed orere as fotlovvs

Quantity4 QualityO 3y the greerl water in the gl(3be A, <s05w of a cultc iI<ch z 80 degrces

93y the green water in the globe B, @ - +x LBy the fpring watel i} tile globe C, llo-s 68

iThe waters in thefe txperimelts were made to boil but for a

momeIltS otherssrifev it is probable, more air might laave beela feparated from them. - ;

GFiladitlg that frefh leaves, expoSed to the aSion of the futa's rays, iil water which llad already turned greerl5 caufed pure air to be fepagated from the water in fo great abundarlce, I repeated the experiment 0311vx itlRead of leaves, I lwow made ute of a flBall quantity of confervs rivglaris; when I had llearly the fame refult as with the leaves.

To arcertal3:l the relative quantities and qualities of the airs yielded by the green fwater when expofed with freSh lea^7es alld 6vhen expofed with raw :filk; alld alSo to aScertai, at the fatme tine, how lotg, leaves, expofed ill greetl tstaterX retai tIzeir power of Sepatatilag air frorn itX I lnadeX

Exy5erizent 19 pI*wo: equal giobesg A and B (containing 46 cubic lnches);

tile forner (A) filled with green potatoe x^rater:Ilrained through iinetlX and fiour peach leaves; the latter (B) filled witla r:he fatl10 potatot vuaterx IlrauesA in llke mauller atad X 7 grains of



ss the ProM2X¢ox sf DephigHicated Sxr. X 23

razv Ei< ^rere expofed £}omj Sunday noon Seprernber Ioth, till lVIonday evetling5 the weather beiE coldX vth many ting cloudsS itl all about <5 or 7 hours futlX

The airs produced were as ilLlowse . .

@uantty XtIgtitt

By the globe A wlth green water and4 peach leaves 2X7wcttbicxazches 292 degt

By the glambe B } with greerl water arld X 7 grs, of raw filk 2, tw 3o y

AIlothev gsobe (C) filied svith greetl water vlUneg was eXpoid

at the rame time s but it was broken lzy an accidellt before the cxperinzent was compIeted

The two gloles (A and B) with thetr coutents, beitlg again expoSed fiom Tuefday noon till tRllurrday everwitlg yielded at: as follosvsX

Qlxantltys QlatzeH The globe A with the peach leaves + cubIc laches 3++ degrees

The globe B, with raw filk q 1Jw 35o

N Ba The weather on TueMay and Wednefx3ay sraS cold u itll very little funfhille; but ThurMay was a very fine warm day, when the greateR part of the air was produced This air was xcmoved alld provted on fsriclay mortlirlg the I sth Sep- tember.

Perhaps all the appearances above defcribel might be tifZ faEto.rily accoullted for lty {;lppO1*1Ng the air prodllced ial the different experimetlts to have beetl generated in the mali of water by the greex materX and that the Ieaves9 the fllk &co did no more than q.6p it ig mafitgg its ey?speg lzy affordlng it a convenietlt furface to which it - could attach itfElf; in order to its colledting itfelf together, and taking upon itSelf lts elaftic formF

1R z The



-Y 2, 4 Sir BEnJ A M I N THOMPSoN S 80^per;nPts7 &c

trle phzaOrncna miglt likewife be accounted for by f;]pS pof1l jg thegr>^y<n matter-to be a vegetable fubhnce agreeable to

the l-ly}zotheI;s of Dr. PRIESTLEY, and that attaching itiTelf to the fill*taces of the bod1es expoSed itl the waterX as a plant is attaclsed to ;ts Coil, it grosvs; alld, in confiquetlce of tlle CXertTOIl Qf itS vegetative powers) the air yielded in tlle experz- meI1t iS produced

I thould LlAOa readily Ilave adopted this OpiSiOl]s had tlot a moR careful atld attetltive examination of tEwe gree1 xvaters under a moR enellent microfcopes at the time when it ap peared to be moft difpoSed to yicld pure air in abtlndallce, COI s7iriced nae tIjat vz zSat perxod5 it colatains nothit3g tllat carx poffibly be fuppofed to be of-a vegetable natureF Tshe colourZ iilg tnatter of the water is evidently of an atlitnal rlature, beitlg nothlrg nzore than the aSemblage of an ;tlfilaite number of very imallS aftive, oval-formed animaIcules) s^7ithout ally thing refernSlitlg tretneXla, or that kind of green mvgtterX or

water mofs which forms Upt311 tJtle bottom and fides of tlae *veISel when this water is fuScred to remaill in it for a cotlIa derable time? atld 1lato wlwictl -Dr INGEN*HOUSZ fuppofes tlae ar-;malcules above-mentiorled to be aflually transformed.

But havitag finiIhed the accc)unt of nzy experiments I thall finifh my lettern not darirlg to vel1ture conjedures UpOIl a fub jeA fo intricate in itSelf, and which is yet fo rlewX and upon wI1ich the ableR philoSophers of the age feem to be fo mucIz

9 § w s e * e

( ,lVlded 1R oplulenf



Phv7ws. fGrZ>. Yo/. L 3ab.n. t 22g. > -

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experiments on the production of dephlogisticated air from water with various substances. in a...

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