(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "A determination of the heat of fusion of ice"

3 1151 02696 4514 



,^AA'>'"'«'"* ^"'^ 












^O^Aa^?'^"'^''^ 





»'^. 


%•. 









'*^(A 



;¥«)»«>«' 






.A/.A'^^^'^,^"' 



/> ». . '»'^ 



■AM^aAa^. 



Jvi 







^"^:;^ 









'RjK^r^ 



LU; 



^wu 



:IC?^^, 






>*«vm^ 



>4/«AA'^A^ 



"'^^n^^^ 



;ii>^^MAǤ^ 









^^r\^f^^^f^f^. 



If 






--^"^/»'^. 



>V_ A.' 



.^^-A« 



^-w^lJfy^W^^M 



-*'^-' 



^.... 



r^A^;^?'^^' 



^^>^■^AAA 



'^'^^^v 













^"^m 



N^f^r^r^T:^ 









rC^;"WA'^M^^ 



^a/^^/>^a^^ rNA 



V ' /. ^ 'T 






oq.c;^J!{pyV'^ 



,'A'>;>A"'^^* 



■ ^.<^C5'^*. 



,^^,'>r> 



'A . '^'^' 



*?**«« 



> • c -'"" 



'^A/^r*A^ 



iJ«}JS;^^^- 



.^^S;;^;:.; 









■,/^^A/V^A 



,r,,^':'>.^'^'^^^n'> 



.^•^^^,^' 



8?MS«Sv»»^ 



«PS; 






f^^^p^^^^ 






"^tiiliy^r.. 



?^*^^ 






:/n/^A^ 



;^^^'*'^/> 



'^AW^I 



■A^/^^.^f"-\'>^ 



^r"-:.: 


^rn.rr. 


HfTnTT 






5«ft.^<?^^A«::c:).*^: 



'r.'»''-^,. 






^.««^-^"i: 



' aa'*^/!^ , 



'>.*«^;«6: 






A UKTKRMINATION OP T>iK HKAT OF FUSION OV TCK 

Pv 
Arthur v. Smith. 

19 OR 



Dissertation stibmitted to the ^oaro of University 
Studies of the .Tohnp "opVins Urvlvyr'sttv 
in Gouforinity vith t>^e ▼•wnulrenients 

of PhllosoobT. 



- OOnTKNTS - 

Introriiiction oisie ] 

PrevloiiF: 'It.tcrtiilnqtlor.K ?, 

(rene-^al niutbod 17 

Description of apparatui- aiva details 

of the laoasuroineuts r^« 

Sources of error «S0 

Prellmlriarv experiments f>F) 

ExperlnentK vltb pure Ice ftO 

SimiTiary 162 

^loj^rapMcal sketch 166 

Certificates of verification 167 



TNTHOTIUOTION . 

At the present tine t>^cjre Is no constant of nature 
of greater Imnor tai;ce , ann at the same tine less well 
Vnown , thai; t>ie hc:at of fusion of Ice. One naturally 
ref'irs to the classic rtssearches of Ret^nanlt. and to 
t^e later ae termination of 'Rimsen as fully determlnlnt^ 
t^ls consta:;t. 'Riit a comparison of the values obtained 
by these two invus tlcjators shOTS that they differ by l 
nart In 100, and a rmre c-»*ltlcal evamlnatlon of the 
o'-lc^lial raeinoirs is sufficient to convince one that 
neither deterjnlnatlon Is all that conld be desired. 
T)eterminations made by other Invest if^ators, while 
agrolnt; well amons thenisel^es, ^Ive restilts which 
differ conslde>*a''^l V f^om each other. At t>^e r)resent 
time it is safe to say t^^t the heat of fusion of Ice 
is Vno^7; T.:lv to 1 pj^rt In POO. This vide variation 
was pointed ou* three years asjo by P^-ofessor J.S.Anes 



Paris Reports. 1900. vol.1. p.l-^R. 



-I't- 



Ir; his paper or* the VttChar.lc^l Kun 1 v^lenlt of Hoat, 
and at that time he suRfitesterl to the writer t>^e 
neei of a more exact ietermlnatlon of this cor.5=;tar.t 
It was not until the present year, however, t>^at It 
was possible to taVo up this Invep tlcatl on anri 
carry It throuf^h. 

The rhole subject of calorlrietry tmist be 
reearded as still in its infancy as lon^ as Its 
measurfcnie:;ts are expressed In v^^irlable and unV-nown 
units. The iiKual iinit employed, viz., the gram- 
decree calorie ca:; :.evc;'»" 



become a satisfactory standaril f'^r t^e Trieasureinent of 
anantltle.s of boat luasu.uch as !♦•. li'.volvus the nieapure- 
ment of cban?es In tempwatii^e of some substance and 
all the i:;htjrent uncertainties connected vltb sncV^ 
neasuruiiicnts. TM.s Is '1on>^lv true when t>'e substance 
employed bas a varying beat capacity, as 1?^: tbe case 
wltb watt;r. A far more satisfactory rinlt wotild be one 
expressea In terms of the heat reonlred to produce a 
change of state wlthoiit ar»y attendent change of temper- 
ature. Tbe most convenient unit fo-"- practical purposes 
and fulfil ing these: conaitlons, is found In the heat of 
f\islon of Ice, ana It !'• surprising t>^at no determina- 
tion ""f this very importai;t constant has beiin attemtited 
for a third of a century, and that no electrical method 
ftas ever been used. 

Klectrical measurei'.ents have now attained such a 
degree of pe^'^ectlon that the heat generated >^v an elec- 
tric current can be determined with an accuracy far 
8\irpasr,ing any dl^e'^t nalorlr letr Ic method. The problem 
which T have \mdertaken to solve is the determination 
of the heat of ftisloi; of ice in terms of tbe electrical 
units . 



-r<- 



PKEVIOUS 1)KTKH]/I NAT IONS, 

The f-^ct V^nt wben beat ir Rl^en to a olece of loe 
Its teruper%ture is raisert tir.til Q'-c. l«^ reached, at 
wh^ch point it reniHlns while la^'j^e qtiant Itles of heat 
contlmie to be added, »hp first oolnted out by T^lacV'ln 
his remarVably clear and explicit lecttire?^ on chenlstry 
dellverea in Kdl'ibur^h in 176P. The he«.t whjch wa? thus 
\ised in meltinfi; the ice without producing any chance In 
temperature wa^^ called bv him "latent heat," a name 
which, altho not altot?ether felicitous, has clunR to it 
ever since. 

TsiacV Qutermined the amount of this "latent heat" 
by seve-'al ii.et^^ods. In one excerinient hu measured the 
time required for the conversion of a known quantity of 
ICe at ."52° F. into water at 40° F. In a room of which the 
temperature roiaained consta2;tly at A'y'F.. and compared 
it wltb the tlnie durint^ which, the temperature of an 
equal welj?ht of wate'?- rose luider similar c1 rcutt, stances 
from ••'.'■''K. to 40° K, Ho thtis obtained for the heat of 

*^lacV. T,.3';fir<3S on Chemistry, voi . I. no. IPO - IPv, 



-4- 

ftislon of Ire tbe mmibtjr l.'*9's'. In fmotht-r evperlnient 
llH parts of lc« Ht .?S*F. wore melted In ir'.F. narts of 
water at 190° W. Klvlnt; 1*^4 parts of water at '^.'^''V, 
Her.ce taVlng into accoiint the different specific beats 
of the water a:;d tbe containing ves«^el. be deduced tbe 
number 14.'''." c. In a third experiment, "A-bicb is r«ally 
a modification of tbe last, tbe water "*'^s rarmed to 
17fl''H. and mixed vitb an eanal welebt of ice. Tbe 
resultlnc; mixture was water at ^P°F., frivine for* tbe 
beat of fusion the numbi^r 144 •?. Tbe last two methods 
are much more accurate than the first, aiid s^ivo tbe 
mean value 14r'-.'. 5 F. or 7<^.7 r, . 

A few years lat«r WllVe, a ,«^wede , determined tbe 
beat of fusion of ice bv a dl f fe-^ent n.ethod. He tooV 
two similar vessels, one filled with wate'r sit 0'^., a'-.d 
the other with an eoual weight o<^ snow at the same tem- 
perature, a:;r; placed tberi both In boiling water. When 
tbe tbeniiometer in the first vessel reached 7P'r. he 
qulcVly renioved thr second, assuHiinsc that It had received 
tbe same aTnoxint of beat as tbe first. Tbe temperatuT"e 
Indicated was ■i2''~'. and a bit of the snow was unmeltod. 



Thls soon n.eltu'l, reauclni^ the teinperattire t.o 0"^.. an'l 
therefore Wilke tooV tbe number 7fi a.s represent Int? tbe 
heat of fnslon of the .snow. The inhereat errors of this 
method are so fcreat. the wonfler Is that they balance 
each other as nearly ^^s they appear to do. 

The first detertuination of the heat of fusion of 
Ice vorthy V^ti nanie was r.ade in 1*780 by Laplace and 
Lavoisier/ In their worV on specific heats they used 
an ice calorimeter consisting of an Inner chamber snr- 
rotmded on all sides by finely broVen Ice. Th's Ice 
was protected from outside heat by another* covering of 
Ice. fi v,arni body placeci •*lthln the chamber would melt 
some of the surroiuidln? Ice, the res\iltlnR water beln^ 
alloi^'ed to drain away to where it was collected and 
measured. Eqtial weights of different sn^^stances. wv»en 
warmed to t>e same teraperatiire ajid placed within the 
calor liueter . were foiind to melt different amounts of 
lu cooling to 0''n. ^y comparlnf^ the amounts of ice 
thus melted the relative specific heats of different 
Riibstancea were obtained. 



* Lavoisier et Laplace. Vemolres de I'Acadeiale des sciences 

l^RO. p.-'^'s.S. 
Oeuvres ^.e Lavoisier, t.I. p.PB,"^. 



-f^- 

Tn or-le- to exprwSP these r«siilts In terms of WHte^* 
It vas necessary to detertnlue tbe amount o^ Ice 'vhich 
would be n.elted by ^ Riven amount of w^ter Ir; coollnt? 
one decree. A vessel of sbeet Iron, we1cbl:ie; vltb Its 
cover 1.7.'^47 po-inds, wap filled with water. P,74.'^4<^ 
poiuioF, a::r. plac<rn In boiling water. The temperature 
attained wis 79 ?R R. The vessel 'vlth t^e hot water was 
transferred to the Interior of the Ice calorlraeter , and 
at the end of sixteen hours It had reached the tenipera- 
tu^e of tbu Ice. The amount of Ice m.elted was .''.<J^a7?^7 
pounds, of which O.PFJP?!^ round was due to the sheet 
Iron Vessel, determined by a separate exper iiaent . The 
ice melted by tbt; hot water was, then. r^.714S7R pounds. 
(Doubtless these figures were obtained bv calculation, 
and do not Imply extreme accuracy. ' 

Tn another experlnient the warm water was pou'^ed 
Into the calorimeter and, apparently, directly upon the 
ice. The amount o*^' water used was 4 lb. ^ oz. at 70*R. 
There *as reinoved froni the calorlJueter 9 lb. IP 07. of 
water at C°B. Hence .*> lb. 4 07, of 1 ce was melted hv 
the 4 lb. R oz. of water. Tn o-^der to bave melted an 
eqrml welgrt of Ice the toinperature of the water should 



have b.^cTi 60°K, Aiiot>ior wxperltnent p:av« the nurubo*' 
«O.RF,«. The nieHii of the^e valnef. , "ar;ri =:«■<'. ;rql other.s" 
not ptihllKhe'l, was tf^Vt*:; ir; rour.o minihers to be f^O'H. 
Th-s Is t;OUlvalent to 7^°C,, and this value of the hesit 
of fiiRlo.'i of Ice was accfcjptHfl and iiReri by TJhvqlrlsfs 
for the following sixty years,- fi-om 1780 till 1-UO or- 
latt-r , 

The first determination of the heat of f>islon of 
ice Thich hears the i.arks of accuracy Is that of La 
Provostaye aiid Desalnsi In 184."^. These Investigator's 
used the ii.cthod of nilxtureK, strictly so calli-d. That 
Is, pieces df Ice from the surface of which most of the 
water had been removed -A-ith t,ic;sue r-aper , were dropped 
Into water a:;d the lowerlne^ of tempe-^ature caused by 
the n.eltinE; of the ICe was measured wlt^^ a the^mor.e ter . 
Their thertiiometers were f^->~aduatbd to tenths of a decree 
ana read to hundredths, aiid were compared with standards. 
The airio\u;tB of water and of ice employed were dete'»*mlned 
by welqhlnp; the calor iineter flr'.-t eiiK tv. f^tiVL wlt>^ t>'e 
water, ai;d finally after the Ice w-^s riielted.Tbu Initial 
temperature of the v.ater v^rlei betwee:i 1^'^, and ."^O"'^. 



"'La Provostaye a:;d l)esali;s, Ann. de Chem. et Phys. 

t .8. lf\Ar^, nt:. '^ - 1«, 



-8- 

for the dlffurwUt exp«T*lifi«;itR . belnt? sncb 1". eac^ OHse 
tbat wltb the ainoiir.t of ice used l;i th<e experiment the 
final teir.peratiire woiila be nearly tbe same as tbat of 
the sur'^omialns^s . ^y this means tbe radiation correc- 
tion of tbe calorliiiett:>' was made as small as possible. 
The rate of coiling of t^^e calorimeter for each decree 
difference in temperature between tv^e water In tv>e cal- 
orimeter and the siirroiindlnfcs was determined by a pr-a- 
llmlnary experiment. Tmrlnt? an experiment the temper- 
attire vas recorded every few seconds, and tbe observed 
final temperature was co>-rected for tbe coollnf^ by 
radiation. 

They estimated tbe amount of '-ate-r clinfi;1n*^ to tbe 
Ice as about one two-tbonsandtb of ^-bi- we1)?bt of tbe 
Ice, and as therefore too small to taVe Into account In 
their eyperln.ents , T^e mean of seventeen determinations 
of the heat of fusion of ice R;ave the value 79.01 calo<i 
r les in terifS of the mean "Specific beat of water over 
the range 10 "C. to ''A' c , The authors show that this 
value Is y.u^\)ect to a p^ob^ble er'^or of 0.7,0 calorit;. 

The Weights of tbe calorimeter with the water and 
tbe Ice '^ere corrected for tby loss due to e"apo*'at Ion . 



-9- 

Tbe loss of beat ine to tMp cniiR© If ts^Ven Into acronn* 
at all riiHv hcwe b«en inclnrtert, oonscloiirly or unronRcl- 
onsly, 1:; the determination of the rate of coolluf^. f'nt 
In the single detailed calculation clven. If an f^mn^1^A. 
of water as ^reat as assntiied, and by which t"e wolcrhts 
a^ts cor>^eCted. actually did evaporate, the coolln? riro- 
duced thereby would be 160^ of the total cooling cor- 
rection appllt:d 1 

The results obtained by La Provostaye and T'esalns 
were co:-.f jrnied by thw experiments of Hegriault' made the 
same year. Vie also ixsed tha method of mixtures and 
pointed out t.hb errors due to the water Introduced on 
the Ice, and to the evaporation of water from the cal- 
orlL.eter. NO correc*^ Ions were made, as thtcc >«*'« con- 
sidered too small to affect the result. T^ls Is true 
regarding the change In welt^bt, as the maximum evipo^-i^^ 
tlon was or.ly 0.07 K^Rni, but the hei^t ■required to evap- 
orate this water. If neglected, would maVe the comcuted 
value of the hc-\t of fusion too great by one third of a 
un 1 1 . 



"'HeKnault. Ann. Chem. et Phys . lR4r'^, ♦.q. t.p. I*'* - rrr 



-10- 

DiirlriK tbo winter of l»4^ Kef^aTilt i.iade several 
determinations of the beat of fiislon of snow. The tem- 
perature of the snow was measured with a thermometer, 
and wap always a few tenths of a decree below 0°C, When 
transferred to the calorimeter the snow melted very 
qulcVly. thus reducing the errors due to radiation. The 
specific heat of the snow was assuiued to he the same 
as for xati^r . The mean of four determinations gave the 
result '79. PA calories. 

There helng little snow in Paris the following win- 
ter, he ustid piece? of ice cu* from a clear hlocV and 
free from air bubbles . The ice was dried with filter 
paper and cjulcVly transfer'"ed to the calorimeter. Its 
n.ass being deteriniued by wetghl!;g the calorinuiter before 
and after the experltuent . The mean of thirteen deter- 
minations -vas 79.06 calories, in terms of water over a 
mean range of from ll^n. to PP°r, 

In 1B48 Hess^ conducted an elaborate series of ex- 
periments to determine t^^e he^t of fusion of ice. He 
avoided ffe errors Introduced by the laye'^ of water on 
melting Ice by using ice several degrees below 7ero. 



■"Hess, St. Petersburg Imp. Acad. r;cl , 'Rtill. de la r-iasse 
Physico-mathematlque, IX. 1R51. pp.Rl-8S. 



-11- 

The room In which ht; wor^e^ whk Vert r.ool . while the 
h«»lance. ice, etc.. were in h class cfise outside one of 
the northern windows. The tcsmperature of t^e Ice xas 
mwasurei by a th«rmoinete»* In the mlist of broken piece? 
in a beaker. The usual method of mixtures vas usud, 
the cold Ice belnc: placed in the water and allowed to 
melt. The temperatures were measured to temths of a 
degree, ai;d the amounts of Ice and water so proportioned 
that the final temperature was that of the room. T?orty 
deteriiilnations were made, each Involving the two unknown 
quantities, the specific heat of Ice and its heat of 
fusion. Solvine; for these qu9j;titles e;ave C.F^ys'. for 
the specific heat of Ice, and for the heat of ftislon 
the value 3C.54 calories in terms of water over the 
mean range of from 7*0. to 1<)T;. 

The last Investigation having as Its object the 
determination of the heat of fusion of Ice was made In 
1850 by Personf Tie crltielses the values found by 
Hognault a:;d La Provostaye '^nd T)esalns because they had 
followed the methods of p'-evlotis Investigators «ind used 
ice at 0°n. and therefore had n">t taken Into account 



^Person, Ann. Ch.em. et P^ys . IRRO. *.?<0, p. 7.-^, 



the extra heat which, accorriinf^ to his notion, 1 c« 
absorbs ''^'efo^'a rwachlne 0°'^. 

Person UFjei ♦by nie*>^ori o*" mlyturen. the tem'- uratnre 
of the water being about tl^'C. and that of tbe l^^e from 

-?'<?, to -91' '^ . Tbe lc« was a cylinderlcal bloc'k, 4 
centltieters in dlamater aj;d 12 centlr.eters bleth. Tb-fs 
▼ as enclosed in a sb>-et iron case and contained a ther- 
mometer to measu^fc; Its temperature . Tbe specific beat 
of the Icu was determined by coollns; it to ~PV ^ . in a 
freezlr.j^ inlxttire, then pliuxgln? It, case and all. Into 
the calor ii .eter , which contained a saline solution a 
few tenths of a degree below 0° '^ , After ten or twenty 
minutes the final temperature were read. Two deterinl- 
natlons gavts C.4R for the mean specific heat of Ice 
from - 2V r . to -?'C. 

The evperlji.unts for tbe determination of tbe beat 
of fuslo:i of ice wer« coi.iucted In a similar manner. 
The block of ice w is cooled In a freezing mixture to 
several degrees below 0"^. and then plunged Into the 
calorlii.eter , which contained water at about -►IR"^. 
Usli;c the above value for the specific bef^t of ice. and 



iinltv for tbtj specific h«!^t. of water, he obtftlned the 
v>^lue RO.O fo*" wb«it he whs pleased to call the "total" 
beat of fnf-.lon, th1«: beint? tbe moa:: of six exper itnents . 
From the recorded data it is InvDOsslhle to say what the 
error of this result laav he. The only correct io;is 
appll.'d are for the water eq\)lvalent of the calorimeter 
thermometer, etc., and a correction for r-adlatlon - the 
determination of which Is not ^Iven. 

In 1B7C 'Rrinsen'' devised the ice calorimeter which 
bears his naine . As with the ice calorimeter of Tjaplace 
and Lavoisier, T^unsen iised his instniment for the study 
of specific beats, ana in order to express the specific 
heats of the substances studied In terms of the mean 
specific beat of water two auxiliary experiments were 
made. In these experiments he iised .-'■"<. r',,7 ^ram of water 
enclosed i:; a j^las.s tube and warmed to the temperature 
of boll ins? water. The wate'^ and tube were then d^^opDed 
l:;to tbu ice calorimeter, and the change In the scale 
readlnj? observed. Tn the second experlinent the sanie 
watur and tube were 'varidea to Identically the same terii- 



''^unsen. Phil. Mag. S';r.4. vol.11, 1971. p.l^p, 



-1 A_ 

peratnre , ti'.'I pro'iuctin almost tbe same cbanece In tb« 
scale roadlns? of the lc« calorimeter. Vvlriently tbe 
two dxperliueiits wer« luarle In gulcV succession vltbotit 
a slntclti variation, ani the two results, RO.Ol and 
R0.04, of necessity atrrire very closely. The mean. 
80. OP, is eypo-wssed in mean calories. 

The results of all these determinations are col- 
lected In Table I. It is difficult to determine the 
exact temperature of the water used in these experiments 
hut the attempt has been made to express the results In 
terms of joules, by maVing use of Thames' values of the 
mechanical equivalent of heat, ana the values set down 
iu the table cnn not be ^ar from rlK^t. 

Tn all of these aeterminat ions of the heat of 
f'lslon of" iCe practically «» single method has prevailed^ 
that of mixtures. The limitations of this method are 
at once evident. no Vnowledj^e of the condition of the 
1 Ce "vhen It enters the calor li .ete** Is possible. Unless 
it Is mel^lne, and has been In that co';dltlon a ve-^v 
Ions; tlrie, its temperatu'*e is entirely unVno'WT;. Kxr)e-«-- 
imonts phow that a blocV of ice whlc>^ has been fo^* sev- 
eral hou'-s In a WFiriii ro.Tni (?0°r:. I may still be cons Id- 



■IB- 



Table 1 . Stmimary of previous determinations. 



Date 


1 
Nnme 


Number of 
Kxper Iments 


Temp . Knnt^e 
of Water 


Heat of 
Calories 


Fusion 
.Joules 


176P 


T^lacV 


P 


80-0 


79.7 






Wlllce 


1 


7P - 


72 




1780 


Laplace ana 
Lavoisier 


2 


100 - 


75 




184?^ 


Provostaye 
and Pesalns 


17 


24 - 10 


79.1 


7,?>1 . F> 


184P 


Recnault 


4 


16-7 


7P.P4 


.•^.•^P.7 


1R4?5 


Ref^iault 


13 


22 - 11 


79.06 


.•^.•^0 . B 


184R 


Hess 


40 


19-7 


80 . .'^4 


.•^J^7 . 1 


1850 


Person 


6 


16-5 


80.0 


.•^.'5.9 


187C 


■Riinsen 




100 - 


80.02 


1 
.•^."5.2 

i 



~lf^- 

arably helow O'C, in the Interior, If such a blocV is 
broken up and soon \iserl, H^un tbe sinalT pieces will be 
colder tl-'an CT., altbo nieltlnf? on tbe exterlc. Attain 
when the Ice has been rneltlrifiC loufC en'^n^h to lnP.iT*e Its 
temperature beini? verv close to C'^. it Is Impos^^l^^le 
to remove all of the vater from the Ice, and an imVnown 
amount of water Ir. thus carried into the calorimeter 
and credited up as Ice, Tt is not necessary that this 
water should be solely th^it of tbe superficial laver 
covering the iCe, Unless the ice has been formed from 
exceedingly pure waty^, and is uniform throughotit, melt- 
Irig will occur at interior places, the revS\ilting water 
remaining in its own cavity. The amount of water which 
mav thus exist throuebout the ice Is neither deternilned 
nor removed, but is coixnted as so Trnich Ice. 

Voreover , this method involves t>^e irieasureiiient of 
changes in temperature, which at best Involves consid- 
erable uncertainty, especially when mercury therinometers 
a»"e used; and as the »*eBUlts are exp'i'essed in Indefinite 
units, the whole subject has been loft in a most unsat- 
isfactory condition. 



-17- 



r.KNERAL V>:TH0T). 

The ri.ethoQ employen In the experiments nox to be 
described may be briefly stated as follows. The sample 
of Ice. vbope host of fiisloi; Is to be determined, is 
broVen Into suiall pieces and cooled several dee;rees 
below 0'^. 'Vhlle at tM fi temperature It Is welched 
and transferred to the calorimeter, which contains 
kerosene oil also two or three dea;rees below 0° ^^ . In 
this state there can be no question that the ice Is 
entirely free from water. e1*heT" on t^e outside or 
Interior. TV-c caiorlme^-er and contents are slowlv 
warmed by a very small electric current until the 
tei.Derature reaches the desired point for commencln<? 
an experiment, \isuallv about - 1° Ci , A larger current 
Is then applied for sufficient time to melt the Ice 
and raise the resulting water to about •+C'°. ?S ^. . At 
this temj eraturc I of eouilibrltim ) the ice has certainly 
all been melted, ai;d the heat cenei-ated bv t^n current 
has bec-n \ised l.\ four wavst l''t. in raisl:;^ the tenw 
perature of the Ice a-.a the calorimeter from about -I'n, 



-in- 
to 0''^. PrA. ir; nieltirit? the Ice. .'^r'l. 1:: ralslnt? the 
temperHttjrf of the vntttr ■ai;<i calorlrioter from 0°^. to 
about +0 . F> C.,fCid 4th. iu suriplylne; whateA'e^ heat is 
lost bv the combined effects of radjatior. , conduction, 
co:;veCtlon, etc. Of these four quaint 1 tltjs of heat. 
the Second is thirty or forty times as srreat as all the 
others co!,.bined, vhjch are determined as corrections. 
ai;d Then su>:'tracted from the total amount of heat «ren- 
erated by the cur^-ent , Rives the heat reoulred to melt 
the ice. Th/'s amount of heat divided by the mass of 
the ice fci"ves the heat of fusion Der p^ram of ice. 

In order to provide a medium for the tra:;sference 
of heat froii, the wire car'^vlnt^ the current to the ice, 
and to e.'iahle the dlffereiit parts of the calorimeter to 
Bttalr* a:: eoujllbrlura temperature, a bath of re^^lned 
Verosene Vnomr^ as "Pratt's astral oil** was used. This 
oil could be cooled to any desired temperature vlthotit 
1 op1j;r Its fluidity, a.nd it i^ad no action or. ♦'"t! Ice,- 
two points vhlch ^**e only possessed by this fluid, as 
far as conla he le'tr;;ed. 

The ai'iount of heat produced in the >-eatin^ coil 
by the cur^ e:-t was deteriiiiued bv rueasurinK the differ- 



-1ft- 

ence of poteUtlMl betweuU the te^'ininalR of tbe coll, 
the current which flowed through It. hj;'1 the time 
diirlr.t; vhlch the current whs flowing. Th« he^t. In 
joules, 1.'- then s^lven by the formula. Kit. 

K=ich experivient Is nHturallv divided Into three 
parts.- 1st. the deterjuiuatlon of t>^e heat capacity 
of the calorlTTiete-^ . ICe, oil. etc, P;id . the rieltln^ 
of the ice. and .?rd . the aeteriiiinatlon of the heat 
capacity of the calorimeter , water, oil, etc. Thene 
are dlscu.s.swd in oraer ^'elow. 

Heat Capacity of the Calorltneter . Ice, etc . 

The anomt of heat requli'ed to raise tbe ice, oil. 
calorlnete->- . etc. from t>^e initial temper- attire to 0" "^ . 
was determined from the rate of warmlns? durlnsr the 
preliminary heating. The current usei for this was on© 
tenf" as large as that employed In melting the ice, th^is 
Gien'iratlnj; one hunaredth as much heat per minute. Thi.s 
small amount wa«--. used In order to warm the Ice slowlv 
and without tieltln^ any of It. fts O"'^. Is aonroached 
It was more and more difficult to acrly heat and not 
allow any portion of the oil. even close to the wl'-e. 



-PO- 

to btjcoirut warmer tban 0°". 'vitb oi^r^; ♦be'-i; wsir novov 
«»r.v t»'on''ile fron; t>^ls so\irce "Vhen. V^e temr «•»"!* tij'^e xas 
as low as - 1° C . 

Thfcs ncHt capacity of tv<e entlrtj apoaratn.s, Inclnd- 
i:i<;? t>^e Ice, was found as follows. TV«e temperature was 
rea'l c'Verv minute, while the ice aui oil were constantly 
sti**red, until t'^e ratvj; of wa-^mlnf^ due to t>^e cotahine'l 
effects of radiation, conduction, con-^ectlon, stl>''rinf?, 
etc.. wa;; nearly constant for ten or fifteen minutes. 
Then t^e small cu'^i^ent was passi^d for ten minutes, the 
stir-1:;^ beini? continued at the san.e rate, while the 
temperatTire rose more rapidly, ""ollowlns this another 
series of tempe''*ature readings was taVen while the cal- 
orliieter continuea to wa>*m up by v^eat "■^'om wtthotit. The 
rate at which the calorimeter was receiving heat from 
without while the current was flowing, hy Newton's law, 
which is show:! below to apply to this case, is the mean 
of the rates just before and just after (since the ton- 
pe"^ature, on the average, is a mean between the temper- 
atures before a:;d af ter • , The total amount of heat 
recelv-d bv the calor iinoter and its contents causes a 
certain r»ise of the thermometer, a.nd since the tempera- 



-'Al- 

tura ^t t)-»h; beB:lnir»(? ^^nei tbe rt.id is c»^a.nRlnR very dlowlv 
It is safe to assnnie that the tbermometer Indicates tbe 
temperature of each part of the calorimeter, inclnrilnsc 
the small pieces of ice. The dlffe»'ence hetweer. this 
observed change in temperature and that which vould 
have bt-cn loroduced dtirlnp the same tlPie by outside 
liiflTieriCcK alone, plves the Change In temperature aue 
to the current. T>\is establishes the relation between 
heat I expressed in joules' anc the change in temperature 
produced bv the adaition of this amount of he'^t. On the 
assumption that the same amount of b^at will produce 
the sajne tei.vDeratnre chaiige at any temperature uo to 
0°C.. It is a sinrole matte-f* of proportion to find the 
number of joules required to raise the calo-** line tor and 
contents from the Initial temperature to 0°^. That 
this assuiiiption is fully "va>'rai;ted is shown by exoeri- 
raents given below. 

y.elt lng the Tee , 

The fi^'rtt part of the experiment is followed 

di-^oitly bv t'^e secono , 'vV- 1 ch differs fro'n i* oi;ly in 

the quantitv of heat employed ai;d the consequently 



^reater ch^af^es in tuniDerat'irts , to^of^er with t'ne 
malting of tbo ice. T^'w cni"reut Is a*^ont t'^'o amperes 
ari'i flows for tveJity or thirty minutes, w»-lle t>-'e 
stirring coutlnues iininterrupte'l at t>e same rate as 
before. Two observers ^re required during t^ls cortion 
of the experiment,- one to continue the sti-^-^lng and 
read the thermometer and Veep the records, while the 
othe'^ attends to the regulation aiid measurement of the 
electrical erier<3:y. 

In series with the heating coil was placed a stand- 
ard hi^if ohm coll which -vas specially designed for car- 
rying currents as gr^at ^s two amperes. The current 
throug'^ thtjse colls was maintained constant at about 
two amperes bv regulating it so that t'^e fall of poten- 
tial in the stai^iard coil always just balanced the E. 
M. ^. of or.e standard Veston cell. Each minute;, or as 
often as possible, tt^e dlffere;ice of potential between 
the tertai.ials of the heating coil was measured with a 
potentiometer and standard cell. The titno during 
which the curre.it was flowing was measured with an 
Rlgln watch with the aid of a reading glass. This 
moasureiaent of both the cur'^ont and the ilffere-.ice of 



potcritiiL I, lakes t>^t! evpfl- u'lt luore cornpl Inate'l and 
laborious than It vouli have been to slrmlv rnalntalu a 

cor.st'^^t cvirrent thr~>nf^h the coil and calculate t^^tj 

p 

beat frotri the formula RT t , where H denotes the resls- 



E^ 



tauce of the heatiuj? cojl; or to maintain a constant 

K. M. F. and calculate the heat from the expression 

W 

Tn each of these cases a Vnowledge of tbe resistance 
R. would be required, a;;d this mean a Vnowledf^e of the 
tBmpe>*ature of the vlre when carrylnsc the current, vhlch 
may be several decrees warruei" tha:; t>>e sn'*"^oundlne: hath 
and in any case Is very dlflcult to determine. All of 
this uncertainty re^ardin? the resistance of the heating 
coil Is avoided by the method here adopted, and the in- 
creased labor is more tha:; repaid in the increased con- 
fidence in tV'-e m«asureiuent of the electrical energy. 

Heat Capacity of the '^alor Imeter , 'Water, etc. 

After t>^e Ice Is melted and t^B current stor<r>ed, 
the water, oil ai;d calorimeter come to some emilli>^»'iijm 
temperature a few tenths of a det^ree above O'C. The 
amo'int of heat which, has been exuended in raising t>^e 
temperature above O'c. is found by another experiment 



-P4- 

Iri all resptcts similar to th^it perforTned below 0°'^.. 
and jiiKt dwscribad, T^e beat capacity will, of conrse, 
be; srtj'tter tbar* before, Plr;cc 'be calorimeter now con- 
tains rater Instead of Ice. It has been sho^-n bv T?arne8 
tbt\t tbe specific heat of vater evbibits no oecul lai- 1 tv 
1-. the neighborhood of Cn., and therefore within the 
limits of accuracy here required, tby beat capacity of 
the entire apparatus is the same at about -fC".*^ ^. . that 
It Is ovei" the rane^e from n. to -f:*. Fj C. 

Correc tion for Kadlatlon, nonductlon, noiwectlon and 
Stlr' -lng . 

There remains another important correction, viz., 
the heat lost to f^e calorimeter by radiation, conduc- 
tion, conve>ttlon. sti'-ring, etc. during the period In 
which t^e ice is being inelted. This is determined In 
much t*^e sanie way as in the auxiliary exper iTiients just 
described. The bul'- of tby thermometer Is near the 
wall of the calorimeter and it Is assumed that the 
temperature of one »'epr«sents the temoe>'atu'*e of the 
ot^er. Newton's law of cooling is assumed, that is, 
tbat ti^e be^t lost each minute is proportional to tbe 



ilffnrencc in telumirHture betwetj!i tbt; 'vall of tbe Cal- 
(T-l >!*'.-f !* -.i the surroTinrilu(?s . ►''roni the dnta alrtjady 
obtaiued thts rate of coollnj? i or warinlru? ) at .sevwral 
teinperaturus both above and below 0° n . i.s ^Ivon. These 
rates of cooling are expressed In terms of tbe equiv- 
alent joules per minute and plotted as ordlnates against 
the correspond Izie tempe-^atures as abscissae. Tbe curve 
joining =*11 t'^ese ooints is very nearly a straight line, 
and If Nexton's lav is true It sbould be absolutely a 
straight line. Therefore th's stralgi-«t line which lies 
nearest to the plotted points Is drawn, and this line 
then gives the heat lost per mlmite at any temperatui~e . 

The heat lost bv the calorimeter through the com- 
bined effects of radiation, conduction, convection, 
stirring, etc.. dijrlng the Interval In which tbe Ice is 
tneltl?ig Is then obtained from this curve as follows. As 
the temper attire is measured each minute, the average of 
these readings gives t^^e mean temperature during the 
experltuent. The ordinate on the ctj-ve corresponalng to 
this tempe'^ature gives the mean loss of heat per minute. 
This quantity nnjltlplled bv tbe time in minutes gives 
t*^e total loss of heat radiation, etc. 



-p«- 



DKSCKIPTTON OF APPAHATUS . 

Tn clBvlslr.t? H fori'i of apparatus sultahltj fn-r tba 
accurate determination of the heat of fusion of Ice, 
two things were especially desired. First, that It 
wonl'i admit using different samples of ice, and ice 
formed under different circumstances, and secondly, 
that it should have as small a radiation constant as 
possihle. The f^»"st condition debarred the ^^insen 
calorimeter, or a:iy similar Instrument, oven if it had 
not b^en sh.o'Am that the density of ice depended upon 
the methoa of maiiufactu"^e , and therefore re:idered this 
instrument liicapable of accurate results. 

Aftur a number of preliminary experiments upon the 
radlatio.. constants of dlfferer.t calorimeters (i.e. ^he 
heat lost or e^alned per minute oar- oecj'"ee dlfferei;ce of 
temperature betve^n the calorimeter and Its sur>"oundlngs ' 
It "vas found t>"at the best protection acai:;st radiation 
▼as the double wall of a Bewar bulb. Accordingly a half 
liter Dowar bulb -vas used for the basis of the calorim- 
eterr. This vas supported within t^e chamber Ti, ?'lg. r>. 



-S7- 



by a .special wooden cl^imp which fitted around the nocV 
of the bulb. The upper portion of this clamp passed 
upwards through the tube T. which it completely filled 
and bj which It was supported. The thermometer .stir- 
rer rod, and current leads passed through appropriate 
holes, drilled lengthwise In this clarap support. 

This form of calorimeter proved very satisfactory 
and fulfilled the >^lghest expectations regarding the 
loss or gain of heat by conduction and radiation, ''ffhen 
filled with water a few degrees below the siirroundlngs 
it warmed up at the rate of 0*. 001*^ n per minute per 1* ^■. 
difference In temperature between the Interior and the 
exterior . 

A preliminary experiment to see how rapidlv Ice 
couli be melted without unduly raising the temperature, 
was performed as follows. Since only quail tive results 
were desired the bulb was filled with water instead of 
Verosene. ai\d a few hundred grams of broken Ice dropped 
in. On suoplvlng heat by a cu»*'*ent t>^rough the coll, 
the gratifying result was obtained th^t f>0 watts raised 



-P9- 



the teiTiperatiire to only +0*5 C. In other wor"ls, ten 
scrams of Ice co\ila be melterl per minute without raising 
the temperature over 0°. 5 ^, . and co?iseo\iently without 
prodTicln? mtich loss of heat by radiation. 

^it this fair beglnlnfi! was doomed to speedy disap- 
pointment. In the midst of the nex-t experiment, the 
inner wall of the bulb expolded with a loud report, the 
contents ai-.d broVen glass being caught and held by the 
oute-^ wall, which did not breaV . No possible reason 
could be fould why the bulb should have given away at 
just t*^at time. Fortunately the thermometer, w>-iich was 
within the bulb, escaped vuiln.jured. Several reeks were 
spent in trying to obtain a dtipllcate bulb. The first 
one obtained had a much smaller 'lecV, and while superior 
to the original in some respects it could not be used 
on t-^e saiie supoorts, and did not give sufficient soace 
for the th.ermonieter , stirrer, current and potential 
leads, etc. ^fter iinic>^ "orrespondcnce , a bulb was 
obtained Very like the orlelnal , and the experiments 
were resutiiBd. 



-29- 



On trylr»(? t^e complete oxperlinont ^Jin usItib; Verosene 
as the fluid, the Ice. as expected, sank to the bottom 
of the bulb. When t>>u curreut was pasRurl to Melt the 
Ice, the teinperaturc was found to be mtich higher than 
It was 1:1 the prel Iniluarv evper Inieuts In which the ice 
floatea at the top of the warmed fluid (water'. This 
was doubtless due to t^e wanner oil risine; to t>^e top 
and away frotri the ice, which remained in a more or less 
compact viiass at the bottom and presenting a mlnlmuii of 
surface to tra action of the oil. 

Ma:;y Ineffectual attempts were made to suDoort the 
ice in t-'e oil with the heating coll below it. Various 
Vlnds of stirrers were tried in hopes of securlnsc a more 
thorough circulation of the oil amongst the pieces of 
ice, but with llrulted success. The principal difficulty 
was In t'c small:;ess of any arrangement whic>^ could be 
passed through the necV of the flask. Finally, almost 
by accident, n forrd of rotary stirrer was found which 
secured complete circulation and promised satisfactory 
results. ■^ut disaptiolntment was again in store. One 
day as tht. bulb containing some oil was resting upon the 



-.•^0- 



bed of tiXCelslor wbere It was Vept when not In use, ft 
loud report was heard, atid that bulb was no more i The 
destruction was complete, some of the pieces beinf? 
thro-n'n a distance of a rueter a'A-ay , T was only thankful 
It did :;ot occur whe:\ in use, with the delicate thermom- 
eter Inside. 

Of co\irse another bulb could have been obtained, 
but t'^ti d.a:-'.?er of its exploding at ai;v mouient. a^id 
especially the risk of destroy Ins; the thermometer, was 
so great, it was declined to use some more stable form 
of apparatus. Moreover it was now tbe first of January 
with, cola Weather arioroaching, du'^iris; w>^lch all the 
expe^liients would have to be ce'^formed. The shortness 
of tiMe forbade much waitine; for the construction of 
elaborate apparatus, and therefore the best that lay at 
hand was tried, "yhlle not eaual to t^^e -lewar bulh in 
preventing loss of heat by radiation, still it was very 
g">od. and tr>e certainty of its remaining intact fully 
balanced a ;y inferiority in othe** respects. 



-.•^1- 



yina l Form of Calorlmoter . 

T>v- calori) lottjr as finally iiserl Is show:'. In section 
In yi--:. I. vhich Is nwarlv self explanatory. A^ is a 
half liter bi-ass vessel, nickel plated a2id Mgbly pol- 
ished on the outside, vithln this Is shovi; the stirrer 
and the heating coll. c_c Is a brass tube ovut* which is 
woiuid five ohms of No. I?J>, allV coverea , mantc'inin wire. 
The wire Is insulated froi.i the tube by a double thick- 
ness of slllc, a::d the whole covered with several coats 
of shellac well baVed on. The ends of t'-'e coll are 
soldered to two heavv copcer leads, aa. to the uprer 
ends of which are solderea the cu'^rent and potential 
leads. The stirring Is effected by i dlsV of 
brass, dd, which nearly fits the calorimeter, and Is 
soldered to the lower end of the brass tube, j2C_. Tt 
Is perforated by a number of small holes throusfh which 
some of the oil can circulate while the i^reate'^ nart 
of It streams throusfh the heatlni? tube as the stirrer 
Is niovea up and dom-n. The stirrer roa, rr.. Is a hard 
rubber tube which screws onto the end of one of the 
h.envy C0(>per leads. It extended u^wara to the outside 
alongside the thermoineter , and also served tn support 



/Jh 




K ^ 1 



-:*,p.- 



the ciirrc.it a:;fl potoziti^il wires, 

Oa one or Vvo occasions durlntj t^o preliminary 
oxperiiutr.its a fo-A' drops of oil weru fotina to have 
spilled out of V-'e calor l?neter , which of course would 
SttTlonsly affect the -volc^t of the apparatus at the end 
of an experiment, to say nothing of the chane;e In t*^e 
heat capacity. To prevent this as far as r)Osslhle a 
tightly fitting cover was made. Openings were necessary 
for the thermometer, ♦•he stirrer rods, and fo-^ the 
tuhe through which t^^e Ice was dropr,ed. A Hi w^n^ 
arrangea to fall and c wer the latter opening when the 
tube was withd'-awn. Ai; eige was Dlaced around the cover 
to hold whatever oil mlsht fln'i its way to t>^e top. 
This precaution may have been uiinecessarv . as no oil 
was evcr found on the cover. 

The calorimeter was supported in the following 
manner. Sufficient cotton wool was wraoped around It 
to just slip into a larc'.e glass battery .jar. TV<ts jar 
rested upon a wooden blocv at t>ie bottom of the rhamber 
U.,,- and to orevent as far as possible the loss of >^eat 



^ JC s^ 



n 




Pif:. :'. 



-.•»;«- 



by convection air current?: the remainlnj? Hcactr vas 
filled with cotton wool. 

T>io dlrienslonK of t^lr cbamber are ."^5 cms. In 
depth, bv p.'=^ cms. diameter, it heln^ circular In Sec- 
tio!;. The larger vessel, K, Is 70 cms. deep and 4R 
cms. In diameter, it also belnjz; circular in section. 
■Roth of these vessels weipe inade of '--eavv ecalvai;l7ed 
iron. The space between them was filled with b'^oVon 
ice, maVlnt^ a lavcrr 11 cms. In thlc'k;iess aronn'i the 
sidt-'S of the Inner chamber, and about twice this thlcV- 
ness over the too and bottom, thus rnaintainini? the 
temperature of thy interior cham.ber very closely to 0° c. . 
The top of this chamber Is a removable cover, made with 
an outside flanj^e to prevent water f^^om gaining access 
to t'-^e inside. At t>^e Cente-^ of this cover Is ^ tube 
4 cms. in dlarueter and SO cms. In lent^th, which extended 
throug>^ the broken ice to the outside, and throusfh which. 
passed the thermometer, stirrer rod, current wires, etc. 
In order to protect this broVon ice as much as possible 
from outside heat, t>'e vessel K was t.laced within an 
extra l^r^e bar'i-el with the intervening space pacVed 



-34- 



wlth excelsior. With tM s protection the amount of Ice 
melted whr about ten Vllos per day, this amount beln? 
added each niornlnsc. The total quantity of Ice reaulred 
for this uaclclnj? around the chamber was about sixty 
Veil OS. As fast as It melted the water was drained away 
thj*0U£?h the tube P., Over the barrel was a wooden cover 
through xhich projected the tube X- "t^« woode:\ post, W, 
which served as a support for the thermometer when In 
use. an.'.. t>ie theruioiiietcjr case, L_, in which the thermom- 
eter was kept during the tln.e between experiments. 

In orQer to fill the caloriiueter with oil and Ice 
a thin brass tube was arrai-.s^ed parallel to the thermom- 
eter and exte:idlng from the outside to about half a 
centliieter below the covur of the calorlraeter . Within 
this tube was a glass funnel t^^rous^'^ which t"'^e cold oil 
was poured. T>'e funnel was t>^en removed and tV'e Ice 
dropr;ed through the tube, aftei" which the tu>-'e was 
removed, the small t'-ap door falling and closing the 
opening in the cover. T>^e tube T^. was the:i filled with 
cottoii to prevent circulation of the air between the 
inner chamber and the outside. It being firmly pacVed 



-.-■S.*)- 



aroiml th<i therniomtster ann stirror rod, but allowlnf^ 
the neCtiSfiarv motion of the latter. 

Ele ctrical Arrai i grimer^ts , 

A diagram of the electrical connectlor.R is shown 
In "^i^. ■■^. il ts the heatl:i? coll ^'Ithln the calorimeter 
M Is the staridard half ohm coll, while D la an auxiliary 
coll of resistance eoual to to j2 '^^'ik. together. The 
current was obtained from el^ht storage calles, 5_, and 
by ii.eans of the s'vltch 5_, could be passed throuG;h the 
auxiliary coll D while It was adjusted to approximately 
t>^e proper value by the variable reslsta:;ce. K_. The 
latter co:;slsted of a rheostat contalnlnji^ a total of 
six ohms of heavy iron wire, in parallel with which was 
a liquid reslstai;ce of copper sulphate solxitlon. T5y this 
means as sii.all variations In the current as desired 
could easily be laade . 'Vben ready to tise th.e current 

in the calorimeter, the double pole, double throw switch 
2.. '»'ar closed on the Other side, *inr: the cur'^ent qulcVly 
brotis;ht to the proper value by a verv sllj^ht adjustment 
of the r«slsta:;ce K. 



< 

■ J ■ 








FlK. .'■^ 



-.•^6- 



The ^alvaniouieter , G. vas tl^« Howlnnd D'Arsonval 
wall type ai;i onlte sensitive. Its free period of 
vibration vas about IfS H«couds, with little iainolnt? and 
requlrlit? several nilmites to come to rest after a deflec- 
tion. In this worV It Is neces'-'arv to taVe readings 
almost continuously, whlcb requires a dead >'eat Instru- 
ment, a^;d the galvanometer was modified In the following; 
manr.er . A Inr^e tnlca vane: was fastened to the bacV of 
the mirror: a copoer tube was fitted over the coil so 
as to turn with it through the magnetic field between 
the poles of the permanent mas^net; and the coil of the 
galvan meter was shortclrculted by the key '£_ when open. 
These thrc= iriethods of damping reiide^'ed the galvanometer 
sufficiently dead beat to be used. If care was taVen 
never to allow aeflectlons of more tha:; SO mm. Usually 
however t^e deflections: were about 1 or I? mm. 

Three Westoii sta:;dara cells, W, were used for the 
measurement of the current ai;d V.. V. V. They were 
corjiected to three pairs of merciiry cups, as shown, a:;d 
any o.;e of them could be Inserted In one of the galva- 
nometer leads by placing t>^e wires. x}x\, into the corr«s- 



•••^7- 



r)on'ilr»<t mercury cnos . T>^e ends of tv-wse -vires were 
fapt«:;t?(l Ir. h hlocV nf bqrd rubbar ai;d projected about 
H Centimeter berveatb , 'Ry simply llftl:iR tMs blocV 
from oj;fc pair of cnp.s to ar.other any one of tbe standard 
Cwlls cotild be brought into use. One cell vas used 

throuehoTit one experiment ( about balf an ho\)r I 
durlnt? which interval itr, constancy was several times 
tested by sijbstltntine an iinHSed cell in its place for 
a simple readlnfC. No sls^n -vas ever found that the 

cells suffered the least chanpie in their K. M. ^' . when 
in use. These Cells we-»-e certified to have a constant 
E. M. ?. at ail temperatures between 10 C. and ."^FS 0. 
bijt they were always used at very nearly SO <^ . 

The absolute valiie of the K. hf. . F. of th«5Se cells 
was determined by the National ^ireau of 5^tandards, 
where o;.e of these Cells (no. ?;p9 ) was compaT-ed with 
ten standard ClarV cells. Assumlnt; the ciarV to be 
1.4.'4 volts^ the K. N' . >-'. of this Cell was foum to 
be 1.0107, volts A-^ /fiiy. 

The results of all the exDerlmonts. save two. are 
expressed in ten m of this cell. In the other two. 



-.•=17^- 



tbe stanaara cell no. ?5PR was used, t^e K. V. v. of 
which was less thaji the other by 1 part in 10000. as 
i5hown by the nalcer's certificates, ajid also by a direct 
comparisor; at the time thev were useo. Hence the 
K. M, ?. of this cell is taVtjn as 1.019? volts. 

The stai-.'iard half ohm coll, M. . is of the Helchs- 
anstalt for^n as niarle bv Leeds ■V Co.. and was made with 
sneclal refe>*er»ce to carrylTig ciir'^e:its as erreat as two 
a'liperes. It Is provided with both current and potential 
terjuinals, the half ohin helnt^ the reslstai;ce between 
t>^e two points where the potential terminals are 
attached. The exact value of this reslstai;ce was 
determined by the National T^ureau of J^tandards, and 
was founa to be O.fSOOOB ohm In terms of the mean 

A 

values of two colls which were redetermined at the 
Heichsanstalt In -luly 1^0?. Copies of these certifi- 
cates are appended at the end of this dissertation. 

As sho-ATi ii; the figure, the cur^e:;t ternilnals 
are joinea ii; series with the heatlnp; coll. and the 



-7;q- 



T>ote:;tial tormiiials are i Tlneri to o-.e slie of the 
double pole, double tbroT switch, T_. When this switch 
Is closud t^ti ilffererice of potential between the ter- 
minals of the standaro half ohm Is balanced against the 
K. M, F. of whichever standard ceil is In circuit, the 
dlffererice. If anv. belnec indicated by the galvanometer 
on closl^.g the Vey K. The main cur*'ent through n_ and M 
Is continually adjusted to Veep the galvanometer deflec- 
tion Zero. The observur sits with his eye at the 
telescope watching t>"e galvanometer deflections, while 
one hand continually tapped the key K, a-nd the other 
varied the resistance H_ whatever was necessary to maln- 
tal:; zero deflection. 

In oraer to be pretected as fa-^ as possible from 
fluctuations in temperature, the star.dard cells and 
reslsta.;ce were placeo In ^ wooden box and covered with 
cotton wool. This box occupied a Dositlon on t>^e table, 
fO'ind by trial, such t'-at that th^- heat from the regis- 
ter and the cola frot.i t^e window balanced to give a 
nearly co:;stant temperature of about PO'^C. Cnilte large 
fluctuations in the temperature of the room. If not 
continue^, too long, produced very little change within 
the box. 



-.•^9- 



Me a svi rtiiiie:;! of Cnrrer'tt . 

As tfxplJilnwi abovtj . thH current tbrouRb the heating 
coll 'vas ;iiHi.;tfili;ei, co;ist=»nt by keepli-.s; the galvanometer 
deflect In; as near 7ero as possible. The deflections 
to one side or the other were usually less than one or 
tTTO ralllimeters, and the corresponding steady deflections 
could they have been observed, would hq,ve been consid- 
erably less. As the deflections were as often one way 
as the other, th^ too small current at one tlr.ie would 
tend to balai;ce the too lar^e cxirrent of another, thus 
maVlng the acttial average current t>^rou£?h the calorimeter 
differ less from its intended value tha:i if the deflec- 
tions were all in the same directions. The sensitive- 
ness of the entire arrangement was such that a steady 
deflection of one millimeter corresponded to a variation 
in the current of about 1 part in 10.000. 

KnoTlne; the resistance of the standard coll, M, 
and the difference of pote:;tiHl >ietween Its terminals, 
the current it car^'les is readily calculated by Ohm's 
law. The current in the heatlnt^ coll. c.« ^^ equal to 
that in M, less the small portion which flows throujjh 
the potentiometer Circuit, PQ . 



-40- 



K'oa stirtjiucr.t of K. I'. V. 

The (iifferttiiCe of potential between tbe terminals 
of tha hj-^ti.ic cotl vas meastire'l ^v t>^e usual potentiom- 
eter juetboi as shown In ?iz, ^. ^ Is a fixei resistance 
of 10,000 ohms, while p in about 1100 ohms. T^oth 
reslstancts in series are joined in parallel vlth the 
heating coll and thnp are subjected to a total fall of 
potantlal of about ten volts, of which a little over 
or^a volt Is in the part j^. As shown in the diagram, 
two lead wires from the terminals of £_ ru:i to the switch 
T. On tbrowlng the switch to this side, the fall of 
pote:;tial in 2. is compared against tbe V.. I', v, of the 
same sta:;dard cell used for the measurement of current. 
The resistance of £_ is varied to give zero deflection 
of the galvanometer. Then lf E 1s the V. . M. V. of the 
sta:;dard cell aiid P. is the resistance corresponding to 
zero deflection of the galvanometer, the difference of 
potential, V_, measureT hv the potentiometer Is given by 
the expression, 

P 

When rui^ning an experiment, the switch, T_' ""^^ 



■41- 



ktjpt clos-ji on th« curruiit slie in order to r,\ja that 
the laf^er remalneri constant. When every thlnt^ was 
gol".^ smoothly the switch was quickly thro^r. to the 
other sl'le - the direction of the galvanometer -ieflec- 
tion noted - and then thrown bacV af^aln. The smallest 
change i:i P^ corresponded to a deflection of els:ht sf^ale 
divisions, a:;d when It was not possible to adjust P_ to 
gjive Zero deflection, the small deflection was observed 
and the value of P corrected accordinficly . 

The temperature of the potentiometer colls, or at 
least that outside of the boxes which contained them. 
was a^out 20°C. in all of the experiments here reported. 
As It is t>-^e ratio of the resistances of these coils 
that is used in the meas\irement of K. M. K". any small 
change ir. temperature would affect this -^atio very miich 
less tha:: it wotild the absolute value of the resistances 
Tn fact It would be proportional to the difference 
between the temperature coefficients of the two (ortlons 
of the total reslstajice , and is therefore Inappreciable 
for a variation of one or two decrees, or even inore. 



-4J>- 



yea sureiuent of Time. 

Tlnie was uiBasurtso hy an Kltjln watch wblcb was 
losliiE loF.v than thirty seconds a month. The secou'ls 
hand wap viewed with a sii.all readlne; Rlass which mag- 
nified flvu diameters, q^nd just as the •''^O-seconds marV 
was covered by the haiid, the switch S. was closed, thus 
starting the current through the coll C. at the beglnlng 
of the ?>lst second. When It was desired to stop the 
current the same procedure was repeated. Tr>>enever the 
length of time was arbitrary and would allow It, the 
current was allowed to flow aji Integral number of min- 
utes, so that the seconds hand of the watch could be 
read In the same position at both the starting and the 
stopping of the currt^Tit. 

In order to obtain some idea of the accuracy with 
which Intervals of tlrne could be measured by this 
method, twelve single minute Intervals as observed with 
the watch Were recorded upon a chror»ograph sheet which 
was !ilso receiving the records of seconds from the 
astronoiiiical clock. 



-4.'<.- 



Th« duritioi; of thtsse tuterv^ls as obtalne'l from 
t^e chromfjrap'r are KClvun below. 

«O.PP -SOJ-fS 60.15 

60. SS 60. 2P 80. S5 

60.15 60.15 60.10 

60. PO 60.15 60.15 

Mean of all = 60.177. Prob. error = O.OIO 
(60 solar seconds = 60.16.'i slderal seconrts i 

The probable error of one observation is 0.0.*^ sec. 
and the greatest dlfferenct; of a single observation 
from the mean is 0.08 second. From this it appears 
tbat intervals of time measured with tbe watch can be 
depended upon to at least a tenth of a second, and 
they probably possess a greater accuracy, 

T>\e. Th ermometer . 

The thermometer Used in these evperlments 'vas one 
made to order by H. J, Green of "Rrooklyn, N. Y. It 
was graduated on the stem to hundredths of degrees fYom 
- l'^'":. to ■+ 1*6 1. Its entire length was Q5 cm, and 
It wa«; 6 tijii. in diameter. The bulb was long (8 cm, I 
and thin, thus quickly talcing the temperature of the 



-44- 



bat>^ tn -vfiich It was plHC«'i. TV'e sttsri fVoi-, - ^°r, \ip 
WHR above the top of the barrel, and with t^e ali of a 
small reading glass tbo temperature could eaKlIy be 
read to thousandths of a d.igrye. 

The Zero of this therir.oiiietiir was too low by 0!0.'=^.'S, 
that Is, the temperature of melting ice eave the readliig 
■V 0'. 0.''^5 C. This difference Is doubtless due In part to 
the fact that the stem was exposed to the temperature 
of the room (about 20'' C. *. btjt as this was the s?jme in 
the actual experiments aiic when the "zero point" was 
determined no error is introduced by not applying the 
stem correction. Tt^e "zero point" was determined before 
and during the experiments by t^^ree different methods, 
viz.. by placing the bulb and several centimeters of 
the stein Into a mixture of clear Ice and pure distilled 
water; by plunging it into freshly fallen snow which 
was saturated with uure distilled water; and bv placing 
It in pure ol. stilled 'vater which was being frozen in a 
large test ttibe . Kach of these methods gave the read- 
l:;g f 0'.0.'5'^ C. as the true zero, and all -^eair.-.gs of 
the thermometer are corrected by t^ls amoir;t. 



-45- 



The brnss case of th« theririOTTieter was Vept staiidlnt? 
In tbe Icfe j-.Tirronn-llrif^ the chambe" D. an*! who:; not In 
use the thermOTTieter was always w1thi'\ this case and at 
a temperature not hlf^her t^^an two or three tenths of a 
dei^ree above Zero. TJtjring the eViti^'e series of exper- 
iments here reported the thermometer was not allowed 
to rise above -t- 2" C . and the lowest temoeratnres to 
which It was subjected rarely exceeded - fS" '^ , 

Man 1 pi ilatlon of the Tee . 

The Ice used in these experiments was very carefully 
selected, only that which was perfectly clear and trans- 
parent a::a free from buhies being taken. The structure 
of all the ice us'jd, both the commercial ice and that 
made from pure distilled water, was decidedly crvstalllne 
the axis of the cryst^^ils be ins normal to the surface at 
which the Ice was formed. A piece of ice which exter- 
nally appeared the same in all directions, qulcV-ly 
revealed its crystalline nature wheJi the attempt was 
made to split It. If the ede:e of a sharp Vnlfe; w*s 
pressed against the ice to divide it along the axis of 



46- 



crysta] llzatioti, it v.uHrilly Heparnte'i nlonj? an almost 
perfect plaiie, Tho sanie Is true of the plai;eK at 
rlii?ht a:;«los to t^e .-ixls, provided It If. not too near 
the end of the crystals. Tri any other direction, and 
oven t>"at perpendlcialar to the axis If too near the end 
of t^'e crystals, the pressure of the knife ■resulted In 
merely shatter i.ig the ice as tho It were a bundle of 
?lass tubes. Tiy cleaving the Ice in planes at ri^ht 
angles and parallel to the axis of crystallization It 
is possible, howevwr, to divided it into small cubes 
with smooth surfaces, each one of which was as clear 
as the original piece. 

As the -.veather was Seldom cold enough to keep the 
Ice from melting, about 100 grams of these pieces were 
drop Lea into a beaker surrounded by a freezing mixtTire. 
To preverit their freezing to the sides of the beaker a 
few pieces were introaucea at a tirie and constant Iv 
stirred ui'^til t>^ey were cooled below 0°*^. and whiitever 
free water there might have b^en on the stir face was 
completely frozen. The beaker was then closed with a 
hall of cotton wool to r>revent the warme" riir from 



-47- 



comliisj In contHct wltb tbo lc«, Hiid luft In tbe freez- 
ing mixture some minutes lont^er. 

In the lueanvhlle the protyor amount of oil was 
meastired out into n flask, wel^hea. ana placed In a 
freozl:;g mixture, where It was cooled to about - 6''n. 
This flaslc was now removed, 5»nd the oil quickly poured 
into t'-^e calorimeter through the special funnel, ^oth 
the flask and the funr.el we'^e then laid aside to assume 
the temperature of the room, when they were rewelched 
to determine just how much oil entered the calorimeter. 

In order to welp;h the ice without its raeltlnf?;. the 
beaker containing It is removed from the free^int? mix- 
ture, quickly wiped dry, wrapped with cotton, and placed 
within a larger beaker, the whole being covered with a 
paper mach.e cap. This arra^igeinent was placed on the 
balance and welgh.eo. It is then carried to t>^e calorim- 
eter, the cover and hall of cotton removed, ni\n the ice 
poxired through the brans tuhe into th« cold oil below. 
The ICe is directed into this tube by a funnel formed 
of filter paper. At i;o time wav the appearance of tho 
ice such as to indicate that any portion was melting. 



-4R- 



nor was ai^y water t»ver r,:\\\fry>t by t^e f liter* paper as 
the Ice passed over It. The fall of the Ice waq 
broVe:i be the ledsfe, T), of t>^e stirrer aiid thus splash- 
Int? Tf the oil Is prever^teri. Usually the ice was In 
the oil of the calorimeter within three mlmitus after 
It was taVen from the freezing mlxtii^'e, and thus the 
opportuiilty for any ineltinsc of the ice, or of any 
change l:i •ffeif^ht due to evaporation, was very sllf^ht 
indeed. After pourlnf^ the ice into the nalorlneter 
the beaker was closed with t^e cotton ball, the cover 
replaced, and the whole lirj-uedlatel;^ weiehed thnc 'de- 
termining the amount of ice employed. 

If the equilibrium terape-^ature of the oil. Ice 
and calorimeter wap irnich below - 2'^- or - P".'^ r. it 
was cautiously raised to this point, a:;d then left 
for abo\it an hour d\irin(? which time it slowly rose 
some tenths of a dep;ree further. At this point read- 
ings of temperature were cotrir.enced , while t^e oil and 
ice Were consta:'»tly stir'^ed ^t a uniform rate. Py 
alternating periorls of wanning due to radiation alone 
with pcrloas ir. which the rate of warming is ir»creased 



-A9- 



by an elentrlc current tbroue;h the coll. the relation 
betwdc^n cbaiij^e of temperature and joules Is obtained 
as alreHoy explained. 

When thu temperature reaches - 1°^., or thereaboaits 
the largc-r coru;ert is applied for a suf'ficle:;t time (as 
determined by p'^evious calculation' to melt the Ice. 
l)urln^ this titae one observe^" constai;tly w atches the 
c;alvanonieter aiid maintains the current constaiit, while 
the othur continues the stirring a:;d reads the thermom- 
eter each, inimite. These readings are utilized in the 
C'-ilcul?tion of the heat lost by radiation during the 
exper inient . 

After the eKper iiuent is conclTided the caloriiaeter 
with the oil and vater Is again weighed to furnish a 
ChecV upon the weig'-'t of ice used. This weight was 
always within a feT centigrams of the sum of the 
weights of the separate portions. 



~^0- 



SOUROKJ^ OF KRHOH. 

The various s")n-^ot;.s of error in tM s net^orl are: 

1. Heat lost by rj^rllHtion, oojidnctlon. convection, etc. 

2. Heat proauced by stirring. 
?i . Klectrolyais of tbe w^ter . 
4. T.oss of heat by evaporation. 
*i . Use of tht! thermonieter . 

Under the first head It must be not 1 ceo that the 
temperature of tbe calorimeter was always within two 
degrees of C'C, while the teiru-erature of the surround- 
ing walls of the chamber were very close to Cf o , it is 
assu",;ci, according to i^ewton's law, that the heat lost 
by radiation is directly proportional to the difference 
between the temperature of the calorlrioter and that of 
the surrou:idlng vails. To prove that the loss of heat 
dii th'is depend upon the teraperature of the calorimeter 
at t^e tlTi.e, and not upon previous temperatures, two 
detenuinatlons of the heat lost at a given temperature 
wore made. In one this temperature was reached by 



-M- 



addlTii^ sotiiw Vary cold oil. af^^er which f^o nate of 
coollntc WHS ob.serveT for a consldtsrahle time. Again 
this tetaptsratiirt; ^ras r«HCh.t;d by quicVly -A'arTnl'.;!? the 
oil Several degrees by the oleCtrlC CU'^^Knt . The rate 
of cooling, after thu flT•^t few mlnnteR. was Identical 
with the former, thus showing that It depended solely 
upon the: teiaueratiire at the moment. 

The loss of heat by convection air currents Is 
reduced to a minimum by filling the space arotind the 
calorliiietcT with cotton v/ool . 

Whatever heat may be conducted to the calorimeter 
from the outside by the wires conveying the current is 
Included in the determination of the heat lost by 
radiation, etc. However this ir, very sinall since 
these four wires are of no. 16 copper wire, and the 
heat wo)ild have to be conducted a distance of ."^O cms. 
and through air at D*C. The heat generated In these 
wlrds by the cur^^-j.-it Is abo\it one joule durl-.g each 
expcrliaent ai:d Is therefore InaoDreclable . 

It thus appears that the los'- or gain of ho'-*^ due 
to these causes Is a definite nuantlty capable of Toeing 



-«SP- 



determlned. As this determination Is b«\5?e<1 noon mois- 
uroiiients iu'Hde just before ai;d JMPt aftur the main 
evrerli.;e:;t , tbe total erro'" Introduced cannot exceed a 
f eT j ^Tlles, 

H ea t produced by stirring . 

^y extremely vigoroti.s .stlr'>*lng it vpir possible to 
produce enongb beat to cause an observable effect upon 
tbe rate of cooling due to radiation, etc. Ar. ordinarily 
used, however, the stirrer was raised and lowered about 
threii centin.eters fifty or sixty timer a minute. At 
this rate no different effect could be obsrved from 
that when the stirring was only four times per minute. 
The heating must therefore be very small, and whatever 
it is it is taVen account of in the correction which 
is determined for radiation, etc. 

KleC trolvHis of tbe water . 

This ii; impossible at the connen cement of aii exper- 
iment a« t'^e" 1 Is n") v^ti-rr n^i^Q.-it. It C^n hardlv be 
present later as the coll is well coated with shellac 
wetted A-l t>^ kerosene oil, and onlv a snali r-i^tion of 
one end is ever below the surface of the water. 



-•i,'^- 



T f Oss o ?_Jv.j it j y evaporation . 

In tn^ visual inothorl of rtilxt;ires tbere Is always a 
considerable ammint of evaporation from tbe surface of 
t'"e vater . an'l «» conseouent loss of heat. Tn these 
experiments, ho'vever, t^e water Is covered bv the oil 
and there is no evaporation. The oil Itself evaporates 
exceedingly slowly, and 'vhatever heat is thus used is 
included in the determination of the loss by radiation, 
etc . 

Use of the thermoiiieter . 

The thermometer was used to measure the initial 
and fi;;al teinperitures for determining the amounts of 
the corrections to be apolied. As this Is a ve^v good 
standard thermor:ieter recently made by Green, it Is very 
improbable that t'-^ere is any apcrociahie erro'' in the 
length of that portion of t^^e scale here used. The 
greatest error is Introduced In the assumption that the 
temperature indicated by thy thermometer trtily represents 
the temperature of all portions of the calorimeter, as 
these readings were taken only whon the temperature was 
changing vorv slowly a:;d while the contents of the cal- 



-S4- 



orlr.ieter wure thoronehly stirred, this asfluniptlon can 
not be Very far from the; truth. 

WEIGHTING OF THp; KXPKHIi.T^INTS . 

Each of the eight experiment <- here reported vas 
conductcrl with the greatest care, and there Is no 
reaso:; for dis^-redlting the result of any one of them. 
Nevertt^eless there are Certain circunistances to be 
notea which warra:;t greater confidence in some experi- 
ments thai', in others, ana these considerations are 
ta1:en Into account by the following system of weighting, 

The maximum weight given to any experiment is ^, 
made up as follows; - 

One point if there has been a direct determi'\ation of 
heat capacity with ice preceding the regular experiment 
of riielting the ICe. 

One polr»t if the regular experiment has been followed 
by a direct determination of heat capacity with water. 
Two points for a short duration of the experir.ient , t^at 
is, ler.r. than forty inlmites. 



-SS- 



One point if nil th^. ice Is melted xj^h h Hir.Bile 
application of the ciirrent . 

One point if tbe rntw of coiling at tbe Hr.ri of tbe 
oxperiiuunt is definite anti constant. 



PRELIiVlNAKY KXPERT".."KNTS . 

The first experiiaents were made: usin? the clearest 
portions of the artificial ice ftirnished to the labora- 
tory. Lt wa?^ intended to use this Ice for the prelimi- 
nary work ^i\ri later to try some ice frozen from the 
piirest Tater obtainable. It was expected from f'-'e 
state!;ients of sone of the earlier Investigators along 
this liny, especially t>^e caper by Person. t>>at t>^e 
specific heat of icci would Increase gradually with 
Incraese of temperature from its value at - ?/ C . and 
lower temperatures, am possibly approach the value 
for water as O" - . vras reached. Tn determining the heat 
capacity of the combined apparatxis with Ice for temper- 
atures approachi.ig 0"'^. this ide^ set-med to he corrobo- 
rated by experiment. A gre^it many experiments were 



-.«S6- 



madtJ to deteriiilue thw exact valiiw of this lrvcrwa«!ert 
beat capacity. At firp;t all deternilmt lor.s *ore for 
teiiipyratnreR below - 0'.F> C . and t^e Increaseri beat 
capacity of tbe ic« did not exceed tbat of water. 
Later, when tbe raiii^e from - 0°.5 o. to 0° r . iras studied 
tbe beat capacity came out as belne; Inversely propor- 
tional to the teuperature below ^., Increaslnj; with- 
out lliv.lt as C" C. was aijproached • Tbls at once raised 
suspicious tbat soiiiethlue; was wrone;, and further Inves- 
tlciatlon showed tbat there had been some meltlne; of the 
Ice. When the temperature of the oil and Ice was 
already very near to O' ^ . It Is probable that the cur- 
rent, tho very small, raised the temperature of some 
portions of the oil to such a tempe-^ature that local 
melting of the ice was possible. Whatevc;r water was 
detached from the ice ai-vd remained In the oil in small 
drons, -ould not freeze again whei; t^e emilllbrlum 
temiierature was reached. However It was never possible 
to find sufficient wnte^ to account for all of the heat 
absorbed, ai'.a do\ibtless the remainder was used In Inter- 
nal melting. As sh.onr. below, unless the Ice Is abso- 



-^7- 



lutwly pure t'prouKhout . those portions contalriinsf the 
groatfst air:0\int of Impurities will melt first and fit 
the loirest temperatures. As the temperature is raised 
a greate'' a;;-! {greater amount of the impure ice 'Aill 
reach, its iaeltli;g point, reoniring an ever Increasing 
amount of heat to proance a given chmige in temperature. 
The -A'ater from this melting could remain on the surface 
of the icc, or if the inelting was internal it would 
remain in its ot*t» cavitv, Altho in contact with the 
Ice this water lor rather solution I could not be expected 
to frei;2e again ana return its heat of fusion to the 
oil, even tho the equilibritim temperature was two or 
three te-.;ths of a degree below O'' C . 

Moreover, at t>^ls time the entire Question was 
comDlicated by the possibility that the oil might have 
sonic action upon the ice. This hardly seemed probable 
from the nature of the substances, and the fact that 
other Ir.vest igators have observed n"> action UDon ice 
when placed in refined Verosene . It is proved below 
that thure is no such actlor.. 



-5n- 



?^peclflc heat of Ice . 

Thoru was uo'*- aii imperative demand tbat the specific 
heat of Ice be carefully studied over the rai-.cjo of tem- 
perature from - I'C. to 0" c, . Ordinary distilled water 
was placed in a larsie test tube with a smaller test 
ttibe suspended in the center. T>'e water was frozen 
from the bottom \ip . thus forming a cylinder of ice 
between the two test tubes, about seven millimeters in 
thlclcness ai:d as many centimeters in height. A nex 
>^eatl".e; coil was arran«ced at the bottom of the calorim- 
eter and occupying only aboxit one centimeter in depth. 
Over this was plaCc^a the test tube containinsc the ice. 
Any possible action of the oil \ipon the ice was now 
entirely eliminated as they were sepa^-ated by the (^lass 
wall of the test txibe . Heat was slowly applied by the 
small curr<j.;t t>^roue;h the coil, and the heat capacity 
of the ice determined as before. Altho much less than 
before, yet at - 0*2 C. It appeared as threat as for 
water and at - 0*. 1 r. it was twice as (n*eat. On removing 
the tube and clost;ly examluln? it, a bit of water was 
seen at th» point where the last ice was formed, lioubt- 



-F)9- 



less this drop coiitalneri the (greater part of whatever 
Impurities existed in the tube of vater, and belnp; the 
last to freeze it wa'-. ^he first to mult. 

After this only the purest water w^s used for 
maVing ico. Such water waf. obtained from l>r, Jones 
who Vlndly ftirnished all that was needed. This water 
was pruparco by dlstlliine; ordinary distilled water 
from a solution of chromate acid, the vapor beln(y then 
passed directly Into a bolllnt? solution of bariuT'i hu- 
(ir*)fide to remove all traces of carbonic acid. The v?»por 
was then condensed 1:; a block tin condenser and collected 
in a B;lass bottle. The latter was previously treated 
with boiling hydrochloric acid for a long time in order 
to render the glass insoluble in water. This water was 
being continually distilled for use in conductivity 
evperlments in the Physical Chemical Laboratory, and 
possessed a specific resistance of one megohm. 

A portion of this water was thoroughly boiled to 
remove the dissolved air mid the test tube filled to 
the deslrei height. The inner tube was not used, but a 
layer Of ice was frozen on the sides of thii tube to 



m 



f ri*o 



-PiO- 



aboiit t^e .same tMcVcness as boforw, tJ^e rw.sldnril waiter 
li; the ceutur being throwr. o\jt. Tho Ice thus formed Is 
very pure, whatever impurities thert; ir.ls^ht have been In 
the rater at the beglnlnsc belne^ thro'vn o\it 1:; the 
residual xater . Two such tubes wore prepared and 
placed In the calorlnieter , which was previously filled 
with, cold oil . 

Observations were made for the determl:;atlon of 
heat capacity, and these are recorded on the followlnsc 
pa^es. The saiiie experiment was repeated the followlntc 
day (Feb. 20 » . The effect of having^ the oil in contact 
with the ice was determined by filling the cavity In 
the center of the ice ttibes with oil, and again taVlng 
a serlc ■ of" observations for heat capacity. Any melt- 
ing of the iCe by the Oil would be manifest by the 
Increased aniou:-*t of heat requlrea to produce a f^lven 
rise 1r. temoerature. 



-<11- 



Obs«rvatious for tbt beat capacity of Ice. Feb.l^.K^Or^, 



Time 


Temp. 




Time 

1 1 


Temp. 


f 


1J>:50 


-0.5:>5 




1 ' 
1 : :'8 


-0.135 




51 


.520 




29 


.133 




52 


.513 




30 


.131 




53 


.5 07 




31 


.130 




54 


.500 




32 


.130 




55 


,493 




33 


.129 




56 


. 4^^7 




34 


.128 




57 


.4R1 




35 


+.126+ 




58 


.474 




36 


.124 




59 


.469 




57 


.122 




1:00 


.463 




SB 


.120 




01 


.458 




39 


.117 




02 


.453+ 


Currer.t on 


40 


.115 




03 


. 435 


at 1:02:30 


41 


.1.13 




04 


.395 




42 


.112 




05 


.3'^.5 




45 


.110 




06 


.315 


Cell NO. 329 


44 


.108+ 


Current on 


07 


.278 




45 




at 1:44:30 


08 


.261 




46 


• 


Current off 


09 


.260-t- 


r^urrer.t off 


47 


.031 


at 1:46:30 


10 


.259 


at 1:07:30 


48 


.031 




11 


.254 




49 


.031 




IS 


.252 


1 


50 


.031 




15 


.250 




51 


.031 




14 


.248 




52 


.031 




15 


.245 




53 


.031 




16 


.241 




54 


.031 




17 


.238 




'^^5 


.031 




18 


.235 




56 


.031 + 




19 


.231 




57 


.o.-^o 




20 


.227 




58 


.029 




21 


.225 




59 


.028 




22 


.222 




2:00 


.027 




25 


.219 




01 


.026 




24 


.217 


Current on 


02 


.025 




25 


.213+ 


at 1:25:30 


0.-^ 


.024 




26 


: • 


Current off 


04 


.023 




27 


• 


at 1:27:30 


05 


.022 





-'ila- 



Tha readlrijy.s of the tberinon.eter wore t'lVe:; at 80 second 
Intervals, aiid are recorded in the second column of tbe 
prec«idl:;e; table, opposite the corresponding; times In 
the first colTimn, Tn the third columiv are Riven notes 
regarding the electric ciirrczit, the tline it was on. etc. 

On the following paRes are tv^e calculations for the 
change in teniperature proauced by tv^H '^nri^eiit . The 
observed changes in temperature are on the right hand 
side of the page, while the calculations for the change 
in teniperature due to the 'varming from o\itslde Influence s- 
are luade on the left ha:;d side, the result being 
carried across to the right hand side where it is 
subtracted f>~otn the observed change in temr erature to 
give the change in ^emnerattire dtie to the current alone. 

The ♦euir e>'aMire readings which are used 1i t-hede 
calculations are marked with a + In the tables. 
Sltuilarly, the final r^^sults of the calculations are 
marked with the san.e sign. 



-«p- 



Halculations 

Ttftup. nt iri;50 = .^2F, 
" 1 : oj? = .AF ).-^ 

Char.f^e In terip.= .072 

I)er i.iiu. = .006D 



Temp, fxt 1:0:^ - ,4'S,', 
" " 1;09 = .PHO 



Temp, at i:D9 = .2H0 

C>^an^^,e i:; teivip. = .04*7 

•* " " per mirv. = .00?;0 
Mean. = .0045 



II II II 



" diirlr^f; "7 lainnteo 



ChriT.Ko in tetap.= .l^,*^ 



.o?;s 



Chnnge l;i t'.imp. aue to current = 



.IfM ■*■ 



Temp, at 1:25 = .Pl."^ 
Chanfte in terap = .087 



Teirip. at l-..-^^ - .l.pr? 
» .. 1 ; 44. - .1.08 

nhviifG I;; toinp = .on 

" per mill. = .OOPO 



( contlnuei • 



-6.3- 



M«a:; cba;;ge; In temp, por niln. = .OOPfS 



I* 



rirtrlr;« 4 win. = .010 



10 



•• — 



Chnna;© In temp, iue to current = 



.OPP 
.065 -t- 



Temp, at 1;?S« = .O.^^l 
" S;05 = .022 

C'hv\sr,fi In teiip = .009 

» •* '• perm in. 

Moan '• 



Temp, at 1 ; 44 = .lOR 

" 1;50 = .C^l 

Change in temp = .O'^V 



,0010 
,0015 



*• 1* I* 



l« n »• 



" ^rtrintr ."'^ mlu. - .0045 

" " 9. " ~ .009 

" " IP " = .Ol.*^ 

Chanscfc; 1^» temp, aue to current = .0«S4 



-84- 



ObservatloiiF for the heat cftpacltv of ice. Feb .PO , 1^0."^, 

Time Temp. 



9:00 
01 
02 
05 
04 
O.S 
06 
07 
03 
09 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 

?;l 

32 
33 
34 



remp . 




1 . 540 




.5P5 




.51P 




.495 




.480 




.465 




.450 




.435 




.422 




.408 




. 396-*- 


Current on 


• 


at 9:10:30 


.32 




.P7 




.23 




.19 


OHrrent off 



.152 
148 
.141 
.133 
.125+ 
.115 
.105 
.096 
.086 
.076 
.066 
.056 
.048 
.038 
1.028+ 
1.000 
0.96 
.92 
.88 



at 9:15:30 



Current on 
at 9:.•^0:30 



10 



9:?;5 

36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
57 
58 
59 

:oo 

01 
0? 
03 
04 
05 
06 
07 
08 
09 
<^t 
r*-- 



-0 



Current off 
at 9:35:30 



Irr 



'I ^. ■f ". t^ 



835 
.81,", 
.810 
.808+ 
.803 
797 
,791 
.785 
.780 
.772 
.765 
.759 
.753 
.745 
.740 

. 730+ 
.705 
.670 
.6.?5 
.585 
."^50 
.526 
. 525 
.5P5 
.524 
.521^ 
.517 
.513 
.509 
.505 
.500 
.497 
.493 
.488 
Ing continued hut no 



Current on 
at 9; 51: 30 



Current off 
at 9:56:30 



{ contlnuea ' 



-65- 



contl.'-.uatlon. 



Time Temp. 



Keb. r>0, 190.". 



Tlmo Temp. 



10:17 


-0.454 


18 


.453 


19 


.451 


20 


.447 


21 


. 443 


22 


.439 


25 


.435 


24 


. 430 


26 


.4P6-(- 


26 


.^10 


27 


.365 


28 


.328 


29 


.293 


50 


.257 


51 


.233 


52 


. 233 


33 


.233 


54 


.233 


35 


.233 


56 


.232 


57 


.231 


58 


.227+ 


59 


. 225 


40 


.223 


41 


.221 


42 


.219 


45 


.217 


44 


.214 


45 


.211 


46 


.209 


47 


.206-t- 


4R 


.193 


49 


.150 


50 


.113 


•=1 


.080 



Oiirrerit on 
at 10 -.25: 35 



Current off 
at 10 •.30:35 



r:\irrerit on 
at 10:''-v;.so 

Current off 
at 10:51:30 



10:52 ■ 


-0.060 




53 


.060 




54 


.063 




55 


.064 




56 


.064 




57 


.065 




58 


.065 




59 


.065 




11:00 


.064 




01 


.064 




02 


.064 




03 


.064 




04 


.063 




or. 


.062 




06 


.062 




07 


.060 




08 


.058+ 


Current on 


09 


.040 


at ll:On:.'^0 


10 


-0.005 


Current off 


11 


+0. 015 


at 11:10:30 


12 


.016 




1.-^ 


.016 




14 


.012 




15 


.009 




16 


.007 




17 


.006 




1^ 


.006 




If^ 


.006 




20 


.006 




21 


.005 




22 


.005 




23 


.005 




24 


.005 




25 


.005 




26 


.005 





-«<^- 



Calciilfit.lons. 



Ternp. at 9:00 = -1.540 
" 9 ; 1 = 1 . r^' iQ 
Cha:-.R« 111 temp = .144 
" " " por nl!i. 



.0144 



Temp, at 9:10 
« " 9 ; PO 

'^b'ln^e In temp 



■ 1 , .-^o^ 
1.1 P5 

. r>'7i 



;oo7 



Temp, at 9:20 = -'.125 

" " 9;;SC = 1^.028 

Cbanf^e ir» temp = .007 

" nor :nln. . = 

Vean. " " •. .. h -- ,oiPO 

" d'.irlng 6 mm = .072 

" - 4_ - = . 059 

.. .. ;,^(> ,. _ 

Ch?»nge III temp, due to current 



• 111 
.160 + 



Change in temp, per nln = .0097 



Temp, at 9:.-^0 = 


-l.OPR 


" 9:,',R = 


0.808 


Changes In temp = 


.P?0 



Temp, at 9; 38 = .808 

- 9; hi - .7.-^0 

CHan?^e t:i temp = .0'''8 

per nln = .OOQO 

Mean " •• = .0078 

" during fi mm - .047 

" " 2. " = .012 



II It 



*t — 



.0^^^ 



Change In tr:mp. <lue to current 



.161 + 



-R7- 

Ttrmp, at 9;:w = .808 
•• - 9;. SI = .730 

'^h'Uif^e In temp = .078 

" •• '• per nin = .00«0 



Temp. Tt <^;si = .7.'*;o 
"10:01 = .5P1 

Ohar^f^e In teinp = .P.09 



Temp, ■^t 10:21 = .F>21 
•♦ " 10:09 - . 433 

CbanHe in telup = . O."^."^ 

•' " " per Piln = .0041 

Mean = .0050 



'• 'iurln<? B mln - ,0P5 

5. '• - .DPI 
'• 10 " = .048 

'^hant^e In temp, itie to current = .l*^.*^ -(- 



M M >• 



Temp. at.l0;19. = .451 
" iO;i>5 = .426 

Ohanf^e In temp - . 0P5 

pe'* I'lin = .004P 



Temp, at 10:25 = .4P6 

'• 10;. "^8 - .PP7 

Change in teiup. = .1^0 

I cont ' 



-88- 



Tdinp. at 10;;-SH - .P27 
" iO;4ft = .311 



Ch«Clt^e li toliip, - .OlM 




'• PBB "iln 


- .OOP.-^ 


Me Pin 


- . 00. -^a 


' i')-^1nn; »> 


mlu =^ .020 


n I* l» M •• r« 


~ ,016 



I* II II 



" 17, 



■ O.-^H 



Change In temp, lue to current = .le.*^ + 



Chnn^B in ttsiiip. per min = .OOS."^ 



Temp, at 10; 47 - .PO*^ 
" 10:58 = .QfjF, 

CbanfTe In tent;. = ,141 



Temp, at 10; 58 - .065 

" •• 11; 04- = .06? 

nhant?e In ter.ip = .0 0? 

" per nin = .000.*^ 

Mean " ' •• = .001.^ 

" 'Inrlnf^ 5 tnln = .006 
6_ •• = .002 

II M 11" "~ 

Ch'antcfe In teinp. riiie to cu'-rent = 



.008 
.l.'^r'i -(- 



Ch«in)?e In tciap. per itiln = .OOO."^ 



Tenn. nt 11; OR 

" 11;PP 

Chfin^e In temi) 



,059 

005 



= , 06.'^ 



Chsinine In temp, pur mln = .0000 

Chin^t; In temp, due to current - 



.06.'^ -r 



-69- 



Kffuct of hHvlnp; oil I n contact with lot? . 

The question wbwtber the oil oxerted 5i:;v motion 
upori the Ice tenrilHR to maVe it mnlt was .sii>).jected 
to eXT t;rl»iie:it In tht: follo^lut? way. Thw Kanitj let; 
tubes 'vhjch wer« URed on tbe niorn1n(? of Feb. POtb, and 
fotmd not to m«lt below C r. , wore filled with kerosene 
oil, a::d the observations repeated that afternoon. 
The dnta Ik e^lven on the following pat^es ana needs ho 
special explanation, as It Is the same arrangement as 
just described 



-70- 



011 In contact wlt>^ t>ie Ice 



Obaarvations for the beat capacltv of 1 ce . fi'eh,r'0.1<^0.'^. 



T Ime Temp . 



Time 



4- 



1 : fto 


-0.955 




51 


.'»50 


52 


.945 


5? 


.9?9 




fS4 


.9^.3 


55 


.927 




56 


.920 


57 


.914 


58 


.908 




59 


.90.? 




2; 00 


.898 




01 


, 893-!- 


Otirrent on 


02 


,870 


at 2 -.01 •..■50 


0?. 


,8P5 




04 


.788 




05 

0*5 

07 


.745 
.709 
.886 


Current off 
at P;06;;-S0 


OR 


.R84 




09 


.685 




10 


.P.85 




11 


.684 




12 


. 682-r 




13 


.678 




14 


.674 


15 


.671 


16 


.666 




17 


.662 





2 



;18 

19 

20 
21 
22 
2.-^ 
24 
25 
26 
27 
28 
29 
."50 
.■51 
.^2 

.■^4 
.■5 5 
.•56 
.•57 
.■58 
.■59 
40 
41 
4f> 

4 4. 
45 



Temp 



■0.657 
. 65.^5 
.648 
.644 
.640 
.6,^55 
. 6.^51 

.626+ Current on 
.605 at 2: 25;. '50 



..568 1 

.530 

.490 

.4 5.'5 

.4.'50 

.430 

.4.^51 

. 4.-^,1 

. 4,'52 

. 4.'53-f- 

. 4.'52 

.430 

.428 

.42.'5 

,420 

.418 



,408 



Ctirrent off 
at 2: .■50:.^^o 



-71 



Oil in contact wlt>^ t^e ir;e 



I continuation ' 



Fob.r>0,190r^ 



Tlraii 

1 


Temp. 




Tlrie 


\ 
Temp. 






' 


-0.406 




.-^ : 01 


-0.213 


Cnrrerit 


off 


47 


• 




02 


.190 


at 3::i 


:30 


48 


.401? 




0."^ 


.193 






49 


.399 




04 


.197 






50 


.396 




05 


.198 






51 


. 393 




06 


.200 






52 


.391 




07 


.200 






53 


.387 




03 


,200-(- 






54 


.3R4 




09 


.199 






55 


.381 




10 


.199 






56 


.37a-f 


Oiirrwat on 


11 


.199 






57 


.360 


at 2:66:30 


12 


.198 






58 


.320 




13 


.197 






69 


.278 




14 


.194 






3; 00 


.245 




1 '' 


1 .193 







-7P- 



Calculatioua. 



Temp. ?it 1; 'sc = .9hr'> 
" 2:01 = .BP.-S 

Oh'inf5« 111 ttjtiip = .06P 

" " " t)er I'llu = .00S7 



Temp, at P:01 = .RQ.**. 
•• ?,:1S = .HHP. 

f^hari,e;e In temp = .?11 



Temp, at 2:iP. = .«8? 

'• 2;;?fS = .826 

'^ha.'lf^e In temp = .0PS6 

•• '• " per min = .004.'^ 

Mean - .0050 



•• I* M H 



5. " = .021 
11 " = .051 



Change In. temp, nue to cnrren*: = .I'SO + 



Chan>^e in liiiiip. pur min = .004r'5 



Temp, at ?:?5 = .'iP^ 
C-ancry In temo = .IP.*^ 



Temp, at '.i'.ZH = . 4r-;.', 
'• 2:42 = .41R 

'^ViH-cTto In temp - .015 

" per nln =: .0025 



-7.^- 



Voar. cha;;(;t! in temp nor mln ~ . 0C.'^4 

" ,. M » iurluj? 6 mln = .OPO 

" •• •• " ,. ^ ,. _ _ Qi^ 

Chansce In temp, due to current = .l.«^0 + 

Temp, at ?.:48 - .40P 
•• *• 2;ft8 = . P.'yR 

Change in temp = .0S4 

'• per luin = .OC-^O 

Temp. n.t P:58 = .."^VR 

•• '• ,S;OB - .POO 

Change In temp = .l*^" 



Terup. at 3; 08 = .200 

Change in temp = ,007 

•• " " per mln = . '010 
Vean = .OOPO 



I* !• 



'• during « mln - .OIP 



•• ■• 



Change In temp, d^ie to currc.vt = .1^0 



•74- 



Thu rwstilts of the calculations on the precefllng 
passes ar« sunimarlz«i1 in the follovine table. The 
sttcond columr; gives the temperature at which the 
determirvatlon was made, the thermoneter readlnt? belnsj 
correctea for zero point. The ntimbers In the thl-^d 
colunn are collected from the preceding pa^es. Tn order 
to render these more comparable, each one is divided by 
the time ( in mimites ' th^t the current was flowing. The 
results are Riven in the fourth cotkuriu; ana express the 
change In temperature produced by t>^e cu^^rent flowing 
for one minute. 5^1nr;e the current was precisely t^e 
same for each determination, the constai;cy of *he;"e 
numbers shows the con?^tancy of the heat capacity of 
the caloriir.eter and its contents, for temperatures 
ranging from - 1''.4 C . right up to practically 0" C. 
In the determinations n.ade with the oil iiv contact 
with t-'e ice, this constancy was as marVed, If not 
more so, showing that even in this case there was no 
melting of the ice below (f r ^ 

Neither is there any increase in the spedt'io 
heat of ice as it apnroaches 0° ^ . , as has bewn tiit^ln- 



-'?h- 



taliied by some Irxvustlsjators , hut It rwiualns a defimlte 
const^vit rl^ht tip to the point at which the ice melts. 
That Is, such is the rase for this very pure Ice, as Is 
shOMiTi by the coiastaiicy of Its heat capacity, and this 
Is what would be expected since Ice Is a crystalline 
substance. As already pointed out, if there are 
impurities In the ice. even In very sraali amoimts, an 
apparent Increase In Its specific heat may be produced 
by the loxerlne of thts nieltlne: point of sotire portions 
of the Ice. 



-7P)- 



Table II. Keat capacity of Ice. 



Date 



Feb. 20 



Change Change 
Actual I in la Ternp, 

Temp. Temp, per mln, 



Feh. 19 - 0.4R 



0.24 




-0.09 



- 0.02 



, o.-^p? 

.0.-^25 
. 0.'520 
.0,-^20 
. 0.'522 
, 0.'»;28 
, 0.'^26 
, 0.-^32 
O.'^lfS 



K'eb. 20 - 0.92 .160 . 0.'^20 



- 0.B6 .160 , .0?520 



With Ice mantles 



In Rla55s test tubes 



Tee mantles flll«d 
vj th Veroae:ie . 



- 0.2.-^ 



IflO 



,0.'^20 



-'77- 



Kf ft^ct of mlxtng wHter a:;a oil . 

■*hor. t^e lew melts the resulting vater Is stirr«a 
up with th« oil, H!;i t^e question arrises whother this 
mixture; of thtj two llq\il^s is accotiiDar.l ed hv any the->-nial 
cl"'anse. Th.e pol.;t was srib.iecte<1 to evpurlment In the 
follo7.1:i(^ way. About ."^00 cc. of oil was placed in the 
calorlMetcr, an^i about 50 cc. of water, the latter 
belnc; 1:; a la'^ge test tube, A glass rod with a brass 
tip was placed within the test tube so that the bottom 
could be brolren from the outside. This arrangement was 
allowed to stand over nl<»>^t to assupie an equilibrium 
temperatiare . The follnwlnt; observations were taVen the 

next tnornlng. 

It will be noticed that after the test tube was 

broken ana the water allowed to flow out and mingle 
with the oil, there aprears to be a rls« in temperature 
of 0°. 001 c. In order to see whet>"er this was due to *ny 
action betw^een the oil and water, or onlv to the 
mechanical e:;ergy put forth in bi-eaVlni? the tube, the 
motion of breaVln;? the test tu>>e was repeated as shown 



-7a- 



lii t^e table of obs«rvat lous or. tbe following jy^tctt . In 
this case? also tber« 1*^ a rise of t';Tni!eratnre of the 
saiiie gjiiount as before, a:;a since In tbls there Is r;o 
question of water iiilxin^ with the oil. this; Increase 
1:; temperature. If rw^i, must be d\ae to the niechanlcal 
eneraiy expendea In the process of breaking the tube. 
[t Is Certainly safe to assert t>^at there Is no 
prodTictlon or absorption of heat when the oil ^n^ water 
are stirred up together. 



-7Q- 



ObStt'^vations on nilxlnj? water aiia oil. Mnr. IP, 1^»0.'<, 



Tlraw. 


Tump. 


Tlriiu 


T»inp. 


1: ftO ^ 


O.-'^IO 


2; 25 -fO.297 




61 


.?04 


28 


.29f=5 




52 


.?-:z 


27 


.296 




53 


.500 




28 


.296 




54 


.500 




29 


.298 




55 


.500 




50 


.296 




56 


.500 


51 


.295 




57 


, 500 




52 


.295 




58 


.298 




55 


.295 




59 


.298 




54 


.295 




2; 00 


.298 




S5 


.295 




01 


.297 




56 


.295 




02 


.297 




37 


.295 




OS 


.297 




88 


.295 




04 


.297 




S9 


.294 




05 


.297 




40 


.294 




06 


, 


T«st tube 


41 


.294 




07 ,?Q7 ' broVen 


42 


.294 




0^ 


,297 




4.'^ 


. 994 




09 


.297 




44 


• 


MoMor. of 


10 


.298 




45 


.295 


breaking 


11 


.298 




46 


.295 


test tube 


12 


.298 




47 


.295 


repeated. 


IS 


.298 




48 


.295 




14 


.298 




49 


.295 




15 .P9a 




50 


.295 




16 


.298 




51 


.295 




17 


.29^ 




52 


.295 




18 


.297 




55 


.295 




19 


.297 




54 


.295 




20 


.297 




5 5 


.295 




21 


.297 ' 


56 


.295 




22 


.297 


57 


.295 




25 


.297 


58 


.295 




24 


.297 


59 


.295 





-80- 



KXPKrtTl»'KNTn WITH P'JKK lOK. 

In view of tV>t! preceainp; InvwstlesitlonR , all 
fti'"tbfcr experiments verw mnde Tltv^ Ice formed frori the 
pxire distilled WHter . About b^lf ^ liter of tMs 
water was boiled for twenty or tblrtv mlmites to remove 
as iMiich of tbe dissolved air as possible. The rtJirrfLlnins 
500 cc. of water w«s potirea Into a beaVer wbicb It 
nearly filled, and when cooled somewhat t^e beaVer w»ig 
set Ir; a freeztnt? mixture of fine Ice and salt. If 
sur-ercoollnK of the water was allowed. Ice crystals 
wo\Ud suddenly form throughout t>^e water. To prevent 
this forni of Ic* and obtain it in a firm compact layer 
a sit;all bit of ire was frozen to the side of the beaVe^* 
just above the surface of the w«iter . and below the 
surface of t^^e frenzlnsj mixture oiitslde. Here It 
woul'i reiiiHln till the outer layer of water was cold 
enoiiech to freeze. Then a film of ice was seen to 
stnrt fVoifi the bit on the ^lass a:id spread over the 
lni\er s-.rfacte of the beaVer. After 'in hour or two 
this layer of ice reached a thickness of nearly a 



-Sl- 



centliaeter. Thw ramalnln? -untav was 'llscar'lw'1, hji-I tb« 
1 Ce rt:luove<1 frotii tbe heiVer by sllKbt, ly warming tV>e 
outslae. This cup of Ice was taVer; to the colrl^Kt 
place avullnble and cut Into cubes raiicrlritf from one to 
one fourth cubic centlrueter In size. These pieces 
were dropved Into another beaVer In a frert7lne mlxtu'^e 
where they were cooled several degrees below 0"^., and 
thtis freed from a:iv cllnglKK water either on the sur- 
face on interior. The Ice was then weighed and qulcVly 
tr a:\sf erred to the caloriiueter as already described. 

Right deterriilnations of the '"eat of fusion of this 
ice were j'lade on as many different days, one entire day 
being requlrea to maVe o?\e determination. Tnirlng the 
greater part of this period the weat*^er was below 0°''. 
in the morning, which greatly facilitated the handling 
and welghi..g of the ice. 

The amoTjnts of ice used in each of these experi- 
ments Is shown in the following table. 



-SP- 



Table ITT. Amounts of Ice use'i In. tbe experiments, 



TlQ ♦ l- 




WolfTbt 


of Toe 




I'H l.fc 


Beaker + Ice 


BeaVer 


lee 


Feb. 


27 


287 . 86 


186.49 


101.. -^7 


Feb. 


28 


292.78 


190.43 


102., •^.'S 


War. 


?> 


274.82 


194.. S9 


80.2.'^ 


Mar. 


.■^ 


28.'^,. 12 

1 


194.67 


88.4Fi 


Mar. 


4 


«07 . 4.-^ 


194.41 


11.'^.02 


Var . 


?S 


289. PI 


198.84 


91.07 


Mar. 


6 


."^02.. "^7 


200.09 


102.28 



27'i.7.'^ 



189.81 8R.92 



■fV<,- 



Kyper liiior»t of Kob . '/'4th. 

Heat c apacity with ICe . 

'VitV'. this vury puro ICe which It hai hecn shown 
coul'i be Aaniiea rls^ht up to C°C, without Hr.y nieltlns? 
or aprarent Increase of Its sreclfic heat, it was 
expected t>'at the Irittlal temperature could safely 
be bro\i2:ht to within a few tenths of a defifree of 0"'^. 
Nevertheless there appeared tinmlstaVable evidences 
that If the temperature was too near 0'*^. a small 
amount of ruelting of the Ice would '■^e caused by the 
current used In the preliminary experiments to deter- 
mine the heat capacltv of the calorimeter with the Ice 
Such dete^'mlnatlons were, therefore, made only at 
tempu-rature." below - 1° C. 

Tn this determination of the heat carjacitv. the 
current, as already stated, was that which wo\ild flow 
thro\igh the heatint? coll when its terminals were 
maintained at a difference of potential equal to t^e 



K. ^'. F. , K, of or.e standard Cell. The heat produced 
~ .P 



K^t , whore H 1s f-e 



is then j?ivi.n by the forti.ula, 

resistance of the coll a -.d t_ the number of seconds thtit 

the curre.^t was flowing? . 



-<3- 



Observations for heat capi 



PtjV,^ r>4 , 1<^0^ 



I 

Time Temp. 


Time j 


TeniD . 




9:50 -l.POO 




10:16 


-1.298 




51 ^ .880 




17 


.286 


"n-^rent on 


52. 


.86.-^ 




18 


.265 


at 10:17:30 


55 


.84.'?; 


1 


19 


.2."^ 3 




54 .8P4 




20 


.204 




5^ .804 




21 


.170 




56 .785 


nurre:;t on 


22 


.14.'^ 




57 .760 


at 9;56:.'^0 


23 


.112 




5R .7?? 




24 


.085 




59 


.680 




25 


.054 




10; 00 


.6 50 




26 


1.025 




01 


.614 




27 


.997 


f^nrrent off 


02 


. 575 




28 


.976 


at lO:27:;^o 


OS 


. 543 




29 


.965 




04 


.507 




30 


.957 




05 


.475 




31 


.950 




06 


.44,'^ 


nirrer.t off 


32 


.940 




07 


.415 


at 10:06:30 


33 


.942 




08 


.402 




34 


.924 




09 


.391 




35 


.914 




10 


.377 




36 


.905 




11 


.362 




••^7 


.897 




12 


.352 




38 


.889 




1.-^ 


.338 




39 


.882 




14 


.326 




40 


. 873 




15 .310 


1 


41 


1 9 





Note - The aniotint or" Ice use : in this exDer ltiie:it 



was 103.26 Kranis. 



-ns- 

^■H^ cnlHttons , 

Temp, nt «:«50 = -1.9C0 
•• •• t):fSH = 1 .^>^<F> 

0>>anf^e 1-; temp = .Tl' 

" '• " per }^-*:\ = .019P. 

Temp, at 9;F16 = -I.-tR^ 
•• '• 10:07 = 1 .415 

Change in temp. = ..'^''0 

Temp, at 10:07 = -1.415 
1. » ic;l'' = 1 . ?Sfi 

CHancry In temp = .ir>9 

•• '• " per !Til]i = ^OIP.9 
Mean " - .01^50 

'iurinsc 11 minutes = .176 

Change in temp d\ie to current - .194 

Change in temp, per riin = .01P9 

Temp, at 10:17 = -1.P86 
" "10 ; ?9 - .Qts*^ 

Change ir* temo. - ..'=^?1 

Temp, at 10:S9 = - .9«5 

•• 10; 40 = . 87.^ 

ovian^^e In temx) = . 09p 

per riin = .00B4 

Wuar. •• '• = .0107 

" " " •• 'lu-rtnK IP mimitor. = .IP^ 

CV>Hn)?e i:; teiup. iue to current = 19."^ 



-B«- 



In tbtf t'*t) detoriti 1 nation K of heat cap^cltv nrlvon 
above, that same amo'iint of beat was suppllefi bv tbe 
current, resulting In a net cban^t! of temperature of 
0.1^4 and 0.19?^ ri^sspectlvelv . Tbese iHnmbers aj^ree as 
closely as co\ild be expected since f^e temperatures 
tbeinselves were read only to thousandths of a decree. 
They further show that t>^e specific heat of the 
coiablr.ed apparatus. If the term can he allowed. In the 
same at - l.H ^. . a:;d at - 1.0 C. 

The aiiiount of heat generated by the current Is 

„ ^ JLX^ JJi.,0i91''^ X 6J0 ^ 125.47 joules. 
H 4 . 966 

Sl:;ce this amount of heat corresponds to -^ mean change 

of temt er«ture of 0.l9.'^fS. for a change of one depree 

the heat would be 

Joules per def^ree = _^?^,^^^2_ = 648. 



-'17- 



The rtJii.al:irlwr of this experlrneit Is aecessir 1 ly 
dlscnrdc;'! as tbe currc^iit used In meltluEC t^e ice w«is 
too variablu to nieaaiirc . aiaa it conlrl not be Vopt 
constant by varying tbe controlluR reKlstance. Tbe 
dlfflGviity was finally located In a riefectiv«! storage 
cell wMch was replaced bv one ^n better condition. 

The pre-'edi:;? determination of heat capacity is, 
bowever, coiv.plete in all respects and it is here given 
for use 1:; cnlctilatlr.g t^^e corrections for some of tbe 
later exper Itiients in which it was not possible to 
obtain a direct deterTdluatlon of heat capacity. 



-nn- 



Kxperiment of Fub , P7t,h 



-RO- 



Observations of the experiment of Kwh. ?7, IQO.*^ 



Part 


1. Heat capacity vitb 


ice. 




Tlniw 


Toiiip . 




1 T inie 


Temp, 




i?:50 


-l.«10 




1;16 


-1.220 




51 


.595 




17 


.211 




52 


.48? 




18 


.?0.'^ 




5S 


.'^69 




19 


.194 




54 


.554 




?0 


.184 




55 


.542 




?1 


.175 Current on 


56 


.528 




?? 


.160 at 1:?1:30 


57 


.515 




23 


.133 




58 


.50? 




?4 


.107 




59 


.490 


Current on 


25 


.080 




1:00 


.475 


at 1?; 59:30 


26 


.055 Current off 


01 


.444 




27 


.033 at 1:26:30 


02 


.41.^ 




28 


.0?7 




OS 


.382 




?9 


.018 




04 


.351 


Current off 


30 


.011 




05 


.329 


at 1:04:30 


31 


1 .004 




06 


.318 




3? 


0.997 




07 


.3C7 




33 


.989 




08 


.?97 




3 4 


.983 




09 


.288 




35 


.976 




10 


.276 




36 


.970 




11 


.268 










12 


.266 






' These readlngp vere 


1.*^ 


.250 




con 


tlnued for 25 minutes 


14 


.240 




vitbot)! In t err T IT' t Ion, 


15 


.230 









-OO- 



OhsurvatiouK of the exi,erlment of CoV. . P7, IPO."^ 



Part 11. I'oltine the ICe 



Tlmo 


Tel;»p . 




Time 


Ten.p , 
1 


?:oi 


-.005 




2:51 


1 
-f.S4 




02 


.793 




52 


.57 




05 


.792 




5.-^ 


.«8 




04 


.7R0 




54 


.*^0 




05 


.777 




.'»;^ 


.71 




06 


.787 




."^6 


.'70 




07 


.7fi? 




.•^7 


1.05 


Our rent off 


08 


.7?sr^-+- 


Oixrrerit on 


58 


.95 


at P:.''i7;00 


09 


-.25 


at P;CR:.*^0 


59 


.90 




10 


+ . P..*^ 




40 


.900 




11 


.P*^ 




41 


.900 




IP 


.P« 




4P 


.898 




IS 


.P-S 


Cell No.r^pg 


45 


.897 




14 


.P'^ 


Q = 10,0:0 


44 


.895 




15 


.P"^ 


U = 1114 


45 


.887+ 




16 


.P'? 


d = -1.00 


46 


.885 




17 


.?7 




47 


.877 




18 


.P7 




48 


.872 




19 


.51 




49 


.865 




20 


..•^0 




50 


.855 




21 


.50 




51 


.845 




2?> 


.."^C 




52 


.845 




25 


.57 




55 


.845 




24 


..'.R 




54 


,8,';7 




2^ 


.57 




55 


. 85P 




?6 


.40 




•if? 


,8P7 




?7 


.44 




57 


.8P.'=^ 




?8 


.44 




58 


.817 




J?9 


.47 




sq 


.81P 




50 


.45 




.•^•.00 


807 





-91- 



ObservFit ioii«^-. of the evperlmtint of ffob. '.'^ , 190.'^. 



P^i-rt TTT. hvHt CHpacl*v 'vltb 'vnter 



T iT'ia Temp . 



.•^:0i 


+ .t^00 


02 


.805 


05 


.317 


04 


.828 


05 


.85?S 


06 


.841 


07 


.842 


08 


.842 


09 


.855 


10 


. 852 


11 


.828 


12 


.821 


13 


.817 


14 


.812 


15 


.807 


16 


.805 


17 


,79Q 


IS 


.79^ 


19 


.'7Q,'' 


20 


.7^7 


21 


.807 


22 


.818 


25 


.825 


24 


.8.' 4 


25 


.845 


2^ 


.8^5 


27 


.8<S2 


28 


.872 


29 


.878 


50 


.878 


51 


.877-f 


52 1 


.872 



i^urreut on 
at 5:C0:.'^0 



•^ur-^er.t off 
at .•=^:05:;'S''' 



(^Tirrer^t on 
at .".;18:30 

Cell NO. 551 



''urrent off 
at .'«:28;50 



Tine Temp 



.•^ : 55 


4.868 




34 


.86? 




35 


.857 




36 


.850 




57 


.847 




38 


.845 




39 


.840 




40 


.855 




41 


. 850 




42 


.826 




45 


.821 


mirrent on 


44 


.818 


at 5:45:50 


45 


.820 




46 


.850 




47 


.858 




48 


.852 




49 


.862 




50 


.869 




51 


.878 




52 


.887 




55 


.8P7 


rrnrrent off 


54 


.^05 


at 5:s,'^;,'^0 


55 


.904 




*^6 


.904 




57 


.898 




58 


.89.'-f 




59 


.887 




4:00 


.88?^ 




01 


,R7q 




02 


.874 




05 


,870 




04 


.866 




05 


.^62 


1 



-OP- 



OhIciiTh * j or;s for Pnrt T. 



Teuip. ^t 12;fS0 = l.«10 

" i ? ; .^9 - 1 .4-90 

r.'h-HT^^jn i:i tomp = .IPO 



Temt. nt IP; ftP = 1.400 

l-.O"? = l.P;07 

r^baa^^ie In temp — .inr^ 



Temp. ^t. 1:07 = l.,707 

" 1 ; 1 "s = i.;j?o 

^■"^Vify^i 1:1 teiip = .'■rr'^ 

" " " per J'lln = .Oj^*^) 

Me-vn '• ' = .0114 

•• '• " '• -lurlr.f^ 6 inin - .0R8 

2. '■ = .019 



!• |< 1« H 

11 11 11 »• 



ChHiige In tenic. due to cu^r«T\t 



.0R7 
.098 



Temp, at 1;1H = l.PPO 

'• 1; Pi = 1 .1^5 

Change 1:; tej;ip = .045 



'• per MlU = .0090 



Temp, at l:Pi = 1 .I'J'B 

" l-.i-^O = 1 .011 

Chaf..6C« 1"- term = .164- 



Temp, at 1::V = I.OIB 

" •• i : ««•> = .970 

Ob U'Vi In. temp = ,041 

'• per lutn = ^OOQR 
Vean. - n ~ , oo79 

•• iurlaK 6 mln = .047 

'* " 9 •• ~ 

Char.j^e iK tenip d\ie to cnr'-er.t = 



.0^7 
.097 



CHlculnt Inn.'-, for PfiVt IT. 
Tmri'it; this pirt or" the experlTnent tv^e f^u^'-rerit whs 
malutaiiied at sticb a vnlne tbnt t^e fall of potential 
throiif^h the star.darn b^if ohir. coll was just equal to the 
K. ;>•. V. of the staiiaard cell No. ."^J?*^ . (= 1.019r>i volts'. 

Hervce , 

K 1 O'lQpf, 
Curre:;t = "= ~~ = S.O.'^^ap.V amperes. 

The nearest balai'ice of the potentloruet er was obtained 
with P = 1114= 1114. R2 ohiTis. At this value the mean 
deflectio:; of the galvano'neter was -1.00 divisions, and 
sl:;ce a chani?e In P of one ohm corresponds to a deflec- 
tion of 8 divisions, t>^ls deflection corresponds to a 
Chansce of -O.l!^ ohm. Hence to have producea an exact 
balance. P should have been 1114.7C/ ohms. This selves 

V^ P_^Ci ^ n064^ ^ 10.117. volts. 
P 1114.70 

The curr^.^t flowing throut^h the potentiometer Is 

lO.ll^'S 

= O.OOOOl amper-^. 

11084.4 

Therefo-r-e the current thT-ou^h the v^oatln^ coil is. 

?.0.'=^8r^7 - 0.00091 = S.0?i7.'^« amperes. 
Since this ctirrent was flowing 1710 seconds the total 
heat 1:^.. 

RIt = ?^fi?4R joules 



-04- 



CHlculatlons for P«*rt TTT. 
Teiup. ^t .'.:1P = .RJ?1 

Oh'^ini?e lii teiiip = .0P6 

'• per iiln = .004.'=^ 

Tomp. nt .'^:1R = .795 

Cv^Hnt^e In ttsMp = ,OBP 

Temp, at ."^ifSi = .R77 

'• .■^•. 4rs - .qpl 

"^^r^cTc 1', tiitiip = .056 

" '• " pe-^ !Tiln = .0047 
Mean - ' - = .0045 

' diif ing-1.'^ • iniiteK = .05^ 

Chsinis^t: In temp, ane to cur-^cut = .140 + 



ChanKe In tuiap. por min = .0047 

Teir.p. at .•^:4.'. = .RPl 

•• " r<i : 58 = . ^,Q.'»; 

nvian^e In temp - .07p 

Temp. 5^t .'.-.SB = .89."^ 

•• " 4;05 = .862 

Oh^n!?e In tkiiip = .0,'=5l 

'• our mln =- .0044 
Mean " '• • = .0045 

^.iirl..g 15 min = .068 

C*i*ir.(?e In temp, iiit: ♦■o our-^cut = .140 



-95- 



Ti; the aeterinluatlonK of haat cap^cltv, b ith with 
ice Hiicl *it>' water, the same our^'en.t was used as on 
?eb. ?.4t>^., namely that which •onl''. fl iw t^^rongrh the 
heat.lr.t: coll when. Its terminal^, ware iiiaintaji;eT at a 
pote:;tlal difference ksnu^l to t^-'e V. . M. c- . of tv-e 
sta-.dar< Cell nj -> . .'■<i-?il . In Part I. the cur^'ent flowed 
for five minute periods, ar;d since the arnom:t o^"" ice i-^ 
n>iarl'/ tht-j s-v.ie -is for Feb. ^4. the chant^e in tempera- 
ture sh-.uld be o:;e h^.lf a? ^reat, as it Is very closely, 
fVt: tvn result«=- helr.c C*096 and C°C97 for the ch'tnge 
prod\iced by 6?.'7P. joules. Fence 
("Vith ice I .Joules per decree = "^ ^ ' • = (SfiO 

The same current war employed In Part IT. hut for 
ten minute periods, hence giving 1P5.47 joules. The 
resulting chanjje In temperature 1.- ''-.140. Honce, 



IP'^ 47 
I "Vi th water' Joxiles per oegree - — TVn ~ ^^^ • 



"^ ^ ^ "^ ^ Taules loey -mi^ (hit) 






< 



- 


^ 


\ 



















A. b. wuirL-iiUL ilruMi n. i. 



J o 01 1 e i h 



Q V ^ N* <-■« 



y 



\ 

















































































































































































































































































_ 


















































































































_ 
























o ' 



















































■5 










^ 









-96- 



Correc tlo:; for radlgitlon. n omuctlon, oonvuctloi; , 
stir r ing, etc. 

The; hc^t lost ( o>- f^^lne'l' to the c- lor Ir.iet er by 
tbt! coir.blrved action of tbese caustjs Is deterTnlne^. by 
the rate of cooling (or w^rniln.s^ > experienced vben no 
beat If. belne supplied by the cu-^-^ent . Tbese rites 
bi»vu be-U observed and recorded In connection 'vltb t*"e 
deturiaiii^ tier; of heat '"a^acl^y. Kxpressed in .3 onles 
per inlraite, they are plotted on the accompany Int; sheet 
as ordinates, ae;ainst the corresponning temperatures 
as abscissae. The resulting curve glve^; the loss at 
any teii-peratnre . 

The "duration" of this experiment was ."^7 minutes, 
and the a^ era^e teiuperatiire during this Inte'^'val was 
. Fil '^. From the curve, the loss of heat at this 
temperature Is 1^.45 .j ou ' es per minute. Vier.Ce the 
total loss Is, 

J>.4fs X :<,7 = PI joules. 



-97- 



Siinini«ry of Kxptrrlnent for s'e^, P7t>'. 

Total heat Klippllefi by tho ctirreut = SFiSlR joules. 
Initial temperature = -O.^ps.*^ 

•• " corrected for zero - -0.7^R 

Heat to rnl'-e oalorliueter -^n'; contents from -0.7RR to C 
= ftfiO X 0.7BB = «ilP jotiles. 

Final temperature = +0.887 

•• " correcten for zero - +0.8.'SP 

Heat to raise cs^lorliueter from C. to -fO.B^S 
= 896 X 85? = 76?; joules 

Heat lost by radiation, convection, conduction, etc., 
= 91 joules. 

Total correction = 51P + 76?- ■+■ 91 - l.'^66 joules 
Total arnour.t of heat reqiilrea to melt 101,. '',7 (rrams of Ice 
= .'55P48 - l.'»i66 = .•^?588P j OTiles 
Z7A .PA i ou 1 e s per sr am . 



— "K' 



-98- 



TMs exporlruuiit '^ppa'^rs completts In evury respect. 
Tbe heat cnpaclty was directly 'leterniined both before 
and after the experiment. T^a current was on for just 
the rls?bt tin.e to melt all the ice and leave the final 
tenperature a few tenths of a degree above 0"^. , t>-us 
maVlnr: possible a short duration. The weight given to 
this evperltiient is therefore the full amount of 6 points 



-OC)- 



Kxnerlrient of c-e^. I^Rtb 



-100- 

Part I. Heat capacitv wlt.V' j cc . 

The aiiioicit of Ine n.sen In this exp«rliiieut was very 
nwfirly the same as on Feb. i^4th., bein^ 10'-'. .'^'S ccrains 
Instead of 102. ?4 Rrams. Tbereforw, afl no riirefjt 
deterii.ination of tbe he?it capacity could be made owlne. 
to Insufficient temperature ranj^e , no appreciable error 
can be Introduced by assuming the same value as deter- 
mined on Feb. ?,4th., vl?.. 

Joules per degree = 64R 

The observations during the period of meltlnt? t>'e 
Ice are given on the following page, the arrangement 
being exact V similinr to those already given. 



-101- 



Observntlons of the experltnent o*" ^uh, r>q, 1«»0'^. 



Part IT. Wulti:ig the lc« 



r'H^t 11'. '^at CH.r>^^-^* 



1 

Tire 

1 


Teinp. 


Time 

1 


Tenip . 


Aftwr 


stlrrlr 


It? SO mln. 








l:?sc 


-.701 




2:27 


-^.68 




F,l 


.879 




28 


.8'5'4 




52 


.'S72 




29 


.877-^ 




55 


.RR7 




30 


.676 




54 


.^R] 




31 


.675 




55 


.'^57 




32 


.678 


Vigorous stlr- 


56 


.<^52 


•Tur-^ent on 


33 


.6*79 


rlnp: to show 


57 


-.20 


at 1 ; '-'« : 30 


34 


.R'J'g 


Its effect. 


5R 


+ .20 




35 


.6-79 




59 


.27 




36 


.H''^ 




2:00 


.27 




37 


.674 




01 1 


.25 




38 


.688 




02 


.2'" 




39 


.669 




0« 


.32 


Cell No.3r^9 


40 


.662 




04 


.28 


S = 10.000 


41 


.657 




0^ 


..•^0 
.30 


P = 1113 
d = 


42 
43 


. 6 53 
.649 




0« 




07 


.33 




44 


.846 




08 


.42 




45 


.643 




09 


.33 




50 


.6r^3 




10 


.30 




51 


.618 




11 


.30 




52 


.614 


Current on 


12 


.31 


j 


5R 


.610 


at 2:53:30 


l.-^ 


.37 




54 


.72 


niirrent off 


14 


.37 




55 


1.330 


at 2:54:02 


15 


.38 




56 


1.345 




18 


.35 




57 


1 . 328 




17 


.42 




58 


1 .310 




18 


.40 




59 


1.295-1- 




19 


.37 


1 


3:00 


1 . 284 




20 


.53 




01 


1.275 




21 


.45 




02 


1.264 




22 


.50 




03 


1.253 




2.*^ 


.57 




04 


1 . 243 




?4 


.73 




05 


1 .2.-^.'». 




25 


.98 


r\iTrv:\i off 


06 


1 . 223 




26 


.^.'S 


«t f: p«^:00 









'^alcnlatlons for Part IT. 

The sta!;aard cbII iised on this day wap njo. Tipo , 
<K. V. F. = 1 .OIP,**; volts ) , and hence the current 
throiis^h the stanfiard coll was 

i.oio.-^ 

"^OOOn" ~ li.O.'^ftPV amperes 

The ne'-^rest halai;ce of the potent loneter was 

ohtalned with P=lll?5= lll?i.7fi ohms, this value 

Klvinc a inea:: deflection of 7ero. fience this ^Ives, 

LOlft,"^ X "— = 10.11^49 volts 

1113.79 

The current through the potentiometer js, 

0.00C91 funpere. 
glvlr.r for the current throu«?h the he-^tlng coll, 

'.> .OP^f^P'y - C.0C091 = P.0:^'7P^e amperes. 
The current was flowing for 1710 seconds, giving a 
total amoimt of heat of, 

.•55f^74 joules. 



-10.*^- 



r;aT dilations for Part HI. 



Teiiip. at ?14«S = .64.'^ 

Chqr.ce In ten.p = .Or-'.^ 

•• '• per Tnln = .0041 



Temp, at P;F,7, = .(=510 
•• " 2:'=.9 = 1 .P95 

n»^ane:u In temr) — .R85 



Temp, at P:59 = 1.895 
" 7,; '6 - 1 . 2P?^ 

f^bfuiPiti In temp - .0*78 



•• '• '• per ii'li: = .ClOfS at 1.86 

= -OlO Q at 1 ..•^?. C. 

Veaiii " •• •• •' •• = .0075 

•• durlne P mln = .0150 
'• " '• " " 4_ " = .04.'^8 

.. H H M •• 8 " = .059 

Cb^nf^e in te,nip. due to CTirreut = .744 



The current user! in this part of the exper inient 

was the same as etnploye'1 '^"or nieltlne t*"e ICe, As it 

was flowlns? 3S seconds t^'e heat generate'! la, 

?,0.'^7.'^8 X 10.1P49 X y<P = R6C joules. 
Therefore, (vlf- -n-ater', 

^^0 — qU7 
Joules Tier deRr^e = 744 




























<U) 



























o 












>1I 

c- 



c; 






L 



a. 6. ijwipt«'M- iln«bA H. r. 



J o u its 



-^ 



-/' 



>- 7T7 / r? 



'/ 



/n *!* J 


















\ 

\ 





<s 









k 



^ 






^« 



-104- 



Correct lou for r«^rilatloi;. conauctlnri , convbctlor. , 
stlrrl;^. otc. 

The ratfcK of coolinec rteterinlne'l at different 
teiTiperaturen are plotted on tbe aijoininfT curve In 
terras of joules per inlnnte. 

The duration of this experlJnent was ^1^ TnlUTites , 
and t)-«e a^/erH£fe temperature dnrlne this Interval vas 
-^0°. 41 C. Froiri the rurve , the loss of heat at this 
tetnperature Is 2.10 joules per raln)>te. Hence the 
total loss Is, 

P. 10 X r'.r^ = «c, joules. 



Sixniniqry of Kxperiineut of Feb. ^Hfb, 

Total heat supplied bii t^e current ^^ .•^5?.74 joules. 

Inltlfil teiuperatiire = -O.R'SS. 

" " correcteT for ^ero = -0.«=?Rv 

Heat to raise calorimeter and contents from -.6R7 tn ^. 
= SAP, X 0.8R7 = 44-5 joules. 

Final teraper attire = +0.6 77 

•• " cor ected for zero = -♦■0.R4P. 

Heat to raise calorimeter and contents from C.to +.64P 
= 887 X .642 = 569 joules. 

Heat lost by radiation, convection, conduction, et-^. 
= 69 joules. 

Total correction -44^ + f,69 -«- 69 = 108? joules. 

Total heat r«QUlred to melt 10?. .'R srranis of 1 ce 
= .•=^?^?74 - lOa*^ - .'=^4191 joules 
= .'„'»4.06 joules per (?ram. 



-10«- 



Tn this eKporliut>i;t there Is a single poljtt onlv In 
which It fails btihlnd the precertliic one In the matter 
of welphtl:;K, - nnd that Is in the fact of no direct 
dete^'TTilnatlon of heat caoactty precedlns? the main 
experlT it^nt . T^^ere Is room for no serious doubt of 
the validity of thus assTimlnc; the valTje of heat capacity 
detern.lned one day as applicable to the sajne masses 
on another day.- else t'-'e entire experiment would have 
been discarded. However, li; t>^e weight Incc there is 
this point lacklne;, civine. for this experiment the 
value of ft points. 



-107- 



Experiment of Mar, Snd, 



-108- 



Obswrv^tlonK of th« experiment of Mar. r^d . 
Part I. Heat capacity with Ice. 



Time 


Temp . 




Time 


Temp. 




1:10 


-^.384 




1:45 


.1.'.56 




11, 


.353 




46 


.'■27 




12 


. .*^32 




47 


.495 




13 


.313 




48 


.465 




14 


.297 




49 


.435 




Ifi 


.2^0 




50 


.406 


rtT>->-ent off 


16 


.260 




51 


.383 


at T:50;a0 


17 


.242 




52 


.573 




18 


.228 




53 


.365 




19 


.210 




54 


..'56 




?.0 


.193 


OlUTelit on 


55 


..■^45 




PI 


.168 


at 1:20 -.30 


56 


. 337 




?2 


.l.'^3 




57 


.32R 




R3 
24 


.097 
.060 


'^ell NO. 331 


58 
59 


.31R 
.310 




25 


2.024 




2:00 


.300 


niirre:it on 


26 


1 .987 




01 


.285 


at 2:OiO:30 


27 


.956 




02 


.260 




28 


.926 




03 


.230 




29 


.885 




04 


.202 




30 


.H52 


Current off 


05 


.l'?6 




31 


.824 


at 2:30:30 


06 


.145 




•'2 


.809 




07 


.117 




S3 


.767 




08 


.093 




34 


.785 




09 


.068 




3 5 


.7'72 




10 


.040 


Cu-^rent off 


36 


.758 




11 


.020 


at 2:10:30 


37 


.743 




12 


.014 




38 


.730 




13 


1.007 




39 


.716 




14 


1.002 




40 


.703 


oiirr-:nt on 


15 


.996 




41 


.688 


at 1:40:30 


16 


.992 




4? 


.653 




17 


.986 




43 


.623 




18 






44 


.587 




19 


• 





~109- 



Observatlons of tbw uxper linen t of h^pir . Pni . 
Part IT. I/oltliit? the Ice. 



Time 


Temp . 




Time 


Temp . 




p:po 


- .?m4 




? : 55 


+ .077 




?i 


.95R 




56 


.082 




?? 


.95? 


Current on 


57 


.089 




s.-^ 


- .55 


at P :'??.'. -^0 


58 


,096 




?4 


-t-.S7 




59 


.104 




Pfi 


.40 




3:00 


,108 




?6 


.37 


r.ull No. 329 


01 


.114 




27 


.36 


Q = 10,000 


02 


.122 


.^mall CTirrent 


?R 


.43 


P = 1114 


OS 


.124 


off at 3; 02: 30 


?9 


.46 


d = -0.37 


04 


.124 




SO 


.4ft 




OR 


.118 




Ri 


.44 




06 


.110 




SI> 


.52 




07 


.105 




.■^."^ 


.60 




08 


.100 




34 


.61 




09 


.095 


^mall current 


SF. 


.65 




10 


.092 


at 3:09:30 


36 


.75 




11 


.095 




?;7 


.6ft 




12 


.107 




38 


.6ft 




13 


.1.18 




39 


.83 




14 


.129 




40 


.84 




15 


.140 




41 


.83 




16 


.152 




4J> 


.84 




17 


.167 




4.'»; 


.85 




18 


.178 




44 


.95 


Current off 


19 


.190 


.«imall current 


4fi 


1.05 


at 2; 44: 4 5 


20 


.200 


Oft- at 3:19:30 


46 


.70 




21 


.200 




47 


.35 




22 


.200 




4ft 


.PZ 




23 


.200+ 




49 


.17 




24 


.1P8 




•SO 


.17 




25 


.197 




fSl 


.10 




26 


.1*^6 




s? 


.085 


Smnll -"tirront 


27 


.195 




53 


.085 


on at 2:52:30 


28 


.194 




54 


.085 


("ell NO. 331 


29 


.192 





-110- 



ObservntiouK of tbe wxperliimnt of iviar . P'l'l . 



Part riT. Hoat capacity with water 



Time I Teinp. 



Time I Tetnp. 



?:?f> 


■f.l^Pt 


Crirrent on 


5 : 59 


+ .544 




50 


.1^? 


at 5: 29; 50 


4:00 


.5 58 




51 


.If'O 




01 


. 568 




52 


.210 




1 02 


..■^82 




55 


.225 




05 


.595 




.'4 


.2. "^7 


r-ell No.-'^Sl 


04 


.407 




«5 


.249 




05 


.418 




56 


. 2^^.'. 




06 


.450 




57 


.276 




; 07 


.445 




58 


.2^R 




08 


.454 




59 


.50 


Onrr^int off 


09 


.466 




40 


. .-<G9 


at rv.59:.-^o 


i 10 


.478 




41 


..■^12 




11. 


.490 




42 


..•^12 




12 


.501 




45 


..■^12 




15 


.512 


rTirr«nt off 


44 


..•^]1+ 




1 ^* 


. 525 


at 4:l.'^:.''.0 


45 


.50R 




15 


.525 




46 


.."=^05 




16 


.522 




47 


.r^C.-^ 




17 


. 5194 




48 


.501 




18 


.515 




49 


.298 




19 


.511 




50 


.297 




20 


.•^07 




51 


.294 




21 

1 


. 50.'^ 




52 


.292 




' 22 


.499 




55 


.289-*- 


f^irrer.t on 


25 


.495 




54 


.289 


at .'.;55:50 


24 


.492 




55 


.289 




25 


.488 




56 


..•^C5 




26 


.485 




57 


.518 




27 


.481 




58 


. .'.55 




' 28 


.4')'8 





-111- 



ralctilatlons for Pnrt I, 

Tump, nt l:lfi = -2.:^'^:*, 

" i;ao = p. 19.? 

rhfcirt; It; tei.ip = .160 

'• pre Till 11 = .0178 

T»nip. nt i:PO = -P.lPr^ 

•• " 1 :.'^1 - 1 . ".P4 

r;b^ifT(i \n temp = .^f^9 

Temp, at l-..-^! = -1.8P4 

" " 1 ; 40 = 1 . 70.'^ 
Change in temp = .IPl 

" '• '• per liiln = .01'^4 

Ve«n " •• •• •• •• = .01R6 

during 11 mln = .I'^l 

Ch?uifi5e ir. temp due *o current = .193 

Change in tenip per mln = .01.'^4 



Terap. at 1;40 = -l.^or; 

" 1:5? = 1 ..'^7?; 

Cbane:e in temp = .3.30 

Temp, at 1 ; 52 = 1..'^''.'^ 

•• s:oo = ' ..'^co 
rban^c in temp = .07,? 

H Ml. pg„ ,njri = .0091 

Meain " h = .OllP 

'• " " " during 11 mln = .IP.*^ 
M .. .. I. » i " =^ .009 

MM M H J^ P " — ^ 1,'^P 

Cbantte in temp, due to current = .19ft 



-11?- 



i^i^lculatlor.s Vo-r oart I. ^cont ' 



ChanKe In teUip. per mln = .0091 



Temp, at 2; 00 = -l..'^OC 

•• Ji:ii = 1 .or>o 
Cban^ti In temp = .PRO 



Ter-ip. at S;ll = -l.OPO 
•• - 2:17 = O.oR Q 

C.haJXfrts 1:; temp = .0R6 

" " '• per mln = . 0080 



Mean = .0075 

" - " •• during 11 mm = .O^P 

Hhance in tenu- . due to current = .198 

These three r^. suits aRree closely, again 5;howlnc: 
the consta:;oy of the sreclflc heat over tt^e r-^ivge from 
-P°? ^- . to -1^0 n. T^e saiiiw cui^^ent 'as nsed as hefo're 
thus gi^;t:;R: 1PF).4'"'' joules In ten minutes. The resulting 
Change In temperaturi- , "'.IWR, Is greater than In the 
preceol:;g cases, as 1' should >^e slr^ce t^ere xas PO gnis . 
less Ice 1:; the calorimeter. The^'efoi-e; , 

•Joules f,er degree - ^ri^julZ - «s.'^4 (with Ice' 



■ll.-^- 



'^alcolatlons for Part IT. 

After the iiiBltlUfi? cur'-ent 'vas stopi.orl tbere 
remained more Ice tb?ir. coiili be melted bv t^e oil In 
co-'llnt^ to 0' ^- . Therefore the small cnr'"er.t p'-ijvj.onsly 
used was passed for silfficlent time to melt '■he remiln- 
lug Ice. Vblle this process Increases the total 
lene;th of the experlnient . no 1are;e errors are Introduced 
as the extra current Is exactly determined, and the 
losses due to radietlon, etc.. are very small owin^ to 
the lov temperature of ♦he c^lorl- eter for the l^st 
two thirds of the experlnient. 

The stai^dard cell nseO for the measurement of the 
lart^er current was No. .■^?p, ( = 1.019- volts », and 
hence the curr nt throuf^h t>^e standard half ohm ro-*l vas 

H'OoSS - i^.0?a?7 amperes. 
The nearest balar.ce of the potentiometer was obtained 
with P = 1114 = 1114. Rfl ohms, this value ^ivlnc a 
mean deflection of - 0,.*^7 divisions, correspond Int? to 
- 0.04 ohm. Hence the value of P which would have 
given an exact bala:'.ce is 1114/^^^ ohns . This Rives. 

1.019.-;'^^'^ lO.n^R volts. 



Tho current t'f^roiieh the poter.tlomutur is 

0.0CC91 Ht.ipere. 
j?lvir»c: for t'p« curre;*t throiij^h the bcattue coll, 

P.O.'.R?'? - O.OCOOl = P . 0.'^7.'-\r, amperes. 
This, current was flowlii^ for l.'^.'^fS seconas, clviriK *i 
total ainovmt of byat of 

J^.7«si7 joules. 
The smaller current was flowinec for PC minutes, eilvln?. 

lP.fS4'7 X PO = P*il joules. 
l^ence the total heat supplied bv the current Is 

PV'SIV + pfSl = P776R joules. 



-11ft- 



rulcnlHtlon?- for P^rt ITT, 

Temp. ?it r^l'M = -f.lPS 

Chan J e 1:. t tup = .006 

•• " - per tnln = .OOIP 

TetriT). Fit .'=^;P9 = .19P. 

•• '• .•^;44 = ■■•^11 

C>''ane:e In tuiuo = .]1« 

Temp, at .'^;44 = .,?li 

•• •• .'-^ : ft? = . P89 
Chance In teti.p = .Q',i2 

" " " v^"!" '"In = .00P4 
Vean = .OOIR 

- .. M H dnrlne B rr.la = .014 

" '* " •• R •• = 019 

•• 16 '• = .07,:^ 

CbHne;ts In tetiip. due to current = .15J? 



Chanejc In temp, por min = .OOPA 

Temp, at :<:fS.'5 = . P89 

T«mp. at 4:17 = .RIP 
Chance in teii.p = .041 

Wean " •' =: .00?.l 

" " - " flnrlnR ?4 mlu = .0'y4 

Change In teinp. due to current = .."^04 



In this 'let.^nnliifitlon of boat OHoaclty witb wnter 
the saiut; current ;is bere^oforu ▼as used. It helnj? 
allowed to flow for ten mi:;utes In one c^sw ^nd twenty 
in the other and giving ^xjco tt^e cbancce In temperature 
In the lat'er cnse. 

The aiiiOTmt of heat generated by this current In 
ten minutes is therefore l?*i.47 joules, ar.ri the chanpe 
In temcerature producer; Is 0". 15?. ^. . Therefore, 



1^5.47 
Joules per ae(?rett = ■"* = 8?.^ (with water' 

0.152 



v3 >r- V Q T^i^Jes 



Uj v5 ^ 



htV T-'f-n . [I o it" 



<? 



^J 






4 



u» 
























« 


\ 









•. b. iMI^mJilUk IIMM* Ik 1. 



JO!4/fi h 



Q *Y >- s> (.^ 

/»^ 777 /'r7 [^£ti'>lt'<J 



> 

i. 






I 









-117- 



Correc tlor; for radlatlor> . c o nduction, convection , 
stir ri ng, otr , 

The ratwK of coollnsc daterinlned ^t ilf*fu»'e:it tem- 
peratures are plotted on the ^djolnlnt? sheet In terms 
of joules pel- tr.lnute. 

The "diiratlon"of this evp-^'iment was 61 mimites, 
and the average toiuoeraturc durlne this Interval was 
+ 0°. ."^1 n. From the curve, the loss of heat at this 
teinperatnrt Is P.. 'SO joules l-er mlruite . ^ence the 
total loss of heat Is, 

?.F>0 X 61 = 15."^ jotiles. 

We_lP^>i 1 1 ug 



As the first application of the current Is this 
experlii,e;.t was Insufficient to melt, the tee It was 
necessary to supply additional heat. This resrilted In 
a prolo:;ged duration of tht; experiment. 

The heat capactty, >^owevt:r , was dete'^mlned hoth 
at the heglnmg and the end of the e-perl''ient . a:;': the 
rate of coiling was per'^ectly definite at t^-e end. 

Thus V.\ weight l-.p; this expor Itient has 7 poir.ts. 



Total he'it Mippllwd bv t^e cur>*ent - 9,^'7(\9, jouleR. 

Initial ten.perat-'^'e = -O.OfjR. 

•• •• correcttid for zero = -0.9^7. 

Heat to r'-ilse calorlineter and contents from -.9^7 to 
= 6S4 X .<487 = f^'p.P, joules. 

Final temper ature = -fO.SOO 

•• " corrected for zero = -f-0.1«'S, 

Heat to raise calorimeter and contents from C.to +.16FS 

= SP.fS X .1^'^ = l.'=^6 joTiles, 

Heat lost by radl'^tlon, conduction, convection, etr., 

= l.S."* joules. 

Total correction = 6?6 + 1.?*^ -e 1'^.'=^ = 9lFi joules. 

Total r.e-it rermlrud to melt RCr*.*^ eraiiis of Ice, 
= p77fiB - 9lFi = J'RR<s?; joules. 
= y,:^A .f,s^ Joules per fc"^^rn of icu. 



-1 1^- 



KxperlTi.un^ of l/ar . P^vi 



-HP- 
Part I, Hnat capacity withi ice. 

Tbf Inltiil BO\il llbr l\nn teniperatnre of tbis 
BXperin.er.t was about - 1"!^., and tha determination 
of heat cai aclty tbtirefo>'e not allowable. Of course 
tMs colli ri r.ot bo verv different froni tbe beat capacity 
on previous days, as tbe sniae calor InieteT and t>^e sari.e 
amount of oil was nse'^ eacb time, and approxlniately 
f^e same amout of icr^ . T'-'e determinations of Feb. TM, 
Feb. ?7, and Mar. P -'-ere all vury satisfactory, and 
tbese are plotted as ordliiates ae;alnst tbe cor"<-eS'nondl';c 
amounts of Ice ap abstlssaa. Tbe result l!;sc curve is 
Clven bere'vlth, ana +"or tbe short rai;R;e reoulred of it. 
It gives tbe tbe beat capacity with varying amounts of 
ice vi-'ry exactly, T>>e amount of Ice used on Mar. ."^rd . 
was "B.4^ grams. The correspondlnt? heat capacity is 

.Joules peT negr«e = P,A-0 I with ICe' 



^fil I twfn^-ry. 



t: 



L... 



a. A. tiMirftMit*. iriHMt «. 1. 



^rcim% oh I c <y 



y 









X 












X 










y^ 









> 



V 






U5~o 



-1?0- 



Obsurvritious of the «vr)H-rliiieut of Var. ."* , I'-JO''!. 



Part TI. ?'oiti:.K tbw ICe. 



Time 


Telip . 


1 __^^^^^^_ _ 


, Timw 


Temp . 






After 


stirring half hour 


^':05 


.213 






1:30 


-.703 




06 


.130 






31 


.697 




07 


.155 






7? 


.690 




08 


.143 






33 


.635 




09 


.143 






.•^4 


.^^79 




10 


.116 






S5 


.874 


•^ur^e:;! on 


11 


.100 






56 


- . ."0 


at i:.''.5:;'^o 


12 


.105 






37 


+ .35 




13 


,097 






3R 


.55 




14 


.095 






39 


.55 


r-ell NO.. "29 


15 


.039 


F?na1 1 cii-^rHnt 




40 


. 55 


= 10,000 


16 


.090 


on at 2:15:;'.0 




41 


.55 


P = 1114 


17 


.091 






4? 


.57 


d = -I. HP 


13 


.100 






43 


.56 




19 


.110 


Cell MO. .'^31 




44 


.58 




20 


.113 






45 


.57 




21 


.127 






46 


.57 




22 


.l.'^5 






47 


.65 




23 


.147 






48 


.63 




24 


.157 


?;mall current 




49 


.65 




25 


.166 


Off at r:24:.'^o 




•SO 


.70 




26 


.167 






51 


.65 




27 


.167 






5P 


.71 




28 


.1^56 






53 


.SO 




29 


.162 






54 


.^7 




30 


. 1 59+ 






55 


.92 




SI 


.157 






56 


.39 




32 


.1F.6 






57 


,3^0 




33 


.154 






5R 


IPl 




34 


.15.-^ 






6» 


.1^8 


'^nrrent off 


?5 


.152 






p-.co 


/ 1.20 


at 1:59:50 


36 


.ISO 






01 


.u:^ 




,',7 


.149 






C?. 


.72 




3q 


.149 






03 


.40 




.•^P 


.149 






04 


.P7 




40 


.149 







-IPI- 



Observatlous of tba eyperltnwnt of K'ar . ."^rd 



Part III. Heat capacity wltb water 



Tlina Tei..p 



?;41 


•+.148 


4n 


,148 


4.". 


.148 


A'l 


.148 


45 


.148 


46 


.14^^ 


47 


.157 


48 


.175 


49 


.19P 


50 


.?05 


51 


.9.90 


sr 


.9^,5 


5.'' 


.P48 


54 


.?6? 


5 5 


.P''5 


56 


.?88 


57 


.?90 


58 


.?90 


59 


.290- 


rs-.oo 


.i?89 


01 


.P88 


0? 


.287 


0.'=^ 


.P86 


04 


.285 


05 


.284 


Ofi 


.pg.-s 


07 


.282 


08 


.281 


09 


.281 



Time Teinp. 



4- 



C\irre:\t on 
Ht 2; 45;. SO 



rell NO. ."^r-Sl 



onrr^r.t off 
at 2;55:rt0 



:io 


-^.280 


11. 


.279 


12 


.278 


l.-^ 


.2-77 


14 


.278 


15 


.2'7'S 


16 


.275 


17 


.28.'^ 


18 


.297 


19. 


..•^09 


?0 


..'.2.-^ 


21 


.338 


22 


.353 


P^. 


.266 


24 


.380 


25 


.392 


26 


.404 


27 


.404 


P.^ 


.104 


29 


.405-«- 


.•^0 


.4C4 


31 


.403 


S2 


.401 


:^p, 


.398 


.'4 


.395 


?5 


..■'94 


.•^6 


..•^92 


y.n 


..■^90 


.',8 


.388 



'^iirrent on 
at 3:lfs;?0 



Current o^^f 
at 3:25:30 



f^alciilatlonF for Part TT, 

111 this eyptrlment atrnin n bl+ of ice rtsriHlned 
uniuelted after thu larRt; cnrre.i*^ whp stopred and tbts 
oil CO led to nearly 0°^!. it was tbere'^'orB r.eCessary 
to aprly the small '?iirr«:'it for a fe'v minutes . 

The staiidard cell No. r-^pg ( = l,01<f<, volts' was 
tiFed In the measurement of ♦>t; curreiit, whinh was 

^;-^~~ = R.OXRP- amperes. 
The nearest balance o*" the potentlomter wac obtained 
with P = 1114= 1114. 8r> ohms, this vq.lue clvine; a mean 
deflection of - 1 .6P divisions, corresponding to 
- O.J?C ohm. HenCfe the value of P which wotild have 
glvnn a:; exact balance is 1114,6? ohms. This Rives 

^•°^^'U14^ ^ 10.1131 volts 
The ciirrcnt through the potentiometer is 

0.0 GO'-*] ampere, 
Kivlne for the curr^,•Ivt in tv^o heatlne noil, 

?.0.'SP7 - C.OOGftl =r r.Cr'.7.*^« amperes. 



- 1 '^.'' — 



This curr^3..t was flowlrify for" 14H0 Kecor»f1s, k1v1;i^ a 
total aiiiom.t of hunt, 

?;0097 joules. 

The pnaller cnrrt;i-;t. was flowlnt^ for 9 minutes, f^lvluf? 

1?JS^4'7 X P = llP^q joules 
HenCe the total heat supplied by the cur'^erit Is, 
.'.0097 + ll.*^ = .'.OPIO joules. 



-l:'4- 



ralciilat lor.K for Part TIT. 



Chance In temp, per mlu nt P;4=i = .COO 

Temp, at P;4fs = .14^ 
rhar.eje In turup = .14^ 

Temp, at 2:«S9 = .PMO 

rhange 1r. temp = .OCR 

'• " •• per in In = . 0010 

Vean - '• ' = ,000ft 

' dflrlntt 14 11,1 1; = .007 

nhan^e In ten.p. due to cii-^^'Br.t = ,149 



Change in temp per mln = .0010 

Temn. nt ."^-.l^^ - .P^fS 
nbanpe In temp - .l.'^C 

Temp, at .T;'P.9 = .405 

•• •• ?,:m = . 7,sq 

Chanpti 5n temp = .017 

•* '• '• per t.iln = .0019 

Vean •• '• = .0014'S 

H .. .. « dTirtn«? 11 mln = .01^ 

n » i< •• f ?^ »* — 004 

•• 14 •• = .OPO 

Change In tnnp . flue to r;iirrc:vt — .1*^0 



-!'."=>- 



Tn this dttturmlnatlor. of the he^it c^ipacltv wit.>- 
water, t'-t; sarue sninll c\irrwn* war, TiKei-;, it b«lnK 
Hllnvfe'*: to flow for t^!n i.. Unites «!^cb u" the tvo times. 
The beat >5e:ieratea is then. 

I2f^.47 jOTilos ~ 

The cb^^npe la tempe^'aturfe prodMCed "hy this heat Is 
0M49 aiid 0''.150. f^lvinR ^ mean of 0*1495 <" . 'Hence, 



joules per decree - ^''^ ' = R.'^9 (witb «'ater > 

. 1 49 5 



<^ 



o ^ •< Q J»>^i-fs hfr mirt, (J p if ) 



ifw, rr«*fil l-invf*^' 






«. <i,. 4.M^»«1tA. lT>UWt R. T, 



<^ 



v» 



joviJe^ ker rn>'n. i4*,i-nf/) 



1 













5 
















- 



























vi 



- 



































il^ 






fi 



4 






-1P«- 



rorrfe c tlons for ri-Jlation. counnctjon. c o gvectl or. . 
stlrriiiu:. et^:. 

The r!=ites of cooling 'Ittteriuiued Ht different 

temperatures are xilottucl on tbe a'ljolriintr sheet In 
teriiis of joules per minute. 

The ''our^tlon'' of this evce'^lrient was 55 minutes, 
and the avcrac;e ter-.rerature durl:ie thiM jn+erval whs 
-♦- 0*41 C . fiVom the curve, the loss of heat at this 
teiiipyatitlire Is 1.5 joules per minute. Hence the 
total loss of heat Is 

1.50 X 55 = B."^ jotiles. 

•yeiehtl:;g. 

While t'^e main part of this evperl' ent Is 
satisfactory, vet the dtiratlon 'vas nearly a:; hour, 
and a direct deterrilnation of heat capacl + v was only 
made at the clost of tht e^per in.'^nt . The weighting 
is thus reduced to P points. 



1 rv 



Sunu;>Hry of Kxperlir.ent of K-ar . ."^rd . 

Total heat .'nipolled by the nir-^wnt - .'^OPIO joules. 

Initial temr>erature - -0.«74. 

" •• corrected for 7ero = -0.709, 

Heat to raise calor ii.ieter and contentK from -.709 to ^^ 
= 640 X ,709 - 454 joules. 

Filial temperature = -♦■0,l'"^9. 

" •• cor'^er'ted for 7ero = -«-0.1P4, 

Heat to raise calorlmet -r and contents from C. to +.1P4 
= a.'59 X ,1:M = 104 joules. 

Heat lost by radiation, conduction, corivuctlon, etc., 

= R? joules. 

Total correction = 454 + 104 + R.''> = 641 joules. 

Total heat reqiilreo to melt HR.4^ ^rariis of Ice. 
= ?50P10 - 641 = 29569 joules 
= ?^:<A,?^C joules per «rain of ICe. 



\pn- 



Kxperii(i«nt. of Mar. 4tb 



-] ;'<» 



P«4rt I. Htjrit rapafiltv with Ice. 

Tbe l:;ltlal oqtill Ibrlimi teuipt;ratnre of tM fi exner- 
Inient raK evwU Mf^ber than tbat of Mar. ?;r'i,, and 
tbercfore the value of the heat capacity nnist he ta^en 
from ti^B curve there given. The amount of Ice used 
this time was ll.'*i.OP crams, of which the cor-^espondl .g 
heat capacity Is, 

Joules pi^r aeerce = 856. (with ice > 

On the followlne; pns^e are the observations made 
during the period in which the Ice was '^elng melted. 
This is a stralE^htforward exper^rlent, all t^e Ice 
belne rr.elted by the first application of the current, 
and the fln%l equilibrium temperatuT'e being only a 
few tei;t''S of a degree above 0°^. 



- 1 r^o- 



Observatious of *.ha experlniaiit of Mar. 4 1> 
P^rt TI. I/oltln? tbt; Ice. 



T itne Tei:.p . 



1:04 


-.521 


05 


.517 


06 


.51.-^ 


07 


.508 


08 


.504 


09 


.500 


10 


-.25 


11 


•+ . .■'.O 


12 


..•^.•^ 


IR 


..'^5 


14 


.40 


1515 


.m 


16 


.4?; 


17 


.45 


18 


.4R 


19 


.45 


20 


.40 


?1 


.54 


2J? 


.45 


?S 


.47 


?4 


.49 


25 


.49 


?« 


.50 


27 


.56 


28 


.57 


29 


.60 


?0 


.55 


?.l 


.66 



'^ur relit 
at 1:09; 



on 
«0 



r.ell NO.. •=■.29 
Q = 10,000 
P = 1114 
s = -0.55 



Tlm« Temp 



?^2 


-*.62 


?;? 


.65 


,'^4 


.67 


.•^5 


.74 


."^6 


.70 


.■»i7 


.'74 


.'^8 


.7S 


«9 


.80 


40 


1.04 


41 


1.04 


42 


.65 


4S 


.48 


44 


.41 


45 


. r<RT 


46 


..•^77 


47 


.."^71 


48 


.."^67+ 


49 


.."^67 


50 


.."^67 


51 


..T67 


52 


.."^67 


5."=^ 


..•'67 


5« 


..•^67 


55 


..•^67 


56 


..•^67 


57 


.?^67 


58 


..■^66-+ 


5<^ 


..•^66 



'^nr^'ent off 
at l:40:.-<'^ 



-l.M- 



Observfttlon.s of tbe experiineut of J/ar. 4tb 
Part III. Huat capacity with water. 
Tln.o T«nip. 



?:00 
01 

OP 

o.-^ 

04 
OF, 
OR 
07 
03 

O^iCfl 
10 
11 
12 
1.-^ 
14 
l.'S 
1« 
17 
18 
19 
PO 
21 
2? 
PS 
P4 
26 
26 
27 
P8 
PP 

.•^030 
.'.1 
."ip 



36 Fi 

ynF> 

.">»-; 4 
.'■>;<i 
.5<-i2 
FF,C 

:<^^ 

•■^57 

354 j 
352 i 

.•^fSO 
.•=^49 
348 
.r47 
.•'.46 
.•=14 5 
7AA 

0^7 

045 

028 

015 

0054- 

996 

987 

979 

971 

963 

956 



Current on at P;20:30 
Current off at ?:21:02 



Cell No. .-^29 




P 



10, COO 
1114 



Calculatlons for P*ir* il. 

The curr»:;t. was tueasurea In tertus of t>^e staiidaro cell 

NO. ,',?<:) (l.C19,'=^ volts), am Is therefore, 

^'-^-t-L— = ^.O.-S^PV amperes. 

The r.earest balaiiCe of the potentiometer was obtained 

with P = 1114 = 1114. MP ohms, this value clvjnsc i 

mean deflection of -O.'^'S division, cori"espondlne; to 

-O.C'T' ohrii. lience the value of P which would have 

give:; an exact balance Is 1114. 7^ ohms. This R:lves, 

1.0193 ^J-V)^"^-^ - 10.11^/0 volts. 
1114. 7F 

The curre:.t through the potentlon.eter circuit Is, 

0.00091 p.Tnpere, 
glvl:ig for the current In the heatlns? coil. 

?.03fl?l7 - 0.00091 = I>.0.'^7.*^6 amperes. 
This current was floxlnp; for 1S65 seconds, glvl:;g ^ 
total aiiiount of heat. 

3B441 jotiles. 



1 ;'..'^- 



'^Hlculatlons for Part Hi. 



Temp, at 2; 10 = ..'■'v'SS 

Cbanffe In tfcti.p = .011 
•* •• •• per mln 



,0011 
Temp, at ?;?0 = ..".44 
rhfir.fce In tciap = .fifil 



Temp, at P; ?8 = 1.005 



n O • BO — 



? : ?;? = 



r'barvjrt; Jn tetup = .049 



Vean 



'• p«r II, in = .0C3P at C.^'a 
- ■ "036 at l.Or-S 

•• '• •• = .004-A 



•• (• •• 



" dflrlndt ? TP.lraites =.0096 
.... 4 •■ = . 0.'^44 



.• M H .. 



.044 



Change In teiap. 'Ine to cn-r^^wt 



,705 



The ourrtnt el.iDloyeo In this part of the experiment 
was the saif.e as in Par* IT., ai;d was allowe'i to flow 
.^? seconds. The heat ^eneraterl Is then, 

10,11'i'O X P.0.'.7.'».8 X 3?. = 680 joules. 



The change Jn teiuperatrire produced by +his heat helntc 
O.^O'v, _ 

•loulos per die^ree = '70^ ~ ^.'^5. (with water > 



^ -> > •' o Jtu lei h*r m ,n {ioit) 













\ 

















\ 
\ 
\ 
\ 


\ 


























\ 















^*^/f^ f^ i> m I'-n . (^ 1 / " <"^/ 



'^ 



O 












^■1 



-l.'^4- 



Oorreo t loii.s for r'^dlatlon. corirluctlon. convaotlon. 
5tlr rl:;g. etc. 

The rattts of cooling determlne'l at i11ffer«!;t 
teniperatnreK ar« plof'ed on tbe adjolninfir sheet In 
teri...s of jollier, per inlmite. 

The "duration" of tMs exper linerit was P^9 minutes. 
and the averr^pti temperature during this Interval was 
+ 0°fS2 C, VvovA the curve, the loss of heat at thl53 
temperattire Is P. 00 joules uer n.lnute. 'Hence the 
total loss Is 

P. 00 X ^9 = 7R .joules. 

Welfrv.t i:;g, 

In this experlir.ent the first application of the 
current was sufficient to melt all the Ice, the dura- 
tion vas short and the heat capacity was determined 
at the close. Therefore the wele'^flnec Is expressed 
hy 4 points. 



Sunui.ary of Kxperlii.ent of Mnr . 4tb , 

Totf\l h-at siippllud by the current = .'^8441 joules. 

InltlHl ter.if er attire = -0..*S0C 

" " corrected for 7Mro = -0.5.3fS. 

Heat to raise calomlriieter and contents from -.'s.'^rs to n 
= 656 X .R.',5 - S51 joules. 

Final tei..perqture - +0,.'^H7 

•• " cor-^ecteil for zero = +0..'^.'^?. 

Heat to raise caloi" inieter an*! contents from 9- O.to -^.:^7,2 

= 955 X ..?.'=^P = r^lO joules. 

Heat lost by radiation, conduction, convcjct lo?-. , etc., 

- '7^ joules. 

Total correction = .351 + r-'lO -^ 78 = 739 joules. 

Total beat required to iv.elt 113. OP Rrams of ice, 
= 38441 - 7.39 = 37702 jOuleB. 
= .333.59 joules per Rrain of ice. 



-i.'<;^- 



Kxperltiient of Vhv . '='t> 



l.*^7- 



Observatlonp of tbn eyperliueat of Var . ^th . 
Part I. V.KiHt capacity with lew. 



T lr,ie 



Ter.p 



12: '>9 


- .75R 


1:00 


.7fSP 


01 


."747 


OP 


.7,'»;8 


0?. 


.7rs4 


04. 


.7P9 


05 


.7?.-^ 


06 


.71"' 


07 


.7-3 


08 


.'700 


09 


.703 


10 


.697 


11 


.672 


18 


.6ftfi 


1.? 


.6. "5 


14 


.618 


15 


.600 


16 


.582 


17 


. 56P1 


IR 


.547 


19 


.530 


20 


.515 


PI 


.512 


PP 


.505 


PS 


.501 


24 


.498 


P5 


.495 


P6 


.492 


27 


.489 


Pfi 


. 4B4 


P9 


.482 


.•^c 


.479 


.•^1 


.176 


yo 


.'174 


.•»;?i.'»;.'^ 


,47P 



Current on at 1 -.09:30 



niirrent off at 1:19:30 



-ir^H- 



Ob.servatlons of tbe exnerltiiont of Mar. ^th . 



Part II, l/o ItiiiR the lc« 



Time 


Temp . 




Time 


Temp . 




1 ; 34 


-.469 




? : 02 


■*-.82 




.'.S 


.466 




03 


.90 




se 


.46.'5 i 




04 


1 .00 




.•^7 


.46: 




0^ 


1.05 




?S 


.453 




06 


1.06 




^9 


.451 




07 


1.02 




40 


.448 




08 


1.00 




41 


.445 




09 


1.00 




42 


.443 




10 


1 . 16 


ni'-rerit off 


4« 


.440 




11 


1.28 


at 2:10:40 


44 


. 437 




12 


.92 




45 


. 433 


Current on 


13 


.50 




46 


-.PO 


Ht 1:45; 30 


14 


.36 




47 


+ .40 




15 


.29 




48 


.50 




16 


.27 




49 


.60 


Cell N0.3PR 


17 


.24« 




50 


.45 


Q = 10,000 


18 


. 232 




61 


1 '"^"^ 


P = 1113 


19 


.228 




52 


. 55 


d = +3.60 


20 


.220 




53 


.F5 




21 


.213 




54 


.5^ 




22 


.208-^ 




55 


.63 




23 


.208 




56 


.63 




24 


.207 




57 


.75 




25 


.207 




58 


.70 




26 


.207 




59 


.71 




27 


.206 




I?;00 


.7.^ 




28 


.206 




01 


.75 




29 


.205 





-13i9- 



Observatlons of tb« exptjrlrnunt of Var . ?sth . 
Part ITU. Heat napnclty with water. 



Tiiiib TeniD. 



.■^0 


+ .P06 


Rl 


.P05 


R8 


.P07 


33 


.?08 


34 


.?06 


35 


.207 


36 


.P07 


37 


.207 


.'8 


.?07 


.?9 


.P07 


40 


.?07 


41 


.207 


42 


.207 


4r-^ 


.207 


44 


.207 


4 5 


.207 


46 


.207 


47 


.600 


4?^ 


.A.'R 



Ttne Tomp. 



'^nrre:it on 
at 2;4e;l5 
rinrrer.t off 
at 2:46:45 



2:49 



3; 



-+ . R30 



50 


.820 


51 


.210 


52 


.802 


53 


.797 


54 


.789 


55 


.785 


56 


^^n'yjL 


57 


.772 


58 


.768 


59 


.7R5 


:oo 


.760 


01 


.7' 5 


02 


.7fS2 


03 


.747 


04 


.7A2 


05 


. 7.'.8 


06 


. 7,-^6 


07 


. 7.'^3 



Cell No. .'28 
Q = 10.000 
P = 1114 



-140- 



ralcul fit Ions for Pr^r+ i 



Temp, Ht i:»;ft^ = -.7«sm 
.. 2 ; 09 - .7C .-S 

Chanj^e lr» temp = .0^5 



'• per riilu = .00 '=5 



Temp, at 1;0<^ = -.70.'^ 

Chmncii Ir. temperature 
- .POP 



Temp, at 1:2.'=^ = -.-SOl 
'• 1 ; ."^.'^ = .'^7P 

Char.ee In temr-/,= .0^9 

" '• per mlu = .G0? ><^ 

Mean " = .004? 

durlne U mm - ,046 

M .. ■• t. !• ^ I. _ 009 

Char.ge 111 temn. (ivie *-o onr-^ent 



.OfSfi 



147 



141 



I:i tM s expcrlnitint the aiiiou.\t of oil usert In the 
calorliiitttr was Increased fYoni POO cr. to ."iOO cc. In 
order to Introduce some va'f-lat.lon In beat capacity, 
rate of coollnp;, etc. Altho tbe eomilbrlnm terrrper- 
ature vas not ap low as would have ■Heer. desirable for 
a deteriulnatlon of heat capacity, yet In viev of the 
fact that the he'^t capacity had been changed p.o frreatly 
by f^e addition of more oil. such a deternilnatlon was 
made. The saiie snnll current was nsud, it helnt; 

allowed to flow for ten njlmites as iisxial , The rise 
In ter X t^rf*TTt . as sho^r. on the preceding pace. Is 

0.147, RlvinK, 



Joules per der.ree = ^—-'^ = 85.'=; Iwlth ice) 



-14'^- 

raiculfit louF, for Pfirt ir. 
The CTir-^ent whs nieasDed In te-^ms of the Btandari 
c«ll No. r'.f;". I 1 .0192'voltH I, arid hence Is. 

"^008 ~ '''"^^^^^"^ amperes. 
The nearest balai;ce of the potent loneter WHS obtained 
with P - lll."^ = Ills. 79 ohms, this value RilvlnR 
a mean aeflcction of 4- 7,. HO divisions, corresponding 
to +0.4F ohTii, Hence tht; value pf P whinh would have 
producfei ^i exact bala::ct; Is 1114. ?4 ohins . This jflves, 

1.01^^ T^^^"?^ = 10. IPO? volts. 
1114 . ;-'4 

The current through the potentlonieter colls Is, 

C.0CC91 ampere, 
Rlvlnc for the cur'*e:~.t through the heatln? coil;., 

P.O.'.RO? - 0.00091 - 'P .OT^'yifi ampe-^es. 
This current "ahs flowlner fo** 1F»10 seconds, f^lvine a 
total amount' of heat of. 

."^11. "^1 joxiles. 



1 4."- 



'^•^1 cnl -I*- 1 ^••.. for* Part ITT. 



CbH"flre In tuiup. bof 're P:46 = 000 

Teinp. fit P,:4^ ~ ,QOv 

" " ? ; •=>« r: , '^/'7'7 

TeniD at P:^6 = .77? 
'• :^:CH = .7.'=^6 

^^Hr.p:e in ti.-)ip= .041 

'• " '• r-i^r in in = . 0041 

Vean " " ' = .OOf^l 

- during 1 rain = .OOPl 

" " " " " 9 •• = . 0? ^69 

H .. .. „ .. 10 '• = . O.-^o 

C>>ai*t?tj In ttemp due to current = .f$00 

The ctirrisnt was the saine as used for melting t^e 
Ice. a:;a ^as alioweT to flow for ."^C seconds. The 
heat producea Is 

10.1202 X P.0.'^716 X 30 = 618 joxiles. 
Kence , 

Joules per deforce - — — - 1018 (with water » 









I 

is 



\ 



















\ 
























\ 


V 



•0 ^ ^- 



J O it t 



-'5 hfY -m'-n. [ft^infJ) 



1 






^ 

'C 


















\ 





















rv 






\ r 



144- 



Correctl ons for rHrjia t lor;. conrinct l ou. convtjctlon. 
stl rr luK. t;tc . 

Tbe rattjfi of coolln*; letertiiliie'i ^t il^forerit 
ttsmperatures are plottea on tbe aijolnlnt? sheet In 
terns of joules per trilmite. 

Tbe duration of this exoerijuent was 7/1 minutes, 
and tbe average temperature during tM s interval was 
-♦- O'.Pll C. From tbe curves, t>'e loss of heat at t>iis 
temperature is ?.P0 joules per lainute. Tioace the 
total loss of beat is, 

P.PO X r-^v = Rl joules. 

Veightln^ . 

Ir* thlR experiTi.ent all of the factors taVen Into 
consideration in weli^htlne are present, arid therefore 
it 1.'- Give:* the full value of 8 points. 



SunmiRry of Kxperlriwut of K'^r . 'St^ . 

Total heat supplied by tbt^ ciirrtnt = .•*;ll.'^l joules. 

Initial teii.perature ~ -O.A."^,"^ 

•• •• corrected for 7ero — -0.46R. 

Heat to raise calo'-l!,.oter ir.d couterits from -.46'^ to r: 
= 85."^ X .4«8 = :^^9 joules. 

Final temperature = -♦- 0.208. 

•• " corrected for z^ro = +0.17,'^ 

Heat to raise calorimeter- and contents from r.to -♦-.17.'', 
= 101« X .IV.*^ = 17fi jotjles. 

Heat 3'^r.t by radiation, conduction, convection, etc., 

= 81 joules. 

Total correction = ^^9 + 176 = 81 - f>f=>e joules. 

Total heat required to iielt 91.07 (?rams of ice, 
= .'^ll.'^l - «5^ = .■=^047*S joules. 
= ."^.•=^4.6.''' joules per ?ram of ice. 



\AP,- 



Exp«rlit.«nt of K'ar . <^tb 



-147- 



ObservatloiiK of the exptjrltnout of ^ar. f^f.h . 
Part I. Keat capacity v1t^ Ice. 



TlCib , TeHiP. 



15 
in 
17 
18 
19 
20 
21 

22 

2.-^ 
?4 
25 
26 
27 
28 
29 
?0 
,';l 
r^2 

.?4 
."^5 
56 
?7 
.■^8 
F.9 

40 
41 
4P 
4.'. 



-1.164 
.1^5 
.149 
.143 
.136 
.127 
.120 

.lis 

.105 
.007 
.0^1 
.080 
.065 
.0?.6 
1.014 
.995 
.974 
.t»53 
.^-»33 
.914 
.894 
.880 
.876 

.865 
.861 
.8«S5 
.851 
.846 



Currc:^t on 
at 1:25:30 



rnirreut off 
at l:.'^5:yo 



Tine 



Temp 



1 :'t4 


-.'Ml 




45 


.8.'S5 




46 


.830 


'^irrent on 


47 


.823 


at I; 46; 30 


48 


.803 




49 


.7^4 




50 


.rrf^rf 




51 


.750 




52 


. 7.-<0 




53 


.7ir< 




54 


.69'? 




56 


.678 


Ourrer^t off 


56 


.^«5 


at l:5<s:30 


57 


.(^^O 




58 


,6 56 




59 


.653 




g:oo 


.650 




01 


.646 




0? 


.643 




0.' 


.640 




04 


.636 




05 


.6.'^3 




06 


.6.',0 




07 


.«P6 




; 08 


.623 




09 


.620 





StlrriuB cor.tlnnen 
NO reaoluKs taVen. 



- 1 4.R- 



ObstsrvHtlons of the tj^perlinuut of Mar. Rth. 



P>\rt IT. J/oltl:ie the lc«. 



Time 


Toiup. 




Time 


Temp. 
1 




?:17 


- . Stt.*^ 




?;4« 


1 
-f .93 




1^ 


.5R0 




47 


.94 




19 


.577 




48 


.98 




2" 


.57.'^ 




49 


1.07 




PI 


.570 


rni-!"rer.t on 


■SO 


1.20 


Current off 


22 


-.25 


Ht ?;:5i:;^0 


?S1 


1.02 


at 2; 50: 15 


25 


•f..'^0 




52 


.82 




24 


.?5 




53 


.73 




25 


..■^5 


Tell Mo.?^29 


54 


.7284^ 




26 


.40 


= 10,000 


^5 


.7P8 




27 


..•^5 


P = 1114 


56 


.728 




28 


.42 


d = -i.a.-^ 


57 


.728 




29 


.48 




58 


.7284 




.■^0 


.40 




59 


.726 




.•^1 


.'^5 




3; 00 


. 723-f 




32 






01 


.718 




SS 


.♦^5 




02 


.715 




,"^4 


.71 




03 


.713 




.■^fs 


.H5 




04 


.708 




56 


.7« 




05 


.704 




37 


.75 




06 


.700 




S8 


.83 




07 


.696 




59 


.90 




08 


.692 




40 


.81 




09 


.688"< 




41 


.75 




10 


.684 




42 


.74 




11 


.680 




4S 


.81 




IP 


.677 




44 


.89 




13 


.67J^ 




45 


.8fi 











-149- 



Obsorvatloiis of tb« experlJ'ient of y'ar . 61^ 
Part TIT. Heat capaclt-" w1 tb water. 



Tlno Temp, 



;i4 


H-.«f50 


15 


.«fift 


16 


.660 


17 


.658 


18 


.655 


19 


.610 


SO 


.64« 


PI 


.840 


22 


.9?P 


P.-^ 


.g.-^p 


?4 


.9P5 


P5 


.918 


?6 


.910 


?7 


.904 


PR 


.898 


P9 


.891 


."^0 


.886 


?^1 


.880 


,•7 


Qr74 



Time Temp. 



Current on at .•*.:;^0;?0 
Current off at .',: P.O-.r'.s; 

Cell NO. .•=^P9 
= lO.OCO 
P = 1114 



-IftO- 



Oalcu 1 atloi;.'-; for Part T 



T«mp , at 1 ; i s - - 1 . 1 H4 
'• 1 : i>Fi = 1 .091 

Ch^iT.Pie 1:. tonip = . 07^ 

'• •• " per ihi:-. =: 



,CC7.'^ 



Temp. Rt 1:?*^ - 


-1 .091 


'• ] ; ."-^V - 


.T'ft 


r-ba'^fre 1:; tellip - 


.^^IR 



Temp, at 1 : P;7 = .R7« 
•; ; 48 = . Rr-'-O 

C^?tr.^t.• !:. ttn.r = .048 

•• " •• per Mln = .00r>l 

Vear. teiiip per ir In - .0C8P 

•• durlrif^ 11 mm = .063 

2^ " = .oOfs 
1? " = 






Change Inteinp. i^e to curreiit = 



.07.-^, 



,14? 



nha:;g;e 1:; teiap. per rnln = .0051 



Temp . at T : 4« := , R.'^O 

" 1 : 5« = .856 

Chrtiifre iu tuliiU = .1.74 



Temp, at 1:58 = .656 

•• " ?:0& = . 6^0 

C>-ar.p;e In tcii.p = .Or-',6 

• per II. Ir. = .OGr''..'^ 
•• •• = .004J> 

• -inrlr.K 10 riln = .C4R 
_p •• = .007 
IP •• - 



I' !• 



!• n 



.04R 



'^baii^e In tump, -lue to current 
10 



1?6 X 



9 



.1P6 

.140 



-l.Sl- 

The saint! aiiiour.t of nil I .'■^OC cc, > was tisd In t>is 
expt^rlniBUt as In tht predertlng, ^1Jt ritb ^ riifferent 
calorimeter. TMs calorimeter was slmll^ir to to the 
other, v.uiK;hiutt three (grains less anri not havlnt? quite 
as b^liT'nt a s\irfact: tbns plviiiR a nlfferent radiation 
constant. Two aeterinlnatlons of heat capacity with 
ice were n.ade . ^Ivlnc; a ch^neio In temperatnrL,- of 0.1''? 
In the first ir.stance with the onrre:.t on ten mluites, 
and 0.126 for .;ine minutes of t>-'e cnrrf;:;t . 'vhich is 
equlvale;;t to C.140 for ten minutes. of thw curre:;t , or 
125.47 joulei-. HenCe , 

Jotiles per ae^ree = o^'i^a.t'^ ~ ^^"^ (with Ice >' 



rftlculatlor^K for Patt IT. 

The cnrrunt wa« T'Hit:,,ri-a in terirus of t^^e staiiiar^l 

cell No, ypu 11.019,'^ volts', and benccls, 

1 019.'5 

~^CCR ~ ''^.OmP.y amperes 

The nearest balance of tbe potentiometer was obtained 
with P = 1114 = 1114:. B^^ ohms, tbis value (?ivl:i6r a 
mean deflection of - l.a,"? division, corrwspondlne; to 
- . p.' obn. ^-e.'Xt! tbe value of P vblcb •*ould have 
produced an exact balajice Is 1114.^9 obms . Tbls elves 

l-01^»-'^i^4^| = 10.1174 volts. 
Tbe current tb.rou^b tbe potentiometer colls Is, 

O.OOOOl ampere, 
giving for tbe cur'^r^nt tbrougb tbe beatlriC; coll. 

2.0ft8P'V - 0.00091 = S.O.'^Vr-'.r, amoeres. 
Tbls current was flowlnc; fo^- l^pfs seconds, (giving; a 
total a!,iou::t of heat of, 

.'^fi»S60 joules. 



- 1 h.-^- 



C>ilc\riatloi;R for P«rt TTT. 



Temp. Ht .■^:14 = .6«9 
D-an^H In teiap.- .0P3 



Temp, rit .'S;?!0 = .84^ 
r'bpjif't! In ttsmu = .PH4- 



Temp, at .':S« = .«10 

•• .■=;;.?^ - .«2L1 

r^smre In teiip = .0.'',r> 

per TTiln = .006C 

Mean • " '• = .0049 

dvirlnc; 1 mln - ,0049 

•• • •• 3. " = .0''^Q0 



.O.*^!^ 



Chan£?e of teinp. aue to ciir^'tr^t = . P99 

T^e ciirrer^t was tbe SHiiit «s nseri for rieltlng tbe 

Ice. and was allowed to flow fo- l'^ secoms. The heat 
produced was, 

2.0,'5'7.'^-0 V 10.1174 y iFi =r .'^09 joules. 

Hence , 

Joules per degrwe = 75^577 = 1C.'^4 (with water 






^ 






\ 



\ 



^^ Jitilei) hey rrnrt. {( aj^J 









\ 

\ 

\ 
\ 
\ 





























] 
















<■! 






















































.)^ 








■•• 
































i 

































\ 


\ 






\ 

\ 













^ 


\ 
\ 
\ 















\ 



'1 i. 

■r 
X 






rv 



-.-9 



Q >y v^ ^ vxi ^ 7* 



-I'i4- 



Corre ctl ons for rg^-llatlon. cori'lnotlon. cortvoct lor4. _ 
stl rrl ; ; g. utc. , 

The mttfK oL' cooilr.e; detcrtiilue'l nt rilffermit 
tenperatiirts are plotted on tba adjolnlnt? sheet In 
terms of joules per n.lnute. 

The duration of tMs experiment was P^F, minutes, 
and the avera(?e tem; eratTire durlne; this Interval was 
■f 0°.63 0. From the c\irVe t>^e loss of heat at this 
temperature Is 4.00 joiiles oer minute. 'Hence the 
total loss Is, 

4.00 X r^.""; = 1:^9. joules, 

Velg htl.'ig. 

This evperin.ent falls behl'.i'l the first one only 
in the fact that at the close it was ^ few minutes 
beforw the rate of cooliiit; became riertnltely ustabl ished 
In weighting, therefore. It is Riven the value of F> 
poijits . 



-IF,F>- 



Sixnunary of Kxper Itiiervt of J/ir . 8tb, 

Total huat supplied bjn tb« ciirrerit ^^ .'•^fSfi^O joules, 

lultial tenteratiire = -0,570 

•• " corrected for 7ero = -O.oOR 

Heat to raise calor Iniete'^' and contents from -.no's to C 
= 890 X .605 = '^SR joiiles. 

fi'lnal temperature = +0.728 

•• •• corrected <"or 7nro — -♦-O.fif^.'^ 

Heat *'^ r'-.iy.Kj calor Ir.ieter from C.to -i .H9?> 
~ lOTM X .69:'\ = 716 joules. 

Hent loF.t hy radiation, conduction, convection, .etc . , 

- l.*^? joriler. . 

TotF\l rorrectlon - F,^F^ + 716 + 13P = 1p;R6 joules. 

Total beat renulrea to ? ,el t lOP.P^ jr^'ans of Ice 
= ?55?>60 - l.'^86 = .'=^4174 joules. 
~ .'^•'^4. IP .] oule;-. ( o^ c/>»^m tT 1 '^e . 



-lF>fi- 



KxperlTuunt of Vnr . vr> 



'IF>7- 



Pnrt I. Hunt capacity with Ice. 

On tMj? n«y tht! F-.i;.Rller airioimt of oil I P'O nn . I 
was tjstrQ, but vlt)'' tbe kbooiiI calorimeter. The Inl'-lal 
equll ibrl\iiii toriipe-rat\irc; wa« too blcjh to permit a direct 
deteriiiluatlon of be^it bapaclty. bTjt a? tbe mT^ntlty of 
oil Ik the saiiie as li; the ealler experiments the curve 
there established Is applicable here. The heat 
cppaclty correspomlrit? to 85. «f' e;ram.s of lc« Is then. 

Joules per aee^ree = f^P^^ (with Ice' 



-iFiR- 



Observatloi;s of th« experln.eut of V«ir . vt^^ . 



Part II. WoitluK tb*» lc«. 



Tl: 



Teiiip, 



2; 



Time 



00 


-.404 




01 


..'.94 




02 


.J^91 




OS 


.?83 




04 


..-=^85 




OS 


• 




06 


..'^82 




07 


..•=^80 




08 


. :^7'i 




09 


.,•^7?^ 




10 


..•^72 




11 


..•^69 




12 


..•^67 




15 


• 




14 


. r-^^.? 




15 


..•?6l 




16 


.?.59 




17 


..757 




18 


..7 54 


'^iirrtnt on 


19 


-.05 


f\t 2:18;. 70 


?0 


-^ .48 




21 


.50 




22 


.*^5 




23 


.48 




24 


..51 


' rttll NO. .728 


25 


..50 


= lO.OCC 


26 


' ..56 


P = 1114 


27 


! .62 


d rr -1.90 


2«^ 


.60 




29 


.64 




.•^0 


.70 




.'.1 


.7.7 




S2 


1 .64 




.'..'' 


.69 




.'.4 


.^6 





.7 



Temp . 



:.75 

.76 
.77 

,78 
.79 
40 
41 
42 
4,7 
44 
45 I 
46 
47 
48 
49 
50 
51 
52 
5.7 
54 
5=; 
56 
57 
58 
59 
;00 
01 
02 
0.7 
04 
05 
06 
07 
08 



-^.^5 

.88 

.90 

.95 
1 .02 

..50 

.25 

.12 

.05 

.70 
1.03 

.50 

.23 

.90 
1 .48 
1 .45 
1.425 
1.410 
1 . .797 
3 ..784 
1 . .767 
l.,758 
1 .345 
1.3.73H 
1 . 321 
1.310 
1 . 300 
1.287 
1.280 
1 . 270 
1.260 
1.250 ' 
1 .240 
1 , 230 



rnrrer^t off 
nt 2:.7c*:.'.0 



Oiirre:\t on 
at 2:43:00 
Ciirreiit off 
^t 2:45:00 
•^urrtsr^t on 
at 2:47:00 
<^nrrent off 
at 2:48:2«> 



Oalculat.lons for Pnrt ll. 

The c\irrvi:;t was measured in teri'is of the stai^nar'l 
cell NO. ."^P.B (1.0192 volts', aiirl Vience Is, 

1 01 Q'> 

. "SOO'J.'^ 

The nearest balance of the ootent loinetor was obtained 
with P = 1114 - 1114. BP. ohms, this value f^lvlnf^ a mean 
cleflec*lonr; of - l.wo divisions, coTespondln? to -0.24 
ohm, 'Henco the value of P which Tould have p^-oduced an 
exact balance is 1114. 5H ohms. This selves, 

1.0192 2d03^.^ = 10.117S volts. 

1114. "^.R 

The current through the potentiometer colls is 

0.00091 anpe-^e, 
fCivlni; for the curre.\t t^roucih the heat^'n? coll, 

2.0.'»iR0'7 - 0.00091 - 2.0.'^7in amperes. 
This 'current was flowLie; for 1465 secor.ds In all. When 
it was flrKt taVen off some ice remained \mmelted and 
It v-^ic; ^''-trefore out on ae;aln, Tbe total amount of 
heat Is, 

.■^0195 joules. 



■1«0- 



Part III. Hunt capacity with water. 

The fl;;al equilibrium tetnperattire was too high to 
allor LiaVli;? a dlrtsct determination of '-^eat capacity 
with rater. However, the conditions of the experiment 
were very llVe thore of Mar. P^ii . and ."^"^o , , the amount 
of Ice used belnt? about a mea:; between the amountK used 
on those days. Therefore no i^reat e^rc* can be Intro- 
duced by taking the heat capacity as the mean of the 
heat capacities dete-^mlned for those experiments. 
That is. 

Joules Der ninute = B,*^P {with water' 



T 



^ 






iii- 



rr. 



ouiti jofT -ni I n. [loir] 

~ r T \ — -; , ,'i — r-TT> 





\ 




















\ 























\ 

\ 
\ 

\ 
\ 


\ 

\ 

\ 





« 



J C It, 65 h 



er 777/77. 



/4'^/ 77 fj/J 












^^ 



■? 



;v 



-1^1- 



Corrtic tlons for '"'^^Ifttlon. ''ondnctlnn. convection. 
H.tlr rl r ;k . utc. 

The rntes of CoolliiR 'lete-rmlnei «it ilfforont 
tempe'^Htnres are plotteil on the adjoining sheet In 
terms of joules per mlmite. 

The duration of this experliuent r^s 40 minuter., 
and the averaece temperature durlnp; th*!?: interval vas 
+ O'.RO C. Froiri t)-<e curvt; the lopp. Of heat at this 
temperature is 4.00 joules per minute. Hence the 
t'ltal los^s Is, 

4-. 00 X 40 - 160 joules, 

Weig h ting . 

In this experiment the duration was short, and 
the rate of coolint? at the end was perfectly definite 
The welehtlne it reCeiveF 1 p. therefore ?^ points. 



??umrr«iry of l':Tporlinunt of J/ar. "^t". 

Total boat supplied by tbe curre:;t - 7.01OF, joules. 

Initial teiiiperature ~ -0.."^*^4' 

" •* correcte'i for zero = -©.."^RO 

Heat to raise calorltieter aiiri couterits from -,?;.S9 to '^ 
= 6rSS X .:^''<9 = P48 joules. 

Final temperature = -fl . ."^.^S 

•• '• corrected for 7ero = +1.P9R 

Heat to raise calor I'neter and contents from f^.to 1.P98 

= a,52 X l.pnn =r 1080 joules. 

Heat lost by ^aalation, cond\ictlon, convection, etc, 

= 160 joules. 

Total correction = P48 + 1080 + 1«0 = 1488 joules. 
Total heat required to melt 85. 9p <?r»ams of ice 

= 30105 " 1488 - 28707 joules. 

- .'^.'^4, IP joules pe'' ^ram of ICo. 



- 1 «.'»i- 



Ti; the followl:ifiC tnhle Is aciven n siiirnT.Hr.v of* the 
prlnnlpal facts In the prace'llnj? experlineuts . All of 
the determluatlons 'ire seen to 5»^rce closely with the 
mean, the ccreatest variation belnp; for the experiment 
of War. 4th, There Is nothing to Inflicate why this 
value comes out thiip fa** from the mean. 

The probable error of the weighted mea:;, calculated 
by the methoo of least squares, is 0.08 joule, thus 
qlvlne for the final value of the heat of fusion of Ice 

.'^.'^4.?1 :t O.f^^ joules. 
taking the value of the OlarV Cell as l.A.'.A volts,a^ /S"^ 

Tf there Is an error of 1 part In 1030 In thtj 
value of the ClarV Cell. It would alter this value of 
the heat of fiuilon of Ice by 9 parts In lOCO, since 
the electrical energy ha«=; been calculated froti. tha 
formula Kit , and both K and X a'^e determined In terms 
of the stai'.dard cell, the K.K'.K. of which Is expressed 
In terms of the '^larV cell. 



-l^j.'-Sa- 



ThiH rasult oh:; be wxp^-usotjcl la terms of mwan 
calo'^les if 'vo take the value for a »nea:; calorie to bo 
4.lS?r^ joules, HH afctcrrnined by HeynoliK anrl Moo'-by' 
and rece:»tly corroborated by Baruesf T^ls gives for 
t^e >eat of fusion of ice 

vg.Bflfi mean calories. 



'Reynolds a;;a Woorby , Pbtl. Trans, vol, 190, p..'^Rl. 1^97 
-^^arnes. Phil. Trans, vol.199, p. J. 49, 190P. 



-Ifl4- 



Tr^blo IV. «ium;riar.y of rtjpMlts. 







Total 


Total 


-"or , 


VelfTht 


Heat of 


WelfiTht- 


T)at 


-e 


.Tonles 


cor . 


•Toulos 


of ico 


Fuslor* 


itl? . 


fi'eb. 


9.^ 


.S«iV4a 


13^)6 


3388? 


101.37 


334.24 


6 


Feb. 


?B 


««i27a 


1083 


34191 


10P.35 


334.06 


ft 


Mar. 


P 


P7V68 


Q1«S 


26 8 48 


«0.f>3 


3.', 4, 6 9 


3 


War. 


3 


.•^0210 


641 


P9fi69 


88 , 4ft 


.■^34.30 


2 


War. 


4 


38441 


739 


.■»;770P 


113. OP 


333 . 59 


4 


Var . 


F> 


31131 


6fi6 


3047 ft 


91.07 


334.63 


ft 



War. 6 3ftft60 1386 34174 102.28 334.12 5 

I 
War. 7 3019ft 1488 28707 85.92 334.12 3 



WelEThttn mean = 334.21 
Probable error of '• " = .08 



105- 



Thls value t'or t^^tj >^e^t df t>|C!lor. of Ice iR Bome- 
whnt lower thaj-» tbat obt'^lr.ed by hes.s , sv.d which appears 
the most truBtworthy of previous fletermluatlonB. 
However Hess stai;ds alone In flndinjf a value e;rt»ater 
than 80 mean calories, or ^^^^ jouleK. while the value 
here obtained is near the mean of all the previous 
rieturi7iinatlons . it vo\jld ho interest InR to rompare 
f^e heats of fusion of samples of ice prepared by 
different i.ethods and of vnrious nepirees of purity. 
?ome of the preliminary experinients with commercial 
ice s««iMt,d to indicate a slle;htly less heat of fusion, 
but these experiments will not warrant a more definite 
statement, However for this very pure ice, riade as 
specified above, the value 

.'..'^4. SI joules 
in terms of the OlarV as 1.4.r4 volts^ will stand. 

The writer's thnjiVs are extended to Professor Ames 
for his interest and many helpful sut^tjestions throup;h- 
out this investlf^atlon . valuable assistance has also 
bean re.tdered by Mrs. "mlt>^ li; that part of the worV 
which requirea two observers. 



-l««- 



Arthu-'" VMtniore ot:ilth, f^ .'^ . , >'.55c., wns born In 
Hartfor-I, ^'uriaont. Kny 11. 1R74. His enrV education 
was obtalnod 1:: t^-e a1 strict ar.^i village snbools, and 
In 1BS9 be entertsO tb« N«w Hatiipsblre Oolle^w of AtCTl- 
cnlture ana tbts Mecbaiilc A*"ts, ♦"ecelvinp; tbe "def^ree of 
S.'R. four years later. Tbe following; year was spent In 
era-in^^te stnay at ro-^neil UnivH^-slty. Diirlnc^ tb.e years 
1^94 - 1899 be was pbysical assistant in tbe nutrition 
investigations at Mirldletov^n, Conn, conrincted by tbe 
T)epartriie:;t of Art iciiltnre . T>nrln<^ tbis time be -vas 
als'i oo;i .ectel "vitb 'VtJ'^ltivan Unlversltv, first as a 
PCradnate student, recelvlnf? tbe de^rew of M.5^c. in 1*^95, 
and later as assistant In pbyslcs. 

Tbests positions ve-^e roslf?!;wn in 1899 for graduate 
study at tb« Jobns Hopkins Unlversltv. 1900-1 ^e was 
Instructor In pbyslcs ana electrical onclneerinK '^t 
Tulane Univei-sitv, H.nd 1901-?. professor of electricity 
and electrical engineering at tbe University of Missis-^ 
slnnl . 190?-.*=^ ^^e was fellow in pV^vslcs at tbe .lobns 
HopVins University. 



-107- 



rKKTlFTOATl«:r; OF VKKIPT'^ATTON . 

As tjvplalned tn the bonv of this paDer , the 
stannara cell Hj\n the stai;nard half ohm coil w«>'e 
callbrattid by th« Natior.al T^nrean of Standards 
Ir.imedlattjly at'^'.er thoy were usel in this work. 
The partlciilar reRlstances of the potentiometer 
Circuit v'ntch wore used In ^he 'iie^isurtoment of 
the voltag^e we^'e liVowl.se cali>>rated. Gopies of 
the Certificate.'-, of ve^'if 1 cat "l '-'!\ 5^>*e b«->-e 6;iven, 
and these values are used in the orecedln^ calcu- 
lations for the heat of fusion of J ce . 



TrwH.snry Tiapfirtrinn*. 
(ropy) 'VeiRM".p;tor. 

April J'M-l^^o:^. 
Tent No.?506. 

rKK'l' m-l^ATK OK ^^MKf^'"! ^AVI OM 

Of 

Two KuKlst-C^.Ce "RoyiiS 

snhtiiitto'l >^" 

K,''J .r,r\ith , ,ToVi".s Hopvir^.s Unl^'ur.si tv . 

_r)_ 

VaVer: Mot stHtefi, 
K'ater lal ;not stated, 
-o- 

Kiisistanoe in 
livteruat jonal ohms, 
at y.O*f^. 

Pox of nominal value 
10000 ohms, Inclunlng 
oorc\^ctU\P: v'ire 9949.7 

^ox of noTninal value 

11 1.*^ ohms 1 1 i."^ . 79 

Same ^ox, pliii^s set for 

1114 ohKis 1114.RP 



NOTK: - These values are correct to 

rit^^m o.ccF)'^*. 



SlPTied) S.V.55trHtton 

TM^-cCt or . 



NATIONAL ViUKKAU OF 5?TANTAH1)S 



April PR-IQC*;. 
Test No.r',C<S. 



PKHTrK'T'^ATK 0^ vi;:htg't'^atton 

of 
Keslstn:;oe .St'^:iaara No,'i'-^*>o 

sn knitted by 
A .W..^i:iit'n , nyiris HopVins Univ«'-slty, 

-3- 

Mh ter 1 Hi : Mantfa:-; in- 
i TiiiuHl vs\lne : J . fS ohm , 

-o- 

TemperHture 

of oil liHtb . F^Bslstance. 

?o*.o 0. o..«»ooon 

1 titer" ^ M or4al ohms 

when c-^rrylnr ^ 
cnrre \t of" f^.04 amne-^es. 



The Hbove value 1<» ha<^e'l on the 'Tiein values 
of y-KO coils halor.^lnc; to the Natlon-^l 
T*(ireaii Tf St'4:;'lar'1s , as reoetermlne'l at 
the Felchsauptalt In Julv, lt»0?, and Is 
corr«ot to '*'l^hl:; two units in tv^e fifth 
decimal place. 

ISlf^nedl «;.w.5;tratton 

Tifrec+^or . 



NATION At. ^UKKAU O^ 5^7 AN HA HI 1.9 



Test. N^.-'-O*^. 



nKHTTFTHATK OF VKRIFICATION 

Of 

'^admlnm Stari/larri rail No.?if>9 
Port'^blti Tvpe (with iins^Jturateil OJidTnliirn R\ilphate solution' 
Maker; Westo.; Klectr leal IriKtrTiTner.t r.o . 

submitted by 

A."V.r>riit^ , .Johns Hopkins Unlversitv. 

-o- 

Teniperature . Kltjctroinot ive Fo-»'ce. 

18*0. 1.010.-^ international 

volts , 



The above value Is based on the niean valtie of 
ten staiidaro (^larV cells belon^lnt^ to the 
National VTi-r-t-jiii of ;^tamard9, t'nVlnc tbe 
value of the oiarv to be 1.4.'^4 International 
volts at I'S o., and tbe result Is co'^-oct 
to Tithin two units in the fotirth de'^linal 
nlace . 

(Sidled) S.w.itratton 

TM'^t.'Ot o'^ . 






"^iiiilfA 



^^''^^'^'-^S'^^i**^ 



w^w^i 



^'.^.J^- 



^...J.^.^'w^w^k/^fvy 






w*'w'^ 



*k(%w^. 



.-,*■' ,',0'.%"'y^> 



'^VV^if, 



;;?t,>K 






7^\j\J^'jyV\j\J^ 



';yi\^Jw.>'v,-.,-''-'^«V' 












,^:v^y-vv 






yr¥m^i 



'u^y^J^ 






yj^^i\ 












!!^r:^^-^ 






Vvv^v, 



}'>m 



'vH>^« 






V>^vvv 



Mi^ 






;W^^VM 






^•^'w* 






w^ww w 






:!'r!^yyc 



•ww-w- ^^^^w 



V^wu' 



^^MPll\.: 



.W*"--^--, 



,^r-*.-LA^ww»^»''? •- 






VWWwW^v*''*^^. 






,^^^w\jVvAi'VV> 



-'v>^vw::; 



S>V*'WV 



v*W^W^I 









'VW^^''^ 



-""'''''^■■jyk)iiLjLLLiLtLLL-_' """'''" llitttfllMiilii<i>"4i¥r 



:^«»«'»W*vv*^vv^--^.^^^ 






^ , ■ ^ ^ - 
^*t:b. 



'"*^^ww»JL^.^^'rrr-""^-"'■'-w..w^w»^<.^^Vm^^ ^ 






'WUT,^^: . , 



,-'tJ"v "'^^ 



>^kw^5:^^;H>H^ 



^^■jj 



?!"vv:>r^>''!....-'v:-yvv^,^^ 









VWW'WW^^^ 



^*^^y^***»l(IWlWV^ 









.-..v^O.^^^^^,WWw^v 



>'*VW- 






,-v^WW^Vv- 



1^ . .L.v.U»J*U»^»^^. ^ V.'.WW 



■'^ — ^<;s::;'***% , 



-vvvc 



VVVVi 



^'v^^^^'Wvv. 



^^x^'>^^^ 



. .L.v.uU'U^' 



. -^^ 



^^V^VI^^ 



'-v^iT^^^^^^;:-'"''''^^ ''^'^'w*vv 



• )..■ ii'">i-J' r': w'JlV.'.