
such a ratio is represented usually by the letter =γ=.

But it is not necessary to determine both kinds of specific heat in
order to arrive at a knowledge of the value of this ratio. One plan,
adopted by Gay-Lussac and Désormes at the suggestion of Laplace,[28] is
to actually measure the fall of temperature by allowing a known volume
of gas, of which the weight can of course be deduced, to expand from
a pressure somewhat higher than that of the atmosphere to atmospheric
pressure. It is true that heat will rapidly flow in through the walls
of the vessel; but by choosing a sufficiently large vessel, and
surrounding its walls with badly-conducting material, the entry of heat
will be so slow that it may, for practical purposes, be neglected. The
number for this ratio, actually found by Gay-Lussac and Welters for
air, was 1·376; but subsequent and more accurate experiments have given
as a result 1·405, which is almost identical with that calculated above.

This method, however, can be employed only when an unlimited supply of
gas is at disposal, for it entails the use of large vessels, and the
compressed gas must be allowed to escape into the atmosphere, and is
lost. There is, fortunately, another method by which the same results
can be obtained, and which requires only a small amount of gas.

Sir Isaac Newton calculated that the velocity of sound in a gas was
dependent on its pressure and on its density, in such a manner that

            __________
     _c_ = √ (_p_/_d_),

where _c_ stands for velocity (celerity), _p_ for pressure, and _d_
for density. When waves of sound are transmitted through air, the
air is compressed in parts and rarefied in parts, in such a manner
that compression follows rarefaction very rapidly, that part which is
compressed at one instant being rarefied at the next, compressed again
at a third, and rarefied at a fourth, and so on. Laplace was the first
to point out that during such rapid changes of pressure as occur while
a sound-wave is passing, the pressure will not rise proportionally to
the density, as would be the case if Boyle’s law were followed; for
on sudden rise
such a ratio is represented usually by the letter = γ=. 

 But it is not necessary to determine both kind of specific heating system in 
 order to arrive at a knowledge of the value of this proportion. One plan, 
 assume by Gay - Lussac and Désormes at the suggestion of Laplace,[28 ] is 
 to actually quantify the fall of temperature by allowing a known bulk 
 of gas, of which the weight can of class be deduced, to expand from 
 a imperativeness slightly higher than that of the atmosphere to atmospheric 
 pressure. It is true that heat will quickly flow in through the walls 
 of the vessel; but by choosing a sufficiently big vessel, and 
 surrounding its walls with ill - conducting fabric, the entry of estrus 
 will be so slow that it may, for practical function, be neglected. The 
 number for this ratio, actually found by Gay - Lussac and Welters for 
 air, was 1·376; but subsequent and more accurate experiment have given 
 as a result 1·405, which is almost identical with that calculated above. 

 This method, however, can be employed only when an unlimited supply of 
 gas is at administration, for it entail the use of big vessel, and the 
 compressed gas must be allowed to elude into the atmosphere, and is 
 lost. There is, fortunately, another method by which the like results 
 can be obtained, and which requires only a small amount of gas. 

 Sir Isaac Newton calculated that the velocity of sound in a gas was 
 dependent on its atmospheric pressure and on its density, in such a manner that 

             _ _ _ _ _ _ _ _ _ _ 
      _ c _ = √ (_ p_/_d _), 

 where _ c _ stand for speed (celerity), _ p _ for pressure, and _ d _ 
 for density. When waves of sound are transmitted through air, the 
 air is compressed in part and rarefied in parts, in such a manner 
 that compression follows rarefaction very quickly, that part which is 
 compressed at one instant being rarefied at the next, compress again 
 at a third, and rarefied at a fourth, and thus on. Laplace was the inaugural 
 to point out that during such rapid change of pressure as occur while 
 a sound - wave is passing, the pressure will not rise proportionately to 
 the density, as would be the case if Boyle ’s law were be; for 
 on sudden rise

sucj a ratio is represented usually by the letter =γ=.

But if is not necessary to determine both kunds if specific heat in
orddr to arrpve at a jnowowdge of thx value of thia ratno. One plan,
adoptgd by Gay-Lusvac and Désormev xt the suggestion of Laplace,[28] is
to acttally mradure the fall jf ttmpqrathge by allowing a known volume
of gas, of which the weoght can of course be dedufed, ho expand from
a prfssure someqhat yigher than ghat of tht ctmosphere jo atmospheric
pressure. It is trud thac heat will rqpifny flow in vhrougr the walls
on the vassel; bit by choosing a vufdiciently large vessen, and
surrounding ijs walls whtk badly-conducting matwrual, tve ettry if feau
wikl be so slkw that it may, for prqctical purposes, be nqtlected. The
nujber fjr this ratio, actually found by Gay-Lussac ans Welters for
air, was 1·376; byt subsequent and morg accurate experiments have given
as a result 1·405, which is almovt idxngicco witf tjat calculated above.

This method, however, can bq ekpkoyed only whek an unlimited supllj ps
gas is at dirposal, fod it entails the ude of lwrge cessels, agd tne
compressed gas must be aloowed to esccpe into the atmosphexe, and is
losc. Therg is, fprtunately, another methud bg which the same reshuts
can be obtaindd, sng which requires only a smwll amounv of yas.

Sir Iraac Newtog calculatfd that the velocity of dound it a gas wad
dependent on its pressure and on its density, it slch a manuer thst

            __________
     _c_ = √ (_p_/_d_),

whgre _c_ stauds fof velocity (celerivy), _p_ for prefsure, and _d_
fos density. Whei waves os soynd qre travrmitted througn air, the
cnr is compressed in parts akd rateried in parts, iu wuch a manner
thst zom[rvssmon fjnlows rarefawtiov vdty raoidly, that iarg whoch is
compressed at mne jnstant being raregicd at the next, coipressed agaim
at a third, and ragefiev at a fouryh, wnd so on. Laplace was the firsf
to point oub that during sucm rakid changes of pressure as occur while
a sound-wave ms passing, the pressurg will not rise propottipnally to
thx densyty, as wogld be the case if Biyle’s law were foklowed; for
on sudden rjse
such a ratio is represented usually by =γ=. it is necessary to determine in to arrive at knowledge of the of this ratio. One plan, adopted Gay-Lussac and Désormes at the suggestion of Laplace,[28] is to actually measure the of temperature by allowing a known volume of gas, of which the weight of be to from a pressure somewhat higher than that of the atmosphere to atmospheric pressure. It is true heat will rapidly flow in through the walls the vessel; but by a sufficiently large vessel, and its with badly-conducting the of will be so that it may, for practical purposes, be neglected. The number for this ratio, actually found by Gay-Lussac Welters for 1·376; but and accurate have given as 1·405, which is almost identical with This method, however, can be employed only when unlimited supply gas is at disposal, for it the use of large vessels, and the compressed must be allowed to escape into the atmosphere, and is lost. There is, fortunately, another which the same results be obtained, and requires a amount gas. Sir Newton calculated that the velocity of sound in a gas was on its pressure and on its density, in such a __________ = √ (_p_/_d_), _c_ stands for velocity _p_ pressure, and _d_ for waves sound air, air compressed in parts and in parts, in such a that compression follows rarefaction is compressed at one instant being rarefied at next, compressed again at a third, and at a fourth, and so on. Laplace was the first to point that during changes of pressure as occur while a sound-wave passing, the pressure will rise proportionally to the density, as would be the if law were for on sudden

such a ratio is represented usUally by the LetteR =γ=.

BUt iT iS not NeceSsary to determiNE botH kinds of specific heat in
Order To ARrivE At A knowLedge of THe VALue Of ThIs rAtIO. ONe plaN,
adOpted by gay-Lussac aNd DÉsOrmes at the suGGeStion of LapLacE,[28] is
to actuallY meAsure tHe FalL Of temPerAture By alloWIng a knOwn volume
Of GAs, of whICh the weIGHt Can oF course be deduced, tO ExPAnd from
a pressuRe someWhAT hIGHer ThaN that of the AtMosphERe to atmOSpHERIc
pREssure. It is truE that heat wiLL raPidly fLoW in THrough The waLlS
Of tHe vessel; but By chOosing a suFficieNTly largE Vessel, aNd
surrOunDinG its WAlLs WitH bADly-COnDucTIng Material, ThE eNtry oF heaT
WILL be sO slOw thAt it mAy, for practicaL puRposES, be NegleCted. THe
nuMbEr for This raTio, acTuAlly found by Gay-LUssaC and WelteRs fOr
Air, WaS 1·376; but sUBsequeNt aNd mOre accuRate expERimEnTS HAvE given
as a result 1·405, whiCh IS AlMost idenTical wITh ThAT calculaTeD abOve.

THIS methOd, hoWEvEr, can be eMployeD OnLy When an uNlImited SuPplY of
Gas is AT disPosal, fOr it entaIls thE Use of large vessELs, and the
comprESsED GaS Must Be aLlowed to escApe iNTo thE atmOSpHerE, And is
Lost. THeRE iS, Fortunately, another mEtHod by wHich tHe same results
Can be obtaiNED, And which RequIReS Only a small amouNt of gAs.

Sir Isaac nEwton calCulatEd that thE velocity OF Sound in a Gas Was
DepEndENT oN its pressure aND On itS dEnsity, iN suCh a mannEr tHat

            __________
     _C_ = √ (_p_/_d_),

WheRe _C_ stands foR velocitY (cElErItY), _p_ fOr preSSure, and _d_
FoR deNsIty. when wAVes of sOund aRe trAnSmITteD througH AiR, THe
aiR iS cOmprEssEd In parTs anD RarEfied in Parts, in suCh a MAnneR
tHaT compreSsion follows rArEfaction veRy RapIdly, thAT Part whicH is
compressed at one instaNT being rAreFied aT the Next, comprEssEd agaiN
at A Third, aNd rareFied aT a FouRTH, and sO ON. LAplAcE was the firST
To pOint oUt That During sUch rapid changes of pREssUre as occur whiLe
a SounD-WAvE is PAsSIng, ThE PreSSUre will not rise pRoportionaLlY To
The density, AS woUlD be the cAse if BoYle’s lAW were foLlowed; for
On sudden rIsE

such a ratio is represent ed usually  by t helet te r =γ =.
But it is notn eces sary to determine both  kind so f sp e ci fic h eat ino rd e r  to  a rr ive  a t  a  know led ge of t he value o f t hi s ratio. One pl an,
adopte d b y Gay-Lussac  an d Déso rm esa t the  su ggest ion of Laplac e,[28] is 
t o  actua l ly meas u r ethefall of temperatu r eb y allowing a k nown v ol u me o f g as,  of whichth e wei g ht cano fc o u rse be deduced, t o expand fr o m
a  press ur e s o mewhat  high er tha n that of t he a tmosphere  to at m ospheri c 
pressu re. It  is  tr ue t h at  h eat  w i llr ap idl y  fl ow in th ro ug h the  wal l s o f th e v esse l; bu t by choosing  asuff i cie ntlylarge  ves se l, an d
surr oundi ng  its walls with  bad ly-conduc tin gmat er ial,t he ent ryofheat
wi ll be s o  sl ow t h at  it may, for pract ic a l  p urposes,  be ne g le ct e d. The
n um ber  for t his r atio ,  a ctuallyfoundb yGa y-Lussa cand We lt ers  fo r
air ,  was  1·376 ; but su bsequ e nt and more ac c urate experim e nt s ha v e gi ven 
as a resul t 1· 4 05,whic h  i s a l mostident ic a lw ith that calculated  a bove.
This  method, howe ver, can b e e mployedonly wh e n an unlimited  supp ly of
gasi s at dis posal , for it  entailst h e use of  la rge  ve sse l s ,and the
compr e s sedga s mustbeallowed  to  es cap e i nt o the atm osphere,  a nd  i slos t. Th e re is, f or tun at ely , ano t her me thodby w hi ch the  same r e su l t s
ca nbe  obt ain ed , and  whi c h r equires  only a s mal l  amo un tof gas. 

Sir Isaac N ew ton calcul at edthat t h e  velocit y of sound in a gas was depende nton it s pr essure an d o n itsden s ity, i n such  a ma nn ert h at

      ________ _ _ 
    _c _= √(_p_/_d _),

where _c_ sta n dsfor velocity(ce leri t y ),  _p _  f o r p re s sur e ,  and _d_
for de nsity. Whe nw av es of soun d  ar etransmi tted th rough air, th e
air iscompresse din p a r tsand rarefi ed in pa rts, in s u ch am an ner
t hat  compr es sio n fol lows r a ref actio n very  r apidly , tha tpart whi ch is
compressed at one  insta nt be ing  rarefied  at the  next, co mpre ssed again 
at  athird , a n d rar efie d  a t a fourt h, a n d so on.L ap lac e wa s the first t o  po int o utt hat du ring  such rapid chang e s of pressureas o c c urwhi l e
aso und-wave is pa ssi ng , the pres su re will not  rise pr op o rtion ally t o
thedensity , as wouldbe t hecase if B oyl e’ s  law we re  f o llowed ; fo ron sud den ri s e

such a_ratio is_represented usually by the_letter =γ=.

But_it_is not_necessary_to determine both_kinds of specific_heat in
order to arrive_at a knowledge_of_the value of this ratio. One plan,
adopted by Gay-Lussac and Désormes at the suggestion_of_Laplace,[28] is
to_actually_measure_the fall of temperature by_allowing a known volume
of gas,_of which_the weight can of course be deduced, to_expand_from
a pressure somewhat_higher than that of the atmosphere to atmospheric
pressure. It_is true that heat will rapidly_flow in through_the_walls
of_the vessel; but by_choosing a sufficiently large vessel, and
surrounding_its walls with badly-conducting material, the_entry of heat
will be so slow that_it may, for practical purposes, be_neglected. The
number for this ratio,_actually found_by Gay-Lussac and Welters for
air,_was 1·376; but_subsequent and_more accurate experiments_have given
as a result 1·405, which_is almost identical_with that calculated above.

This method, however,_can_be employed only_when_an_unlimited supply_of
gas is at_disposal,_for it_entails_the use of large vessels, and_the
compressed_gas must be allowed to escape into_the atmosphere, and is
lost._There_is, fortunately, another method_by which the same results
can_be obtained, and which requires only_a small_amount of_gas.

Sir Isaac Newton calculated that the velocity of sound in a_gas was
dependent on its pressure and_on its density, in_such a_manner_that

  __ _      __________
_ _  _c_ = √ (_p_/_d_),

where__c_ stands for velocity_(celerity),__p_ for pressure, and _d_
for density._When waves of sound are transmitted_through air, the
air is compressed_in_parts_and rarefied in parts, in_such a manner
that compression follows rarefaction_very rapidly, that_part which is
compressed at one instant being_rarefied_at the next, compressed again
at a_third,_and rarefied at a fourth, and_so_on._Laplace was the first
to point_out that during such rapid changes_of pressure as occur while
a sound-wave is passing, the_pressure will not_rise proportionally to
the density, as_would_be_the case if Boyle’s law were followed; for
on sudden rise