 the fact
that when the globe was empty of air, its capacity was somewhat
reduced, owing to the external pressure of the atmosphere.

It was next deemed necessary to test whether nitrogen was homogeneous
by preparing it too by several different methods. In the same paper
Lord Rayleigh (p. 146) mentions that nitrogen, prepared from ammonia,
its compound with hydrogen, is somewhat lighter than “atmospheric
nitrogen,” the deficiency in weight amounting to about 1 part in 200.
Now it is evident from inspection of the numbers quoted above, that
the accuracy of the density determination may be trusted to within
1 part in 10,000, and that the balance would detect a discrepancy
one-fiftieth of that observed in the densities of “atmospheric” and
“chemical” nitrogen. In a letter to _Nature_, Lord Rayleigh asked for
suggestions from chemists as to the reason of this curious anomaly, but
his letter went without reply. He himself was inclined to believe that
the difference was due to the decomposition of some of the ordinary
molecules of nitrogen, usually believed to consist of two atoms in
union with each other, into molecules consisting of one atom; and as it
is held that equal numbers of molecules inhabit the same volume,
temperature and pressure being equal, if the total number of molecules
in his globe were increased by the splitting of some double-atom
molecules into single-atom molecules, the effect would be that, owing
to an admixture of some lighter molecules, the density would be
somewhat reduced.

But two other suppositions were entertained as possible. The oxygen
might have been imperfectly removed from the nitrogen derived from the
atmosphere; or, on the other hand, the nitrogen from ammonia might
conceivably have retained traces of hydrogen. In the former case, the
nitrogen would have an increased weight owing to admixture of some
heavier oxygen; in the latter, a diminished weight, due to the presence
of the lighter hydrogen. The first of these suppositions is out of
the question, inasmuch as it would have required that the nitrogen
should contain one-thirtieth of its volume of oxygen, or one-sixth of
that present in air, in order that its density should be raised by one
two-hundredth; for the densities of oxygen and nitrogen are not so very
different. The
the fact 
 that when the globe was empty of air, its capacity was somewhat 
 decreased, owe to the external pressure of the atmosphere. 

 It was next deem necessary to test whether nitrogen was homogeneous 
 by train it too by several unlike method acting. In the same composition 
 Lord Rayleigh (p. 146) mentions that nitrogen, prepared from ammonia water, 
 its compound with hydrogen, is somewhat lighter than “ atmospheric 
 nitrogen, ” the deficiency in weight come to about 1 part in 200. 
 Now it is evident from inspection of the numbers quote above, that 
 the accuracy of the density determination may be trusted to within 
 1 share in 10,000, and that the balance would detect a discrepancy 
 one - fiftieth of that observed in the densities of “ atmospheric ” and 
 “ chemical ” nitrogen. In a letter to _ Nature _, Lord Rayleigh asked for 
 suggestion from chemists as to the reason of this curious anomaly, but 
 his letter went without reply. He himself was inclined to think that 
 the difference was due to the decomposition of some of the ordinary 
 molecules of nitrogen, usually believe to dwell of two atoms in 
 union with each other, into molecules consisting of one atom; and as it 
 is held that equal numbers pool of molecule inhabit the like bulk, 
 temperature and atmospheric pressure being equal, if the total number of molecules 
 in his globe were increased by the splitting of some double - atom 
 molecule into single - atom molecules, the effect would be that, owing 
 to an admixture of some lighter atom, the density would be 
 somewhat reduced. 

 But two other supposition were entertained as potential. The oxygen 
 might have been imperfectly murder from the nitrogen derived from the 
 atmosphere; or, on the other hand, the nitrogen from ammonia might 
 conceivably have retain traces of hydrogen. In the former case, the 
 nitrogen would take an increased weight owing to admixture of some 
 heavy oxygen; in the latter, a belittled weight, due to the presence 
 of the easy hydrogen. The first of these guess is out of 
 the question, inasmuch as it would have necessitate that the nitrogen 
 should contain one - thirtieth of its book of oxygen, or one - sixth of 
 that present in air, in order that its density should be raised by one 
 two - hundredth; for the concentration of oxygen and nitrogen are not so very 
 different. The
 thf fact
that when the globt was empty of ait, uts ca'acity sas somedhat
reduced, owing to the extxrnao prewsure of the atmospherd.

It was nvxt deemee neressary to test xgether kntrogsk was iomogeneous
by pteparing it doo by several dkfyerent methods. In the same paper
Lord Rayleibh (p. 146) mentions trat mytrofvn, prepared from ammonia,
its comlound wpth hydrogen, is spmewhat lighter than “atmosoherlc
nitrogen,” the deflciency in qeigrr amounting go about 1 kaxt in 200.
Now ij is evident from inspection of ghe nbmbers quotgb ablee, that
the eccuraby of the density detarminatoon may be truxtev to within
1 part in 10,000, and vhat the balance woujd detect a discrepancy
one-fidtueth mf tvat uvsefves mn fhe dejsivies of “atmkspheric” ane
“chemical” nitrogen. On q letter to _Nzture_, Jowd Rayleigh asked for
suggestions from cvemjsts as to the reason od this curious anomali, but
his lqtter went without reply. He himself was inclined do bemkevt bmat
tfw fifference was due to the decomposition of sois pf the ordinary
mjlecules of nlttjgen, usually celievzs fo consist of two wtoms ig
uniob with eash oyher, into molecules consistung of one anom; qnd as it
is held tkat equal nuoberx of kolecules inhabit the scme vomume,
temperahure and lfessure being eqjal, ix the touxl number of molesules
in hms glpbe werd invreaseq by the solittltg of some double-ahom
mopewules into single-atom molecules, the effecv would be thst, owpng
to an cdmixtmre of some ligrter molecules, the deusity dould be
sojewhat ceduced.

But tro other suppmditions were entertayned as possibld. The oxygen
mignt have bveu imperfextly removed from bhe nkfrogen derived yxon the
atmosphere; or, on tje oever hand, the nitfogdm froo ammonia mlghg
conveivably have retainad tdaces of hydrogen. On the forner case, the
nitrogen eould have an incrtased xeight owinb tj admixture of some
heavier oxyfen; in thf lwtter, a dimigishcd wgight, due tp the presence
of the lighter hydrogen. Tie first of these suppowitions is out of
thg qmestion, inaskuch ws it wound have required thar the nitrogen
shomld contain one-thirtiefh of hts vllume of oxygen, or one-sixth of
that present in air, in order that its densiry shonlq be raised by pne
twm-hbndxedth; fjr tie densities of oxjgen and nitrogen are not so verb
different. Tke
the fact that when the globe was air, capacity was reduced, owing to atmosphere. was next deemed to test whether was homogeneous by preparing it too several different methods. In the same paper Lord Rayleigh (p. 146) mentions that prepared from ammonia, its compound with hydrogen, is somewhat lighter than “atmospheric nitrogen,” deficiency weight to 1 part in 200. Now it is evident from inspection of the numbers quoted above, that accuracy of the density determination may be trusted within 1 part in and that the balance would a one-fiftieth of observed the of “atmospheric” and nitrogen. In a letter to _Nature_, Lord Rayleigh asked for suggestions from chemists as to the reason this curious his letter without He was inclined to the difference was due to the of the ordinary molecules of nitrogen, usually believed consist of atoms in union with each other, molecules consisting of one atom; and as it held that equal numbers of molecules inhabit the same volume, temperature and pressure being equal, total number of molecules his globe were by splitting some molecules into molecules, the effect would be that, owing to an admixture of lighter molecules, the density would be somewhat reduced. But two were as possible. The might have been imperfectly from nitrogen derived from the on other from might have retained traces of In the former case, the would have an increased some heavier oxygen; in the latter, a diminished due to the presence of the lighter The first of these suppositions is out of the question, inasmuch as would have the nitrogen should contain one-thirtieth of its volume oxygen, or one-sixth of present in air, in order that its density should raised one two-hundredth; the densities of and nitrogen are so very different.
 the fact
that when the globe waS empty of aiR, its cApaCitY wAs soMewhAt
reduced, owing TO the External pressure of the aTmospHeRE.

It wAS nExt deEmed necESsARY to TeSt WheThER nItrogEn wAs homogEneous
by prEpaRiNg it too by sevERaL different MetHods. In the samE paPer
LorD RAylEIgh (p. 146) mEntIons tHat nitROgen, prEpared froM aMMonia,
iTS compouND WiTh hyDrogen, is somewhat lIGhTEr than “atmospheRic
nitRoGEn,” THE deFicIency in weiGhT amouNTing to aBOuT 1 PARt iN 200.
now it is evidenT from inspecTIon Of the nUmBerS Quoted Above, ThAT
thE accuracy of The dEnsity detErminaTIon may bE Trusted To withIn
1 pArt In 10,000, anD ThAt The BaLAncE WoUld DEteCt a discrEpAnCy
one-FiftIETH Of thAt oBserVed in The densities oF “atMospHEriC” and
“cHemicAl” niTrOgen. IN a lettEr to _NAtUre_, Lord Rayleigh AskeD for
suggeStiOnS frOm ChemiSTs as to The ReaSon of thIs curioUS anOmALY, BuT
his letter went withOuT REpLy. He himsElf was INcLiNEd to beliEvE thAt
thE DIfferEnce WAs Due to the DecompOSiTiOn of somE oF the orDiNarY
moLeculES of nItrogeN, usually BelieVEd to consist of tWO atoms in
union WItH EAcH OtheR, inTo molecules ConsIStinG of oNE aTom; ANd as iT
is heLd THaT Equal numbers of molecUlEs inhaBit thE same volume,
teMperature aND PRessure bEing EQuAL, if the total numBer of Molecules
iN His globe Were iNcreased By the spliTTIng of somE doUblE-atOm
mOLEcUles into singlE-ATom mOlEcules, tHe eFfect woUld Be tHat, OwiNg
To an admixTure of soMe LiGhTeR moLeculES, the densItY woUlD be
SomewHAt reduCed.

BuT two OtHeR SupPositioNS wERE entErTaIned As pOsSible. the oXYgeN
might hAve been imPerFEctlY rEmOved froM the nitrogen dErIved from thE
aTmoSphere; OR, On the othEr hand, the nitrogen from amMOnia migHt
cOnceiVablY have retaIneD traceS of HYdrogeN. In the FormeR cAse, THE
nitrOGEn WouLd Have an incrEASed WeighT oWing To admixTure of some
heavier oXYgeN; in the latter, a DimInisHED wEigHT, dUE to ThE PreSENce
of the lighter Hydrogen. ThE fIRsT of these suPPosItIons is oUt of
the QuestIOn, inasmUch as it woUld have reQuIred THAt tHe nitrogen
Should coNtain one-tHIrtieTH oF its vOluMe of oxYgEn, oR one-sIxth of
THat PreseNt in aiR, iN order That iTs Density sHould be raised by one
two-huNdredtH; for tHe dEnsities oF oxYGen And nitrogEn arE not so very
DifFerEnt. ThE
 the fact
that when the gl obe was em pty o f a ir,  i ts c apac ity was somewh a t
re duced, owing to the ex terna lp ress u re  of t he atmo s ph e r e.
I twas  n e xt  deem ednecessa ry to test  wh et her nitrogen wa s homogene ous 
by preparin g i t tooby  se v eraldif feren t meth o ds. In  the same  p a per
Lo r d Rayle i g h(p.146) mentions tha t  n i trogen, prepar ed fro ma mm o n ia, 
it s compound  w ith h y drogen, is s o mew h at lighter th an “atmosph e ric 
nitro ge n,” the de ficie nc y  in  weight amo unti ng to abo ut 1 p a rt in 2 0 0.
Nowit isevi den t fr o min spe ct i ono fthe num bers quo te dabove , th a t t he a ccu racy  of t he density de ter mina t ion  maybe tr uste dto wi thin
1  part  i n 10,000, and t hatthe balan cewo uld  d etect a disc rep anc y
one-f iftieth ofth a t ob served in the dens it i e sof “atmo spheri c ”an d 
“chemic al ” n itro g e n. In  a l e tt er to _N ature_ ,  L or d Rayle ig h aske dfor 
su ggest i onsfrom c hemistsas to the reason oft his curious a n om a l y, buthis  letter wen t wi t hout  rep l y.  He himse lf wa si nc l ined to believe tha tthe di ffere nce was due t o the deco m p o sition o f so m eo f the ordinary 
mole cules of n i trogen,usual ly belie ved to co n s ist of t woato msinu n io n with each o t h er,in to mole cul es cons ist ing  of  on eatom; and  as it
i she ld  t hat  equa l  numbers  o f m ol ecu les i n habitthe s amevo lu m e,tempera t ur e andpr es sure  be in g equ al,i f t he tota l numberofm olec ul es 
in his  globe were i nc reased byth e s plitti n g  of some  double-atom
moleculesi nto sin gle -atom  mol ecules, t heeffect  wo u ld bethat,owing 
t o a n admix t u re  of  s ome lighte r mol ecule s,  the  densit y would be
somewha t  re duced.

But t woothe r su ppo s it i ons  w e ree n tertained as po ssible. Th eo xy gen
mighth ave  b een imp erfectl y rem o ved fro m the nit rogen der iv ed f r o m t he
atmosph ere; or,  on the o t her h a nd , the  ni trogen  f rom  ammo nia mi g htconce ivably  h ave re taine dtraces o f hydrogen. In the form er cas e, th e
n itrogen w oul d  ha ve an inc reas ed weightowi ngto ad mix t ure o f so m ehea v ier o xyge n ; in thel at ter , adiminishedw e i ght , due  to the pr esen ce
of the lighter hydrogen. Thefirs t ofthe s e su pp ositions is ou t o ft h e questi on , inasmuchas it wo ul d  have  requi red th at then i tr o gen
sh ould  co ntain one -th ir t ieth of  i ts volume  ofox ygen,or one - sixt h of
that presentin ai r ,  in o r der  that  i ts dens i ty s hould be r aised by on e
two- hund redth ; for t he  densi tie sof oxygena nd nitrog en ar e not s overy 
di fferen t. T h e 
 the_fact
that when_the globe was empty_of air,_its_capacity was_somewhat
reduced,_owing to the_external pressure of_the atmosphere.

It was next_deemed necessary to_test_whether nitrogen was homogeneous
by preparing it too by several different methods. In the same_paper
Lord_Rayleigh (p._146)_mentions_that nitrogen, prepared from ammonia,
its_compound with hydrogen, is somewhat_lighter than_“atmospheric
nitrogen,” the deficiency in weight amounting to about_1_part in 200.
Now_it is evident from inspection of the numbers quoted_above, that
the accuracy of the density_determination may be_trusted_to_within
1 part in 10,000,_and that the balance would detect_a discrepancy
one-fiftieth of that observed in_the densities of “atmospheric” and
“chemical” nitrogen. In_a letter to _Nature_, Lord Rayleigh_asked for
suggestions from chemists as_to the_reason of this curious anomaly,_but
his letter went_without reply._He himself was_inclined to believe that
the difference was_due to the_decomposition of some of the ordinary
molecules_of_nitrogen, usually believed_to_consist_of two_atoms in
union with_each_other, into_molecules_consisting of one atom; and as_it
is_held that equal numbers of molecules inhabit_the same volume,
temperature and_pressure_being equal, if the_total number of molecules
in his_globe were increased by the splitting_of some_double-atom
molecules into_single-atom molecules, the effect would be that, owing
to an admixture of_some lighter molecules, the density would_be
somewhat reduced.

But two other_suppositions were_entertained_as possible. The_oxygen
might_have been_imperfectly removed from the nitrogen derived from_the
atmosphere; or,_on the other hand, the nitrogen_from ammonia might
conceivably have_retained_traces of hydrogen. In the former_case, the
nitrogen would have an increased_weight owing to admixture of_some
heavier_oxygen;_in the latter, a diminished_weight, due to the presence
of the_lighter hydrogen. The_first of these suppositions is out of
the_question,_inasmuch as it would have required_that_the nitrogen
should contain one-thirtieth of its_volume_of_oxygen, or one-sixth of
that present_in air, in order that its_density should be raised by one
two-hundredth; for the densities_of oxygen and_nitrogen are not so very
different._The