( 553 ) 



1 -f 0.1 :Wr,,/,- -":.Ia'+ ÖA- 



'^pK i"e])i-(^S(Mils \\\o (•()('r(ici(Mil of prcssiii-c-x.iriatioii of llie niixtiire 

 (the mean (■(leClicicni lictwccii 20' .ind / . jf iIk. di-iiiiiial pressure (iit 

 20 C.) is I alm. l-'rdiii llicsc iwo i-('lali()ii> J/^ i";iv he dei-ived ; it 

 niust Ite reiiiari<('(l ilial now an error in ^f^,^ pa.sses o\er diiuinislied 

 ink) the rcsnll. \\\ means of ili: J/v'.,,, may he dei-ixed from .1^ . 



So I found f<n- llic mixlure under considei-alioii : 



for 2<»'M:^ ('. : Ak — l.<»(>HO()*t . />'/,- = — 0.008521. 



Fni-llier I aec(>|iied for «^,a': 0.003445, found Im' linear inlerpolalion 

 accordiiiii- lo ,/• Ix^lween llie value O.00o454 for eai'lion dio.xide dciixcd 

 from CiiAi'rris' data, and the vahie 0.001)42!^ for oxyiien derixed 

 from JoiJ.v's data, ll then follows that . lyv.,, = 1 "03524. 



'ÏU(^ dilferent values thns found are eond)iiied in Table XIll. 



Ï xl B L E XIII. 



^Jr.„ 



Weight. 



For o.xygen Aa..^^ is derived from ilie data for .lj.,^^ajid /Jj.,^ given 

 on p. 54U. 

 I have put : 



and lia\e ealeulatcd llic coefficients l»y means of llie niel hod of least 

 s(juares. Theiv ./• as c(unpared witji ,,Ia.,„ - ^ iiia\ he considei'ed as 

 [>erfectl\ accui-alely known. I found: 



„.^ — 0.00570 

 <A„, — 0.00142 

 a, = 0.000(35. 



In tahle XI\' (p. 554) the values ^'(leri\ed from them are com- 

 pared with the \alues derixed directly fr(mi ohserxalion (f. 



In order to dei-ixc the coeflicients J i^^ from llie coeflicienis . 1 a.,„ 

 an aecuiale k no xx ledge of the co(>li(icient of [u-essure-x ariation is 

 reipiired. In a folloxxing j)aper, hoxvevei . \xill he des<'riheil hoxv the 

 coefficients Ai^„^ may be used to derix e from the volume of a gas 



