( 566 ) 



2"'\ (lifliciiltios lijid tirisc'ii iiboiit some (|u;uiti1ies at thecrilical point 

 üf ciirboii dioxide, wiiich are iinportant tor the theorv ot' the mix- 

 tures. AiMACiAT, foi' instance, liad (k'tei'niined the critical ])i'essni'e at 

 72.1) atni., wiiile \'krs{iiaffklt IVoni AmactAt's isothernials derived 

 73.6 atni. ^). Ohxioiislv tliis may uive rise lo an eri-or in the deter- 

 mination of tlie data of the critical point of the mixtnres, if as in 

 Comm. N". 55) ") lh(> louai-ilhniical systems of isothei'mals are shifted 

 o^'er each other. Moreoxer in Comm. N". 75, I^-oc. Dec. 11)(M p. 291), 



A).T^ . , 



for at the crilical point trom A.MA(iAT s isttthermals : t .A 



had heen deri\'ed; from his dcterminalions of the satni-ated \aponr 

 pressnres : 6.5. This points to an nncertainty in the detei'minalion 

 of tlie ci'ilical \(»lnme. A>iA(iAT has determined the critical ]ioint 

 and the vapour pi-essnres in dilferenl a[>pai'atns and hence ])rol)ably 

 also with other carhoii dioxide than the isothermals; hy detei"minin,U' 

 the two in the same tid»e \\ ith the sam(! carhoii dioxide 1 hoped to 

 arrix'e at more certainty on these points. 



',V''^ . 1)\ comparinu' the isothernials of the mixtiii'es after IvWKAu's 

 method with isothermais of carbon dioxide obserxed in the same 

 experimental tube some systematical ei'rors which miii'ht occnr in the 

 obserxalions are eliminated from the determnialion of the critical 

 data of the nnxtni'es. In this way an error iji the determination 

 of the diametei' of the Lii'adiiated stem of the ex})erimental lube 

 xx'onid liaxc no iidliieiice on the critical pi'essm-e and Lem|)eratnre of 

 the mixture. 



§ 2. In the following' tables /' is the volnme expi-essed in terms of 

 the thi'oi-etical normal xctbinic, /> the pressure in atmospheres (0"'(!., 

 45^ Korthern latitude), i'i,;j the \<diime of the li(piid. The points of 

 the beuinninii' and the end of the condeiisation are marked l)y the 

 letters /u- and I'c I'^or ihc point />c we adopted the point where 

 after havinu' decreased the xolnme there appeared for the tirst time 

 with proper slii-rinu' a li(|nid "Schlier" o]i the wall, oi' after hax'ina' 

 increased the x'oluiiic with [trojH'r slirrini;' only such "Schlier" 

 reinaine(l. These two |)oiiits a.ureed snfticienlly. 'J'he point re conid 

 be obserxcd sharply, a^ with a small ^•ariation of the; \-olnme the 

 last jiart of the phase disappeai-ed or reap|)eai'e(|. Especially here, 

 howcxcr, phenomena of retardation had to be ax'oided Iw foi'cible 

 stirriiiLi'. 1 //,a' stands for the theoi-etical normal \()liim(\ the meaning" 

 of .1a'.,„ ifi explained in the 2'"' part of this t'(unm., p. 552. 



1) Clomp. Comm. X". .■).'). I'luc. Apiil I'.KIO. 

 i) I'roc. Sept. T.lUO. 



