( 28(5 ) 



the uiixtiircs of" cai-lion dioxide and iiuMlivl cldoi'idc aCfoi'd for luoa- 

 sureincnty on eillicr side of llic ciilical slate, (reason wliv in ahont 

 1890 it was elioscn for I lie lirsl iiivesliualions of the i|'-siii'Jace) a 

 considerable portion i-ound I lie critical state lias Ixmmi immediately 

 investi,i>aled l>y Kiknkn (('(tmm. \". 4, Api-il '1>'2). II ak'TM w in ( 'omm. 

 N". 43, .Inne '1)H lias added to this ai-ca lliat of llic (•(►e,\istin<»- phases 

 at 9". 5 (\ We have extended the ai-ea invest iualiM I in two dircM'tions. 

 albeit only by a few preliminai-y reseairhes. 



The results of some of those measurements, ihouiih a few are 

 only preliminary and serxcd chielly as a means for us to decide 

 upon the method of invest iiiatiitn, seem im|)()rtant enoiiiih now that 

 still so little is known about the dilïerent de,ure(>s of a])|)ro.\imatioii 

 to A\hich the law of correspond iiii»' states hohls for nii.\lni-es in difïb- 



T 



rent fields of rediu'cd state M-' = . t = 



V '7,- I L- 



Our measurements refer in the lirsl place to <>aseons mixtures 

 nndei' almost normal condilions, in ihe second ])lace to coexisting 

 phases at low lemperaliires. 



For the normal gaseous |»hase we found llic^ law of corresponding 

 states to be confirmed to a high degr(H' of ap|troximation. The virial 

 coenicient />. which delermines the dexiation of mixture- of methyl 

 chloride and carbon dioxide froni Hovlks law at small densities, can 

 be snfliciently dei-i\(Ml by means of the law of corresponding states. 



(irreatei' de\iatious wei-e found when we investigated the coexisting 

 phases at low 1em|)eratnre. Ilei'c we have determined by means of the 

 dew-poini apparatus, described in the lirsl pari of this comnumicatio]!, 

 the begin condeiisalion pressure of the mixture,/' =ri \.'.^ at — 25" C: the 

 temperature for which we ha\"e constructed the j|'-sui'face in Sup])l. 

 X". (S, Sept. "04. The deviations found ai'e ratlicr great, they poijit 

 to an increase of the deviations tVoin the law of corresponding states 

 in the mi\tui-es at low tempei'atures in the li(piid state. The deter- 

 mination of the end condensation pressure for the same mixture .c = '/.^ 

 at — 25''(*. with the pi(v,ometei- of the tirst |tart of this communication 

 would in\()l\e com[)licalions (comp. ibid. § 5). in order to obtain an 

 idea of the deviations of the licpiid bi-anch of the Imiodal curve at ,t' = ^ j^ 

 from that according to the law of corresi)onding states, we have 

 investigated the condensation pressure for ,r = ^/.^ at a lowei' tem- 

 perature, viz. — 38^.5 ('. This corroborated the result of the investi- 

 gation of the \apour phase at — 25^ C 



I . The coiiiprcss/ht///// in the ih'Kjhhoin-luxH] of tlh: iiornnil stntc. 

 § 2. iJcli'rni/i/nfioi) of the si'coiul rir'nil cocfficii'iit. The mixtures 



