( li9 ) 



It will be seen (lial (lie figures I .uul 2 of (he plate belonging to 

 the lli's( paper (Conini. 8J) refei- (o points situated in the part on the 

 right of (he ^-axis of the fields 1 and 2 ; (igs. 3 and 4 to the same 

 fields on the left of the /?-axis; figs. 5 and 6 to the fields 7, 8 and 

 9; figs. 7 and 8 (o the part of the fields 3, 4 and 5 lying on the 

 right of the /3-axis; figs. 9 and 10 to the same fields on the left of 

 the /5-axis; and lastly figs. 11 and 12 to field 6. 



In the figure I ha\^e marked three points P, Q and 7^, of \vhicli 

 the first relates to carbon dioxide wilh a small quantify of hydrogen 

 (« = — 1,17, i^ = — 1.62), the second to carbon dioxide with a 

 small quantity of niethyl chloride (« = 0,378, /?== 0,088) and 

 the third to methylchloride with a small quantity of carbon dioxide 

 (« = — 0,221, /? = 0,281). From the situation of F, viz. in field 2, 

 it should follow that Tx^d'^ Tk, whereas the observations showed 

 that Tr„[<^ Tk; this deviation has been pointed out before. ^) More- 

 o\ev the situation of F in field 2 points to a system of isothermals 

 of the mixtures as represented in figs. 1 and 2 of the first paper, 

 while in reality this system of isothermals corresponds to figs. 5 and 6, 

 that is to sa}^ to one of the fields 7, 8 or 9. The point F lies very 

 near the limit of field 9, and hence it is possible that a more accurate 

 determination of a and /? would remove the point Pinto field 9 where 

 indeed it should lie according to the plait point constants observed 

 and the character of this field, if at least the law of corres})onding 

 states can be applied. The points Q and R, so far as we know with 

 certainty, are situated in the right field. '') 



The straight line (5 = p,,i" agrees with Kortkweg's second boun- 

 dary. It is determined by the circumstance that along the couuo- 



dal line f— ) =0; we find from the formulae (37), (41) and (26) that : 



f,lv\ 

 so that — becomes zero with ///,,. Tims al)Ove the straight line ^Aa 



is positive, below it, negati\e, hence in comiection n\ i(h (ne 



') Gomp. 2nd paper, p. 334. 



-) It must be remarked that the deviation of the point Q in consequence of our 

 insufficient knowledge of a and /3 would be much less striking than in the case of 

 point P; e. g. whether Q ought to be placed in the neigiibouring field 4 or not, 

 could ))e only conc-luded fiom the sign of ?•.,/</— r/.-, l)ut we do nut know willi certainty 

 what this sign should lie fur mixtures of carl)on dioxide and mt'lhylcbjoi-ide. 



