( 191 ) 



u'.o doubt, and that is, that according to thfi results obtained by 

 me formerly (Yerslag Kon. Akad. 27 Nov. 1897) «, + t»» — 2 «,, 



would be negative for CO, and CH^ CI or o,, /* ~ , and this 



would require a greater value for a,., than would be found from 



Mr. Küe>'En"s values for — Ap. In order that a,„ >^ should 



hold good, e.g. at rr=343°, o,, would have to be greater than 

 0.00126, while from the calculation of — A^, a,, is found to be 

 at the utmost 0,0116. That from Mr. Kuenen's observations 



«,5 <. -Ï ^ follows, is confirmed by the observation, that mixing 



of CO, and CH, CI gives increase of volume. 



If this is really the case, it would prove that I ought to have 

 expressed myself with still greater reserve than I did in my: "Ap- 

 proximative rule for the course of the plait-curve of a mixture" ^). 

 Though I have drawn the attention to the fact, that the real plait- 

 curve will deviate from the curves drawn, jet I had thought, that 

 the deviations would not be so great, as to make the different types 

 no longer to be distinguished. Yet so great a deviation really 

 occurred in this case. 



If we look back on the two rules discussed here : A» = and 

 A,) ^ 0, we are induced to qualify the first rule as an approximative 

 law. Throughout the course of the isotherme, from an infinite volume 

 down to the smallest possible volume of the substance, there may 

 be deviation, but the deviation remains within finite limits. The 

 second rule holds perfectly good for infinite rarefaction, but it 

 would be utterly impossible to apply it also to liquid volumes. 

 Such a law may be qualified as a loi-limite. Considered from this 

 point of view, the law of Boyle too is not an approximative law, 

 but only a loi-limite. 



Chemistry. — Prof, tax Bemmelen reads a paper of Dr. F. A. 

 H. SCHKEINEMAKERS On : ^Equilibriums in systems of three 

 components. Change of the mixing-temperature of hinary mix- 

 tures by the addition of a third component." 



Among the different systems composed of the components A^ B 

 and C we suppose the case, that iu two of the binary systems f.i, 

 A — B and A—C two liquid phases can appear, but not in the system 

 Ji—C. An example of this we find f.i. in the system formed of: 



1) Verslag ton. Akad. Nov. ib97. 



