Nl 
( 639 ) 
Excepting the value of 7 for the concentration 1.1077 gr. mol., 
which is very probably too small on account of an experimental 
error, we also notice here a perciptible increase of ¢ with increasing 
concentration. 
LANDSBERGER says regarding the results: 
„Die angeführten Zahlen für Natriumchlorid lehren, das die Disso- 
ziation in wässeriger Lösung mit steigender Konzentration fortschreitet.” 
Although this conclusion seems to me to be erroneous I have 
quoted it in order to show that LANDSBERGER regards the observed 
changes as essential. 
For concentrated solutions of NaCl and K Cl, Learanp !) has 
already noticed the same phenomenon as I have now done for the 
more diluted ones. 
From the following table this progressive change is plainly visible. 
Number of grams Number of grams Number of grams Increase 
of NaCl of K Cl of K NO, | in the 
per 100 grs. of H,O. | per 100 grs. of H,O. | per 100 grs. of HO. boiling point. 
ro 9.0 12.2 1° 
’ 13.4 ied 26.4 go 
18.3 24.5 42.2 30 
23.1 31.4 59.6 42 
pee | 37.8 78.3 5e 
We see from this table that with NaCl and KCl the elevation 
of the boiling point increases more rapidly than the concentration, 
whilst with KNO; the reverse is the case. At greater concentrations 
the molecular elevation of the boiling point of solutions of Na Cl 
and KCl seems to increase with the concentration, whilst for solu- 
tion of KNOs it steadily declines. 
Summary of the results. 
The result is, therefore, that the progressive change observed with 
concentrated solutions of KNOs; also oceurs with dilute solutions, 
whilst with concentrated solutions of NaCl and KCl it ends at a 
concentration of 0.5 gr. mol. where it takes another direction. 
In my determinations of vapourpressure with the micromano- 
1) Ann. de Chim, et de Phys. T. LILI. Poggend. Ann. Bd. XXXVII. 
46 
Proceedings Royal Acad. Amsterdam. Vol. II. 
