( 165 ) 
that e. g. for NaCl at the concentration 1 gr. mol. the deviation in 
the manometer was + 60 m.m., and the uncertainty of the reading 
was 0.1 m.m. The error in p, and therefore also in i amounts 
therefore to + 0.17 pCt. at the concentration 1 gr. mol. It increases 
however with the dilution, so that it amounts to + 1.7 pCt. at 
0.1 gr. mol. and to + 3 pCt. at 0.05 er. mol. It is obvious that 
at the small concentrations the absolute value of p„ is comparati- 
vely untrustworthy. At the same time it is clear, that a very small 
difference of temperature between solutions and water or an exceedingly 
small leakage may conceal the minima from us. 
With regard to the measurements with K NOs-solutions it is 
noteworthy that, as was previously found by me, pm increases 
with the dilution in opposition to the solutions with NaCl and H,S80,. 
Very remarkable is also the quick decrease of p, and ¢ at increase 
of concentration, so that 7 has reached the abnormally small value 
1.3 already at 0,9288 gr. mol. 
The results found by means of the boiling-method'), are in 
qualitative concordance with the above mentioned. Owing to the 
great difference in the temperatures at which the observations are 
made (100°), a quantitative concordance could not be expected. 
At 100° I found namely that the molecular increase of the boiling- 
point and so also ¢ for the salts NaCl, KCL and Sr (Nos), reaches 
a minimum between the concentrations 0.1 and 0.5 gr. mol., whereas 
for the salts KNO;, NaNo3, Ba (NO3)s, AgNOs; and Pb (No's)s a 
regular quick decrease of i was observed in case of increase of the 
concentration *). 
It occurred to me that possibly also for these latter salts a minimum 
might appear, but not before the concentrations are much greater ; 
by consulting tables about determinations of the boiling point 
of concentrated solutions *) however, I observed that even for very 
great concentrations the mol. increase of the boiling-point preserves 
the same quick decrease. 
When considering the here-mentioned results, we should be inclined 
to generalize and say: all salts which behave abnormally at higher 
concentrations, as NaCl, KCl, He SO4, Sr(NOs)o and probably a 
great many substances more, will behave normally in very diluted 
state and show a minimum. 
') Proc. Royal Acad. at Amsterdam. Vol. IL p. 469, 
2) Proc. Royal Acad. at Amsterdam. Vol. III p. 717. 
3) LEGRAND, Ann, de Chim. et de Phys. T. LID, Poggend, Ann. Bd, XXXVII, 
