1046 
represented 7 graphically from the solidifying and the boiling points 
as a function of c. 
From this I have interpolated the values of 7 at the same concen- 
trations as used in the determination of A. The third decimal of 2’ 
is, however, very vague on account of the powerful bends in the 
vicinity of the minima, which the thus obtained lines exhibit. From 
the differences of the dynamically obtained values of 2’ and those of 
i from A at corresponding temperatures we can control the previously 
mentioned views with a sufficient accuracy. From this appears the 
following. 
At O° 7’ is always greater than z and the difference increases 
regularly with the concentration (with KCl we found small oscillations 
in the third decimal, so within experimental errors). With the most 
hydrated salt, namely MgCl,, the increase of 2’—z is the strongest, 
then follows CaCl,, then NaCl, whilst the feeblest hydrated salt KCl 
shows the least increase of 7’—7. With MgCl, and CaCl, the factor 
6 seems to predominate in the large concentrations for there the 
decrease of 2’—7 with the dilution is much stronger than it is in the 
case of NaCl. Not in the case of a single salt does the factor a 
become so predominant that the influence of the hydration becomes 
also subdued. At 100°, on the other hand, 2’—, in the case of all 
salts, occasionally becomes negative, so that the influence of a is 
there stronger than that of 4 and the hydration together. With NaCl 
and KCl 7’—z even exhibits a minimum, so that with these salts in 
the smallest concentrations the hydration seems to gain the best of a. 
With MgCl, and CaCl, the differences at 100° are smaller than 
at O° owing to the lesser hydration of these salts at a higher tem- 
perature. At the smallest concentrations the predominance of a 
steadily increases so that finally 7’—z becomes fairly strongly negative. 
As in the calculation of 7 the choice of A, had to be rather 
arbitrary, whereas the molecular depression of the solidifying points 
and the rise of the boiling points could not be determined in a 
direct manner in consequence of the same perturbing influences that 
occurred in the solutions investigated, | cannot credit the results of 
i—i with possessing absolute values. The direction in which 2’—< 
changes with the concentration will, however, remain the same 
when another choice is made from the said constants. This direction 
and the velocity with which the change takes place can, however, 
just give us some insight into the strength of the influence of the 
perturbing causes, each separately. For a more detailed discussion 
on this point, I must again refer to the more elaborate article in 
the Chemisch Weekblad (1915). 
Dec. 1914. Chem. Laboratory of the H.B.S. Bois le Duc. 
