( 100 ) 
Nor has Mr. Raovuir!) found a minimum, but he found nearly 
constant values down to 0,1 gr. mol. for the molecular lowering of 
the freezing point. They did not differ more than 0,1 pCt. 
In my opinion, however, the question remains, whether at this 
moment the highest degree of accuracy has already been reached in 
the method of the lowering of the freezing point. 
It is quite possible that the air which is solved in the water and 
the solutions, causes the results, obtained for the determination of 
the lowering of the freezing point, to be faulty. 
If e.g. the quantity of air in a solution depends upon the quantity 
of salt solved in it, the error made is not constant, and it can even 
render the course of the mol. lowering of the freezing point, quite faulty. 
Mr. Raourr has tried to reduce the error caused by solution of 
air in water and solution to a minimum by saturating at the tem- 
perature af the room the water and the solution with air. Mr. Raoutr 
states further that diluted solutions absorb the same quantity of air 
as pure water. Prof. Jann, however, communicated to me in a 
letter that the coefficient of absorption of air for diluted solutions 
depends on the concentration and increases by diluting. 
It is therefore of the greatest importance for the determination of 
the freezing point to examine accurately the influence of the concen- 
tration on the coefficient of absorption for air. As long as this 
influence is not sufficiently known, Mr. Raovunt’s determinations, 
however accurately made, are in my opinion not quite reliable. 
In connection with what precedes, it seems to me, that Mr. ABEGG *), 
who, led by the differences between the results obtained by means 
of the lowering of the freezing point and the decrease of vapour 
tension, came to the conclusion that there must be a fault in the method 
of the determination of the decrease of the vapour tension of 
Mr. Drerericr, has attached too much importance to his deter- 
minations. 
In the first place the influence of concentration on the absorption 
of air has not yet been fully ascertained, as [ said before, and 
secondly, even though this influence were perfectly known, a quan- 
titative comparison between the results of the determination of the 
decrease of vapour tension and the lowering of the freezing point 
is not yet raised above doubt, when the solutions and the water 
are not in exactly the same circumstances in both methods. There 
would, however, be no objection to a comparison, when the lowering 
1) Zeitschr. f. Phys. Chemie: 27. pg. 617. 1898. 
2) Wied. Ann. 64, pag. 487, 1898. 
