1078 
Chemistry. “On the behaviour of gels towards liquids and their 
Al 
vapours’. By Dr. L. K. Wor and Dr. B, H. BÜcHner. 
(Communicated by Prof, A. IF, HOLLEMAN) *), 
(Gommunicated in the meeting of December 28, 1912). 
A paper by Mr, Bancrorr’), which came to our notice only a 
short time ago, induces us to publish the following account of an 
investigation, whieh we do not yet consider completed. It concerns 
a phenomenon, discovered by von SCHROEDER, ®) who found that 
velatine, swelling in water vapour, behaved differently from gelatine, 
swelling in liquid water: in the first ease it absorbs much less water 
than in the second. This phenomenon seems to contradict the second 
law of thermodynamics, whieh immediately leads to the principle, 
that, if a certain number of phases are in equilibrium, the equilibrium 
will not be disturbed, if one of the phases (in our ease, the water) 
is taken away. Being convineed of the validity of the seeond law, 
and not satistied by the given explanations, we started this research. 
We can at onee refute a seemingly obvious remark. It might be 
supposed, that the absorption of water vapour finally takes place so 
slowly, that the equilibrium would only be reached after a very. 
long time, # e. that we have a false equilibrium. The erroneousness 
of this suggestion is immediately proved by the fact, that gelatine, 
swollen in water, loses water, when brought into a space saturated 
with water vapour, 
Von Scurorper found, that agar-agar showed the same phenomenon, 
though not so markedly, but he observed the reverse in the case of 
filter paper. As far as we know, no other experimental investigation 
of the subject has been published after von ScHROEDER’s paper, though 
theoretical considerations have been given by FREUNDLICH and Ban- 
crort, Which we will treat of later on. 
We first repeated vor ScHROEDER’s experiments, concerning gelatine 
and agar; and we obtained the same results. 
Both substances, when used in the proper concentration, can be 
quite easily dried with filter paper, which is an essential point, as it 
Was suggested that mechanical adhering of water to the surface of 
the gelatine might serve as a means of explaining the phenomenon. 
When the plates grew mouldy or the growth of bacteria was noticed, 
') Although much work has been done, since the original paper was written 
(Dee, 1912), we prefer only to present the translation of the Dutch communication 
and to postpone the publication of our new results. 
) J. physic. chemistry 16, p. 395. 
‘) Z. physik, Chemie 45, p. 76. 
