970 
Thus at constant temperature different properties of aqueous 
solutions of hydrate-forming substances, as e.g. spec. gravity, surface 
tension, refraction ete. were studied as function of the concentration, 
in which curves were obtained, which on the whole taught little or 
nothing of importance. Also the determination of the viscosity for 
a few systems yielded at first but inconclusive results; in the con- 
viction, however, that nevertheless this method promised most on 
the whole for the end we had in view, the investigation was con- 
tinued with the favourable result that in a few cases curves were 
obtained which very convincingly pleaded for the existence of 
hydrates in the aqueous solutions. 
The system H,O—FeCl, was chosen, of which part of the melting- 
point figure, as it was studied by Baknvis KoozrBoom, has been 
reproduced in Fig. 1. 
The plan was to carry out the experiment at the temperature of 
40°, because then, passing very close over the top of the compound 
conc. in weight 0/) Fe,Cle (Times of outflow in minutes). 
0 1.70 
33.50 | 6.15 
39.58 | 8.70 
46.13 | 12.50 
50.19 | 16.45 
52.57 | 18.05 
55.39 | 19.32 
51.45 | 18.66 
58.69 | 17.92 
60.18 | 17.50 
62.44 | 16.90 
65.09 | 16.95 
66.84 | 17.50 
68.45 | 18.60 
71.06 | 21.73 
12.88 24.63 
13.83 28.17 
14.12 31.00 Gan 
