190 j— 4.] The Viscosity of Aqueous Solutions of Chlorides, etc. 241 
The differences between the conductivity at 0° C. of equivalent 
solutions of KC1, KBr, and KI are very similar to the differences 
at 18° C. {cf. Kohlrausch, — Leitvermogen). 
An explanation of the equal mobility of Cl', Br', and I' has 
been suggested — that molecules of the solvent may be associated 
with an ion ; that the number of molecules associated depends 
on the electro-affinity of the ions ; and in this case the difference 
in number of molecules associated with Cl', Br', and 1' causes the 
mobilities to be the same. The formation of complexes is also 
referred to the electro-affinity of the element.* Some influence of 
this might be expected in the viscosities of the solutions ; but 
whether the differences observed, especially with variation of 
temperature, are to be connected with this, it is not possible to say ; 
we have worked with concentrated solutions only, and possibly 
dilute solutions would be better for this purpose. 
Summary. 
1. We have determined the relative viscosity of aqueous solu- 
tions of KC1, KBr, KI, HC1, HBr at 0°, 15°, and 25° C. ; and at 
concentrations of 1 mol., 2 mol., and 3 mol. per litre. Also the 
equivalent conductivity of the same solutions at 0° C. 
2. The change of viscosity with change of temperature dimin- 
ishes from Cl-Br-I. 
3. The effect of concentration on the viscosity depends on the 
temperature : it may affect the viscosity in opposite directions at 
different temperatures. 
4. There are considerable differences in viscosity of chloride, 
bromide, and iodide, and especially in the effect of changes in con- 
centration and temperature. 
* Cf. Abegg and Bodlander, Zeit.f. anorg. chem., 20, p. 453 (1899), and 
Baur, Ahren's Sammlung diem. u. chem. tech., Vortrage viii. No 12 (1903). 
(. Issued separately June 16, 1904.) 
PROC. ROY. SOC. EDIN. — VOL. XXV. 
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