THE PHYSICAL PROPERTIES OF AQUEOUS SOLUTIONS. 
159 
For p Kohlrausch gives the values 
KC1, p = 3-280, NaCl, p = 2-649, 
which gives for n the values 
KC1, n = 1-187, NaCl, n = 0 • 766. 
For the tangent of the inclination of the curve at and near the origin we have for KC1 the value 0 • 39, 
and for NaCl the value 0 • 25. 
These agree well with the diagram. 
The accurate empirical law deduced by Kohlrausch is, in fact, not sensibly different in the part near 
the origin a = 1 from the Van ’t Hoff law for which p = f. That is, in the region where, from the 
present point of view, ionic size and viscosity may be regarded as constant, Van ’t Hoff’s law, there 
equivalent practically to 1 - a = const x m. 1/2 , is to be taken as the starting point for substances of the 
class here considered. 
