COMPLEX SOLUTIONS.—ARCHIBALD. 37 
zero for balf an hour at a time. An error of this amount in the 
determination of the temperature of the solution would cause 
an error of about 0.1 per cent. in the determination of the resist- 
ance. The temperature of the room in which the observations 
were made was from 2° to 5° C. That one might be sure that 
the temperature of the solution to be measured had ecme to be 
that of the bath, measurements of the resistance were made at 
short intervals, and that reading taken which was found to be 
constant for successive intervals. The thermometer used was 
graduated to tenths of a degree centigrade, and could easily be 
read to twentieths. Its errors had recently been determined at 
the Physikalisch-Technische Reichsanstalt, Berlin. 
The factor for reducing the observed conductivities to mer- 
cury units was found by plotting observed conductivities at 18° 
C. against concentrations, reading off from these curves the 
conductivity values for concentrations examined by Kohlrausch, 
and comparing them with his results. The value thus obtained 
was found to be the same for each salt and to be practically 
constant throughout the concentration range of my experiments. 
As the cell was of glass the reduction factor would not be 
appreciably different at 0° C. from what it was found to be at 
18°C. To make sure that no change occurred in the position of 
the electrodes during the course of the experiments that would 
appreciably affect the reduction factor, every second or third 
solution was measured at 18° C. before reducing its temperature 
to 0° C., and the value of the conductivity obtained was compared 
with that previously obtained at the same temperature. 
Determination of equivalent conductivity at infinite dilution 
on O 1G. 
For this purpose a series of simple solutions of each electro- 
lyte, of concentrations ranging from 0:01 to 00001 gramme- 
equivalents per litre, were prepared, and their conductivities were 
measured both at 18°C. and at 0° C. The conductivity of the 
water used in their preparation was also measured at both tem- 
eratures and subtracted in each case from the conductivity of 
