202 



JONES AND SCHUMB. 



served as the source of alternating current. The bridge, by the same 

 manufacturer, was made with extension coils, by which the wire 

 could be lengthened ten-fold in accordance with the design of Wash- 

 burn.^ The bridge wire and resistance box were carefully calibrated. 

 An electrostatic condenser was used to balance the electrical capacity 

 in the arms of the bridge and was a great help in securing a sharp 

 minimum of sound in the telephone. Measurements were made at 

 both 25.00° ± 01° and at 0.00°. The 0.1 N solutions were made up 

 quantitatively by weight and the more dilute solutions made from 

 these. All dilutions were made by weight rather than volume on 

 account of the greater accuracy of this method. The densities of 

 the 0.1 N and 0.05 N solutions were determined at both temperatures 

 and the densities at lower concentrations computed on the assumption 

 that the density is a linear function of the concentration. 



Two completely independent series were carried out. The following 

 table shows the results of these measurements. 



TABLE I. 



Conductivity of Thallotjs Nitrate Solutions at 25° C. 



8 E. W. Washburn, Jour. Amer. Chem. Soc, 38, 2431 (1916). 



