WORK OF BINGHAM. 



EXPERIMENTAL. 

 APPARATUS. 



CONDUCTIVITY. 



The Kohlrausch method of measuring conductivity, with Wheatstone 

 bridge, telephone receiver, and induction coil, was employed. It was not 

 difficult to read to less than 0.1 of 1 per cent. The bridge-wire was made of 

 "manganin" and was calibrated before beginning the work. The resistance 

 coils were carefully standardized. 



In order to work successfully with acetone, it 

 was necessary to provide cells of special construc- 

 tion, so as to avoid the presence of rubber or 

 wax, which would be dissolved by the solutions. 

 The cells were made of hard glass with ground-glass 

 stoppers, and had the form shown in fig. 20. The 

 glass tubes carrying the electrodes were sealed into 

 both the upper and the lower walls of the glass 

 stopper. The distance between the electrodes thus 

 remained permanently fixed. 



The zero-bath was prepared by filling a large 

 battery-jar with clean, finely crushed ice, moistened 

 with water. This was placed in a pail made of 

 compressed paper pulp, and the annular space filled 

 with finely crushed ice. Thus protected, the bath 

 could be used for a much longer time than with the 

 methods usually employed. The 25 bath was of 

 the usual form, the stirrer being driven by means 

 of a hot-air engine. An Ostwald regulator was 



employed. The thermometers were regulated to tenths of a degree. They 

 were tested at the beginning of the work. Burettes and flasks were care- 

 fully calibrated. 



VISCOSITY. 



The viscometer was of the form recommended by Ostwald. 1 A fixed 

 volume of the liquid to be measured was introduced into the apparatus. The 



FIG. 20. 



Physiko-Chemische Messungen, 2d ed., p. 260. 



81 



