OF CERTAIN ORGANIC BASES AND ACIDS. CREIGHTON. 157 



A 2/3-iiormal solution of mannite and boric acid, whoso 

 small negative temperature coefficient was compensated with 

 potassium chloride (O.OGg. per liter of the mannite solution), 

 was used as the electrolytic resistance. 



A diagram of the complete apparatus is shown in figure 2. 

 A and I are the accumulator and induction coil. W, W, W" 

 and W" are the arms of the bridge (W and W are 5 mm. 

 in diameter, and W" and W" are 0.8mm.) ; D and B are two 

 resistances which remain constant during an experiment ; 

 K' and K" are variable condensers ; T is the telephone ; X is 

 the cell for the unknown resistance ; S is a two-way switch for 

 introducing X behind W or in shunt with it, and C is a com- 

 mutator used for making D and B equal. 



The resistances W, W, W", and W" were calibrated by 

 means of a known electrolytic resistance in the cell X. By 

 using the same cell, for the acetophenone solutions of the 

 substances under investigation, their resistances were readily 

 calculated from the length of resistance W required to give 

 a balance 1 . 



In order to test the accuracy of this method, the conduc- 

 tivity of a sample of ordinary distilled water, the conductivity 

 of which was also measured by the Kohlrausch method, was 

 determined. By the first method it was found that at 15.0 

 K = 1,23 10~ 5 , and by the second method, at the same tem- 

 perature, that K = = 1,17 10~ 3 . 



The acetophenone used in the following measurements was 

 first purified by distillation and recrystallization. This 

 acetophenone had a specific conductivity of fc = 2,02 10" 7 . 



The measurements given in the following tables were all 

 made at room temperature (16-17). 



i. For a detailed description of the method, apparatus, etc., see Maltby, M. E. 

 loc. cit. 



PROC. & TRANS. N. S. INST. Sci., VOL. XIII. TRANS. 11 



