Measurement of Electrolytic Conductivity. 



25 



The temperature coefficient used in the reduction was 

 taken as 2*1 per cent, per 1° C. 



The galvanometer gave a clear indication for a variation 



of 10 ohms. 



21125 

 Specific Resistance= ._ . .. — 46*47 ohm-centim. units. 

 r 454*6 



Specific Conductivity in c.G.s. units = 21 51*9 X 10~ 14 . 



Conductivity compared with mercury = 2024*4 x 10 -9 . 



k_ 



1012-2 xlO- 8 . 



Solution III. (prepared by Dr. Ewan). — The details of 

 preparation of this solution were similar to those employed 

 in the previous case, except that the salt was not recry stall ized 

 from dilute hydrochloric acid, so that it is possible that a 

 trace of chlorate or perchlorate might have been present, and 

 this would tend to diminish the conductivity. 



Table II. 



Direction of 

 current. 



Temp. 



t> . , Eesistance reduced 

 Resistance. | f is° n 



! 



-f 



1811 

 17-98 

 17-84 

 17-70 



21155 

 21225 

 21275 

 21345 



21204 

 21214 

 21204 

 21211 





+ 











Mean 21208 



k 

 whence as before — =1008*3. 



Kohlrausch , s latest result for the same strength of solution 

 of the same salt at the same temperature is 1009, Bouty's 

 value is 1035, Krannhal's 1003 (obtained by graphical inter- 

 polation from the data given in Ostwald's Lehrbuch der 

 allgemeinen Chemie, p. 732). 



Let us now investigate the different errors which are pre- 

 sent in the determination, and assign to each its relative 

 importance. Taking the numbers given in Table L, the 

 mean error of observation comes to be + 4"8, and the pro- 

 bable error +3'2. The mean error of a single observation 

 is 12 ; and the probable error of a single observation is 8, so 



