98 Prof. E. Edlund on Galvanic Resistance as 



Experiments with distilled water. 



Series 1. — The glass tube had an internal diameter of 5*5 

 millims. ; the distance between the side-tubes was 70, and the 

 length of the entire tube was 270 millims. The gold disks 

 were drawn so far back in the side-tubes that the distance from 

 the inner surface of the glass tube amounted to 1 centim. 

 Trial was first made whether a deflection could be obtained 

 merely by the motion of the liquid, without inserting an elec- 

 tromotor at K. In this the gold disk in the middle side-tube 

 was connected immediately with the binding-screws g and h 

 by a simple conducting-wire. As was to be expected, in this 

 experiment not a trace of a current was observed. 



A series of two Daniell's elements was now inserted at K. 

 The rest of the conducting-wires were arranged as shown in 

 fig. 1. The position of equilibrium occupied by the needle 

 when the glass tube was filled with water at rest is denoted by A 

 in the following. As soon as the cock was opened and the 

 water set in motion, the magnetometer-needle made a deflec- 

 tion. The scale-division at which the needle, after a complete 

 deflection, began to return, is given by B ; and D gives the 

 difference between A and B. 



The negative pole of the electromotor was connected with 

 the middle polar disk ; the water-flow was from a to b : 

 A. B. D. 



617-0 619-0 2-0 



617-0 618-8 1-8 



617-0 619-1 2J* 



Mean . . 2*0 

 The deflection shows that the part of the galvanic current 

 which passed from c to d (that is, in the same direction as the 

 water-flow) was more powerful than the other. 



The glass tube was now inverted, so that the water flowed 



through it from b to a ; every thing beside remained unchanged : 



A. B. D. 



618-0 616-0 2-0 



618-1 615-9 2-2 



618-0 615-9 2-1 



Mean . . 2*1 

 The deflection (the direction of which was opposite to that 



of the previous one) indicated that the part of the current 



which went from e to d, and therefore had the same direction 



as the water-flow, was the more powerful. 



The positive pole was connected with the middle disk ; the 



water flowed continuously from b to a : 



