94 Prof. E. Edlund on Galvanic Resistance as 



the same manner. Although we try as much as possible to 

 give them the same magnitude, form, and position, yet a 

 slight difference in this respect may be present ; and in con- 

 sequence of it the variation in polarization effected by the flow 

 of the liquid may be a little greater in one plate than in the 

 other. Under all circumstances a difference between the two 

 plates is present, consisting in the fact that during the flow of 

 the liquid the upper disk is exposed to a greater pressure than 

 the lower one ; it is therefore possible that this may cause the 

 needle to make a slight deflection. The deflection which 

 results from variation of polarization, however, we can make 

 as small as we please, by selecting for the experiments liquids 

 ihe resistance of which is sufficiently great. Moreover it results 

 from the experiments which have been made, that the direction 

 of the deflection is determined exclusively by this — that the 

 resistance of the liquid becomes less if it flows in the same di- 

 rection as the galvanic current, but greater if the directions 

 are opposite. 



The form of the experiments was as follows : — When the 

 positive pole of the electromotor was connected with the gold 

 disk in the middle side-tube, as soon as the liquid was set mo- 

 ving from a to b I obtained a deflection which indicated that 

 the part of the current passing through the liquid column d e 

 (therefore the portion that had the same direction as the flow 

 of the liquid) possessed a greater intensity than the other. 

 Now the cause of this might either be that the resistance in the 

 column d e became less, and in column c d greater, than when 

 the liquid was at rest, or possibly that by the motion of the 

 liquid the polarization of the polar disk e was rendered feebler 

 than that of the disk c. If the change produced in the polari- 

 zation of the one disk by the motion of the liquid actually dif- 

 fered from that produced in the polarization of the other, this 

 must have depended on the disks in the side-tubes c and e dif- 

 fering somewhat in size, form, and position, or else it was 

 because the one was exposed to a greater pressure than the 

 other. Therefore it cannot be with safety concluded from a 

 single experiment that the resistance to conduction is depen- 

 dent on the motion of the liquid. Thereupon the glass tube 

 was inverted, so that the liquid flowed from b to a, while all 

 the other conditions remained unchanged. The direction of the 

 deflection obtained was the opposite of the previous one, from 

 which it follows that the part of the current which passed 

 through the column of liquid from d to c (and consequently 

 had the same direction as the liquid stream) was more intense 

 than the other. From these two experiments it follows that 

 the difference in form, size, and position that may have existed 



