422 LIVING TORPEDOS IN BERLIN. 



ends, divided by the resistance of the circuit plus that of the organ, 

 of the fish, and of the surrounding water, etc. between those points. 

 The linings serve not merely to lead off from the ends of the elec- 

 trical organs, but so far as they extend over their lateral surfaces, also 

 constitute good conductors between these surfaces and the ends. 

 As by this conduction part of the shock is short circuited, the 

 difference of potential at the ends is the less the smaller the 

 distance between the two linings. In other words the difference is 

 the less the longer the linings. Further it is not quite inde- 

 pendent of the position of the point at which the lining is con- 

 nected with the circuit ; for as the linings themselves conduct 

 from the ends of the organs to the opposite borders, the potential 

 varies in them in the same direction. Consequently the arrange- 

 ment adopted on constructive grounds, according to which the ends 

 of the circuit are respectively united to the anterior border of anterior 

 lining, and posterior border of posterior lining is theoretically the 

 most correct, although in practice the difference can scarcely tell. 



The resistance of the organ, fish, etc. between the leading-off 

 points of the two linings, is according to Helmholtz's law the 

 same which the conducting mass would oppose to a current pro- 

 duced by an electromotive force acting in the experimental circuit. 

 But in relation to such a current the linings constitute in accordance 

 with known principles 1 isoelectric surfaces. Thus the resistance in 

 question becomes larger the shorter the linings, smaller the longer 

 the linings : inasmuch as their extent determines the area of the 

 surface of application of the moist to the metallic conductor. 



Let PI and P k be the differences of potential of the ends of the 

 experimental circuit with a long and short lining respectively, and 

 the corresponding resistance between the linings W and W k ; and 

 further, let the great resistance in the experimental circuit be R> 

 the small r, then, according to observation, we have the two 

 following inequalities : 



this involves the inequalities P k > P/, R > r, and as we have seen 

 the latter to be proved, the observed relations are explained. The 

 current flowing through the experimental circuit combines in every 

 point of the conducting mass between the linings, with the current 

 which would exist at the same point if there were no experimental 



1 G. S. Ohm, die galvanische Kette Mathematisch bearbeitet, Berlin, 1827, p. 128. 

 G. Kirchoff in PoggendorfFs Annalen der Physik und Chemie, 1843, p. 500. 



