442 LIVING TORPEDOS IN BERLIN. 



were taken from the middle or the outer edge of the organ in 

 larger or smaller fish, their average length therefore amounted to 



2 cm., and their average force was - - =0-009 Raoult, 



or about 0-0085 Daniell 1 . Double this length the force would 

 have been 0-0170, and thus only a little less than the average 

 force of much larger bits of the organ of Gymnotus. 



This correspondence may indeed be followed still further. If 

 one reckons an average of ten plates to a millim. in the Gymnotus 

 organ, the medium organ-current force of the individual Gymnotus 



.,, , 0-0000375 + 0-0000750 

 plates will be - - = 0-00005625. On account 



of a correction which is probably necessary to be made in all Sachs' 

 figures this value is raised to 0-00006. If in the Torpedo the 

 medium number of plates to the mm. is reckoned to be 30 this 

 gives 615 as the number of plates to the columns of medium 



fj r\ _t T n 



height, that is - = 20-5 mm., but only 500 of these would lie 



between the conducting clay points. If we divide the average 

 organ-current force observed by us, viz. 0-0085 Daniell, by this 

 number, we have 0-0000117 Daniell, as the mean electromotive 

 force of a single Torpedo plate. This value is 3-3 times less than 

 that found for a single plate of Gymnotus. According to my ideas 

 it ought to be about 8-5 times less on account of the thickness of 

 the Gymnotus plates being about 8*5 times greater 2 . 



A closer coincidence between two numbers obtained under such 

 circumstances is not to be expected. It is sufficiently surprising 

 to find that the numbers are in similar order. Possibly it may be 

 only a result of coincidence. Yet it may be regarded as a rare 

 coincidence that from the same assumptions as those on which the 

 above calculation is founded, I should arrive at the remarkable 

 conclusion according to which the electromotive force of the whole 

 Gymnotus bears to that of the whole Torpedo (in adaptation to the 

 conditions of each), almost the same relation as, according to 

 Christiani's determination, the resistance of fresh water to sea 

 water 3 . 



1 Compare E. Kittler, ' Die elektromotorische Kraft des Daniell' schen Elements.' 

 Sitz. der math. phys. Classe der k. b. Akad. der Wissensch. zu Mtinchen, vol. xii. 

 1882, pp. 501, 502. Also Wiedemann's Annalen der Physik und Chemie. N. F., 

 1882, vol. xvii. p. 893. 



3 Untersuchungen, pp. 174, 175, 278-280, 286. 



3 Ibid. pp. 414, 415. 



