( 112 ) 



An example may explain this ^). 



Tlie following fig. 1 represents tlie eui-\e tmeed for the electro- 

 cardiogram of Mr. V. D, W. when the current was derixed from 



s 







o^Sec: 



"T ' ' > fill I—] r— T— I — I I I I 1 1 I I I 



FiL'. 1. 



FiK. 2. 



the right and left hands, whereas fig. 2 is the constructed curve. 

 The differences are obvious. Especially the tops C and D in the 

 registered curve should be compared with the corresponding tops 

 R and T in the secondary curve which latter alone truly represents 

 the ratio of the heights of the tops. 



We shall now try to compare the string gahanometer as a research 

 instrument with the capillary electrometer and must first of all bear 

 in mind that the deflections of the string galvanometer measure a 

 current, that of the capillar}' electrometer an electromotive force. 

 But it nuist be remarked that whenever \ariations in current or 

 tension are measured, the mercury meniscus as well as the string 

 moves. And during this movement the capillary must be charged or 

 discharged by an electric current, whereas the string in the magnetic 

 field develops an opposed electromotive force. Moreover, when there 

 is a constant considerable resistance with negligeable self-induction, 

 such as commonly occurs in electro-physiological investigations, the 



1) See Pflüger's Arch. Bd. 60. 18'J5 and '"OndeizückingeQ". Physiol. Laborat. 

 Leyden. 2nd series, vol. 2. 



