244 



LOCALIZED ELECTRIZATION. 



ments. The use of this primitive instrument having shown me all 

 its faults, I was led to make successive important modifications, 

 which have produced perfect simplicity of construction, and have 

 consequently diminished the frequency of accidents capable of 

 arresting the course or diminishing the power of the current. 



Moreover, the modified instrument presents a more perfect 

 system of graduation, and more varied methods of producing more 

 or less rapid intermissions. 



In order better to explain the importance of the alterations, I 

 have represented the original instrument in fig. 51 ; and the 



Fig 51.— Large double-current vulta-faradic iustruiueut. JJucheime's original model. 



perfected instruments in figs. 52 and 55. In the former, the coils 

 are concealed by a covering ; in the latter, they are exposed to 

 view. 



§ I. — Description. 



A. — Large volta-faradic apparatus dosed (latest model.) 



The first model of the volta-faradic apparatus (fig. 51) ^ was 

 composed — 1, of a flat battery, ; 2, of two superposed coils ; 3, 

 of a graduator formed by the external movable coil, which could 

 be moved upon the internal coil by means of the stem K ; 4, of a 

 magnetic rheoraeter, V ; 5, of a toothed wheel, D, fixed to a little 

 plate shut within the drawer U, and which, when required for use, 

 could be lifted up, as in fig. 51 ; 6, of a trembler, A. 



The last model (figs. 52 and 55),'^ differs from the foregoing, 1, by 



5 This apparatus was presented to the 

 Academy of Sciences of France, in 1848, 

 by M. Despretz. 



^ This modified apparatus was pre- 

 sented to the Academy of Medicine of 

 Paris in 1850. 



