394 Prof. R. Clausius on the different Systems of 



magnitudes to be practically measured ; so that the latter can 

 on! j with the aid of very large or very small numerical values 

 be represented by those units. To avoid this inconvenience, 

 the British Association, and in connexion with it the Congress 

 of Electricians at Pai'is, have decided to multiply or divide the 

 electrical units resulting from Thomson's system of funda- 

 mental units by certain (some of them very high) powers of 

 10, and thus to form units of practically suitable magnitude. 



For these latter, names borrowed from celebrated men spe- 

 cially meritorious with respect to this branch of physics were 

 then chosen. Among the units we have above discussed, only 

 one is left without a name, and, indeed, just that which 

 forms the base of the dynamic system, namely the unit of 

 magnetism. Hence I would take leave to propose that for 

 it the name " weber " be introduced ; for to Weber we are 

 indebted for singularly great advances in regard to elec- 

 trical measurements, and he, in conjunction with Grauss, was 

 the founder of the electrodynamic system. Hence also, for- 

 merly, one of the units, the unit of current-intensity, was 

 designated by his name. In the practical system now intro- 

 duced, however, it turned out that the unit of current-intensity 

 which fits into this system differs from that designated by the 

 name of Weber in the proportion of 1 to 10; and as it was 

 feared that confusion might be produced by employing the 

 same name for the new unit, another name, ampere, was given 

 to it. Accordingly, if the name of Weber were not intro- 

 duced for the unit of another kind of quantity, it would be 

 missing in the system of names, which would not be in keep- 

 ing with justice. I therefore think I may reckon upon my 

 proposal meeting with general assent. 



The practical system of measures established by the Con- 

 gress of Electricians, with the inclusion of the above-discussed 

 unit of magnetism, if the gram and the centimetre be, as is 

 usual, denoted by gr and cm and the second by s, can be 

 written as follows: — 



Weber [m d ] =gri cmi s~ l . 10 8 , 



Coulomb ... [e d ] =gr% em?. 10 _1 , 



Ampere [i d ] =grh cmk s~ x . 10 -1 , 



Volt [E rf ] =gri em% s~ 2 . 10 8 , 



Ohm [_~R d \=cms- 1 .10 9 , 



Farad [C rf ] =em~ 1 s 2 .10 -9 . 



