ELECTRICAL MEASUREMENT. 433 



merely definite measurement, but measurement on 

 a certain absolute basis, which, even if all the 

 instruments by which the measurements were 

 made were destroyed, would still enable us to 

 get perfectly definite results. The absolute 

 system of units was, for the first time in physical 

 science, worked out in consequence of Gauss' 

 foundation of the system for terrestrial magnetism. 

 That, then, is really the beginning of absolute 

 measurement in magnetic science, and in electro- 

 magnetic, and electrostatic science. Gauss and 

 Weber carried on together the work for terrestrial 

 magnetism, and Weber carried on by himself 

 I believe, during Gauss' lifetime and also after 

 his death the system of absolute measurement 

 in electrostatics. One most interesting result, 

 brought out by Weber, is that the electric 

 resistance of a wire, in respect of electric currents 

 carried by it, is to be measured in terms of 

 certain absolute units, which lead us to a state- 

 ment of velocity in units of length per unit of time, 

 as the proper statement for the electro-magnetic 

 measure of the resistance of a wire. It would 



F F 



