476 Royal Society : — 



No. 14 Gauge Strand (seven No. 22 wires twisted together). Pairs 

 of samples in different states of preparation, each 1000 inches long. 



The specific resistances of the specimens of copper wire from the 

 manufactories A, B, C, D, of which a compar.ative statement is given 

 in tlie first Table above, I have estimated in absolute measure by 

 comparing each with F,„ of which the resistance in absolute measure 

 is 6,580,000 X -1999, or 1,316,000. The various results reduced to 

 specific resistances per grain of mass per foot of length are collected 

 in the following Table, and shown in order of quality in connexion 

 with four determinations of specific conductivity by Weber. 



Specific Conductivities of specimens of Copper expressed in British 

 Absolute Measure. 



