ELECTRICAL MEASUREMENT. 447 



electric experiments taken in connection with 

 other experiments of his on the dynamical equi- 

 valent of heat, show some disagreement from 

 the British Association measurement of their unit 

 of resistance. There is something to be reconciled 

 here. Joule on the one side holds that the British 

 Association unit, the Ohm, is too little, but on the 

 other side, in Germany, Kohlrausch holds the Ohm 

 to be a little on the other side of the exact thousand 

 million centimetres per second. I believe if you 

 eliminate doubt by the method of averages, 

 Kohlrausch and Joule's experiments would show 

 the British Association to be very nearly right, but 

 I do not approve of that method of removing 

 doubts, and we shall not be satisfied until both 

 Joule and Kohlrausch are satisfied. 1 



I will now mention a number of experiments 

 with electrometers which however, I am afraid, 

 are of little interest to any one in the world, but 

 myself. Here is the first attempt at a quadrant 

 electrometer. It is well known now to many elec- 

 tricians, and a descriptive pamphlet regarding it 

 1 See pp. I33I3 6 above. 



