TRANSFERENCE OF ELECTRICITY. 121 



of the machine is turned a certain amount of 

 electricity is evolved, as you will see by the rise 

 of the little straw indicator (at A). Now I know 

 from the appearance of repulsion of the pith 

 ball at the end of the straw that electricity is 

 present in those brass conductors (B B), and I 

 want you to see the manner in which that elec- 

 tricity can pass away [touching the conductor 

 (B) with his finger, the Lecturer drew a spark 

 from it, and the straw electrometer immediately 

 fell]. There, it has all gone ; and that I have 

 really taken it away you shall see by an experi- 

 ment of this sort. If I hold this cylinder of 

 brass by the glass handle and touch the con- 

 ductor with it I take away a little of the electri- 

 city. You see the spark in which it passes, and 

 observe that the pith-ball indicator has fallen a 

 little, which seems to imply that so much elec- 

 tricity is lost; but it is not lost, it is here in this 

 brass, and I can take it away and carry it about, 

 not because it has any substance of its own, but 

 by some strange property which we have not 

 before met with as belonging to any other force. 

 Let us see whether we have it here or not. [The 

 Lecturer brought the charged cylinder to a jet 

 from which gas was issuing ; the spark was seen 



