128 ELEMENTS OF STATIC ELECTRICITY. 



on the rapidity of the discharge ; and when the spark 

 is made so short and rapid as to be apparently contin- 

 uous, the carriers appear and disappear with each snap, 

 like a succession of views in a rapidly moving panora- 

 ma, proving that the apparently continuous spark is a, 

 succession of sparks so rapid as to give the impression 

 of continuity. 



As a flash of lightning is only the same thing on a 

 grander scale in nature's own laboratory, we must con- 

 clude that the passage of electricity from cloud to cloud, 

 a distance often of many miles, is so rapid as to defy 

 human calculation. We notice this in chain lightning, 

 when the flash, sometimes three to five miles long, is 

 seen throughout its entire length at the same instant, 

 as if suddenly photographed on the cloud. 



TRANSMISSION OF POWER BY STATIC ELECTRICITY. 

 Two machines are necessary for this experiment 

 one called the primary, and the other secondary. The 

 secondary should be a very light running machine ; 

 hence it is better to make it smaller than the primary, 

 and the driving wheel and switch may be dispensed with. 



Let the machines be placed near each other, in the 

 same relative position, the secondary in front ; and 

 connected together by conducting cords or wires, joining 

 similar pairs of Leyden jars: and let the sliding elec- 

 trodes be separated beyond sparking distance. Now 

 let the primary machine be put in operation, and the 

 movable plate of the secondary will rotate in a direction 

 opposite to that of the primary. If the electric energy 

 should not be sufficient to overcome the friction and 

 inertia, in starting, the plate of the secondary may be 

 put in rotation by hand, and its motion will then be 

 sustained by the electric action. 



