On Electro-Dynamic Induction. 



227 



coil No. 1, while coil No 2 is placed over this to receive the in- 

 duction, with its ends joined to those of coil No. 3. By this dis- 

 position the secondary current passes through No. 3 ; and since 



Fig. 8. 



cb coil No. 1, I coil No. 2, c coil No. 3, d helix No. 1. 



this is at a distance, and without the influence of the primary, its 

 separate induction will be rendered manifest by the effects on 

 helix No, 1. When the handles a, h are grasped, a powerful 

 shock is received, proving the induction of a tertiary current. 



80. By a similar but more extended arrangement, as shown in 

 Fig. 9, shocks were received from currents of a fourth and fifth 

 order ; and with a more powerful primary current, and additional 

 coils, a still greater number of successive inductions might be 

 obtained. 



81. The induction of currents of different orders, of sufiicient 

 intensity to give shocks, could scarcely have been anticipated 

 from our previous knowledge of the subject. The secondary 

 current consists, as it were, of a single wave of the natural elec- 

 tricity of the wire, disturbed but for an instant by the induction 

 of the primary ; yet this has the power of inducing another cur- 

 rent, but little inferior in energy to itself, and thus produces 

 effects apparently much greater in proportion to the quantity of 

 electricity in motion than the primary current. 



82. Some difference may be conceived to exist in the action of 

 the induced currents, and that from the battery, since they are 

 apparently different in nature ; the one consisting, as we may 

 suppose, of a single impulse, and the other of a succession of such 

 impulses, or a continuous action. It was therefore important to 

 investigate the properties of the currents of different orders, and 

 to compare the results with those before obtained. 



83. First, in reference to the intensity, it was found that with 

 the small battery a shock could be given from the current of the 



