332 



LESSONS IN ELECTRICITY. 



came to take place, not only the elec- 

 tricity which had passed from my body 

 into the body of the other person, but 

 also the electricity which had passed 

 from my body into the earth (through 

 the other person), did suddenly return 

 upon inc from his hand F to my 

 hand B, at the same instant that the 

 discharge of the prime conductor took 

 place upon the ball L. This caused the 

 returning stroke to be stronger than be- 

 fore." 



Lord Mahon fused metal?, and pro- 

 duced strong physiological effects by the 

 return stroke. 



In nature disastrous effects may be pro- 

 duced by the return stroke. The earth's 

 surface, and animals or men upon it, may 

 be powerfully influenced by one end of 

 an electrified cloud. Discharge may oc- 

 cur at the other end, possibly miles away. 

 The restoration of the electric equilib- 

 rium by the return shock may be so 

 violent as to cause death. 



This was clearly seen and illustrated by 

 Lord Mahon. Fig. 57 is a reduced copy 

 of his illustration. JL B c is the electri- 

 fied cloud, the two ends of which, A and 

 c, come near the earth. The discharge 

 occurs at c. A man at F is killed by the 

 returning stroke, while the people at D, 

 nearer to the place of discharge, but far- 

 ther from the cloud, are uninjured. 



TVith the viow of still further testing 

 your knowledge of induction, I have here 

 copied a portion of this admirable essay ; 

 but the entire memoir of Lord Manor, 

 would constitute a most useful and inter- 

 esting lesson in electricity. 



For our own instruction we can illus- 

 trate the return shock thus : Connect 

 one arm of your universal discharger, fig. 

 49, with a conductor like c, fig. 20, and 

 the other arm with tho earth. Bring c 

 within a few inches of your prime con- 

 ductor, but not within striking distance ; 

 on working tho machine a stream of fee- 

 ble sparks will pass from point to point 

 of the discharger. Let the prime con- 

 ductor be discharged from time to thtoe 

 by an assistant ; at every discharge the 

 returning stroke is announced by a flash 

 between the points of the discharger at *. 

 If gun-cotton with a little fulminating 

 powder scattered on it, or a fine silver 

 wire, be introduced between the points 

 of tho discharger, the one is exploded 

 and the other deflagrated. 



The stream of repelled sparks first seem 

 may be entirely abolished by establishing 

 an imperfect connection between the con- 

 ductor c and tho earth : a chain resting 

 upon the dry table on which the conduct- 

 or stands will do. The chain permits 

 the feebler sparks to pass through it in 



Fw. 58. 



