216 ELEMENTS OF STATIC ELECTRICITY. 



In this case, as in that of a discharge from the clouds 

 to the earth, elevated objects reduce the resistance, es- 

 pecially if they are good conductors, or furnished with 

 sharp angles or points; and become the electrodes 

 through which the discharge takes place. 



LIGHTNING RODS. Franklin first proposed the 

 lightning rod. The identity of lightning and elec- 

 tricity, strange to say, was unknown, till, by the erec- 

 tion of a metal rod at his suggestion, and subsequently 

 by his well known kite experiment, sparks were drawn 

 from the cloud, Leyden jars charged, and various similar 

 laboratory experiments, previously known to electric 

 science, performed by means of atmospheric electricity. 



The first lightning rod was erected, May 10, 1752, a 

 month previous to the kite experiment, by M. Dalibard, 

 in France, according to the plan proposed by Franklin 

 for testing the identity of lightning and electricity: 

 and sparks similar to those from the electric machine 

 were drawn from it. 



The identity of lightning and electricity having been 

 established, Franklin showed how the rod could be used 

 as a means of protecting buildings. The result is the 

 lightning rod, as we now have it, in its numerous forms. 

 And though ignorance, greed, and dishonesty have cast 

 their shadow upon it, yet thousands of well con- 

 structed rods, standing as the silent guardians of life 

 and property, sufficiently attest its value. 



The proper construction of lightning rods was re- 

 cently investigated by a conference of leading English 

 scientists, specially appointed for that purpose : among 

 whom were several eminent electricians. And, after 

 three years of thorough investigation, during which 

 practical information was collected from all parts of 



