THE FLASH. 265 



contrary electricity is drawn towards it; so that 

 by this influence the two are sundered, and can 

 now work each by itself. 



The Electric Spark is an appearance presented 

 at the instant when two unlike mutually attracting 

 electricities pass over to each other through a 

 layer of air that had been between them, and thus 

 join, to return to the common state of insensible 

 electricity, of winch I have just spoken. 



Benjamin Eeanklin was the first to show with 

 certainty that the electrical discharge of a thunder- 

 cloud, the flash of lightning, differed from the 

 spark obtained from the electrical machine only in 

 the amount of force put forth. He remarked of 

 it, that the zigzag of the flash has the closest 

 resemblance to the shape of a strong electric- 

 spark discharged through a good distance ; — that 

 the flash strikes most often on high objects over- 

 topping others near them, such as the peaks of 

 mountains, the masts of ships, lofty trees, towers, 

 &c, just as the electric spark most readily passes 

 over to the most jutting parts of neighbouring 

 bodies; — that the flash chiefly seeks out things 

 that are good carriers of electricity, such as metals, 

 water, &:c, avoiding non-conductors; — and lastly 

 that, just like any strong electric spark, it kindles 

 substances that will burn, fuses such as will melt, 

 rends such as can be torn or split, and destroys 

 animal life. 



