TEE FORM OF LIGHTNING-BODS. 



4.0 ) 



although, to the mind of every scientific physicist, such experiments 

 are conclusive, the objection has been raised that they do not fairly 

 determine the case for electricity of such high tension as lightning. 

 To meet such objections, the writer of this article, many years ago, 

 instituted the following experiments: 



Take a strip of gold-leaf half an inch wide, and two or three inches 

 long ; pass through it a moderate charge from a six-jar electrical bat- 

 tery, and it will be entirely burned up. The circumference of the gold 

 in this case is one inch, and this, of course, is the measure of the sur- 

 face. Now, take a gold wire one-sixteenth of an inch in diameter, and 

 pass through it the most powerful charge that can be obtained from 

 the same battery ; the wire will remain unaffected, although it pre- 

 sents but one-fifth the surface. 



The difierence between the action of static electricity and electri- 

 city in motion is very well shown by the following simple experiment : 

 Take a large Leyden jar, one of say two gallons measurement, having 

 the usual knob and other arrangements, as shown in the figure. In 

 the wooden cover insert a glass tube, carrying at its upper extremity 



^j^.-J^ 



Illustration of the Effects of Static and Dynamic Electricity. 



a wire lying horizontally across it, this wire having a good-sized ball 

 at each end, so that the discharge may take the form of a spark or an 

 explosion, and not pass off silently. Between the horizontal wire and 

 the knob of the jar stretch a strip of gold-leaf {JS), and charge the jar 

 in the usual manner. So long as the electricity does not flow through 

 the gold-leaf, the latter will remain uninjured, although it is evidently 

 charged as intensely as the machine can charge it. But, if we dis- 

 charge the jar by laying one ball of the discharger on the outer coat- 



TOL. TII. 26 



