422 



RECENT PROGRESS IN PHYSICS. 



until another discharge occured. The number of sparks of the mea- 

 suring jar required to produce the first discharge of the battery was 

 counted, then the number of sparks necessary to replace the quantity 

 of electricity which had disappeared at the first discharge. 



The previous table shows how large the entire charge was under 

 different circumstances, when the discharge took place at a given 

 striking distance, and the following table shows how much electricity^ 

 the battery had to receive again, to obtain the second discharge at 

 the same striking distance : 



We see from this table that the quantity of electricity q', which has 

 to be imparted to the battery after the first discharge at the striking 

 distance, to produce a second discharge at the same distance, or the 

 quantity disappearing by discharge at the striking distance, is always 

 almost exactly the same, whether the short copper or long platinum 

 wire be interposed. 



With three jars, and at the distance 1 of the knobs of the spark 

 micrometer, the quantity of electricity required for the first discharge 

 was 5 z= 6 ; to produce the second discharge, the battery had to re- 

 ceive afterwards the quantity (/ =: 5 ; thus f of the entire charge dis- 

 appeared at the distance 1, or, in other words, we have 



q' 



rr A =0.833. 



For s =: 4, d = 1, we have (j =: 8, q' -=2 6.5, hence 

 ^ = ii5=. 0.812... 



For s = 5, d =. 1 



q' 



we have q = 10, q' =zd, hence 



^i.= 0.9. 

 q 10 

 For s =r 5, d=.o, we have q=: 27, f/ = 22.5, hence 

 (/_22.5 

 'q~ 27. 



