1891.] 



the Discharge of Leyden Jars. 



35 



include none of the leads in the discharged capacity, S/K = 134 cm. ; 

 if we include the whole, S/K = 195 cm. 



As for the self-induction, we get that approximately by putting 

 u = 34 in the expression (24), which gives it as 1768 cm. 



So the calculated wave-length is, with the whole of the leads capa- 

 city, 27rv/(195 x 1768) = 3690 cm. or 37 metres; and the agreement 

 is not very good. If the leads capacity is not supposed effective in 

 forcing the vibrations, its charge being merely forced to vibrate by 

 the jar discharge, then the calculated wave-length is 31 metres, which 

 is suspiciously accordant with observation. 



38. Single Voss Jar,* still with " Shorter Leads." 



Here the maximum is evidently off the scale ; so that, to show it, 

 the discharging circuit requires to be still further diminished in size : 

 which is impracticable. As to calculated wave-length, the lowest 

 estimate makes it 30 metres, when u = 5 : the highest estimate makes 

 it 32^ metres, either of which is so far accordant with observation. 



Two Pint Jars in Series, with " Shorter Leads.' 1 



Although the back kick was now fairly vigorous, no particular evi- 

 dence of its being greater at one place than in another was observ- 

 able. Evidently the leads are too short. Hence added the extensions 

 already described ( 31). 



* Probably the one with the larger capacity of the two, but unfortunately not 

 quite sure of this. 



D 2 



