1891.] 



the Discharge of Leyden Jars. 



In addition to these ordinary jars, a couple of large condensers 

 were made, each consisting of 16 pairs of 11-inch square' tinfoil 

 sheets, separated by double thicknesses of window glass, each pane 

 about -j^g- inch thick, and with a good margin ; tinfoil strip con- 

 nectors protruding on alternate sides, and copper wire prolonga- 

 tions, with all joints soldered, terminating in a pair of knobbed rods 

 projecting upwards through stout glass tubes more than a foot apart ; 

 the whole thoroughly soaked and embedded in a mass of paraffin, 

 poured molten into a strong teak outer case 22 X 20 X 13 inches, 

 the whole when finished weighing about 3 cwt. 



The capacity of one of these condensers was 0*028, of the other 0'02, 

 microfarad. Single glass thickness would have given much greater 

 capacity, but preliminary experiments showed that single thicknesses 

 of glass were punctured by very modest sparks. 



It is important in these experiments to have joints better made 

 than is usual for high-tension electricity. Fizzing or sparkling 

 inside jars is abominable. 



ACCOUNT OF THE LONG CONDUCTORS USED IN THE EARLY EXPERIMENTS. 



2. Round the Lecture Theatre,* supported on four vertical posts a 

 good way from every wall, were stretched and supported, either by 

 silk thread or silk ribbon according to 'the strength demanded, four 

 or five wires, two of them of copper, one thick (No. 1 B.W.G.) and 

 the other thin (No. 19) ; two of them of iron, one thick (No. 1) and 

 the other thin (No. 18). They are called respectively " long thick 

 copper," "long thick iron," "long thin copper," "long thin iron." 

 Sometimes a " thinnest iron " of No. 27 B.W.G. was used too. The 

 thick wires formed a rude rectangle 840 x 515 cm. ; being joined 

 mechanically not far from their ends by a foot or so of silk ribbon, 

 and sufficient free ends being left to connect directly with jars or 

 machine ; connexion being usually made by wrapping tinfoil tightly 

 round the joined conductors. The thinner wires formed rather 

 larger rectangles. 



Particulars of these conductors here follow : 



* University College, Liverpool. 



B 2 



