ELECTRICAL CONNECTIONS 



181 



removed from the tree the end of the stalk is at once sealed, 

 either by a resinous or gummy excretion or by becoming 

 fibroid. The earth charge is cut off and therefore one 

 would think electrification would cease. That is not so, 

 however, The flower end is never closed and so long as it 

 is exposed to air the core and stalk are negatively charged 

 by induction ; the rind or peel conserving the energy of the 

 cell. 



You cannot polarise this piece of electrical apparatus, 

 not even if you short-circuit it for six months on end. 



The Onion is even more remarkable : 



/bs./er/T7. 



Onion — in Section. 



It is a standard cell of a very perfect description. The 

 current evolved by it, in accordance with established laws, 

 varies directly with size, but the electromotive force of 

 them all is the same, *.e., 0.086 volt. The outer insulation, 

 consisting as it does of a number of dry, non-conducting 

 layers, is very high and both negative and positive terminals 

 are well defined, rendering it invaluable for all purposes 

 where a standard cell of low electromotive force is required. 



