32 GERMINATION 



takes place. The brown seed coat dries and becomes 3u 

 non-conductor and the moist layer c, also dries up and 

 interposes a layer of non-conducting fibre between the 

 seed coat and the inner membrane /. We have then the 

 Leyden-jar minus its outer coating of tinfoil, and without 

 that coating no inductive action can occur. 



That is to protect the seed until such time as it is buried 

 in the soil. When that happens moisture transforms the 

 seed coat into a conductor and the Lej^den jar is an accom- 

 plished fact. The seed coat is the outer coating of tinfoil, 

 the fibroid lining, c, and the inner membrane, /, the glass, 

 and the seed substance the inner coating of tinfoil ; air 

 in the soil completing the circuit. 



If the seed is cut in section a knob-shaped piece, like the 

 end of a dumb-bell, will be noticed and as growth commences 

 at this point it would appear that the embryo radicle and 

 plumule are ensconced within it. 



Next in order we will take an acorn. 



In its electrical aspect this seed is practically identical 

 with the horse chestnut except that the seed coat is not 

 so fully closed at the apex as to be airtight and it has not 

 therefore the keeping quaHties of the chestnut. In other 

 respects also there are differences between the acorn and 

 other seeds. For example, the seed substance of the hazel 

 nut, which it resembles, mostly remains whole during ger- 

 mination, except at the point where the radicle and plumule 

 emerge, but the acorn is formed of two halves within the 

 inner membrane, and the radicle is connected with each half 

 by a band or tongue some 3/32nds-inch in width. The 

 cotyledons of the horse chestnut plant grow from the inner 

 margin of the seed substance and the central portion, at a 

 certain stage of growth, becomes detached and, if handled, 

 falls away. 



Acorns are always connected in series upon the parent 

 oak. The stalk is a continuation of the (earth) battery 

 wire and inasmuch as the seeds do not, whilst adherent to 

 the tree, receive a static charge but a direct and continuous 

 supply of current the circuit is completed by a point at the 

 apex of the seed being left open to the air. The following 



