172 GERMINATION 



weak galvanic currents set up by the needles in contact 

 with the acid secretion of the fruit. Dr. Trowbridge, Dr. 

 RadclifEe, and others had given this explanation of the 

 phenomena and, like everybody else, I had accepted it for 

 fact and, in all probability, should not have given the 

 matter another thought had it not been for one thing — ^in 

 making one of the contacts I obtained a reversal of sign. 



Now, it is quite certain that if the deflections were due 

 to currents set up by difierence of polarity in the needles 

 no reversal of sign could occur unless the connections were 

 reversed — and they were not reversed. In that fortuitous 

 way an investigation was initiated and valuable knowledge 

 gained. Like many other discoveries it had its origin 

 in pure accident. I just happened to sit up for a moment 

 and take notice ! 



With this preamble we may pay a visit to the garden 

 and see what further information we can obtain. 



Repetition is apt to become wearisome but it is necessary 

 to remind the reader that the air is the positive and the 

 earth the negative terminal of Nature's electrical system. 

 Electrical circuits are of two kinds, i.e., " earth return " 

 and " metallic." In the former one pole of the battery 

 at each end is connected with the earth ; in the latter with 

 a second wire. That, I take it, is understood. 



In the natural circuit the negative terminal is necessarily 

 " earthed " because it is the earth itseK. To complete 

 the circuit the plant or fruit must have access to the positive 

 air. In trees and plants this is gained through the stomata 

 of the leaves, while in fruits the flower end — whether the 

 flower is decayed or not — is never quite closed. 



In these days of electric lighting everyone is more or less 

 conversant with the fact that there are several ways of 

 connecting or joining up incandescent lamps. Those in 

 common use are called respectively Series, Series-pairaUel, 

 and Parallel. 



Series is when the lamps are strung, so to speak, one 

 after another upon the feed wire ; Parallel is when a group 

 of lamps takes the place of one, and Series-parallel a mixture 

 of the two methods. In the arrangement of batteries. 



