Electricity—-Radium-, N-, and X-rays 
Pollacci’s careful experiments with flowering plants 
also led him to believe that plants are distinctly in- 
vigorated and assimilate more under electric currents. 
His statement that plants can form sugar in the dark 
when so stimulated has not yet been confirmed by 
other observers. 
The effect of electric currents on roots is still very 
obscure. When a current is passed through water in 
which there are seedlings growing, the rootlets often 
turn towards the positive pole. This is supposed to 
be due to some kind of electrolysis, injurious products 
accumulate at this pole, and the turning of the little 
roots towards them may be compared to the usual 
bending of injured roots towards the source of irrita- 
tion’--This would mean that the electric current may 
in itself have no effect upon them. 
But many ingenious and interesting experiments have 
shown that it is possible to use electricity in order .to 
help to accelerate the growth of plants. 
A Scotchman, Maimberg, tried to stimulate two 
myrtle bushes in 1746, but his results (the first to be 
attempted) were not conclusive. 
Next came the Abbé Nollet, who grew pot plants on 
an iron tray supported by silk threads. The plants so 
isolated were charged by means of an electrostatic 
induction machine. Both maize and mustard seed 
germinated much more rapidly. 
Bertholet set up a tall pillar with cupped points, so 
collecting atmospheric electricity, which was conducted 
into a series of plants at the base of the pole. Another 
ingenious system consists in sinking plates of copper and 
zinc in the soil of a greenhouse, and connecting them 
by a wire. Speschnew, a Russian, invented this method, 
which has also been followed by Priestley in 1906.2 
Others have used an arrangement of wires supported 
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