194 
THE EFFECT OF ELECTRICITY UPON PLANTS. 
Speschnew ^ obtained his current simply by using plates of different 
metal connected by a wire, the small earth current thus obtained 
apparently proving amply sufficient to produce a marked result. 
Rawson and Le Baron ^ have used the same method at Arlington, 
Mass., quite recently. The plates of copper and zinc joined by a wire 
are sunk at either ends of forcing beds in the greenhouses, and are 
said to be very efficacious in bringing on lettuce at an early time, in 
fact they state that the lettuce thus electrified was ready for the 
market a week earlier than that in the control beds. 
The potential difference between the plates was about 0*5 volts, and 
the current flowing varied from 0‘4 to 15 railliamperes approximately. 
The results obtained with this method at College will be described 
later. 
In many cases electricity has been artificially generated and then 
used to increase the plant’s growth, either by a system of discharge on 
to the plants from above or by being passed through the soil in 
which the plants are growing. 
Professor S. Lemstrom ^ used the method of overhead discharge in a 
great number of experiments which he has conducted and which were 
often upon a very large scale He usually employed an influence 
machine of special construction driven by some continuous source of 
power ; one pole of this machine was earthed, while the other was 
connected to a system of wires stretching over the plants and studded 
with fine discharge points. 
His results show a definite increase in yield in the case of many 
crops, whether the overhead vyires were kept positively or negatively 
charged. 
The current was applied sometimes at night, sometimes in the day- 
time with apparently equally satisfactory results. 
Lemstrom points out that precautions have to be taken in using his 
method of electrification, as in dry weather the electric discharge may 
easily be given for too long a time, when its effects are deleterious, also 
the treatment should vary according to the plants experimented upon, 
strawberries, for example, usually showing a very marked increase, 
whereas beans with the same treatment may often show considerable 
retardation in development. 
At the Clifton Laboratory Dr. E. H. Cook^ has carried out experi- 
ments the results of which seem to point to an increased power of 
germination, either with the use of low tension currents (up to 20 volts 
and current passing up to 100 milliamperes) or with high tension dis- 
charge from a Wimshurst machine. 
^ Referred to by R. Green, Phil. Trans, of the Royal Society. — Vol. 188, 
R. p. 188. 
2 The Electrician. —Vol. 57, p. 305. 1906. 
3 Lemstrom. Electricity in Agriculture and Horticulture. — The “Elec- 
trician ” Series. 
‘^E. H. Cook, D.Sc., F.I.C. British Association, Bristol Meeting. 
