8 ELECTRICITY IN AGRICULTURE 
intensity. When these manifestations appear, principally 
in the Polar regions, it must be admitted that the current 
there possesses the highest intensity. The effect of it must, 
therefore, be more remarkable there than elsewhere. 
Once convinced not only of the necessity for finding a 
cause for the above-mentioned phenomena of the vegetable 
kingdom in the Polar regions, but also for the existence 
of the electric current from the atmosphere, I was strongly 
induced to connect the two phenomena, and to regard the 
electric current as the cause of the peculiar phenomena in 
the vegetation, and all that has been said about these 
peculiarities will find its explanation in this:—(1) The rich 
harvests and their periodicity ; (2) the periodical increase 
’ in the year rings of the fir woods; and (3) the needle- 
formed leaves and the beards of the ears will, from this 
point of view, only be the means by which the electricity 
is conducted from the atmosphere to the earth. As the 
intensity of the current is highest in the Polar regions, its 
effect must also there be the greatest. 
It must not be overlooked that electricity has hitherto 
been regarded as of little or no importance in the complex 
life of a plant, and a great effect from its application 
was not anticipated. From a further consideration of the 
subject it will, however, be clear that this conception must 
be changed, and that electricity must be numbered among 
the principal factors in plant life. , 
THE EXPERIMENTS. 
§ 4 Since the year 1746, when the Scotchman, Maim- 
bray, made his experiments on the influence of electricity 
on two myrtles, a great number of researches have been 
performed to examine this influence. The most striking 
feature of these experiments is that they are a/ways con- 
tradictory. “Hardly has one explorer obtained favourable 
results before another presents himself with directly oppo- 
