ELECTRO-CULTURE. 91 
The discharge is usually kept on from five to six hours 
daily, the hours for running it varying according to atmos- 
pheric conditions. During periods of bright sunshine it is 
run in the early morning and late evening; on dull days it 
may be on all day; but on wet days, owing to leakage off 
the wires and down the poles, it is practically of little use to 
have it on at all. 
The field chosen for the experiment is one in which the 
soil is as uniform as possible, and the amount of fertiliser 
applied is carefully weighed and distributed equally over both 
the electrified and control plots. 
For the first three years, 1912, 1913, and 1914, the crop 
experimented on was potatoes, with the result that each 
season there was a considerable difference between the weight 
of crop lifted off the electrified and unelectrified areas. 
For purposes of weighing with the greatest accuracy, 
the two plots were divided into spaces measuring one-tenth 
of an acre each—the tubers were put, when lifted, into sacks 
and weighed on scales which were placed near at hand. 
The following table may be of interest as showing the 
increase in yield of tubers lifted under the discharge wires 
over those from the control :— 
1912—Electrified, 10 cwt. 3 qrs. 5 Ibs. more per acre 
than control. 
1913—Electrified, 13 cwt. 3 qrs. 21 lbs. more per acre. 
1914—Electrified, 1 ton, 3 cwt. 2 qrs. 1 lb. more than 
control per acre. i 
The great experimental difficulty lies in the impossibility 
of obtaining an absolute control area for comparison; the 
discharge is greatly effected by windage conditions, and 
sometimes is carried as far as three hundred yards beyond 
the network, when the wind attains a high velocity. Even 
on days when it is quite calm a slight charge always finds its 
way over to the control area. 
' It was attempted to obviate this drawback by erecting a 
wire screen between the two plots, raised three feet higher 
than the electrified network and well earthed at the bottom, 
hoping by this means to intercept the current before it reached 
the control area; but though by means of this screen the 
