AND HORTICULTURE, 67 
wire and a zinc plate. When the wire between the net 
and the machine is led through a wall it must be insulated 
with a round plate of ebonite (4 cm. diameter), as shown 
_in Fig. 7. 
After some sparks have been taken between the spheres 
of the discharger, the spheres are to be put in contact and 
the wires connected with cand c. Here, after the spheres 
are separated, the wire net is charged. To prove this 
the spheres of the discharger are brought to within a short 
distance of one another (I mm. or less), and a small spark 
will be seen between them, notifying that the net is charged, 
well insulated, and fitted for its purpose. 
The height of the wire net above the plants must be 
about 04 m. at its lowest point, and this height must be 
increased as the plants are growing. This raising needs to 
be done only once or twice, by loosening the rings of the 
insulators, lifting them up and again fixing them. 
The wire net must be carefully examined to see that 
it does not touch the plants, as all the electric current will 
be conducted away by such contact. 
As the electricity, if given in too large quantity, may 
damage the plants, especially if administered at periods of 
burning sunshine, it is best to apply the current on sunny 
days for only four hours in the morning (from 6 a.m. or 
7 a.m. to 10 a.m. or II am.) and for four hours in the 
afternoon (from 4 p.m. or 5 p.m. to 8 p.m. or 9 p.m.). 
On cloudy days, however, it can be given the whole day, 
and even during the night when the weather is moist. 
During rainy days it ts useless to keep the machine in motion, 
because the wire net then loses its charge instantly. 
In very dry periods, with burning sun, it is best to 
interrupt the applications of the electricity, or to administer 
for only one or two hours a day. 
When the air is very moist the machine will speedily lose 
its charge, because the electricity is going from the wire net 
almost instantly. On such occasions it will be advisable 
