6 The Economical Application 
branch will be in use in the same season, it will be necessary to 
plug up the other. To either of these arms on the surface, light 
cast-iron pipes, of 3-inch diameter, with turned and bored joints, 
are to bo connected, long; enough to form a line of such piping to 
the centre C (see shctcli) of each of tlie 5 acres requiring to be irri- 
gated through the season. It will be necessary to have a yard or 
156 yards X 312 yards. 
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Early Potatoes 
or Peas. 
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so of 3-inch gutta-percha tube connecting this line of pipes with 
the arm from the main-pipe, so as to compensate for any difference 
of inclination in the ground. These pipes, from the nature of 
the joints, can only form a straight level line, and therefore 
require to be propped up, or the ground to be somewhat levelled 
for their reception. The joints of these pipes should be rubbed 
over witli tallow, or some such preparation, to prevent rust, and 
make them easily separate when required. One set of them is 
to bo taken up at the end of the season and relaid in the spring 
on the next 5 acres, which come under irrigation in the rotation. 
