— 162 — advise cultivators that watering must be completed within such period. Water thefts, interference with supply pipes, and the banking up of streams to increase the head to a particular outlet are alike obviated, and the work of supervision is immeasurably lightened.

Evaporation and Seepage.—In an open canal evaporation can only be controlled by a suitably devised section, the regular cleaning of the channel and the expeditious emptying of the canal when pumping ceases. In certain classes of soil, however, measures for the limitations of seepage are of urgent importance. In such cases, experiment has determined that absorption can be profitably reduced by the use of suitable linings in the watercourses. In local conditions it has been found that a single brick lining set in lime mortar is both cheap and efficacious, an experimental section remaining in excellent condition after three years without repair.

The cost, which has certainly been more than recovered by the reduction of infiltration losses, worked out as follows : 145 bricks per metre length 130 milliimes.

1/50 m sand per metre length ...

1/100 m' lime per metre length ... Labour Porterage on materials and water Total cost per running metre 4 9 18 19 180 Labour employed included one bricklayer at 80 millimes per diem, six boys at 30 milh&mes, one donkey at 50 miUifemes, transport of bricks at 90 millimes per thousand, and on lime and sand at 90 millifemes per cubic metre. Work proceeded at the rate of 15 running metres per diem with this staff.

Duty of Water.—It remains to examine the efficiency of irrigation practice as determined by the measures described above. As a preliminary step, careful measurement was made through the module of the water actually applied in ordinary practice to areas on the Research Farm, which was found to average 470 m per watering per feddan, exclusive of the initial watering when absorption is abnormal. Comparison was then effected with a season's records obtained from gauge readings and irrigation returns of the adjoining area of native cultivation, when it was found that an initial supply of 833 m was afforded on the occasion of the first watering, and an average supply of 482 m throughout the season. The difference of 12 m per feddan represents losses between headworks and module discharges, but does not include losses in the subsidiary channels. It is, however, an eminently satisfactory result when compared with similar returns from other centres when unduly extended canals without lining exhibit extraordinary losses of water in transit.

It is, however, to be noted that the soils through which this particular system has been carried are exceptionally retentive, and that a very different result