— sounder this system the distribution of labour for irrigation is very simple. A man is told off to each distributory gadwel, and waters alternately the hods or the sections of four ridges, as the case may be, on either side of the channel.

It has been found that a man with a fair knowledge of the work and the right amount of water at his disposal, under this system can irrigate 100 hods or one feddan per diem.

In practice, however, figures taken over a whole season show that on an average he only waters seventy hods per diem. This is due to irregularities in the water supply, and a certain amount of additional work in repairing banks and gadwels before watering. Further, as the season advances, the erosion of the distributory gadwels becomes very marked, and the growth of the crop prevents mechanical aid being utilised in repairing them. Such repairs as are necessary have to be effected by the workman before he begins irrigating. The cost of actually leading the water and effecting such repairs works out at 49.5 milliemes per feddan per watering.

The large quantity of silt carried by the river during the flood causes all the gadwels to become more or less choked. This is aided by the luxurious growth of grasses on the banks. It is necessary, therefore, thoroughly to clean out all permanent water channels twice a year, once just before the flood in June, and once about October. The cost of this operation, which consists of digging up the grass on the banks, ploughing up the bottom and removing the earth thus loosened, is somewhat expensive, and works out at 7.2 milliemes per metre per annum.

Whenever contour permits, the permanent gadwels are raised above the surface of the surrounding land. Although this demands a stronger bank and more labour and expense in construction, it enables all the water to be drawn from the channel after irrigation is finished, thus allowing the gadwel to dry rapidly, and thereby preventing mosquitoes from breeding.

In lieu of borrow pits the soil excavated to form the gadwel has been cut to form infiltration drains. As the gadwel is raised the banks are subjected to a certain amount of pressure seepage ; and if this water is not carried off, it collects along the base of the earthwork, rendering the land, if not actually waterlogged, decidedly boggy and unworkable. It would be advisable to point out that seepage occurs to the same extent in sunk channels, and an even greater area is affected, if no infiltration drains are cut. Aeration of the soil is in such cases obviously diminished, and consequently the activities of nitrogen-fixing and nitrifying bacteria are retarded. Excessive evaporation over this boggy area increases the salt content of the soil, and mosquitoes find a convenient breeding ground amongst the rank grasses which abound therein.

In some cases the soil composing the banks of the gadwel is so porous that the amount of seepage forms a serious factor of waste. An impervious lining of some description has then to be inserted. A single burnt brick lining laid in