— 90 — liine mortar has been found very efficient and inexpensive. The cost of a small section laid down on the farm worked out at 161 milUemes per metre. This figure may easily be reduced if a considerable length of gadwel, say, two or three thousand metres, is treated.

Savings of the first importance result from the employment of brick-lined canals : (I) There is a permanent decrease in the loss between headwoiks and field, because : (a) There is little seepage.

(b) There is less evaporation as the section can be reduced and the surface of water exposed to the sun thus limited.

(II) The canal does not become choked with silt, as reduced friction spells greater velocity with a given fall ; and the water does not stand in the gadwel after irrigation is completed. A direct result is that the land benefits by the increased amount of silt carried on to it during irrigation.

(III) Infiltration drains are rarely necessary. The land occupied by them is thus available for the growth of crops.

(IV) The risk of mosquito-breeding is almost eliminated, and a further saving is effected on the wages of a special " Mosquito Boy " and on the cost of the oil he pours over stagnant water.

(V) The risk of a burst gadwel in the middle of the season is reduced to a minimum.

(VI) The biennial cleaning and its attendant cost are obviated.

Care must, of course, be taken to see that the bricks are well laid in the first instance, and that stock are not allowed subsequently to trample over the gadwel. The cost of upkeep is practically nil. A section laid down three years ago has not been touched and is still in excellent condition.

Drainage.—An attempt to improve the quality of the soil on the farm by drainage was made in 1912, when a main drain with two lateral branches was cut. (See plan for position.) The bottom section—75 cm.—of the drains remains constant throughout, but the depth increases from a minimum of two metres to four metres where passing through the river bank. The preliminary vertical section of J : 1 made in 1912 has stood remarkably well, though the main drain is begiiming to call for an increased width of cut. The outlet of this drain is below the flood level of the river. It was therefore necessary to construct a brick culvert with a sluice gate through the river bank and to erect a small oil engine over it, in order to remove drainage water during the flood. At