— 14S — improvements in this type of engine, and demonstrated economies in running costs as compared with those of steam plant, which gave promise of solving the problem of cheap pumping in the Sudan.

Egyptian crude oil is offered in Suez at less than £E.3 per ton, and it was thought that the projected establishment of oil-tanks at Port Sudan and a system of bulk carriage on the railways would encourage general employment of the crude-oil engine, if its applicability could be shown. A trial shipment of 25 tons of crude oil was consequently procured at Suez, but, pending completion of arrangements for bulk carriage, the economic value of the fuel was practically killed by freight and handling charges of nearly £E.5 per ton.

The oil on analysis compared very favourably with American and Russian oils, its viscosity being slightly greater—a matter of little moment in the high temperatures obtaining in the Sudan.

The abilities of the native engine-driver being very limited, it was considerfed inadvisable to instal a full Diesel engine, with its complicated construction and abnormal pressures, and an order was placed with a well-known maker for a machine of the semi-Diesel type.

As in the case of Plant No. 2, the engine and pump were floated in a barge, this method possessing such . great advantages that its ultimate adoption throughout the Sudan will doubtless be effected.

The pump was of the centrifugal type with suction and delivery pipes of 12 inches diameter, and was belt-driven from engine shaft. The delivery pipe line was arranged similarly to that of Plant No. 2, having two short lengths of flexible leather piping to take up the movement of the barge. The flume is brickhned and runs a length of 100 metres before delivering over the measuring weir into the main canals, and had a capacity of 10 cubic feet per second, sufficing for the irrigation of 500 feddans.

The engine was of the semi-Diesel, two-cycle, vertical type, with double cylinders, and cranks at 180 ; and at 330 revolutions per minute was capable of developing 55 H.P. Compressed air was employed in starting, but was immediately cut off when the engine received the first impulse from the ignition of vapour.

Trouble was experienced at first as a result of the crude oil carbonising and clogging up the vaporiser bulbs, and the makers on being referred to, recommended running on a mixture of 10 per cent, paraffin, 90 per cent, crude oil.

This was done, and the carbonising trouble disappeared ; but with paraffin at £E.16 per ton, the cost of running was necessarily enhanced.

The shop-test figures of this engine before delivery from the makers were extremely good, the consumption of fuel per W.H.P. hour being -44 lb. paraffin and •57- lb- crude oil. It at once became apparent, however, that in actual working conditions these consumption figures could not be touched, and a test was arranged to determine the actual result.