— 152 — It was found impossible to float this unit, there being unfortunately no barge capable of holding it, so it was temporarily housed on the river bank, the pump being belt driven by a countershaft at low-water level and directly from the engine shaft during flood season. The pump supplied with the Semi-Diesel engine is utilised, and proves to be very efficient.

This unit is of the compound, composite, undertype pattern, the boiler being fixed directly over the engine, all being carried on a girder-frame bed.

The locomotive-type boiler is arranged to burn either liquid fuel or wood, and tests have been made to determine comparative consumptions.

The engine cylinders are of 7| inches and 13 inches diameter, the pistons havinga stroke of 16 inches. A horizontal jet condenser is fitted and actuated by a tail rod from the L.P. piston. A feed heater is provided for use when running non-condensing, the boiler feed being supplied by a pump driven by an eccentric on the engine shaft, and provision is also made for an auxiliary horizontal duplex pump.

The tests were made immediately on erection of the unit for inclusion in this report, and furnish interesting comparative figures.

First Trial of Plant No. 4. Tuti Island.

Date Duration of trial ... ' ...

Kind of fuel used Total fuel fired Fuel fired per hour Steam pressure at boiler Steam pressure at engine Eevolutions per minute Average vacuum Average weir reading ...

Discharge of pump Discharge of pump Total lift Water Horse-power Fuel per W.H.P. per hour Cost per W.H.P. per hour Cost per 1,000 m**. water delivered The test may be regarded as very satisfactory, particularly the cost per W.H.P. per hour, this figure being the lowest yet reached.

Slight slipping of the new countershaft belt took place during the test, and consequently the pump was not running quite up to its maximum speed.

July!