— 150 — After a three months' working period, the engine cylinders showed signs of excessive wear, and, this being unequally distributed, the insertion of new piston rings did not eliminate the escape of gases into the crank chamber, which caused a gradual loss of engine efficiency and rise in running cost.

A fracture of the right-hand crank web closed the career of this interesting plant, the whole of one cylinder, details and bed plate being wrecked.

The failure of this engine is regrettable, for its purchase was made with a view to determining its suitability for general adoption in this country, and its performances with ultimate breakdown has probably created a prejudice against the system.

In fairness it should be" pointed out that, when first installed, the plant provided water at a cheaper cost than any other employed, and its failure does not in any way affect the desirability of adopting the type, provided that better material be used in construction.

Thoroughly skilled labour is so scarce in the country, and wages are at such an excessive rate, that the wages bill on a complex, full Diesel engine would in all probability narrow the margin of pumping profits to vanishing point.

A semi-Diesel engine is comparatively simple in operation and construction, and if the prevailing local conditions were considered during its manufacture, this type of pumping plant would meet al! requirements.

First Trial of Plant No. 3, Tuti Island.

Date ...* Duration of trial Kind of fuel used Total fuel consumed Fuel consumed per hour ...

Revolutions of engine ... ...

Revolutions of pump Average weir reading Discharge of pump ...

Discharge of pump ...

Total lift of water Water Horse-power ...

Fuel consumed per "W.H.P. horn-Cost per W.H.P. hour Cost per 1,000 m water dehvered It is noticeable that the fuel consumed per W.H.P. per hour is far in excess of the makers' figure on shop test, these being • 57 lb. crude oil, or,, with allowances for efiiciency losses in pump and belt transmission, -8 lb.