I. C. ENGINES
Gas engines continued to be developed up to the end of the war; in fact orders for spares were being received as late as 1940. Complete power installations were undertaken for public electricity supply and for industrial purposes, the largest double-acting engines built being two 26-in x 30-in 1500-b.hp three-cylinder units for the Mersey Power Company. Small horizontal single-cylinder engines from 2 to 30 b.hp were designed in 1910 and found a ready market.

From 1912 onwards a few vertical Diesel engines were made in a single-acting four-stroke design developed by the Company, the largest being a 485-b.hp four-cylinder engine for the Linotype factory at Broadheath. Towards the end of the war submarine engines were being built to a Vickers design employing the Ricardo solid injection system, which facilitated the use of compression ignition on small high speed engines.

STEAM TURBINES
Meanwhile the Company's impulse turbines were winning golden opinions for efficiency and reliability, and the engineers under Baumann were soon getting out their own designs and establishing characteristic features for subsequent development. In 1910 when the manufacture of impulse turbines began on a large scale, they were generally fitted with a velocity-compounded stage followed by a number of single impulse stages. The condensers were of the jet type with rotary air pumps, surface condensers being used only where the feed water supply was very limited.

One of the earliest impulse turbines was a 5000-kW machine installed at the Greenwich power station of the L.C.C. in 1910. A turbine was chosen for this work because the delicate instruments at the Observatory had been disturbed by the vibration from large reciprocating engines, and though the speed was only 750 r.p.m. the authorities sent inspectors to the works to watch the balancing at each stage of rotor assembly.

The ability of the turbine to utilize steam at high vacuum seems to have been quickly appreciated: more than a third of the two hundred and thirty machines put in hand during the next five years were of the mixed pressure type, generally for use with reciprocating engines driving colliery winders or rolling mills. In 1911 the Company made the first pass-out turbines in this country—two 1500-kW 3000-r.p.m. units for the Runcorn works of Salt Union.