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aa er "TAE. Marine. REVIEW _ Engines of the British Cruiser Defence. The main engines of the new Brit- ish cruiser Defence are of special in- terest 'because in all probability they will be the last set of engines of the reciprocating type to be built for the British admiralty, on account of the adoption of the steam turbine for na- val vessels. The Defence was built by Scotts Ship Building & Engineering Co., Ltd., of Greenock, and the princi- pal dimensions are as follows: Length, 490 ft.; breadth, 74 ft. 6 in.; mean load draught, 26 ft.; weight of hull, includ- ing armor and backing, 8,215 tons; dis- placement on load draught, 14,600 tons; estimated 'horsepower (forced draft), 27,000 I. H..P.; corresponding estimat- ed speed, 23 knots; coal capacity at load draught, 1,000 tons; armament, four 9.2-in. breech-loading guns, 10 7.5- in. ditto, and 16 small quick-firing guns. Total estimated cost of ship, including guns, $6,885,535. The propelling machinery 'is arranged in two separate watertight compart- ments and consists of two sets of four-cylinder, triple-expansion engines, balanced on the Yarrow-Schlick and Tweedy system. Each set has one high, one intermediate and two low- pressure cylinders, all fitted with liners and steam jacketed. The diameters of the cylinders are, respectively, one of 4056 in. one of 65% in., and two of 7456 in., with a stroke of 48. They are capable of developing collectively 27,000 I. H. P. at 125 R. P. M., with a steam pressure at engines of 250 Ib. per Square inch. Tle cylinder covers and pistons are of cast steel and conical in form. Both sides of the pistons are machined, as is also the case with the inside of the covers and the cylinder ends. Stephenson's link motion is adopted for working the valves, which consist of one piston valve for each 41 high-pressure cylinder, two piston valves for each intermediate-pressure cylinder, and one flat treble-ported slide valve for each. low-pressure cyl- inder. The 'starting platforms are ar- ranged at the sides of the ship. All gear for starting and working the en- gines is led to' convenient positions on these platforms. Forged steel col- umns support the cylinders at the front of the engines, The back columns are made of cast iron of the usual box section, and are formed to carry also the crosshead slipper guides, which have large heating surfaces. The crank shaft for each engine is in four pieces, each piece being forged from the solid. The journals and pins are bored hollow, and are 197 in., and 27% in. in external diameter respec- tively. The engines are reversed by means of a double-cylinder steam en- gine, through worm-wheel and screw gearing, connected to a reversing shaft supported off the 'back columns and 'cylinders, and extending the whole ENGINES OF THE BRITISH CRUISER DEFENSE.