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te 26 and fitted with two Morrison renewable suspension furnaces, with large grate surface arranged for burning Indian coal under forced draft supplied by a TAE MaRINE. REVIEW gines were in use on land, and the ex- perience of details necessary to make the large cylinders capable of withstanding the shocks of explosion and the high som ENGINES OF FERRY STEAMERS FOR THE HOOGHLY. 48 in. fan on the closed stokehold sys- tem. The machinery includes auxiliary feed pumps, large auxiliary bilge pumps and bilge ejectors. The vessels are. lighted throughout by electricity furnished by a 3.3 K. W. engine and dynamo set gen- erating current at 100 volts. ' The boats, engines and boilers have been entirely constructed by Messrs. Thornycroft, and the accompanying photos of the machinery well illustrate the design and construction of the en- gines. INTERNAL COMBUSTION OF MARINE ENGINES. Mr. J. T. Milton, of Lloyds Register, read a: paper on "Internal, Combustion Engines for Marine Engineers," at a meeting of the Institution of Civil En- gineers, on Jan. 22. The economy and the increasing use of internal-combustion engines on land had led, Mr. Milton. said, to considerable interest being taken in their application to marine purposes, and already a large number of such engines had been fitted in small craft on the continent, in most of which heavy min- eral oil was the fuel used. On land various fuels were used for these en- gines, such as petrol, refined oil, heavy oil, coal+gas, producer-gas, coke-oven gas, and blast-furnace gas, but for ma- rine purposes generally producer-gas and heavy oil were at present the only avail- able fuels, Only the mechanism and ar- rangement of the engine were discussed, however, in the paper. Very large en- temperatures of the burning fuel would be available for marine engines. if the other necessary mechanical requirements were complied with. The special condi- tions required for a successful marine engine are: (a@)The engine must be re- versible; (b) it must be capable of be- ought not to be greater than one-quarter. of the full speed; (d) it must be capable of working well, not only in smooth water, but in heavy weather in a seaway in which the varying immersion of the propeller causes rapidly changing condi- tions of resistance. In large engines these conditions pro- hibited the use of movable-bladed pro- pellers, clutches, and toothed gearing, and also of a fly-wheel, and necessitated the use of a reversing engine with a direct drive on to a fixed propeller. They re- quired also a fairly equable turning mo- ment at all working, speeds. In marine engines the revolutions were practically - proportional to the speed of the ship, and as the vessel's resistance increased much more rapidly than the speed, it followed that for a reduction of speed of revolu- tion the mean effective pressure must be reduced much. more than in proportion to the revolutions. This was a much more difficult problem in marine engines where no fly-wheel was practicable, than on land, where the use of a heavy fly- wheel. permitted the suppression of al- ternate fuel charges. With the four- stroke cycle, where one single-acting cyl- inder only was employed, the fluctuation of moment varied from 7.7 times the mean moment in a forward direction to 1.5 times the mean moment in the re- verse way.' With two such 'cylinders, or with one double-acting cylinder, the mo- tion was better, but was still unsuitable, and the minimum number of cylinders which would always give a positive turn- FERRY STEAMERS FOR THE HOOGHLY. ing quickly stopped and of being quickly started, either ahead or astern; (c) it must be capable of being promptly speeded to any desired point between full speed and dead slow, which latter speed ing-moment was four single-acting or two double-acting. Diagrams were shown of the turning- moments resulting from a vertical two- cylinder tandem engine with one crank;