Kingdom.] RAILWAY AND MARINE MECHANISM. 211

North Areas A. B. 10 to 34 ; C. D. E. 1 to 10, &

be doubted, with much greater risk of accident. Itwill be readily understood that the system must be con-sidered irrespective of the particular arrangement exhi-bited which had in view to economise space in the vessellongitudinally ; and that cylinders, disposed horizontallyor otherwise, are equally apjilicable, and the horizontaldisposition would be adopted for war steamers. ^ In dhis-tration of the above, the marine condensing engine exhi-bited (100 horses power), may be regarded as dividedinto two parts comparatively distinct one from the other,the steam portion working directly on to the screw shaftwith all the simplicity of a high-pressure engine, at aspeed of 120 revolutions per minute; the vacuum appara-tus, as well as the supply and bilge pump, being made towork at the reduced speed of 40 reciprocations, or aboutthe approved speed of paddle-wheel engines of samepower. It may here be well to state that the relativecapacity of the vacuum pumps and the steam cylindersmust be calculated in reference to the difference of speed;and that, in practice, the vacuum produced in the. con-densers is found to be as perfect as that in any existingengines, viz., 28 and upwards. A pair of engines, iden-tical with these, is at work in the Bristol Channel . Thesystem has been'proved with equal success in a small ex-perimental vessel, in which the speed of vacuum appara-tus is only i instead of ] of that of the steam pistons.The following advantages are claimed:—High speed uponthe screw shaft, in connection with slow speed of vacuumapparatus, in the same machine. No reasonable limit tothe high speed required for screw shaft, giving facility forsecuring the best form and angle for propeller. No rea-sonable limit to the reduction of speed required for va-cuum apparatus, with diminished risk of accident result-ing therefrom. Saving of power by reason of relativelyreduced proportion of vacuum pump, and consequentsaving of fuel. The Plate (288) represents elevationsand afplan of these engines as applied to river steamers.

5 Taplin, It., 7 Upper Woodland Terrace, Woolwich—Inventor.

Model of a telescopic funnel or chimney for marineboilers. This telescopic funnel or chimney is on thecompound principle, and not simply telescopic. It is de-signed to accomplish the desideratum of striking thefunnel of any steam vessel below the upper deck; andthe principle may be applied in a variety of ways. Topaddle-wheel vessels it affords the power of working thesail nearest the funnel; and while under sail, the vesselis not hindered by its resistance to the air. To the screwvessel, in particular, it offers more advantages, as by re-lieving the deck of the cumbersome and unsightly appear-ance, as well as inconvenience of the funnel, it enablesthe vessel to chase or approach an object almost unob-served; and if the masts, rigging, &c., be dispensed with,which is also possible, nothing but the hull might be

19 to 33 ; F. 1 to 32 ; G. II. 1 to 13, & 19 to 26.

seen, when steaming to effect some special purpose, as asecret expedition, &c.

6 Watt, James, & Co. (late Boulton & Watt),18 London Street, and Soho, Birmingham —Designersand Manufacturers.

Marine engines, of the collective power of 700 horses,with four cylinders, 52 inches diameter, and 3 feet stroke,designed for driving the screw propeller by direct actionat 65 revolutions per minute.

The object of the inventor has been to combine light-ness and compactness relatively to the power, with sim-plicity of arrangement. These engines can be placed inthe ship entirely below the water-line, whereby they areprotected from the effects of shot in vessels of war: andin the mercantile marine the decks are left clear forpassengers or cargo.

Two working models, made in the year 1785, by Mr.William Murdoch, of Soho , who was at that period con-nected with the firm of Messrs. Boulton, Watt, & Co. Thefirst is of a “ locomotive,” showing the original applicationof steam for the purposes of travelling; and tried uponthe common road in Cornwall , in 1785 and 1786. Thesecond is a model of an oscillating engine, constructedat that early period for the purpose of illustrating Mr.Watt’s patent of 1784, for making the cylinder work onits axis.

7 Koughton, R., Dockyard, Woolwich —Inventor.Improved slide-valve.

8 Penn, John, & Son, Greenwich —Manufacturers.

Pair of marine oscillating engines. One paddle-wheelis fitted on the patent feathering principle; and the otheron the ordinary plan. Collective power, 24 horses.

Pair of patent marine engines on the trunk principle,arranged and adapted for the driving of the screw-propeller direct. Collective power, GO horses.

Pig. 1 represents a section of the patent marine trunkengines, the piston being at half stroke.

Fig. 2 (p. 212) shows a section of the marine oscillat-ing engines at the air-pump.

Working model of a pair of marine oscillating enginesas made and fitted on boardH.M. steam-frigate “Sphynx.”Collective power, 500 horses.

. Working model of a pair of oscillating engines, used inriver vessels.

Working model of a pair of patent trunk engines asfitted on board H.M. steam frigate “ Arrogant,” 46 gunsand H.M. steam-sloop “Encounter,” 12guns. Collectivepower, 360 horses.

An auxiliary or “ donkey ” engine for pumping waterinto marine boilers when the larger engine is not atwork.

Venn & Son’s Valent Trunk Engines.

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