IX. NAVAL ARCHITECTURE, ETC. 493 



2161. Model of a Paddle Marine Engine, designed by J. 

 Scott Russell, F.R.S. ; having three oscillating cylinders, all con- 

 nected to one crank on the paddle shaft. One of the cylinders is 

 vertical, the other two are inclined inwards at about 45. J. Scott 

 Russell, F.R.S. South Kensington Museum. 



2152. Model, on a scale of 1^ inches to 1 foot, of the 

 Horizontal Condensing Screw Engines of H.M. Turret 

 Ship "Monarch," 8,164 tons. Built, 1868. 1,100 horse- 

 power, nominal. Lent by Ilumphrys and Tennant, Engineers, 

 Deptford. South Kensington Museum. 



*' The engines of H.M.S. "Monarch," are of C,600 indicated horse-power, and 

 were designed and built in 1868 by the lenders of the model. The engines 

 make 60 revolutions per minute, and are on the direct-acting principle, with 

 return connecting rods, and have surface condensers. There are four piston 

 rods to each engine piston. The cylinders are 120 inches in diameter, having 

 a stroke of 4 feet 6 inches. 



The condensers are of wrought iron, their tops being of cast brass. They 

 can be used either as surface or jet condensers. They contain 17,264 copper 

 tubes, each 6 feet long, giving large condensing surface per nominal horse- 

 power. The water is driven through the condensers passing outside the tubes, 

 by a reciprocating pump, the inlet and outlet pipes being of ample diameter. 



The cylinders of the engines are steam jacketed. 



The crank shaft is 22 inches in diameter, and the propeller shaft 18 inches. 



The starting, stopping, and reversing gear is placed on a central platform 

 between the cylinders and condensers of the engines. 



The crossheads to piston rods are forged solid; their guides have very 

 large surfaces, and are easily adjusted. 



The boilers are tubular, having brass tubes. They contain 21,000 square 

 feet of heating surface, and about 770 square feet of grate surface. 



The ship's propeller is a two-bladed Griffith screw, of gun-metal ; 23 feet 

 6 inches diameter, Avith adjustable pitch from 23 feet 6 inches to 28 feet 

 6 inches, weighing 22 tons. 



2153. Model, on a scale of 1 inch to 1 foot, of the Hori- 

 zontal Condensing Screw Engines of H.M. Turret 

 Ship "Prince Albert," 2,529 tons. Built 1860. 500 horse- 

 power, nominal. Humphrys and Tennant, Engineers, Deptford. 



South Kensington Museum. 



The " Prince Albert " was built in 1864 by Messrs. Samuda. She is an 

 armour-plated turret ship, 240 ft. in length, 48 ft. beam, 25 ft. 3 inches in 

 depth. She is driven by engines, of which the model is a representation, and 

 fitted with a four-bladed screw propeller. 



2178fa. Whole Model of the Cunard iron paddle steamer 

 " Scotia." Built 1861. Constructed for the British and North 

 American (Cunard) Royal Mail Steam Packet Company, by 

 R. Napier & Sons, Glasgow. Length 366 ft., breadth 47 ft. 6 in. ; 

 tonnage, builder's measurement, 4,050; load displacement, 6,520 

 tons ; horse-power, 1,000 nominal; diameter of cylinders, 100 in. ; 

 length of stroke, 12 ft. ; diameter of paddle-wheels, 40 ft. ; size of 

 floats, 1 1 feet 6 in. by 2 ft. South Kensington Museum. 



