VII. NAVAL ARCHITECTURE, ETC. 423 



This is a working model of Mr. J. White's plan, adopted by the Admi- 

 ralty for H.M. ships of war and Indian relief troop ships, for carrying and 

 launching life-boats from ships' upper deck. 



2154k. Model of Dawes and Holt's Marine Engine. 



Henry S. Holt, C.E., Leeds. 



This is of the vertical compound condensing type, without intermediate 

 receiver between high and low pressure cylinders, and very short passages, 

 reverse action of pistons, parallel motion, single crank and connecting rod, 

 one vertical and one horizontal air pump, the former forming a counterbalance 

 to connecting rod, and the latter is arranged to be used as a starting cylinder 

 when required. 



2155. Model, on a T L scale, of the horizontal condensing 

 screw engines of H.M.'s ships " Nelson," built 1814, altered for 

 the screw propeUer 1860; "Conqueror," built 1833, altered for 

 the screw propeller 1859 ; and "Tamar," built 1863. The engines 

 are of 500 horse-power, nominal. Diameter of cylinders, 71 

 inches ; stroke, 3 feet. Ravenhill, Easton, and Co., Engineers, 

 Ratcliff, London. South Kensington Museum. 



2156. Model (working), on a 3 inch to 1 foot scale, of the 

 condensing vertical screw engines of steamship " A. Lopez," Cadiz 

 and Havannah Spanish Mail Service. 



South Kensington Museum. 



The engines are constructed on the hammer or inverted cylinder principle, 

 and have condensers, air and feed pumps, variable expansion gear, &c. The 

 model is a complete working condensing engine of about 15 horse-power. 

 It was made in 1866-7, and exhibited in motion at the Paris Universal Exhi- 

 bition of 1867. W. Denny and Brothers, Engineers and Shipbuilders, 

 Dumbarton. 



Note. The condensers of these engines are on Spencer's surface plan. 

 They comprise a large central box, on the top edges of which rest the cylin- 

 ders. The piston rods, two to each piston, work down by the sides of the 

 condenser, and move in guides carried by the sides of the box. The pumps 

 are worked off the cross heads, which are suitably prolonged for the purpose. 



2157. Screw Engine. High-pressure non-condensing screw 

 engine of 3 horse-power, for screw steam launches. Constructed 

 on the hammer or inverted cylinder principle. Diameter of cylin- 

 der, 5 inches. Stroke, 6 inches. A. Verey and Co., Engineers, 

 Dover. South Kensington Museum. 



2158. Drawing, on a 1 inch to 1 foot scale, of the compound 

 inverted cylinder screw engines of the steamships " Edinburgh 

 Castle" and "Windsor Castle," built and engined in 1872 by the 

 donors of the drawing. R. Napier and Sons, Engineers, Glasgow. 



South Kensington Museum. 



Note. The engines are of 270 horse-power, nominal, having surface con- 

 densers, air and feed pumps, link motion for reversing, &c. 

 Diameter of high-pressure cylinder, 44 inches. 

 Diameter of low-pressure cylinder, 72 inches. 



