426 SEC. 12. APPLIED MECHANICS. 



2166. Drawing of Messenger's patent high-pressure vertical 

 water-tube boiler ; for steam yachts and launches. Designed by 

 Thomas Messenger about 1869. A. Verey and Co., Engineers, 

 Dover. South Kensington Museum. 



2167. Steam Donkey Engine and Pump, single-acting, 

 for feeding steam boilers with water. Alexander Wilson and Co., 

 Engineers, Vauxhall Works, Wandsworth Road, S.W. 



South Kensington Museum. 



Note. Diameter of steam cylinder, 3^ inches ; stroke, 4 inches. Diameter 

 of pump, 1| inches. Will pump 460 gallons per hour, and feed a 30 h.p. 

 steam boiler. 



2168. A Helm Indicator for the prevention of Collisions 

 at Sea. John James Nickoll. 



It is a lantern which is hoisted under the mast-head light of a steamer, and 

 connected with the helm by rods or chains, and acts automatically with the 

 rudder like a toll-tale, showing a green light when she is starboarding, and a 

 red light when she is porting her helm, thereby showing the course a vessel 

 is about to steer, and before she answers her helm or deviates from her 

 course. 



2168a. A pair of Ship's Side Lights with lenses. 



* John James Nickoll. 



Guaranteed to show the light on all the points, the distance required by the 

 regulations for preventing collisions at sea. The lenses are so constructed as to 

 prevent the smallest amount of absorbing light colour, and the burner requires 

 no chimney. 



2168b. Wave-Indicator. An instrument intended for the 

 direct tracing of the height of the. waves, and for deducing their 

 form. Vice-Admiral Paris, Paris. 



21G8c. Soiling-Indicator. An instrument indicating the 

 rolling of ships, not only at its extreme amplitude, but during all 

 its periods. Vice-Admiral Paris, Paris. 



These two instruments are due to the late Lieutenant Armand Paris, son of 

 the Admiral. 



2169. Set of (eight) Models of the Block-making 

 Machinery invented by Sir Isambard Brunei, for the use of 

 Government, and set up in Portsmouth Dockyard by Messrs. 

 Maudslay and Sons in 1804, where it has remained in use to the 

 present time. Royal Naval Museum, G)*eenwich. 



2170. Plan for Feathering a Screw Propeller, proposed 

 by Messrs. Maudslay, Sons, and Field, 1848. 



Royal Naval Museum, Greenwich. 



2171. Hirsch's Screw Propeller. 



Royal Naval Museum, Greenwich. 



