128 ROYAL SOCIETY OF CANADA 



The dimensions of the cylinders are : — 



No. 1 ()^ inclies diameter. 



No. 2 9 '• 



No. 3 13 " 



No. 4 18 " 



The stroke of each engine is 15 inches. There arc two cranks which, 

 during tliese experiments, were phiced opposite to each other, although 

 it is possible to alter the angle between them by means of the coupling in 

 the middle of the shaft. For convenience of experimenting the engine is 

 so arranged that the piston rods of either or both of the top cylinders 

 may be disconnected from those of the bottom ones, drawn up out of 

 their way and fastened in that jiosition. Crreat care has been exhibited 

 in the design of the steam piping and it is possible to Jead the steam 

 direct from the boiler into one cylinder, or into any two cylinders. This 

 fact, united with that of being able to disconnect either of the top 

 cylinders from the bottoni ones, or of being able to disconnect by means 

 of the coupling in the middle of the crank shaft the right hand from the 

 left hantl engine, attords a possibility of making a great range of ex- 

 periments with varying cylinder ratios and grades of expansion. 



Each cylinder is capable of being jacketed at the top, bottom and 

 sides. Cylinders 1 and 2 are fitted with steel liners, the space between 

 the liner and the cylinder body being used for jacket space. Cylinders 3 

 and 4 have liners of cast iron. These are constructed with heat ribs as 

 shown in Fig. 2 and are remarkably efficient. As will be seen" from the 

 results of the trials the difference between the jiowei'S developed by the 

 engine was very considerable when working with or without the jacket 

 steam. At the outlet from each jacket is fitted a bi-ass mounting with 

 cocks and a gauge glass, to allow the outflow of the water condensed in 

 the jackets to be regulated. Fi'om theuce, pipes lead down through a 

 small condenser at flu; foot (jf the engine. By this means the condenst'(l 

 steam niay be sufficiently cooled to prevent any re-evaporation when it 

 gains access to the open air. It is thus possible to measure sei)arately the 

 water c(mtained in the top, bottom or side of any special cylinder. A 

 Willans's coil is attached to cylinder No. 4. It has fittings similar to 

 those of the jackets, to measure the amount of steam that is condensed in 

 it. The sides and top of each cylinder are covered with cork asbestos 

 non-conducting composition inclosed with sheet iron cleading. 



The condenser is separate from the engine, and the air pump attach- 

 ed to it is worked by a special engine. Situated near to the hotwell 

 discharge :ire two tanks each capable of holding 500 lbs. and each 

 sup])Oi'ted upon a weighing machine. The discharge from the hotwell 

 can be diverted into cither of the tanks, so that whilst one is being 

 emptied the other is being filled. Large cocks are attached to the 

 bottom of each of the tanks to allow the water in them, after it has been 

 weighed, to escape. 



