GOCOMOTIVE ENGINES.

7 ° 9

wide, and secured on the inside by Drummond’s patent clip ringtyre fastening. The cylinders are 17 in. diameter and 26 in. stroke,2 ft. 3 in. centres; the back ends are cast solid. They are laggedwith wood and covered with sheet iron. The thickness of metal inche cylinder barrel is I in.; in the steam ehest, y 2 in.; the steamports are in. by 14^2 in.; the exhaust port 2^ in. by 143^ in.;bridges, i l /§ in.; width over faces, 10^ in. The cylinders have aninclination 1 in 34. The slide valves are made of gun metal; theyhave an outside lap of 1 in., a travel of in., and a lead of y in.The buckle is of wrought iron, solid with spindle. The pistons areof gun metal 4 in. deep, with two cast-iron rings y in. wide by3 g- in. thick. The piston rods and crossheads are forged solid ofselected Yorkshire iron. The slide blocks are of cast iron of thesame quality as the cylinders, 12 in. long by 3*^ in. wide, forcedon the gudgeon pins with a pressure of 4 tons, and accurately fittedto the slide bars. The connecting rods are forged in one piece,without weld, from the best selected scrap iron; section at largeend, 5 in. by 2 in.; at small end, 334 in. by 2 in.; and 6 ft. 6 in.centre to centre. The outside rods are made of the very bestselected scrap iron forged in one piece without weld, and fittedwith gun-metal bushes. Bushes are pressed into the rod ends,secured in their places with taper pins and set screws. The inter-mediate valve spindles are made of the best selected Yorkshire scrap iron 334 in. diameter. The bushes are gun metal.

The reversing gear is of the screw type with cast-iron columnand wheel, worked by a bell crank and rod. The eccentric rodsare made from the best selected scrap iron, having a foot forged onfor bolting to the straps. The straps are of cast iron and fittedtogether without liners. The two eccentrics of each side are casttogether in halves, the outside eccentrics are bored, recessed, andtapped to receive the screw, securing it together. The inside has around Hange which abuts against a similar flange on the oppositeeccentrics; both flanges are tightly embraced with a wrought-ironhoop, bolted together with two 1 in. diameter bolts. A projectinglug is cast on the outside eccentric, and carefully fitted to the webof the crank for driving the eccentrics. The throw of the eccentricsis 6j4 in.; they are 2^ in. wide.

The boiler is fed by two injectors, No. 8, with movable cones. Atank is provided on each side of the engine to carry 950 gallons ofwater. The iron plates are T 3 T in., excepting the flanged plates for