The Author, metals. Mr. Tritton's remarks regarding American injectors were fully borne out by the Author's experience. The American injector was perhaps rather more expensive than the English, but its advantages i n working were manifold. It would take water a t a temperature a good deal higher than the English forms, taking feed-water a t over 130" F, Once started it could be regulated over a very considerable range without blowing off, and if it did blow off it restarted with scarcely a pint of water wasted. It would work with steam-pressure as low as 25 lbs. per square inch. All engineers would agree with Mr. Robertson in his statements on elongation; but the fact that the object of the Paper was to ' describe what was being done, and not what should be done, must be the Author's excuse for not presenting the figures in any other form than that in which they appeared in the Paper.

Proceedings.] DISCUSSION OX COMPOUND LOCOXOTIVES. 101both goods and passenger, Xr. Webb's three-cylinder engines were &Jr. Worthinglikely to be employed, and the almost untried three-equal cylinder system gave promise of success. The four-cylinder system, while being complicated, presented adrantages of the highest power and nniform well-balanced action.Correspondence. CORRESPONDENCE ON conwoum LOCOJIOTIVES. [1\Iinutcs ofAir. B0ot.h. of one diameter, and their pistons, covers, and rods interchangeable.Any departure from a cylinder ratio of 1 : 2 would be made by means of a shorter stroke to the inside high-pressure cylinder.With such an arrangement, uniformity in shop work would be attained ; the high-pressure cylinder would be kept warm in the smoke-box ; the disagreeable surging motion at starting would be so mitigated as to be perhaps imperceptible, whilst none of the advantages now apparent in the Webb engine would be sacrificed. Further, with three cylinders of uniform diameter, the engine could be used as a simple engine, with boiler steam in all cylinders, and in this way would be enabled to perform an enormous duty for a short time, or for such time as the boiler would provide steam. The difficulty in starting would be overcome by the use of boiler steam in the low-pressure cylinders, the high pressure being then allowed to exhaust independently. Certain extra valves would be needed, FIG. 4. FIG. 5. PROPOSED DESIGN. WEBB TYPE. Downloaded by [ University of Liverpool] on [17/09/16].