In Fig 2 the shaft has turned through one-eighth of a revolution; in Fig. 3, a quarter turn; Fig. 4, three-eighths of a turn. Another eighth turn brings two parts into position represented by Fig. 1, except the second pair of cylinders now replace the first pair. The bearings, KL, support the two shafts and act as stationary valves, against which faces formed on the cylinders revolve; steam and exhaust ports are provided in the faces of K and L, and two ports in the revolving faces, one to each cylinder. The point at which steam is cut off is determined by the length of the admission ports in K and L. The exhaust port is made of such a length that steam may escape from the cylinders during the whole of the return stroke of pistons. Fig. 5 shows the complete engine. It will be seen that the engine is entirely incased in a box frame, with, however, a lid for ready access to the parts for examination, one great advantage being that the engine can be worked with the cover removed, thus enabling any leakage past the pistons or valve faces to be at once detected. The casing also serves to retain a certain amount of lubricant. The lubrication is effected by means of a triple sight-feed lubricator, one feeder delivering to steam inlet, and two serving the main shaft bearings. Figs, 6 and 7 are an end elevation and plan of the same engine. There is nothing in the other details calling for special notice. Figs. 8 and 9 show the method of machining the cylinders and pistons, the whole of which can be done by ordinary lathes, which is evidently a great advantage in the event of reboring, etc., being required in the colonies or other countries where special tools are inaccessible. Figs. 11 and 12 are sections which explain themselves.--_The Engineer_. * * * * * THE NATIONAL TRANSIT CO'S PIPE LINES FOR THE TRANSPORTATION OF PETROLEUM TO THE SEABOARD. While Englishmen and Americans have been alike interested in the late project for forcing water by a pipe line over the mountainous region lying between Suakim and Berber in the far-off Soudan, few men of either nation have any proper conception of the vast expenditure of capital, natural and engineering difficulties overcome, and the bold and successful enterprise which has brought into existence far greater pipe lines in our own Atlantic States. We refer to the lines of the National Transit Company, which have for a purpose the economic transportation of crude petroleum from Western Pennsylvania to the sea coast at New York, Philadelphia, and Baltimore, and to the Lakes at Cleveland and Buffalo.