A.The area of the injection orifice proper for any engine can easily be told when the quantity of water requisite to condense the steam is known, and the pressure is specified under which the water enters the condenser.

First, twice or thrice the power may be obtained, with the same weight of boilers and machinery, and with considerable economy, by carrying very much higher steam, employing simple surface-condensers, and maintaining a high rate of combustion and vaporization, in accordance with the best commercial-marine practice.

This being so, the engineer, when he wishes to start the engine, first opens a small valve called the blow through valve, which permits steam from the boiler to enter the engine both above and below the piston, and also to fill the condenser and air pump.

Oscillating engine, advantages of, futility of objections to; details of cylinder; framing; condenser; air pump; trunnions; valve and valve casing; piston; piston rod; air pump connecting rod and cross head; air pump rod; eccentric and eccentric rod; valve gear; valve sector; shaft plummer blocks; trunnion plummer blocks; feathering paddle wheels; packing of trunnions.

The air pump is a pump set in the same cistern of cold water that holds the condenser, and it is fitted with a piston or bucket worked by the rod L, attached to the great beam, and fitted with a valve opening upwards in the manner of a common sucking pump.

A.The pipe leading to the condenser from the cylinder is made somewhat bell mouthed where it joins the condenser, and the gland for compressing the packing is made of a larger internal diameter in every part except at the point at which the pipe emerges from it, where it accurately fits the pipe so as to enable the gland to squeeze the packing.

The circulating pump is not available, because it has virtually no existence, a very small pump on the same shaft as the centrifugal being used merely to drain the condensers.

The cold water round the condenser will condense some of the steam contained in the eduction pipe, and its place will be supplied by some of the air from the cylinder.