They consist essentially of two elliptical rotary pistons, cogged and working into one another in an air-tight case.

These shops were open sheds; the fire was made upon the ground, and two wooden cylinders, whose valves were in the bottom, served for bellows; when used, they had movable pistons, which were worked by a man on an elevated seat, and answered the purpose better than could have been expected.

The air pump bucket is a solid piston of brass, 6-1/2 inches deep at the edge, and 7 inches deep at the eye; and in the edge three grooves are turned to hold water which answers the purpose of packing.

This valve consists substantially of a cylinder open at both ends, and capable of sliding upon a stationary piston fixed upon a rod the length of the cylinder, which proceeds from the centre of the orifice the valve is intended to close.

The terminal strain, which is so severe in air compressors, is here considerably reduced, as in this case it is only equal to the area of the initial air piston multiplied by its low air pressure.

Their expansive social force is imprisoned as a working power, to show itself only through its legitimate pistons and cranks.

Our car has a broken piston, so we have had to walk more than usual and my leg gets so worn out in a short time that it is slow going.

In rotatory engines the steam acts at once in the production of circular motion, either upon a revolving piston or otherwise, but without the use of any intermediate mechanism, such as the crank, for deriving a circular from a rectilinear motion.

The smooth piston slides backward and forward as a lady might slip her delicate finger in and out of a ring.

At the same instant the compressed air is exhausted from the little piston connected with the balanced steam valve and the steam is automatically throttled, so that only enough steam is admitted to keep the engine turning around, or to overcome the friction, no work being done.

The almost perpendicular ladder is just beside the powerful pump, which, worked by a steam-engine, exhausts the water from the mine, and its busy piston, in monotonous measure, keeps time to our climbing.

They consist essentially of two elliptical rotary pistons, cogged and working into one another in an air-tight case.

The hydraulic piston or plunger compressor is largely used in Germany and elsewhere on the Continent of Europe, but the duplex may be said to be the standard type of European compressor at the present time.