The steam, therefore, after it has urged the piston to the end of the stroke, escapes into the atmosphere.

The steam therefore admitted from the steam pipe through the open valve V to the top of the cylinder, not being resisted by pressure below, will press the piston to the bottom of the cylinder.

Now, by lowering the piston we increase the capacity of the cavity containing the bag.

The passage communicating between the condenser and the top of the balance piston was too small, and the pins at the ends of the link connecting the valve and balance piston were formed with an inadequate amount of bearing surface.

The object of converting the steam into water by cold, upon that side of the piston towards which the motion takes place, is to relieve the piston from all resistance to the moving power.

A.In a high pressure engine the steam, after having pushed the piston to the end of the stroke, escapes into the atmosphere, and the impelling force is therefore that due to the difference between the pressure of the steam and the pressure of the atmosphere.

A casing set beside the cylinder contains the valves, by means of which the steam which impels the piston is admitted and withdrawn, as the piston commences its motion in each direction.

If I hold an open cylinder in my left hand and a piston in my right, and place the piston within the cylinder, I here have a confined volume of air at the temperature and the pressure of this room.

NEWCOMEN, THOMAS, blacksmith, born at Dartmouth; invented a steam-engine in which the piston was raised by steam and driven down by the atmosphere after the injection into the cylinder of a squirt of cold water, which cooled it, so that the steam when injected did not raise the piston at once up.

I had previously introduced an injection cock into each end of the air pump in steam vessels, from which I had obtained advantageous results; and in all horizontal air pumps I would recommend the piston and valve plates to be so constructed that the whole of the water will be expressed by the piston.

If I instantly release the piston which I hold at one-half stroke it will return to its original position, less only a little friction.

When it was full, he replaced the piston, telling Mrs. Puckridge to put her thumb on his wound, turned the point of the syringe up and drove a little out to get rid of the air, then, with the help of a probe, inserted the nozzle into the wound, and gently forced in the blood.

A slight grinding, or polishing, with powdered Turkey stone and oil, appears to be expedient in ordinary cases, and may be conveniently accomplished by setting the piston on a revolving table, and holding the ring stationary by a cross piece of wood while the table turns round.

Water at all times surrounds the piston, and fills alternately the upper chambers.

It so happened that the expert had heard of one other such case, therefore he made the experiment of trying a fractionally larger piston as a last resort; imagine the predicament of the amateur, or the mechanic who had never heard of such a trouble.

(1) Those which inject water in the form of a spray into the cylinder during compression. (2) Those which use a water piston for forcing the air into confinement.

"Broke a piston, and had to be towed in," he replied carelessly, "We'll be off again presently.

As soon as the sun rose the factory chimney began to smoke, the hammer broke the stone, the file bit the metal, the plough furrowed the earth, the ovens were lighted, the pump worked its piston, the hatchet sounded in the wood, the locomotive moved amidst clouds of vapour, the cranes groaned on the wharves, the steamers cut the waters, and the little barks danced on the waves dragging their nets.

Since the explosion of gas in the cylinder drives the piston out only, and not, as in the case of the steam-engine, back and forward, some provision must be made to complete the cycle, to bring back the piston, exhaust the burned gas, and refill the cylinder with a new charge.

The stream must be dammed before it will drive wheels; the steam compressed ere it will compel the piston.

Since the explosion of gas in the cylinder drives the piston out only, and not, as in the case of the steam-engine, back and forward, some provision must be made to complete the cycle, to bring back the piston, exhaust the burned gas, and refill the cylinder with a new charge.

The air that is thus generated, forces up a piston through a cylinder, which piston, striking the arm of a wheel, puts it in motion, and with it the machinery of the mills.

Q.Is the piston of an oscillating engine made deeper than in common engines? A.It is expedient, in oscillating engines, to form the piston with a projecting rim round the edge above and below, and a corresponding recess in the cylinder cover and cylinder bottom, whereby the breadth of bearing of the solid part of the metal will be increased, and in many engines this is now done.