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On-On doly considering the vnpt increase of powe: by some of their combinations, it cannot be master et further wonder that first-rate whips of war, and other wuch vrent obfreti, are casily constructed. In some in. stancen, one man in enabled to lift up as much as 1,000, and powers may be applied equal to the strength of a hundred thousand meu,
186. Clocks and watches are nothing more than a simple arrangement of wheels of different dianieters and numbers of teeth, so as to indicate seconds, ininutes, hours, days, and even moons.
Clocks are not in motion by a weight which turns a cylinder, and this cylinder sets the whole in motion.
Watches are kept in motion by a coiled spring. which, in seeking to uncoil itselt
, exerts a power that gives motion to one wheel, which turns all the others.
Obs. A lecture of ten minutes at a watch-maker's, with the wheels and other parts under the eye, will exa plain more than could be done by verbal description in u volume.
186. The triumph of mechanics is the steamengine. The inventor observed the excessive force of steam in lifting up the stiff lid of a kettle as he sat at breakfast, and he and others have since applied this resistless power to produce a motion applicable to all kinds of machinery.
187. In constructing these engines, sicam from a copper is thrown into a hollow iron cy, linder, with a close lid or stopper, whicle risci as the steam rushes into the cylinder, and falls when the steam is condensed by cold water thrown in for the purpose,
An upright orosa rod in lixed to that lid, and
to one end of a large beam; which, in consequence, has an action communicated to it similar to that of a see-saw, and is lifted up and pulled down with wonderful precision and force.
THE STEAM ENGINE. on 136
Obs.--A regular and powerful motion being thus pro. duced, the mechanic scizes upon it, and applies it with ease to all kinds of machinery. The apparatus itself has been slightly varied by different persons, and for didee reat ohjects, but the principle remains the same, and it is, perhaps, the greatest discovery that ever was made in mechanics.
2. Mr. Watt, of Birmingham, bas made many i provemento in the steam engine ; and, among others, he fastens the top of the cylinder, working the red through it, and injecta steam above as well as below, so that the motion downward is produced hy steam, as well as that upward, he also condenses the steam in an adjoining versel. One horse can, by common machinery, raise 28,000 pounds one foot high in a minute, but some steam machines perform the labour of 60 or 80 havseg! Asmall one of a ten-borse power, with the steam produced by a single dushel of coals, will raise 30,000,000 of pounds one foot high; or it will grind and dress thice sacks of whesia slit nad draw intuneida Ave ewt: "of" iren, ahd'arive at
the sume time 1.000 cotton spindley. Stenm Eoginen have lately been applied with success, to in pel boats and ships.
3.-Mr. Blenkinsop. of Leeda, has, with great naccesa, lately applied steam to move coul-waggong on i rail-wny, instead of drawing them with the power of horses. Here is represented his machine, tu which any carriage may be annexed.
188. The Pump for raising water is a very useful machine ; and its principle, which is founded on the elasticity or pressure of the air, should be understood. It can raise water, if required, to the height of thirty-three feet, by the pressure of the air on the water.
- a long glaw tabe, closed at one end, were de. prived of air, and its open end immersed in quteksilver, the quicksilver will rise in it about 29 tochen 1 or, ir placed in water, 89 feet of water wilt rise in it, the weight of 39 feet of water being equal to 99 inches of quicksilver. The rise of those fluids in such a tube, is raused by the pressure of the air on the surface of the external mercury or water: hence it is inferred, and with reason, that the elasticity of the air which we breathe, is in all places equal in force to the weight of about 29 inches of mercury, or 33 feet of water,
189. To raise water 33 feet high, nothing more then is requisite than to put one end of a pipe in it, and to draw the air out of that pipe, when the water will instantly ascend in the
Such is the purpose and effect of a pump: and all that is to be done is by proper contrivances to draw out the air above, and keep up a supply of the water below.
190. A pump consists of' a wooden or copper pipe, with a long iron rod to work up and down within it, by means of a handle,
At the lower end of the iron rod is fixed a metallic hoop, provided with leather to fit the pipe : in the centre of the hoop is a little trapdoor or valve, which opens only upwards, and when down, shuts very close,
At the bottom of the pipe, near the water, another suelt valve also opening upwards, is fured tight within the pipe itselt.
191. The handle of the pamp being raisert; the iron rod (called the piston, with its valve At tho bottom of it is forced down the pipe.
As the valve opens upwards, the air in the pipes passes up through the valve.
On pulling down the handle, the piston is "rqised, and with it the valve, leaving a vacuum or vacuity between it and the lower fixed valve.
To fill up the vacuum, the water rushes up through the lower valve.
On again raising the handle, the piston again descends ; and the water now rushes through its valve, and, on pulling down the handle again, the piston and its closed valve rise, bringing up the water,
Its ascent creates a new vacuum, and more water rushes through the lower valve; the upper valve is made to descend again, to rise again, closed, and bring up water.
102. Fire-engines, and other forcing-engines, have no valve or flap fixed to the piston; but a solid plate is moved up and down by it, and the rising water is thus violently driven into an adjoining air-tight vessel.
Through the top of that vessel, the playing pipe is to inserted, that its mouth may lie below the water, leaving the upper part of the vessel filled with air.
Then the elastic power of that portion of air, forces the driven water up the playing pipe,
The energy of the stream, will of course de pend on the power applied to force down the piston, and drive the water into the air-vessel.
Odo. An inspection of a pump, or bre-engine, will teach moro io ien minutes, than mose description in w