MACHINERY. 



moved in the great cylinder, with a power or force equal to by cocks admitting it into various cylinders, many power. 



2304 tons, and it is obvious, as in 'he cafe before-n-.en'ioned, ful operations arc performed: it works an immenfe prefs 



that any other unlimited degree of f-rce may be acquired by for bending ftrong iron bars, or breaking cait iron for the 



machines or engines th'.is conftrufted. By the hydroftatic foundery. It moves the carriage of the planlng-cngine ; 



principle, the power and motion of any machine may be and he has brought the methods of packing the cylinders 



transferred or communii-ated to another, let their dillai.ce and to f';ch perfeftion, that they are employed to make the 



local titualion be what they may. Suppofe two fmall tubes or mod delicate adjudments in the parts of the machine. (See 



cylinders, m the iniide of each of which is a pifton made a fidl defcription of this in Planing Engine, and alfo Press, 



water and air-tight, a tube may be conveyed under ground Hydrojlatic.) In another part of the tattory, it works u 



or otherwife, from the bottom of one cylinder to the o:her, crane for lifting the heavieft goods, by merely opening a 



to form a communication between them, notwithftanding their cock, and lowers them down, by opening another, with the 



dillance be ever fo great. Let tliis tube be filled with water, utmoft fafety. A very large Floodgate is alfo raifed up by 



or other fluid, until it touches the bottom of the two pidons ; two cylinders. (See that article.) It may be ufed for 



then, by deprefling the pifton of one cylinder, the pillon of turning the bridges of canals. (Sec Canal.) On the 



the other will be railed. The fame effeft will be produced, whole, we cannot conclude this article, without recommeild- 



■vice verfd ; thus bells may be rung, wheels turned, or other ing the hydroltatic principle very Itrongly to engineers, as 



machinery put invifibly in motion by a power being applied a method the moll perfeft of all others of communicating 



to cither cylinder. 



By ihefe mean", it is obvious, that moft commodious ma- 

 chines of prodigious power, and fiifceptible of the greatefl 

 tlrength, may readily be formed. If the fame multiplication 

 of power be attempted by toothed- wheel pinions and rackh. 



notion, which is to aft only for fhort extents, or with great 

 power, as it can fo ealily be condufted through any cir- 

 cuitous rout, and lofcs fo little power by friiHion. The 

 eafe with which it is relieved from the aftion, or caufed to 

 operate in a contrary direftion, is not its finallell advantage ; 



it is fcarcely polTible to give ftrength enough to the teeth of and by means of the air-vcflel the power may be accumu- 

 the racks, and the machines become very cumberfume, and lated while the machine is preparing tor aftion, and then an 



of (Treat expence. But Mr. Bramah's machine may be 

 made abundantly ftrong in very fniall compafs. It only 

 req"ires very accurate execution. The hjdroltatic prin- 

 ciple on which it depends has been well known for near'y 

 two centuries, and it is a matter of furpnie that it has 

 never before been applied to any ufcfui practical piirpofe. 



The application v.hich Mr. Brauiah has made of this 

 truly valuable principle is very general : it was firll applied 

 for preffes inftead of large fcrews, for which purpofe it is 

 greatly fuperior in every refpeft. PrelFes being generally 

 moved by the ftrength of men alone, the faving of power 

 becomes a great objeft ; and tins it accompliihes, having 



immenfe pouer fuddenly given. We have little doubt the 

 hydroftatic-prefs would anfwer the bell of any method for 

 expreffi' g oil. The prefent oil-prefs is defcribed under 

 QlL-MUl, a.d operates by a wedge, driven by repeated 

 blovvs ot a heavy Hamper. The method is ingenious ; but 

 great part of the power is expended in triftion, as is evident 

 from the wedge requiring nothing to retain it, as it is driven, 

 the friftion over-balancing all the re-adion of the fubllances 

 prelTed. 



A motion is very frequently required in machinery for 

 giving to any piece of wheel-work an increafed or diminillied 

 velocity at pleafure. The molt complete of thefe are the Ex- 



no proportion of the friftion of the fcrew, and immenfely panding Riggers (fee that article); but many other means 



greater power. In a fcrew-pref?, it requires nearly as may be employed. Thus, on two parallel fpindles, which are 



much labour to unfcrew as lo fcrew it up, an evidence of to turn each other, place a number of wheels, increafing in 



the enormous friftion of a fcrew, when afting againll a great fize by regular fteps, the fmalleft wheel of one fpindlc being 



prefTure : but the hydroftatic-prefs only requires a cock to oppofite to the largcll of the other. The fame cndhfs ftrap 



be opened to let out the water from beneath the pifton, wiil fit any pair of them, and give a great variety of powers 



which then defcends quickly, by its own gravity, or the 

 elafticity of the fwbttaices under the prcHurc. But the 

 greatell convenience of the hydroilatic priiciple is, that 

 its power can fo eafily be tranf itted to any diftance, and in 



and velocities : the fame may be effefted by having a number 

 of cog-wheels ; and, inftead of a llrap, ufing an intermediate 

 cog-wheel, which can be applied to connedf any pair of the 

 wheels at pleafure. A very ingenious application of double 



any dirv.-v.'^ion, by means of pipes condufted along in fitua- cones is ufed in a cotton-niachine, called the double fpceder. 



tions wh' re all other means of conveying the motion would See Manufacture o/'C««on, alfo Mr. Braithwate's Chane. 



be complicated, and expenfive in the extreme. Thus, in a It is very cuftomary to add what is called a fly to ;: a- 



large paper-mill, an injetling-pump may be kept in conftant chines. This is a heavy did': or hoop, or other mafs of 



action by -he water-mill, or fteam-engiiie, and injeft water matter, balanced on its axis, and fo connedted with the 



into an air-vel'el, from which pipes are coiidufted to preflTes machinery, as to turn briflcly round with it. This may be 



in all par's of the mill, and by fimply opening a cock at any done with the view of rendering the motion of the v,-hole 



prefs, any required prefTure will be inilantly given by the more regular, iiotwithftanding unavoidable inequa'ities of the 



elafticity of the confined air operating on the ealargcd fur- accelerating forces, or of the relillanccs occalioncd by the 



face of the pifton cf any prefs. The air-veffel has, of courfe, work: it then becomes a regulator. Suppofe the refiltance 



a fafety-valve, to allow the efcape of the water when the to a machine extremely unequal, and the impelling 



preffiire becomes fo great as to endangei the rupture of any power perfeftly conftant ; as when a bucket-wheel is em- 



of the vetfels ; for it is to be obferved, that the power of ployed to work one pump ; when the pillon has ended its 



this principle is irrefiftitle, when the pump is worked by a working-ftroke, and while it is going down the barrel, the 



mill, and will burft any velTels, without the Icaft appearance power of the wheel being fcarcely oppoled, it accelerates 



of rtrain on the movino- parts of the pump.' the whole machine, and the pifton arrives at the bottom of 



In Mr. Bramah's extenfive vvork-fliops at Pimlico, and the barrel with confiderab'e velocity ; but in the rifing 



anotler at Mill-Bank, London, the ftejm-engines which again, the wheel is oppofed by the column of water now 



turn the laih. s, boring-machines, planing-machines, &c. preffing on the pilton : this immediately retards the wheel ; 



work 3 fmall injefting-pump, as above-mentioned, and and when the pifton has reached the top of the barrc, all the 



fmall coppsr pipes are laid to every part of the works, and acceleration is undone, and is to begin again. The motion of 



2 fuch 



