A descriptive and historical account of hydraulic and other machines for raising water, ancient and modern : with observations on various subjects connected with the mechanic arts: including the progressive development of the steam engine . The following figure, (No. 90) represents a common metallic suckingpump ; the cylinder of cast-iron or copper, and the pipes of lead. Itwill serve to explain the operation of such machines in detail, and toshow the extent of their application. ^A^hen this pump is first used, wateris poured into the cylinder to moisten the leather roimd the sucker, andthe pi
A descriptive and historical account of hydraulic and other machines for raising water, ancient and modern : with observations on various subjects connected with the mechanic arts: including the progressive development of the steam engine . The following figure, (No. 90) represents a common metallic suckingpump ; the cylinder of cast-iron or copper, and the pipes of lead. Itwill serve to explain the operation of such machines in detail, and toshow the extent of their application. ^A^hen this pump is first used, wateris poured into the cylinder to moisten the leather roimd the sucker, andthe pieces which form the clacks or valves ; it also prevents air from pas-sing down between the sucker and the sides of the cylinder when theformer is raised. Now the atmosphere rests equally on both orifices ofthe pipe, the open one in the well, and the other covered by a valve bottom of the cylinder: in other words, it presses equally on thewater in the cylinder and in the well wliich covers both ;* but when by ^Not absolutely so. or in a strict philosophical sense, but the dilTereiice i. so slishl inan aliiiiide ofil or 28 feet, (the ordinary limits) as to be inappreciable in a praclicjijoiut of vitjw. 222 Common Pumps. [Book U. No. 90. Metallu; Ilinii). the depression of the handle or lever, the sucker is raised, this equality isdestroyed, for tlie atmospheric column over the cylinder, and consecjuently over the valve O is lifted up, andsustained by the sucker alone; ittherefore no longer presses on theupper orifice, while its action on thelower one remains as the external air cannot en-ter the pipe to restore the equili-brium except through its orifice im-mersed in the well ; in its efforts todo so, (if the expression is allowa-ble^ t necessarily drives the waterbefore it on every ascent of thesucker, until the air previously con-tained in the pipe is expelled, andboth pipe and cylinder become filledwith water. The subsequent operation is ob-vi
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Keywords: ., bookcentury1800, bookdecade1870, bookiddescriptiveh, bookyear1876
