278

Lifting Pumps.

[Book III.

If the head of a common pump (No. 90) be closed, except an openingthrough which the rod works, or may be worked, it is then convertedinto a lifting pump, and will raise water to any elevation through a pipeattached to the spout. The earliest specimen that we have met with isrepresented by the 128th figure, from Agricola. Although a rüde device,it is interesting as illustrative of the resources of old mining engineers, inmodifying and applying the common wooden pump under a variety ofcircumstances. The upper parts of two atmospheric pumps terminatein a close chamber or strong box, (two sides of which are removed in thefigure to show its interior,) their lower ends extending into water collectedat a lower depth in the mine. From the top of the box a forcing pipe iscontinued to the surface of the ground, or to another level in the mine,from which the water raised through it can be discharged. The pistonrods are worked by a double crank, one end of which turns in a socketformed in the inside of the chamber, and the other is continued throughthe opposite side and bent into a handle by which the laborer works themachine. Two collars are formed on the crank axle, one close to the Out-side, and the other to the inside of that part of the chamber through whichit passes, and some kind of packing seems to have been used to preventthe water from leaking through. Four iron arms with heavy balls at theirends are secured to the axle to equalize the movement. These were theold Substitutes for the modern fly-wheel: they were quite common inall kinds of revolving machinery in the 15th and 16th centuries.

No. 129. Modern Lifting Pump.

No. 128. Lifting Pump from Agricola.

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The modern form of the lifting pump is represented in figure No. 129,The working cylinder being generally brass or copper, and having astrong flanch at each end : the upper one is covered by a plate with astuffing box in the centre, through which the polished piston rod moves;and the under one by another to which the suction pipe is attached, andwhose orifice is covered by a valve. To the forcing or discharging pipe