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Chap. 6.] Application of Pumps in Modern Water-works.

extends through the entire length of die cylinder and is made air andwater tight to both ends, and also to the plate upon which its lower edgerests. The upper edge extends to the under side of the axle to whichthe piston B is United. One end of the axle is passed through the cylin-der and the opening made tight by a stuffing box ; it is moved by a crankorlever. Near the clacks c c two other openings are made through theplate, to which two forcing pipes are secured. These tubes are bentround the outside of the cylinder and meet in the chamber C where theirorifices are covered by clacks. Thus when the piston is turned in eitherdirection, it drives the water before it through one or other of these tubes;at the same time the void left behind it is kept filled by the pressure ofthe atmosphere on the surface of the liquid in which the lower orifice ofthe suction pipe is placed. The edges of the pistons are made to workclose to the ends and rim of the cylinder by means of Strips of leatherscrewed to them. Modifications of these pumps have also been used inEngland as fire-engines.

Reciprocating rotary pumps have Sprung up at different times both hereand in Europe , and have occasionally obtained “ a local habitation and aname,” but have never become perfectly domesticated, we believe, in anycountry. We have seen some designed for ordinary use that were ele-gantly finished, and decorated with gilding and japan—they resembledthose exotic plants which require peculiar care, and are rather for Orna-ment than for use.

Reciprocating rotary pumps have also been proposed as steam-engines.Watt patented one in 1782.

CHAPTER VI.

Application of pumps in modern water-works: First used by the Germans —Water-works at Augs-tmrgh and Bremeh—Singular android in the Iatter city—Old water-works at Toledo—At London bridge —Other London works moved by horses, water, wind and steam—Water engine at Exeter—Water-works erected ou Pont Neuf and Pont Notre Dame at Paris —Celebrated works at Marli—Error of Rau-nequin in rriaking them unnecessarily complex. American water-works: A history of them desirable—Introduction of pumps into wells in New-York city—Extracts from the minutes of the Common Councilprevious to the war of Independence—Public water-works proposed and commenced in 1774—Trea-sury notes issued to meet the expense—Copy of one—Manhattau Company—Water-works at FairMount, Philadelphia .

Before noticing another and a different dass of machines, we proposeto occupy this and the two next chapters with observations on the em-ployment of pumps in “ water-works,” and as engines to extinguish lires—both in this country and in Europe .

The hydraulic machinery for supplying modern cities with water gene-rally consists of a series of forcing pumps very similar to the machine ofCtesibius , (No. 120;) and when employed to raise water'from rapidstreams, or where from tides or dams a sufficient current can be obtained,are worked like it by under or by overshot wbeels. An account of oldEuropean water-works is an important desideratum, for it would throwlight on the history of pumps in the middle ages, during which little ornothing respecting them is known. The older cities of Grermany were thefirst in modern days that adopted them to raise water for public purposes;but of their construction, materials, and application under various circumstances, we have no Information in detail. Rivius, in his Commentary on