Water-works at, Marli.

297

Chap. 6.]

for a long time unwilling to undertake its elucidation, on account of thedifficulty of describing it with sufficient precision. Its general featuresmay be sketcbed in a few words, but a volume of letter-press and anotherof plates, would be required to explain and delineate the whole minutely..

The reservoir or head of the aqueduct, into which water from theSeine was raised by this machine, was constructed on the top of a hill,614 toises, or three quarters of a mile, from the river, and at an elevationof 533 feet (English ) above it. To obtain a sufficient motive power, theriver was barred up by a dam, and its whole width divided, by piles, intofourteen distinct water courses, into each of which a large undershot wheelwas erected. The wheels, by means of cranks attached to both ends oftheir axles, imparted motion to a number of vibrating levers, and throughthese to the piston rods of between 200 and 300 sucking and forcingpumps ! The pumps were divided into three separate sets. The first con-tained 64, which -were placed near the river, and were worked by six ofthe wheels : they drew the water, by short suction pipes, out of the riverand forced it through iron pipes, up the hill; but instead of these pipesbeing continued directly to the reservoir, (which might have been doneby making them and the machinery of sufficient strength,) Rannequinmade them terminate in a large cistern, built for the purpose, at the dis-tance from the river of 100 fathoms only, and at an elevation of about 160feet. In this cistern he then placed 79 other pumps (the second set) toforce the water thence to another cistern 224 fathoms further up the hill,and at an elevation of 185 feet above the other. In this last cistern 82pumps more (the third set) were fixed, which forced the contents to thereservoir.

In thus dividing the work, Rannequin made a mistake for which no in-genuity could compensate : as the second and third sets of pumps con-taining no less than one hunäreA and sixty-one, with all the apparatus forworking them, merely transferred through a part of the distance, the waterwhich the first set drew directly from the river, they were in reality un-necessary, because the first set might have been made to force it throughthe whole distance ; hence they not only uselessly consumed (at least)four fifths of the power employed, but they rendered the whole mass ofmachinery cumbersome and complicated in the highest degree ; and con-sequently extremely inefficient, and subject to continual repairs. Thefirst set of pumps, as already observed, were worked by the wheels nearwhich they were placed, and the remaining wheels imparted motion tothe piston rods of the second and third sets, in the two cisterns on the hill:of these, therefore, eighty-two pumps were stationed at an elevation ofupwards of three hundred feet above the power that worked them ; andnearly half a mile from it ! and seventy-nine were one hundred fathomsfrom the wheel, and 160 feet above them! To work these pumps, a num-ber of chains, or jointed iron rods, were extended on frames above theground, all the way from the cranks on the water wheels in the river toboth cisterns, where they were connected to the vibrating beams to whichthe piston rods were attached. It was the transmission of power to suchelevations and extraordinary distances by these chains, that acquired forthe machine the title of “ a monument of ignorance.”

A writer in the Penny Magazine (vol. iv, page 240) who examined themachine in 1815, says the sound of these rods working was like that of anumber of Wagons loaded with bars of iron running down a hill withaxles never greased. The creaking and clanking (he observes) must haveconvinced the most ignorant person that the expenditure of power wasenormously beyond what was required for the purpose effected. It has

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