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the Florentine pump is a proof; and others might be adduced from mucholder authorities. Plate 48, in Besson’s Theatre , represents an atmos-pheric pump raising water from a river to the top of a high tower. Thecylinder is square, formed of plank and bound with iron clamps. It isshown as nearly four times the length of the suction pipe, which is round.When pump rods are required of great length, they should be inade ofpine. This wood does not warp, and as it is rather lighter than water, itsweight has not to be overcome (like iron rods) when raising the sucker.
A circumstance to which we have slightly alluded, was announced inthe public papers of Europe , in the year 1766, which roused the attentionof philosophers ; for it seemed to threaten a renewal of the disputes abouta vacuum, and the ascent of water in pumps and siphons, &c. A tinmanof Seville , in Spain , undertook to raise water from a well 60 feet deep,by the common pump. Instead of making the sucker play within 30 feetof the water, he made the rod so short, that it did not reach within 50feet of it. As a necessary consequence, he could not raise any. Beinggreatly disappointed, he descended the well to examine the pipe, whilea person above was employed in working the pump; and at last in a fitof despair, at his want of success, he dashed the hatchet or hammer inhis hand, violently against the pipe. By this act a small opening wasmade in the pipe about ten feet above the water—when, what must havebeen his surprise! the water instantly ascended and was discharged atthe spout!
The fact being published, it was by some adduced as a proof that thepressure of the atmosphere could sustain a perpendicular column of watermuch longer than 32 or 34 feet, and consequently that the experiments ofTorricelli and Pascal were inconclusive. M. Lecat, a surgeon at Rouen in Normandy , repeated the experiment with a pump in his garden: hebored a small hole in the suction pipe ten feet above the water, to whichhe adapted a cock. When it was open, the water could be dischargedat the height of 55 feet, instead of 30 when it was shut.
As might be supposed, these experiments when investigated, insteadof overthrowing the received doctrine of atmospheric pressure, morefully confirmed it. It was ascertained that the air on entering the pipebecame mixed with the water; and which therefore, instead of being car-ried up in an unbroken column, was raised in disjointed portions, or in theform of thiek rain. This mixture being much lighter than water alone,a longer column of it could be supported by the atmosphere : and by pro-portioning the quantity of air admitted, a column of the compound fluidmay be elevated one or two hundred feet by the atmospheric pump; butthere is no advantage in raising water in this manner by the pump, andwe believe it is seldom or never practiced. In a paper, on the duty per-formed by the Cornwall Steam Engines in raising water, in the Journalof the Franklin Institute for May, 1837, it is stated that a little air issometimes admitted in the pump pipes, which it is alledged, “ made thepump work more lively, in consequence of the spring it gave to the co-lumn of water, and caused less strain to the machinery.” In the samepaper Mr. Perkins States that forty years before, an attempt was made toimpose upon him in this country, a pump which raised water by atmo-spheric pressure 100 feet: but he detected “a small pin hole” in the pipethrough which the air was admitted.
The same deception it seems gave rise to the humorous poetical Satire,‘ Terrible Tractoration.’ the ingenious author States in his preface, thathe was employed in 1801, as agent for a Company in Vermont , and ofwhich he was a member, to proceed to London , and secure a patent for