184 New Hydraulic Machines, [March^ 



dentally, among the numerous combinations of fixed matter 

 which nature offers to our view. From such combinations it 

 might follow^ for example, that a reservoir of water formed on 

 the shoulder or in the interior of a mountain, by means of rain 

 water, might produce a jet of water upon the sumAiit of the 

 mountain — an effect wHiich appears chimerical, because at the 

 sight of a source of water at the top of a hill, we conclude in 

 general immediately that this source comes by means of subter- 

 raneous currents from some mountain in tbe neighbourhood of a 

 higher elevation. 



Yet M. Mannoury has solved this problem in various ways, 

 <]uite unconnected with each other. Facts answer all objections: 

 and the theory, though it cannot always foresee the truth, serves 

 at least to confirm it, and to generalise individual facts. 



Notwithstanding the surprising variety of the machines pro- 

 posed by M. Mannoury, and the very complicated nature of 

 some of them, yet, if we compare them with care, we shall find 

 that they consist of various combinations of three principal 

 methods, employed either together or separately, ^hese methods 

 ^re distinguished by M. Mannoury by the three following names: 

 the intermitting syphon^ the hydreole, and the oscillatijig column. 

 Vve shall satisfy ourselves with describing here in what each of 

 these three methods consists, without entering into the detail of 

 all the applications of them that the author has made, which 

 would be very tedious, and would require the description of 

 machines too complicated to be understood without figures.* 



INTERMITTING SYPHON. 



The intermitting syphon is not a thing unknown in physics; 

 for it is by its means that those fountains, called reciprocating, 

 are emptied each time that their reservoir is found filled with 

 rain water, or any other water, up to a height above the top of 

 the syphon. Then the water begins to run by the longest branch, 

 and the water continues to run out till its surface comes to a level 

 with the mouth of the shortest branch ; but the novelty in the 

 mechanism of M. Mannoury is the use to which he has put this 

 intermitting syphon, so as to make it the principle upon which 

 various machines are constructed, which have none of their parts 

 moveable, and notwithstanding elevate water above the reservoir. 



To conceive this intermitting effect, we have only to suppose 

 it applied to the ordinary fountain of compression, called the 



* Considering the grtot number of machines presented by M. Mannoury 

 Dfctot, M. M. the Cf mmissioners of the Institute have thought it requisite 

 «nly to make known his general principles. The author ^vill speedily publish 

 his memoir, in which he has described all his machines with care. He will 

 e.^tablish their throry from a series of coiTsparative experiment?, from which he 

 iv'iU d dace practical ins tractions. 



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