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distance between the upper and lower orifices of the pipe in which themotive column flows, shall be equal to the force required to raise the otherto the proposed elevation.
A pressure engine on the principle of Heron’s fountain, erected by M.Hoell in 1755, to raise water from one of the mines in Hungary , has longbeen celebrated. In the vicinity of one of the shafts at Chemnitz , there isa hill upon which is a spring of water, one hundred and forty feet abovethe mouth of the shaft. This spring furnishes more water than that whichrises at the bottom of the mine, which is one hundred and four feet belowthe mouth of the shaft. The water in the mine is raised by means of thaton the hill by an apparatus similar to the one figured in the annexed cut.
A represents a strong copper vessel eight feet and a half high, five feetdiameter, and two inches thick. A large cock marked 3 is inserted near
the bottom, and a smaller one 2 near the top.From this vessel a pipe D, two inches in dia-meter, reaches down and is connected tothe top of the vessel B at the bottom of theshaft. This vessel is smaller than the upperone, being six feet and a half high, four feetdiameter, and two inches thick, and of thesame material as the other. A pipe E, fourinches diameter, rises from near the bottomof B to the surface of the ground, where itdischarges the water. The pipe C conveysthe water from the spring on the hill; it isalso four inches diameter, and descends tonear the bottom of A. It is furnished with acock 1. Water is admitted into B through acock 4, or a valve opening inwards, whichcloses when B is filled. The vessel A is sup-posed to be empty, or rather filled with air,and its two cocks shut. The cock 1 is thenopened, when the water rushing into A con-denses the air within it and the pipe D,and this air pressing on the water in B,forces it up the pipe E. As soon as it ceasesto flow through E, the cock 1 is shut and 2and 3 are opened, when the water in A isdischarged at 3. The cock or valve at thebottom of B is opened, and the water enteringdrives the air up D into A where it escapesat 2. The Operation is then repeated as before.
If, when water ceases to run at E, the cock 2 be opened, both waterand air rush out of it together, and with such violence that the liquid is,by the generation of cold consequent on the sudden expansion of the Con-densed air, converted into hail or pellets of ice. This fact is generallyshown to strangers, who are usually invited to hold their hats in front of thecock so as to receive the blast; when the hail issues with such violence,as frequently to pierce the hats, like pistol bullets. This mode of pro-ducing ice was known to the marquis of Worcester, who refers to it in theeighteenth proposition of hisCentury of Inventions, relating to an “ artifi-cial fountain, holding great quantity of water, and of force sufficient tomake snow, ice, and thunder.” Some additions to the machine at Chem nitz , by which it might be rendered self-acting, were proposed in 1796.They consisted of small vessels suspended from levers that were secured
No. 164