Lowell Hydraulic Experiments: Being a Selection from Experiments on Hydraulic Motors, on the Flow of Water Over Weirs,in Open Canals of Uniform Rectangular Section and Through Submerged Orifices and Diverging Tubes |
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acting on wheel apertures apparatus arithmetical mean bell crank bottom brake canal cent chamber cistern coefficient of effect computed correction corresponding crest cubic feet cubic foot curve deduced depth of water diameter distance diverging tube downstream fall acting feet per second figure FLOW OF WATER foot forebay formula friction fully raised given in column guides Head of water hook gauge boxes horizontal hydraulic inches interior circumference irregularities length Logarithm of h Lowell Mean depth Mean height Mean shortest distance mean velocity measuring flume ment Merrimack Canal Merrimack River mouth-piece nearly Number of buckets Number of revolu observed obtained orifice passing the weir Pawtucket Falls plate pounds pounds avoirdupois proportional difference purpose quantity of water Ratio regulating gate represented stream surface taken thickness tions transit station Tremont Turbine velocity due Wasteway water acting water discharged water Logarithm WATER OVER WEIRS water passing width
Popular passages
Page 205 - We know now that the underlying principle is the same as in a mercurial barometer : it is the pressure of the atmosphere on the surface of the water in the well that pushes the water up into the pump.
Page 12 - ... the weir. The depth of water flowing over the weir is the distance between the point of the hook in the position named and the exact surface of the water. To ascertain this, the hook is raised by turning the milled -head nut until the point of the hook, appearing a little above the surface, causes a distortion in the reflection of the light from- the surface of the water. A slight movement of the hook in the opposite direction will cause the distortion to disappear, and will indicate the surface...
Page 66 - No correct formula for the discharge of water over weirs, founded upon natural laws, and including the secondary effects of these laws, being known, we must rely entirely upon experiments, taking due care in the application of any formula deduced from them, not to depart too far from the limits of the experiments on which it is founded.
Page 150 - ... is suspended in the water, the deviations of the rod from a perpendicularity to the surface of it may indicate which end of the cylinder...
Page 68 - Francis's book) that the quantity to be subtracted from the absolute length of a weir having complete contraction, to give its effective length, is directly proportional to the depth. It is also assumed that the quantity discharged by weirs of equal effective lengths varies according to a constant power of the depth. There is no reason to think that either of these assumptions is perfectly correct ; it will be seen, however, that they lead to results agreeing very closely with experiment.
Page viii - Mr. Morris also published an account of a series of experiments, by himself, on two turbines constructed from his own designs, and then operating in the neighborhood of Philadelphia. The experiments on one of these wheels indicate a useful effect of seventy-five per cent, of the power expended, a result as good as that claimed for the practical effect of the best overshot wheels, which had heretofore in this country been considered unapproachable in their economical use of water.
Page 41 - Tremont turbine is 8^- in diameter, and, according to the proposed rule, should have fifty-five buckets instead of fortyfour. With fifty-five buckets, the crowns should have a width of 7.2 inches instead of 9 inches. With the narrower width, it is probable that the useful effect, in proportion to the power expended, would have been a little greater when the gate was partially raised.
Page 22 - Magistrate having jurisdiction in such place, to ascertain the content of such measure of capacity by direct reference to the weight of pure or rain water which such measure is capable of containing. Ten pounds avoirdupois weight of such water, at the temperature of...
Page 138 - ... g representing as usual, the velocity acquired by a body at the end of the first second of its fall. Energy may be of two kinds (1), Kinetic energy, or energy of motion, and (2) Potential energy, or energy of position or of condition. Thus, the energy of a ball shot vertically upward, is entirely kinetic at the moment of its discharge, while its energy is all potential, or one of position, when it...