. The cyclopaedia; or, Universal dictionary of arts, sciences, and literature. Encyclopedias and dictionaries. WATER. have before diredted, and take two-thirds of the produft for the mean velocity; this multiphed by the number of fquare feet in the area of the feftion of the aperture, will give the cubic quantity of water which flows per minute in cubic feet. Note, in taking the area of the feftion, we muft meafure the whole depth from the level furface, and multiply it by the horizontal width of the aperture, and not fimply the feftion of the water. This is becaufe, the theory upon which the
. The cyclopaedia; or, Universal dictionary of arts, sciences, and literature. Encyclopedias and dictionaries. WATER. have before diredted, and take two-thirds of the produft for the mean velocity; this multiphed by the number of fquare feet in the area of the feftion of the aperture, will give the cubic quantity of water which flows per minute in cubic feet. Note, in taking the area of the feftion, we muft meafure the whole depth from the level furface, and multiply it by the horizontal width of the aperture, and not fimply the feftion of the water. This is becaufe, the theory upon which the rule is founded fuppofes the water in the aperture to have no ve- locity at the iurface, and tobe upon the level of the Handing water. Neither of thefe fuppofitions is true in reality, but the refult is very nearly true, becaufe the feftion of the moving water is diminilhed in proportion to the ve- locity which the water has at the furface, and in confequence the errors of the two affumptions always correft each other. We have therefore only to apply a correft theorem to obtain the velocity due to the whole depth, according to the nature of the aperture, and take two-thirds of the produft. All the neceflary information for this purpofe may be taken from the table of multipliers lad given, for the velocity of the difcharge through apertures ; or otherwiie, if we take the velocity at the bottom, and multiply it by the depth, and take two-thirds of the produft, we fhall have the mean velocity. But to make the fubjeft clear we fhall give another table for this objeft. Rules for obtaining the Velocities and Quantities of Water difcharged tlu-ough reftangular Apertures, which are open at Top. Defcrlption of the Aperture. Wo(e. —The depths are fuppofed to be meafiired from the level furface of the wattr to the bottom of the aperture, in inches. To find ihe mean Ve- locity of the Water running through tlie Aperture in Feet per Minute. iJli/c —Multiply the Square Root of tlie Depth
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Keywords: ., bookcentury1800, bookdecade1810, booksubjectencyclo, bookyear1819
