Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . ntre is ft. below the surface, would be equal to a cylinder 4 diameter and ft. long, and containing 4, cubic inches, or about gallons. The actual discharge from a thin orifice not furnished with an ajutage is however much less, beingonly about two-thirds of the theoretical amount. The loss is owing partly to friction, but mainly tothe interference of converging currents moving within the vessel toward the orifice. This interfer-ence may be shown by employing
Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . ntre is ft. below the surface, would be equal to a cylinder 4 diameter and ft. long, and containing 4, cubic inches, or about gallons. The actual discharge from a thin orifice not furnished with an ajutage is however much less, beingonly about two-thirds of the theoretical amount. The loss is owing partly to friction, but mainly tothe interference of converging currents moving within the vessel toward the orifice. This interfer-ence may be shown by employing a glass a perforation in its bottom, as represented in HYDRODYNAMICS. 121 Fig. 2331. If particles of some opaque substance having nearly the same specific gravity as water,so°that they will remain suspended in it for a space of time, be mingled with the water, they will beseen to move in the direction indicated by the lines in the figure, which are nearly direct. If the jetis carefully observed, it will be seen that it is not cylindrical, and that for a distance from the orifice 2333. 2330. /? ;i K® af— bl of about half its diameter it resembles a truncated cone with the base at the orifice. This contrac-tion of the stream is called the vena contractu, and its smallest diameter is stated to be from of that of the orifice. When the stream has a direction downward nearly vertical, it continuesto diminish beyond the vena contracta, in consequence of the increased velocity caused by the forceof gravity, the size being in the inverse proportion to the velocity. The increased velocity at thevena contracta is due to the pressure which forces the particles of water into a narrower the jet continues to fall, it forms a series of ventral and nodal segments, as shown in Fig. ventral segments are composed of drops elongated horizontally, as seen at a a «, while the nodalsegments are elongated vertically, as seen at b b b ; and
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