. Johnson's new universal cyclopaedia : a scientific and popular treasury of useful knowledge. ter; let i ig. 5. the head acting on the centre of the ori-tice be ;i feet. The eoellicieiit of effluxshould be about ; area of the ori-fice, 4 square inches = squarefoot; velocity due head by Table 1, feel per pocond : theoretical di>-rharge, x = 0.:i89 ; actualdo. = X = cubic foot]ier second. Vnr an orifice of the sanu-size not rounded the coefficient, according to Table 3, should be , and x = cubiL-fuot per second. T
. Johnson's new universal cyclopaedia : a scientific and popular treasury of useful knowledge. ter; let i ig. 5. the head acting on the centre of the ori-tice be ;i feet. The eoellicieiit of effluxshould be about ; area of the ori-fice, 4 square inches = squarefoot; velocity due head by Table 1, feel per pocond : theoretical di>-rharge, x = 0.:i89 ; actualdo. = X = cubic foot]ier second. Vnr an orifice of the sanu-size not rounded the coefficient, according to Table 3, should be , and x = cubiL-fuot per second. The discharge is, there-fore, increased Gl per cent, by rounding |the orifice. Difft-f-vnt Degrees of Contraction.—The more the direction of the water is changed in passingthe orifice, the smaller the coefficient of efflux. The greatestFig. 6. Fig. 7. TabI/E 4. Part of tlic I)cr!Inl^?ttr or tile iiriliccDtiwhich the conlruc-tioQ is suppressed. DiMihsrgc, R3 cum-l.:ired Willi lli;afrom a simiJle ou-nce uudcr the samecoaditioos. change of direction undergone by any particle of water in Fig. 10. passing an orifice maybe as much as ISO de-grees, and from thatdown to nothing. In theorifice Fig. 0 it is 180degrees; iu Fig. 7, be-tween ISO and 90; inFig. 8, 90; in Fig. 9, lessthan JO; and in Fig. 10,nothing, this being arounded orifice involving no abrupt change in the directionof the water. Wcisbach gives the following as the result of his experi-ments on this point : Greatest eliaiifc nf direction- , »„ IW^ 157^0 13i^ 1I2H^ W> 67^ «« 22M° M^ 5« (^ Co. of 5U « *1 OMii «6
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