520 



HYDRODYNAMICS. 



Motion of 



Water in 



Pipes and 



Canals. 



SET. II. EXPERIMENTS WITH A WOODEN CANAL. 

 Trapezium Canal. 



Pipes and 

 Canals. 



The slightest inspection of the preceding Table will Motion of 

 show the reader how much the science of hydrodyna- Water in 

 mics is indebted to the labours of M. Buat. The co- 

 incidence of the calculated with the observed velocities 

 is extremely striking. 



New Tables for Facilitating the Application of 

 Du Dual's Formula. 



In order to facilitate the application of the formula 

 in practice, Dr Robison in his dissertation on Water- 

 works, published in his System of Mechanical PhUoso- 

 phi/, has computed two tables, one of which contains 

 calculated values of the numerator of the fractional 

 formula, or value of V, also the value of the negative 

 quantity 0.3 (y* d 0.1) corresponding to the different 

 values of d from 0.1 to 100; while the other contains 

 the value of the denominator of the formula for dille. 

 rent values of s from 1.0 to 24-000. 



As these Tables were neither sufficiently correct, nor 

 extensive, we have inserted the following tables, which 

 were calculated with great care and trouble by Mr 

 John Lourie of Glasgow, who has permitted us to 

 publish them for the first time. 



The column of natural numbers has been added in 

 this Table, which will enable the engineer to calculate 

 the velocity V without having recourse to logarithms. 

 The logarithmic differences are likewise added. 



Explanation of the Tables. 



Table I. contains values of the denominator of the 

 fractional formula. Col. 1. contains the values of s or 

 the length of the pipe ; and col. 2, 3, 4. the natural 

 numbers, the hyperbolic logarithm, and the logarithmic 

 difference from the denominator 307 (Yd 0.1), all 

 of which are computed from 1.0 to 24CO. 



Table II. which has not been calculated in any 

 shape by Dr Rabison, has been computed by Mr Lou- 

 rie, and contains the values of the numerator 307 

 (</d 0.1), and the negative quantity 0.3 (\/7 0.1) 

 suited to conduit pipes of all diameters, from |- of an 

 inch to 1 8 inches in diameter. 



Table III. contains the values of the numerator of the 

 fractional formula, and also the values of the negative 

 quantity 0.3 (\/d 0.1.) The first column contains 

 the values of d, the mean radius or the hydraulic mean 

 depth ; col. 2 and 3. contain the natural numbers, and 

 also the hyperbolic logarithms, and the logarithmic 

 difference for the numerator 307 (Vrf 0.1); and 

 col. .'5. contains the values of the negative quantity 0.3 

 (\/rf o.l), all of which are computed from 0.1 to 

 100. 



Kxplami- 

 of the ta- 



