HYDJJAULIC8. 95 



13. A pipe that is inclined will discharge more water in 

 a given time than a horizontal pipe of the same dimen- 

 sions. 



14. The friction of a fluid is greater in small than in 

 large pipes, when equal quantities are discharged. 



15. In perpendicular pipes, the discharge being governed 

 by the law of gravitation, the greater the length of the 

 pipe, the greater the discharge. 



16. When a prismatic vessel empties itself through an 

 aperture, twice the quantity would be discharged in the 

 same time if it were kept full. 



17. In a stream, sluice, or ditch, the velocity is the 

 greatest at the surface and in the middle of the current. 



18. The time occupied by a given quantity of water 

 passing through pipes or sewers of equal apertures and 

 lengths, and with equal falls, is in the following propor- 

 tions, viz. : In a straight line, as 90 ; in a regular curve, as 

 100 ; and in passing a right angle, as 140. 



To find the velocity of a stream issuing from a head 

 of water. 



KULE. Multiply the height of the head in feet by 64.33, 

 and the square root of the product will be the velocity in 

 feet per second. 



EXAMPLE. What is the velocity of a stream projected 

 through an opening by a head of 12 feet ? 



