EXAMPLES. 261 



4. The height of a manometer, which is placed upon a 

 pipe 3 1 inches in diameter through which the air is passing, 

 is 2 inches, while the air is discharged through an orifice 



2 inches in diameter at the end of the pipe. Find (1) the 

 theoretical velocity of efflux, and (2) the theoretical dis- 

 charge, if the barometer in the external air stands at 27| 

 inches, and the air in the pipe is at a temperature of 10 C. 



Use (5) of Art. 132. 



Ans. (1) 421.8 feet ; (2) 9.2 cubic feet. 



5. If in the last example the height of the manometer is 



3 inches, the diameter of the pipe is 4 inches, and the ori- 

 fice at the end of the pipe is 1 inch in diameter, find (1 ) the 

 velocity, and (2) the discharge when the barometer stands 

 at 29 inches and the temperature of the air in the pipe is 

 20 C. Ans. (1) 447.06 feet; (2) 2.438 cubic feet. 



6. If the sum of the areas of two conical tuyeres of a 

 blowing machine is 3 square inches, the temperature in the 

 reservoir is 15, the height of the manometer in the regu- 



lator is 3 inches, and the height of the barometer in the 

 exterior air is 20 inches, find the discharge. 

 See (3) of Art. 132 ; take // = .92, and a = .004.* 



Ans. 8.242 cubic feet. 



7. The height of a quicksilver manometer, which is placed 

 upon a regulator at the head of an air pipe 320 feet long 

 and 4 inches in diameter is 3.1 inches, the height of the 

 barometer in the free air is 29 inches, the diameter of the 

 orifice in the conically convergent end of the pipe is 2 

 inches, and the temperature of the compressed air in the 

 regulator is 20 C. Find the quantity of air that is deliv- 

 ered through this pipe. 



Suo. a = 0.004, ft = .75, //j = .92; .-. etc. 



Ans. 5.735 cubic feet. 



* On account of the ordinary humidity of the atmosphere, it ia advisable in prac- 

 tice to take a - 0.001 



