[boyle-tory] physical TEST ON A NATURAL GAS WELL 



141 



The exact relation is given by V = K\ 2gH, where g is the accelera- 

 tion due to gravity, and H is the height of a column of the gas in 

 question which is equivalent to the difference of level, h, of the liquid 



h 



PITOT TUBE 



t 

 K 



I 



Fig. 1. 



columns in the manometer, when the temperature and pressure of the 

 gas are the same as that of the flowing gas at the point of measure- 

 ment. K is a constant, usually nearly equal to 1, which is of the 

 nature of a velocity correction for the position of the Pitot tube tip 

 in the delivery tube. The volume of flow of gas per unit time is 

 the product of the velocity of flow and the area of the delivery tube. 



The liquids used in the Pitot tube were mercury, water, or oil, 

 as the magnitude of the fiow or the temperature of the air required. 

 For larger flows mercury gave sufficient difference of level, but for the 

 smaller the head was increased by using water. When the air tem- 

 perature was below the freezing point of water it was necessary 

 to use oil. 



Determinations of the specific gravity of the gas from the well, 

 compared with that of air at the same temperature and pressure, 



