﻿978 Dr. Thomas on Discharge of Air through Small 



relation between u and e being linear, it follows that 

 the best value of e that can be employed in this relation 

 is approximately half the maximum excess pressure. Taking 

 € = 12*5 cm. of water, we find /c = 166(0'500 — a.). 



From (v.), we have the volume discharge V ' measured 

 at 0° C. and 760 mm. pressure given by 



1/2 



S , (2e /0l ) ] 



Po 



(-?)• 



where p ' is the density of air at 0° C. and 760 mm., 

 Pi representing the density under atmospheric conditions 

 during the experiments. S' uas calculated by means of 



10 



< 

 la. 

 O 



■ 







■ 







: ■/ 



/ 



Fig. 4a. 









-0-5 



-1-6 -1-3 -10 -07 



LOGARITHM OF DIAMETER OF ORIFICE 



this formula, employing the value of the discharge corre- 

 sponding to an excess pressure of 12'5 cm. of water, and 

 the coefficient of contraction of the jet was calculated there- 

 from. The results are set out in Table II. herewith. 



The relation of A' in the empirical formula AV for 

 the discharge given in the fourth column of Table II. 

 to the diameter d of the orifice is shown in fig. 4 a, in 

 which the logarithms of A' and of d are plotted as 



