﻿972 Dr. Thomas on Discharge of Air through Small 



conditions of flow became steady before the time of the 

 water surface crossing the lower mark was taken. In some 

 of the larger vessels a small bulb was blown on the lower 

 limb for the same purpose. 



The pressure in the vessel A was measured by a water 

 manometer connected to F, and the temperature was 

 measured by a thermometer hanging near A. Air was 

 delivered to the orifice through the tube G, and passed over 



^ 



Fid 2 



calcium chloride and then through a small plug of glass 

 wool. Throughout, the volume of air delivered was corrected 

 for pressure, temperature, and humidity. The tube H served 

 for drawing air into A, the cock K being meanwhile closed. 



The device maintained a very constant pressure at the 

 orifice, any variation occurring being somewhat less than of 

 the order of 0'5 per cent, of the total pressure. 



(d) Preparation of the Orifices. — Considerable attention 

 was given to the preparation of the orifices. Throughout^ 



