PURIFIERS. 



113 



A is a cast- or sheet-iron tank, three feet diameter and two feet six inches 

 deep, generally filled with tar to within six inches of the top. 



B is a light sheet-iron or tin gasometer-shaped vessel of less diameter, 

 divided into three partitions by the plates C D and E, of less depth than 

 the rim. 



F is the pipe from the wash-vessel or condenser. 



G is the pipe leading to the first set of purifiers. 



H is the outlet or return pipe from them. 



I is the pipe leading to the meter and gasometers. These pipes, in the pre- 

 sent position of the valve, are all in action. 



Fig 25 (1). 



