162 Journal of the Asiatic Society of Bengal. [N.S., XVI, 
without fracture into a lead structure in the manner illustrated 
in Fig. 3, the tube being made in two portions and then burnt 
together. If the whole apparatus were made of glass or 
pottery the seating would be ground directly in the taper- 
ing end of the cup C, in Fig. 1. 
In order that the float should remain floating, it is essen- 
tial that a certain amount of liquid should remain in the cup, 
This is provided for by bending the run-off pipe upwards so 
that the point D on the curve, Fig. 3 (C), is at a height suffi- 
cient to allow liquid to pass between float and seating when 
From Dippinc Pans ——>@] 
To Stronc Waste Acid To Weak Waste Acio 
Fie. 4 (DIAGRAMMATIC). 
Figure 4 (diagrammatic). The first ‘cup controls the run-off of strong 
waste acid, the second controls the run-off of weak waste acid and 
ber’ pipe D allows the unrecoverable residues to flow down the 
rain. 
the float is just immersed, i.e., just as it is about to descend 
to its cut off position. In order that this tube may not act as 
a syphon (in which event the flow is intermittent and the float 
bobs up and down), an air hole is made in the top of the upper 
side of the run-off pipe and is fitted with a small tube which is 
attached to the top of the cup to give the apparatus additional 
strength. e diameter of the run-off pipe should be suffi- 
