1920.] Automatic Control of the Separation of a Liquid. 163 
edges of the cup. As soon as the float sinks and blocks up 
the exit, the cup fills up and the float is pressed home by a 
slight head of liquid. The excess liquid flows across the pas- 
sage provided, (Fig. 4, A) into a second cup provided with a 
cut-off control of lower 8.G. and working on exactly the same 
principle as that first described. When the second float has 
descended, the excess liquid could be made to flow to another 
cup and’so on in descending order of specific gravities, the 
principle being multiplied as much as desired for the process 
under investigation. 
Completely successful experiments have been performed 
with this apparatus, one of which was in use for several months 
LEAD CONNECTION 
BUANT ON TO RUN-OFF 
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Fia. 5. 
controlling the run-off of weak waste acid from one set of pans. 
ecording to present practice, weak w 
the lower limit by S.G. Except to demonstrate its efficiency, 
the appliance has not been used for 
th : to be taken is controlle 
SMaoons oO eee d from the Chemist in charge 
of the Acid Section. For use with strong acids, the apparatus 
uld obviate the 
necessity for the use of tall-boys and se bearer teen If, in pre- 
sent practice, the S.W.A. were not 
proper time or the W.W.A. were not 
