1920.] Automatic Control of the Separation of a Liquid. 161 
het the seating provided for it. Glass floats of the de- 
red 8.G. were specially constructed by the author from old 
toppers of the shape shown in Fig. 2. The shaded portion 
the weight of the stopper, wl the weight of the mercury 
introduced, equal to the volume of the float multiplied by 
the 8.G. of the liquid it was desired to control. The end o 
the bulb, A, was then sealed off hermetically. If desired, a 
loop of platinum wire (which must be allowed for in the 
weighing) may be sealed in at A to facilitate the removal of 
APPARATUS, AUTOMATIC, AciID CONTROL. 
GLass SEATING 
IN PosiTiON 
GLASS SEATING—+; |! 
SHCULDER TO 
Receive SEATING 
Fie. 3. 
A shows the lead cup with the commencing portion of the run-off pipe 
shaped internally with a shoulder to receive the glass seating 
for the floa 
B shows the same with the glass seating in positi 
C shows the run-off pipe welded on with the float in the position it 
occupies just before it sinks into the seating 
the float by means of an hook. The float, being of this 
shape, always remains with the mercury in the base and with 
— the float, shook be so constructed that its walls taper 
towards the seating for the float in the manner shown in the 
diagrams of Fig. 3. The float, in sinking, will then always 
run straight into the seating, there rhe slight suction 
owing to the flow of the liquid in additio the directing 
action of the walls of the cup. The sales sen was fitted 
