MOHR AND REDWOOD'S PRACTICAL PHARMACY. 131 
Fig. 23. Fig. 24. Fig. 25. Fig. 26. 
B 
Displacer for Glass Displacer. Glass Displacer. Continuous 
Volatile Liquids. Displacement. 
Fig. 23 represents a displacer on the principle of Gilbert- 
son's. A is an ordinary tin displacer, except that the rim 
c is soldered around the mouth, in such a mariner as to form 
a water-joint when the rim of the cover, d, is placed in it. 
a is a perforated diaphragm: e a tin tube open below and 
above; this is soldered to the lower diaphragm, through 
which it passes, whilst the upper diaphragm slips over it 
loosely. In using this displacer, the ingredients are intro- 
duced around the tube to a suitable heighth, the upper 
diaphragm put in its place, and menstruum poured on, the 
joint half filled with water, and the lid inserted. The at- 
mosphere of the bottle B, communicates with that of A, 
through the tube e. 
"Excellent displacers for small operations are made with 
