Kohlenberg—Osmosis and Osmotic Pressure. 
249 
C contained mercury. At R the tube was somewhat contracted 
as shown, and after putting the required amount of pure clean 
mercury into the apparatus and filling the rest of it with the 
solution to be tested through the orifice F by means of a capil¬ 
lary funnel tube, the apparatus was carefully heated at B by 
means of a small flame and finally drawn off leaving the whole 
securely sealed. With practice this part of the operation may 
be so performed that practically no air bubble remains in the 
apparatus after the tube has been drawn off at B. 
H 
Fig. 6. 
Before placing the mercury and the solution into the cell, 
however, the membrane must be securely put into place. It is 
first of all essential that the opening of the bell of the thistle 
tube E be as nearly circular as possible, and that the points on 
the outer edge of the orifice lie in very nearly the same plane. 
The rubber membrane consisted of a high quality of sheet rub- 
