Kohlenberg—Osmosis and Osmotic Pressure. 219 
unduly rob the cork of its water content, which was necessarily 
small enough to begin with. On allowing the apparatus to 
stand, the mercury rises in the tube as indicated, showing that 
pressure is produced on the walls of A. The mercury rose un¬ 
til the cork either broke or began to slip upward, the experi¬ 
ment being repeated three times. Using a cork not soaked in 
water no pressure was obtained. It is quite probable that a 
cork might be so fastened in place by the aid of mechanical 
contrivances that an ordinary tube would give way before the 
cork would move; but since the maximum pressure could not 
be measured in this manner, the qualitative demonstration of 
the presence of the pressure was deemed sufficient. The ex¬ 
periment just described may be performed also in the form il¬ 
lustrated in Fig. 4, which is more like the usual arrangement 
employed in osmotic experiments. In this figure, the liquid B 
in the bottom of the bottle is ether; the end of the glass tube 
is closed with a tight fitting slice of cork A saturated wtih water; 
in the tube above the cork is chloroform, C; and above the ehlo- 
