Kohlenberg—Osmosis omd Osmotic Pressure. 237 
mometer was immersed in the liquid so that the membrane was 
slightly below (about 0.5 cm.) the surface of the liquid. The 
arrangement is shown in Fig. 5. After five minutes there 
seemed the least evidence that the camphor was being attacked, 
but even after 4 hours there was but little further change. Since 
alcohol is not very readily imbibed by rubber this occasioned no 
surprise. 
43) This experiment was identical with No. 42, except that 
toluene was used instead of alcohol. Plain evidence that the 
camphor was dissolving appeared in three minutes. In forty 
minutes the solid camphor had all disappeared and was found 
in very large quantities in the outer liquid. The membrane be¬ 
came much distended, bulging downward. The level of the 
liquid was alike in and outside after four hours, it having risen 
slightly on the inside. 
44) This experiment was like No. 42 except that xylene was 
employed instead of alcohol. The observations were practically 
identical with those of No. 43 where toluene was employed, 
which might have been expected. 
45) This experiment was also like No. 42 except that pyri¬ 
dine was employed instead of alcohol. After four minutes it 
was evident that the camphor was being attacked. A very thin 
