KaMenherg—Osmosis and Osmotic Pressure. 235 
The iodine also passed through the rubber, as was to have been 
expected; and it disintegrated the septum more rapidly than 
did the FeCl 3 . The liquid, however, first rose in the osmom¬ 
eter. 
33) The inner liquid was a solution of copper oleate in 
benzene, the outer benzene and the septum rubber. The liquid 
in the osmometer rose to a height of 20 cm. showing the main 
current to be toward the solution; however, large amounts of 
copper oleate passed through the rubber into the outer ben¬ 
zene. This was to have been expected,, since copper oleate is 
soluble in hydrocarbons. 
34) This experiment was identical with No. 33 except that 
parchment was employed as the septum in place of rubber. 
No change whatever took place, which was to have been an¬ 
ticipated since none of the ingredients touching the membrane 
have sufficient affinity for it. 
35) This experiment was like No. 33, except that the copper 
oleate was dissolved in pyridine, and pyridine was used as the 
outer liquid. Again the main current was toward the solution, 
but copper oleate passed into the outer pyridine in considerable 
quantity, which is quite in harmony with the theory advanced. 
When we think of a large molecule like that of copper oleate 
readily travelling through vulcanized caoutchouc as in No. 35, 
and that under like conditions cane sugar, AgNO s and LiCl do 
not pass through that septum, it certainly must convince us 
that the membrane does not act as a sieve. Again, No. 34 shows 
that parchment is not a “porous” material as is so commonly 
assumed from osmotic experiments with aqueous solutions in 
which it is employed as septum. 
36) The inner liquid was a strong solution of sodium oleate 
in water, the outer liquid water, and the septum rubber. No 
change occurred. 
37) The experiment was like 36 except that parchment was 
employed as the septum. In this case sodium oleate was found 
in the outer water, though the inner liquid showed slight in¬ 
crease in bulk. 
Sodium oleate though soluble in water is insoluble in hydro¬ 
carbons; bearing this fact in mind, the results in Nos. 36 and 
37 are readily explained. 
