1913] BRIEFER ARTICLES 229 
through the membranes and its consequent rise in the osmometer varies 
considerably, the osmometers with the smaller, dryer membranes showing 
a much slower rise. Membranes with a large osmotic surface, for 
example 5 cm. in diameter, will allow the liquid to rise quite rapidly. 


Fic. 3.—Osmometers filled with potassium ferrocyanide solution and immersed 
na copper — solution; the precipitation membrane is being formed inside of 
‘ie celloidin film 
When an osmometer prepared in this manner is set up, water will rise 
to a much greater height than in those having untreated celloidin mem- 
branes. In one experiment with this type of membrane the water rose 
8 meters. 
I am indebted to Professor J. B. OVERTON for advice and criticism 
during the progress of this work, for which I take this opportunity of 
expressing my appreciation—GitBert Morcan Suitu, University of 
Wisconsin, Madison, Wisconsin. 
