262 BOTANICAL GAZETIE [APRIL 
the Albrecht, but with large vigorous plants it gives results which, 
if not exact, are sufficiently so to be very instructive to beginners, 
It need not cost much over $2. 
4- An osmometer. 
The absorption of water by roots cannot be omitted from an 
elementary course, and osmosis must be demonstrated, necessi- 
tating some form of os- 
mometer. A most efficient 
one is the following: Cut 
off an ordinary burette 
about 2™ below the be- 
ginning of the graduation 
and smooth the end in 
the flame. Over it push 
for a centimeter or more 
a soaked Schleicher and 
Schill diffusion shell of 
16™" diameter,? which will 
fit the burette exactly, and 
tie it very tightly with bs 
Several turns of waxed | 
thread. Fill shell and 
burette up to the zero 
mark with molasses, and 
immerse the shell in pure 
water. The rise of the 
liquid will be very pro- 
nounced and rapid, and 
May be measured on the 
graduated tube. 
This experiment is most 
instructive when per- Fic. 4.—An osmometer- 
formed along side of an- 
other in which a similar burette is attached by rub 
to the cut stump of a vigorous plant with a stem 
New York- 
* These may be obtained at a low cost from Eimer and Amend, 
ROSAS ort 
ber tubing 
about the 
