1897 ] BRIEFER ARTICLES Ill 
one end a portion 10™ in length is bent downward, and at the other 
end a portion 20™ in length is bent into U form. To the U-shaped 
portion is fitted a three-way tube by means of rubber tubing. To one 
arm of the three-way tube is fitted a shoot, by means of rubber tubing, 
which should be wired for safety. An entire plant may be used if a 
A 
A convenient potometer.— 4, base; &, reservoir for water; C, calibrated tube ; 
D, captains funnel for water supply; Z, fitting of plant and tube. 
suitable fitting is used, such as a straight chloride of calcium tube 
with the plant sealed in by means of moulding clay. The free end 
of the three-way tube terminates in a separatory funnel. 
To determine the amount of water used by a shoot proceed as fol- 
lows: Place a plant in a reservoir of water, or if a branch only is to 
be used bend the shoot in such manner that the point of incision is 
under the surface. Cut off obliquely under water, and fit a section of 
heavy rubber tubing of the proper size, 5™ in length, to the end of the 
shoot. For safety the joint should be wired. The fitting should be 
done under water. Fill the funnel and allow the entire system of 
tubes to become filled with water free from air bubbles. Also fill the 
vessel under the end of the tube. Now lift the branch from the water, 
keeping the rubber tube filled and fit to the tube in such manner as to 
