BULLETIN No. 91d. 
13 
The frame-work holding the flasks is fastened to the shaft of an 
ordinary fly-fan (C), by which the frame-work and flasks are revolved, 
thus agitating the water and keeping it at the same temperature in 
all parts of the bath, and making it easy to maintain a constant 
temperature in the bath as a whole. The spring clamps and skele¬ 
ton disk are shown apart in the cut. We use about a 250 c. c. Erle- 
meyer flask, which fits nicely into our apparatus. The thermometer 
extends through the lower disk and nearly to the bottom of the 
flasks, which are about two inches above the bottom of the bath. 
The^Water in the bath comes nearly to the top of the flasks, which 
is two or three inches above the level of the citrate solution. This 
bath has been in use in this laboratory with good results for five 
years. 
