6 EXPERIMENTAL PLANT PHYSIOLOGY 



possible. If ice is available the flask should be packed 

 round with it. Take readings. 



2. Take readings when the apparatus is warmed. 



3. Compare the amount of absorption when the 

 apparatus is in a windy place where the atmosphere is 

 consequently drier. 



4. Take readings when solutions of gradually in- 

 creased strength are substituted for water. 



The following is an account of an actual experiment 

 made with the apparatus shown in the photograph 



Fig. 2 



(Fig. 2). A fuchsia plant was used and this proved 

 very satisfactory, as it was hardy enough to withstand 

 the various changes that it had to undergo during the 

 course of the experiment. To make successful records 

 a great deal of time and patience are necessary. One 

 constant source of difficulty is the recurring leakage 

 of the apparatus caused by varying contractions and 

 expansions when the temperature is changed. This 

 carmot be avoided, and therefore, as soon as a leak 

 occurs, the fittings must be waxed again. The time 



