EXPERIMENT STATION BULLETINS. 



661 



ff V..nV 



m 



Figure 2. Diagram of potometer used to determine if diseased spots transpire. 



sion). Three Lambrecht polymeters were placed in various parts of the 

 chamber and the thermometers and hygrometers were read at each read- 

 ing of water loss. The day was rather moist, and no variation occur- 

 red during the experiment. After noting the transpiration over a def- 

 inite period, the diseased spots were carefully vaselined on both sides; 

 and transpiration was noted as before. The following results were ob- 

 tained : 



TABLE 5.— TRANSPIRATION OF LEAFLETS IN EARLY STAGES OF DISEASE: 

 MEASUREMENTS OF AREAS AND DISEASED SPOTS. 



