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Cannon : A method of measuring transpiration 



gether satisfactory. A very good base for general use can be 

 made of wood, like the one shown in figure 3, for example, and 

 it can be made so that it can be put together or taken apart quickly 

 and with ease. Another form, shown in figure 4, is made of an 



• FiGLRE 4. Method of observing the transpiration of a branch while still attached 

 to the main plant. The plant is Opunlia veisicolor. 



ordinary plant drier, which like the other forms of base described 

 has been made water-proof by the application of vaseline or some 

 other water-resisting substance. It sometimes happens that it is 

 impossible or extremely inconvenient to use any of the bases above 

 described. I have, for instance, carried the transpiration apparatus, 



4 



