Cannon : A method of measuring transpiration 



517 



adapted to this other use. It is a substantially made brass Instru- 

 ment which carries a hair hygrometer and a thermometer, and is 

 provided with a solid base which enables the instrument to stand 



Figure i. Apparatus for determining the transpirauon of plants in place. The 

 pol>raeter method, 



upright when In use. The hygrometer indicates the relative 

 humidity, and it is also provided with a scale by which the temper- 



