s 



Fig. 3. 



Fig. 1. Diagram showing essentials of the Piche atmometer. R, water 

 reservoir; D, saturated paper disk, the latter supported against base of reservoir 

 by metal disk (C). Spring (W) is attached by clip (F) to reservoir and applies 

 pressure to D. (Reprinted from Plant AVorld 14: 286, 1911.) 



Fig. 2. Diagram showing essentials of the Piche-Cantoni atmometer. R, 

 burette reservoir for water, filled at will through tube (T) from higher supply, 

 cut off by cock (P). D, absorbent paper disk, as in Piche instrument, held against 

 the top of supply tube (E) by double spring (W) attached at F and applying 

 pressure to plate (C). (Reprinted from Plant World 14: 286, 1911. 



Fig. 3. Diagram showing essentials of the Livingston paper cylinder at- 

 mometer, the rest of the instrument as in figure 2. E, tin supply tube; D, ab- 

 sorbent paper cylinder; L, cork supports holding lower edge of cylinder in place; 

 S, tin seat, against which top of cylinder is appressed by glass cap (C). The 

 latter is held in place by wire spring (V), cemented to C at K and flexed by fine 

 wires {W), the latter attached to tube at F. (Reprinted from Plant World 14: 

 286, 1911.) 



54 



