308 BURTON E. LIVINGSTON AND EDITH B. SHREVE 



To illustrate the range that may be met with in different 

 plants the following series of tests were carried out, upon various 

 different physiological types of plants that happened to be avail- 

 able at the time the physical and chemical portions of this study 

 had been completed. Corresponding tests with the standard 

 evaporating surface were not carried out, our aim being simply 

 to obtain an idea of the actual experimental time periods re- 

 quired by the new paper and by the different plants considered. 

 The plants were growing in the greenhouse. A number of tests 

 were carried out upon each plant, and the series of values given 

 in each case represent different tests. 



Duranta plumieri (27°C., bright sunshine, 1:20 p.m.). Differ- 

 ent leaves of same apparent age and size, lower surface: 50, 72, 

 58, 43, 61, 43, 43, 47, 40, 50 sec. 



Coleus hlumei (20°C., bright sunshine, 3:20 p.m.). Young, 

 immature leaves, lower surface: 150, 150 sec. Young, adult 

 leaves, lower surface: 65, 90, 100 sec. Older adult leaves, low- 

 er surface: 181, 150 sec. Young, adult leaves upper surface: 

 900, 900 sec. 



Ficu elsastica (27°C., bright sunshine, 2:15 p.m.). Differ- 

 ent leaves apparently alike, lower surface: 67, 70, 90, 90, 90 

 sec. Upper surface: 540, 420, 540 sec. 



Ficus pandurata (27°C., bright sunshine, 11:30 a.m.). Differ- 

 ent parts of same mature leaf, lower surface: 145, 150 sec. 

 Different parts of younger leaf, lower surface: 145, 155 sec. 



Alhizzia saman (28°C., bright sunshine, 11:50 a.m.). Dif- 

 ferent leaves, apparently alike, lower surface: 20, 25, 25, 25, 

 25, 20 sec. 



Yucca aloifolia (20°C., bright sunshine, 12:10 p.m.). Dif- 

 ferent leaves, apparently alike, lower surface: 400, 310 sec. 

 Upper surface: 234, 224, 274, 264 sec. 



Pelargonium zonale (24°C., bright sunshine, 3:00 p.m.). Dif- 

 ferent leaves, apparently alike, lower siu-face: 33, 30, 33 sec. 

 In shade: 70, 150, 160 sec. Upper surface: 175, 150, 160 sec. 



Bryophyllum calycinum (24°C., weak sunshine 4:00 p.m.). 

 Different leaves, apparently aUke, lower surface: 90, 80 sec. 



The above data are simply samples, but they show that tran- 



