PERMANENT WILTING IN PLANTS 



117 



TABLE VI— Continued 



* Calculations made by means of the Briggs and Shantz formula, from the 

 water holding power of the soil used. 



t The word box here denotes the glass box: ch., sh., denotes chamber in shelter; 

 ch., open denotes chamber in open. 



t The hours of the day are simply numbered in a single series, from 1 to 24; 

 thus the thirteenth hour is the first hour after midday, etc. 



taken again as 2 and the constant difference as 0.40 per cent. 

 This curve passes through averages (1) and (5) and passes 

 very nearly through averages (2) and (4). As has been noted 

 average (3) is unaccountably too low to find a place on any con- 

 sistent curve that includes the other averages. This generahzed 

 curve is therefore to be considered as in very good agreement 

 with the experimental evidence. It is convex upward and ap- 

 proaches a vertical line with low values of evaporation intensity, 

 thus showing clearly (as do all the other curves previously dis- 

 cussed) that the only considerable region of its length where 

 evaporation intensity may be without marked influence upon soil 

 moisture residue, is in its upper portion, with high evaporation 

 rates. 



The value given to the calculated moisture residue by the 

 formula of Briggs and Shantz is in this case seen to take an en- 

 tirely different position on the graph from that taken in the 

 series previously discussed; in this series alone, of the five here 



