98 



J. W. SHIVE AND B. E. LIVINGSTON 



TABLE 2— Continued 



85 

 o < 



o " 



- « « 



OS H 6) O 



o 2 



H g M** O 



H ' P. fw 9 

 SO 15 « 



S H M 2 U 



3.7 



K J W 



£ S o 



2h « 



O Z; « 



S « > 



J 2 -^ 



S S > 



»i K ;? 



D H g 



f* •«! £ 



o ^ " 



per cent, of dry 

 wt. 



6.10 

 5.86 

 5.70 



g2 



■<! ^ 



Eh* p 



u a a 



■< H 9 



a, •<! a 



o J w 



o Sos 



e •<! o 



5 O fH 



1.61 

 1.54 

 1.50 



Av. 6.16 (5)JAv. 1.63 



D 



b 

 O 



a 

 0*- 



00 9} 



O « 

 PS 



Open 

 Open 

 Open 



fa 2; 

 Oh 

 « d 



pa Eh 



Aug. 10, 12 

 Aug. 10, 12 

 Aug. 10, 12 



!3 '^ K 



H (u a H 



05 B O 5 



D o " & 



2Ka ° 



a ti s 2; o 



H S 

 - O 



a a 



So 

 && 

 a E^ 



a o 

 o z 

 a H 



26-31 

 26-31 

 26-31 



"go 



S a 



5 « 



o ^ « 



hH -g ^3 



« PS O 



a a u 



Pm cu o 



per cent. 



20-18 

 20-18 

 20-18 



* 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; c/t., sh., denotes chamber in shelter ; 

 ch., open denotes chamber in open. 



X 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. 



averages are possible) are shown by dots. The ordinate for 

 each point shown is indicated by a hght broken line projecting 

 the point to the horizontal line below. The parenthetical numbers 

 near the bases of these ordinates for the main averages refer to 

 corresponding numbers following the main averages in table II. 

 The axis of ordinates is shown in the graph, the numbers at its left 

 indicating percentages on the dry weight of the soil. The axis of 

 abscissas is not shown; the horizontal line below the graph bears, 

 however, the values of the different abscissas. These values are 

 in terms of cubic centimeters per hour, loss from the standard 

 porous cup atmometer. 



The general arrangement of the heavy circles on the graph 

 of figure 1 strongly suggests that these points lie on a regular 

 curve, a curve which approaches a vertical line with low values 

 of X and a horizontal line with high values. This observation 

 leads to the conclusion that, in this case at least, the range of 

 evaporating powers supposed by Caldwell to exist with low values 

 of the intensity of this condition (within which range evaporation 

 intensity is supposed to be without effect upon soil moisture resi- 

 due at permanent wilting) must be very small and must include 



