Further Observations on Heath Association. 
TABLE III. 
123 
Evaporation (in Cubic Centimetres) in Tall Calluna 
(CU Facies). 
Ground level. Just 
BELOW TOP Just ABOVE TOP 
OF VEGETATION. OF VEGETATION . 
Series 
1 
[av. daily 
[av. total 
... -67 
... -63 
2-48 
1-69 
2-96 
L94 
Series 
2 - 
av. daily 
av. total 
. . 113 
... -67 
2-57 
1*65 
3-29 
2-26 
Series 
3 - 
av. daily 
av. total 
... 1*25 
... 116 
2-69 
1-82 
4-33 
2-58 
Series 
L 
av. daily 
av. total 
... 1-02 
... -43 
2-44 
1 50 
461 
2-98 
Series 
8 I 
'av. daily 
av. total 
... 1*36 
... -86 
2-33 
1 33 
2-89 
1-75 - 
Series 
6 I 
av. daily 
av. total 
... 119 
... -58 
2-36 
1-24 
418 
1 55 
Average daily evap¬ 
oration for all 
the 
series 
... 110 
2-48 
3*71 
TABLE IV. 
Evaporation (in 
Cubic Centimetres) in Low Calluna 
(CUE Facies). 
Ground level. Just above top of vegetation. 
Series 
■1 
av. daily 
av. total 
... 1-59 
... 116 
.2-32 
.212 
Series 
2 i 
av. daily 
av. total 
... 1*34 
... -98 
.3-44 
.2-84 
Series 
av. daily 
av. total 
... 1-68 
... 1-20 
.3-65 
.2-37 
Series 
4 i 
av. daily 
av. total 
... 1*27 
... -86 
.2-98 
.202 
Average daily, for 
all series 
... 1-47 
.3-10 
From Tables III and IV it is apparent that the evaporation 
above the general vegetation level is from two to three times greater 
than on the ground, and in the case of tall Calluna the evaporation 
just above the vegetation-level is about half as much again as just 
below. Moreover it is to be noted that the difference between 
evaporation on the ground and just above the vegetation-level is, 
during the day, considerably greater on the ridge (tall Calluna) than 
in the valleys (CUE facies). This is in conformity with the greater 
persistence of solitary projecting shoots in the valleys and on the 
lower parts of the slopes as compared with the higher levels. 
