148 BOTANICAL GAZETTE [AUGUST 
There seems to be no obvious advantage, so far as general con- 
siderations are concerned, in setting forth in detail the results for 
each week in each locality. It has rather seemed simpler to give 
local averages for longer periods, a method already adopted by 
Livincston’ in presenting similar data. The periods selected 
correspond approximately tothe three summer months—June, 
July, August—and the first half of September. The mean weekly 
evaporation rates for the various stations during these periods are 
given in table I. 
TABLE I 
MEAN WEEKLY EVAPORATION RATES IN CC., AS RECORDED BY THE POROUS CUP 
ATMOMETER, FOR 16 STATIONS IN CONNECTICUT, FROM JUNE I TO SEPTEMBER 
14, 1912. FIGURES IN PARENTHESES INDICATE NUMBER OF WEEKS FOR WHICH 
READINGS ARE RECORDED, IF LESS THAN THE STATED PERIOD 







: t to | Aug. 3 to | Aug. 31t A June 1 to 
Station qn ae ag se aa ia. J : Sept. 1 i Faby Aug. 3 
Salisbury........ 152 168 109 69 134 161 
Colebrook 5.0... 133(2)| 119 87 53 100 (14)} 122 (7) 
Cornwall (Cream 
Soa eS ee ee 115 ° 79 65 103 3 
L Recess 113 147 (4) 130 (8) 
Hawleyville....... 119 I 113 89 121 131 
Collinsville. ....... 144 161 8 71 128 154 
See eee 165 182 124 77 148 174 
Southington. ...... 170 167 109 70 140 168 
a ees ea 107 184 99 67 149 189 
os ue 182 175 100 97 146 178 
esa 4 157 156 99 131 157 
Danielson. ........ 181 173 100 IOI 143 172 
Voluntown........ 176 165 112 81 143 179 
MN a 104 105 71 40 8 104 
New Haven....... 146 145 102 68 123 146 
WOKE. Soc 142 165 107 71 134 156 





In considering the evaporation intensity of the air as a possible 
factor affecting the distribution of the vegetation in this region, it 
seems reasonable to assume that its effect on plants is felt most 
keenly during the earlier part of the growing season, at a time when 
gr vied and development are taking place most rapidly and when 
the immature tissues and organs are as yet inadequately protected 
from excessive transpiration. An examination of the first four 
"Plant World 14: 205-222. IQII. 
