Dec. 3, 1917 
Temperatures of Cranberry Regions and Plant Growth 523 
DAILY NORMAL TEMPERATURES 
The daily normal temperature and precipitation for a considerable 
number of stations in the United States have been made available by the 
work of Bigelow (, 2 ). Of the five stations used in the present study, how¬ 
ever, only North Head is included. In computing the normal daily tem¬ 
perature for the remaining stations, the method used was that outlined 
by Bigelow (2, p. 3). 
Figure 2 shows the monthly normal mean temperatures for the five 
stations. North Head differs markedly from the others in having a much 
more even temperature throughout the year, while Grand Rapids, Wis., 
and Farmington, Me., show a greater difference between the summer and 
winter temperatures than do Middleboro, Mass., or Indian Mills, N. J. 
Fig. a.—Curves of the monthly normal mean temperature during 1916 at Middleboro, Mass., Farmington, 
Me., Indian Mills, N. J., North Head, Wash., and Grand Rapids, Wis. 
TEMPERATURE EFFICIENCY 
In order to evaluate the temperature of a region with regard to its 
effectiveness for plant growth, both the height and duration of favorable 
temperatures must be considered. In the absence of exact data as to the 
temperature relations of a given species, and where daily mean temper¬ 
atures are available, a simple summation of daily means probably gives 
as satisfactory an index of temperature efficiency in our climate as our 
present knowledge permits. Briefly, the method is as follows: A certain 
minimum temperature is assumed as a starting point and the amount 
added to the summation each day is the difference between this assumed 
minimum and the number which represents the mean temperature for 
that day. The minimum is sometimes the freezing point, but often a 
somewhat higher temperature. 
Obviously this method of estimating temperature efficiency is far from 
ideal. The daily mean temperature obtained by averaging the observed 
maximum and minimum probably does not exactly represent the heat 
