284 
The flowering and ripening of winter wheat during 1882 and 1883 
has been studied on the basis of data from about 500 stations, com- 
bined with the previous data for 1880 and 1881. 
The mean daily temperature at the time of flowering is for rye 
13.3°; but the individual numbers range from 9° to 18°; similarly for 
winter wheat the mean is 16.2° and the range from 10° to 21°. The 
commencement of vegetation for winter wheat is uniformly adopted 
as December 1. The sums of the mean daily temperatures have been 
calculated from several points of departure and seem to prove that 
the lower limit of useful temperatures is very nearly 5° C., so that 
we can take 6° C. as the point of departure, as has been done by 
many authors. 
The sums of the mean daily temperatures, less 6° C., rejecting the 
negative remainders and counting from the Ist of December, are as 
follows: 
Periods for winter grain. Rye. | Wheat. 
20. | °C. 
Hrom December tonilowerin e222. 52+. seeree eee ee eee a eee eee 420 596 
HromeDecemiberlstovharvests-25:.25 0-2 eae ae ee ee ee ee ee eee 955 | 1,099 
rom) flowering towharvestecncs-.- see oe asec ee Sere ee ee eee eee ae aa eee 535 | 503 
The harvest date for spring barley is shown to depend in 1882 and 
1883 quite as little on the date of sowing as it did in 1881. 
The retardation due to altitude is as before, four days per 100 
meters. Adopting the 20th of March as an average date of sowing, 
the sums of the mean daily temperatures have been considered up to 
the date of harvest, with different assumptions as to the fundamental 
temperature. As before, the best result is given when the sums are 
taken of the excess of the mean daily temperatures above 6° C., and 
the resulting figure, 984, is seen to be between the two figures for rye 
and winter wheat. 
In his third memoir Angot (1888) studies the phenomena of 1884 
and 1885 in combination with the preceding. The same allowance 
is made for rates of retardation. The relation between the times of 
leafing, the mean daily temperature at that date, and the maximum 
