
No. 33.] 25 
was not especially marked. Taking samples of early and late sweet 
_ and Flint corns, the seed from the same source for comparison, we 
have: 
Sweet Corn. 
Planted. Vegetated. First bloom. 
1883. 1884. 1883. 1884. 1883. 1884. 
May May May May July July 
figmieiemumb:. ... 22. 16 19 28 Q7 ery 17 
Aug. Aug. 
Stowell’s Evergreen... 16 19 oer OL 4 3 
lint Corns. 
May May May May July July 
HOUYOWAYS 0.5.0.5). 16 19 28 26 14 10 
Waushakum.......... 16 19 28 26 93 21 
We note a difference in the period from planting to vegetation, 
for the two years, twelve days in 1883, seven or eight days in 1884, 
the sum of the mean soil temperatures at one inch from May 16-27, 
inclusive, in 18838, being 747° or about 62° a day; from May 19-26, 
inclusive, in 1884, being 535° or about 67° a day. 
According to Sachs, in maize, the lowest temperature at which 
growth takes place at the expense of the reserve material of the seed 
is 9°.4 C. or about 49° F. The lowest temperature at which chlo- 
rophylL granules turn green is above 43° I’. and probably below 59° _ 
F. If we assume that the temperature practically required for ger- 
mination is half way between these figures, or 54 F’., we can make 
from our data the following calculation : 
The temperature below 54° but slightly promotes germination. 
The sum of the temperatures below 54° for the twelve days is 648° 
and the mean observed temperature for 1883 was 747°, subtracting 
we have 99° for the available temperature. In 1884, in like manner, 
we multiply 54° by eight days, and subtract the sum from the 535° 
of temperature noted, leaving 103° of available temperature. We 
may hence conclude, from the likeness of these figures, that twelve 
days at 54° + 8° excess per day is the equivalent of eight days at 
54° + 13° excess per day for the purposes of germination, or that a 
sum of daily mean temperature about 100° above a mean tempera- 
ture of 54° is required for the vegetation of maize, under the prac- 
tical conditions of planting in this region. 
It is worthy of note that, although the temperatures during the 
two seasons varied, the variation in the blooming period was but 
slight. 
Days from vegeta- 
tion to bloom. 
: 1883. 1884. 
MrT) WECU far wi os shoe a ee a0. a 5.s eos See ee 50 51 
Bbowelle MKVEToTean DWCbw eyes ec ee oe eee ee 68 68 
Mires Lint ket rity tee ee elo kee es ovale ® 47 45 
Semen D lint tee en eee rte 56 56 
[Assem. Doc. No. 33.] 4 
