84 Adams .— The Effect on Certain Plants of 
humidity between the air surrounding the shaded plants and that around 
the plants left uncovered. For example, on 18 June at 10.55 a - m - 
temperature of the air inside one of the wooden boxes was 76° F., while 
outside the box it was 72 0 F. On 20 June at 3.25 p.m. the temperature was 
88° F. inside and 9i°F. outside the box. At no time were the plants 
covered while rain was falling. During dry weather both sets of plants were 
watered alike. 
In the case of Flax, Wheat, White Mustard, and Soy Bean the seeds 
on the darkened plot were sown in two rows, the distance between the rows 
being nine inches. The seeds on the exposed plot were sown in exactly 
the same manner, and an interval of eighteen inches separated the darkened 
from the exposed plot. There were thus four parallel rows of the same 
length in which the soil was apparently quite uniform. The Sunflower 
seeds were sown in two parallel rows with an interval of twenty-four inches 
between the exposed and the darkened row. 
I 
Flax in Open Ground , it)2i. 
The seeds were sown on 23 May. On 6 June sixty-three plants were 
left on each plot, the number being gradually narrowed down to forty, 
at which figure they remained to the close of the experiment. The plot 
was darkened for seventy hours extending from 6 June to 25 June, and on 
sixteen days the weather was either sunny or partly sunny at the time. In 
the exposed plot seven plants came into flower on 3 July, and on 6 July 
thirty-nine were in flower. On the latter date the first plant came into 
flower on the darkened plot. 
The heights and weights of the plants when they were pulled up on 
12 July were as follows: 
Average 
height of 
stem. 
Tallest 
Total 
No. in 
plant. 
weight. 
floiuer. 
mm. 
mm. 
grm. 
Exposed plot 
566-3 
780 
170.100 
40 
Darkened plot 
553-5 
697 
106-310 
35 
Wheat in 
Open Ground , ic)2i. 
The seeds were sown on 23 May. On 2 June twenty-two plants were 
left in each plot, the number being afterwards reduced to nineteen. The 
plot was darkened for seventy hours from 2 June to 21 June, the weather 
being sunny for the greater part of the time. In the exposed plot one 
plant came into ear on 7 July and on 12 July, fourteen were in ear. In the 
darkened plot the first three plants came into ear on the latter date. The 
plants were pulled up on 16 July with the following results: 
