16 Journal of A gricultural Research voi. xxv. No. i 
drying at ioo° C. the separate portions of tops were ground and sub¬ 
jected to chemical analysis by the official methods (42) commonly em¬ 
ployed. The acid-hydrolyzable material is computed as glucose from the 
reducing power of the extract obtained with boiling 1.25 per cent H 2 S 0 4 
in determining crude fiber. Table I contains the data of climatic measure¬ 
ments and Table II shows the composition of the plants in this test. 
Table I .—Climatic data of the environment of clover culture? 
SAME PERIOD AS OTHER CULTURES 
House temperature. 
* 
Air temperature. 
Total evaporation. 
Ratio of 
evapora¬ 
tion. 
Soil temperature. 
Mini¬ 
mum. 
Maxi¬ 
mum 
Aver¬ 
age. 
White 
atmom¬ 
eter. 
Black 
atmom¬ 
eter 
Black to 
white 
atmom¬ 
eter. 
Mini¬ 
mum. 
Maxi¬ 
mum. 
Aver¬ 
age. 
Cooler. 
°C. 
8. 0 
°C. 
31.O 
0 C. 
14-3 
Cc. 
711 
Cc. 
1,085 
i- 53 
1 ^ 
°- 
. O 
°C. 
15.8 
FULL PERIOD OF GROWTH 
Cooler. 
8. 0 
32. 0 
15.0 
»s 7 
1,306 
I' 52 
5 *o 
31.0 
17. 2 
Warmer. 
13-3 
29. 0 
20.6 
1,047 
I, 420 
! 
I. 36 
11. 0 
32. 0 
20. 2 
Table II .—Composition of clover tops grown in different greenhouse environments 
House temperature. 
Dry matter 
of 
tissues. 
Yield of 
dry 
matter. 
Crude 
protein. 
Ether 
extract. 
Crude 
fiber. 
Pento¬ 
sans. 
Poly- 
saccha- 
rids . 1 
Cooler. 
Per cent. 
/(A) 21. s 
1 (B) i 9 - 8 
Gm. 
12- 75 
10. 80 
Per cent. 
18.5 
21. I 
Per cent. 
5 * 1 
6. 1 
Per cent. 
15.O 
14. 2 
Per cent. 
9.2 
8.3 
Per cent. 
10. $ 
13*9 
Average. 
20. 7 
II. 78 
20. O 
5-6 
14. 6 
8.8 
12. 2 
Warmer. 
/(A) 20. 6 
\(B) 22. 7 
12- ss 
9-45 
21. 7 
22. 5 
5 * 5 
3-4 
13.8 
14. 8 
9. 4 
9.6 
8. 0 
8.6 
Average. 
21. 7 
II. OO 
22. I 
4.5 
i 4*3 
9-5 
8.3 
i Hydrolysis by boiling with 1.25 per cent H2SO4 for 0.5 hour. Results are in equivalents of glucose. 
Inspection of the climatic data shows that, with the exception of the 
maximal values which occurred toward the close of the experiment, a 
difference of about 5 0 C. was maintained in atmospheric temperatures. 
The average observed temperatures of the two houses approximated 
15° and 20.6° C, for the full period of growth in each case. For the period 
of time when both pairs of cultures were growing simultaneously, the 
water loss from the white atmometer was 47 per cent greater in the 
warmer house than in the cooler one. This may be considered an index 
of the relative vapor pressure deficits of the atmosphere in the two cases. 
Apparently the relative humidity was nearly equal in the two green¬ 
houses for the same relative humidity in both cases would bear the same 
ratio to each other as the total vapor pressures at saturation. Thus, 
with the latter values fixed at 12.2 mm. for 15 0 and 18.2 mm. at 20.5 0 
