26 
Journal of Agricultural Research 
Vol. XXV, No. i 
2.5° higher than in the earlier experiments. The attempt to check 
evaporation at the higher temperature was overdone, so that evapora¬ 
tion, as measured by the black atmometer, was io per cent less than at 
the lower temperature. The ratio of water losses from the black and 
white atmometers indicate practically equal illumination in the two 
culture chambers. 
Table VII .—Climatic records of plant chambers in experiment of IQ2I 
Designation of temperature 
range. 
Absolute 
maximum 
tempera¬ 
ture. 
Daily 
average 
maximum 
tempera¬ 
ture. 
Absolute 
minimum 
tempera¬ 
ture. 
Daily 
average 
minimum 
tempera¬ 
ture. 
Total 
evapora¬ 
tion 
standard 
black 
atmometer. 
Ratio of 
evapora¬ 
tion black: 
white 
atmometer. 
°C. 
°C. 
°C. 
°C. 
Cc. 
High. 
34-0 
28. 2 
18.5 
23.2 
610 
1.085 
Low. 
3 °. ° 
23*3 
14. O 
16. 9 
678 
I. 085 
Table VIII.— Yield and composition of buckwheat , sand cultures of climatic chambers 
in IQ 2 I 
Range of temperature 
(daily average). 
Num¬ 
ber of 
seeds 
at 
har¬ 
vest. 
Dry matter 
yield. 1 
Ether extract. 
Composition of dry matter. 
Polysaccha- 
rids.* 
Insoluble 
nitrogen.* 
Leaf. 
Stem. 
Leaf. 
Stem. 
Leaf. 
Stem. 
Leaf. 
Stem. 
°C. 
Gm. 
Gm. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
23.2 to 28.2. 
O 
O.47 
0.66 
6.6 
4 . 5 
18.3 
14. 8 
2 -3 
0. 7 
16.9 to 23.3. 
6 
• 5 ° 
• 79 
7 * 1 
4.1 
17-9 
19. 6 
2-5 
.8 
1 Thirteen plants at high temperature, 16 at low temperature. 
I Determined by boiling with 4 per cent H2SO4 for 2.5 hours after extraction of sugars and dextrins. 
■ Determined on the residue from acid hydrolysis with one-half the acid extract added. 
