920] 
DUGGAR—H-ION CONCENTRATION AND NUTRIENT SOLUTIONS 21 
TABLE XI 
(Series 4, I—Wheat [moist, high temperature]) 
SALT REQUIREMENTS AND H-ION CONCENTRATION IN RELATION TO GROWTH 
Total Total | Greatest Pu 
No. Pin gr. wt. dry wt. length 
irai (gms.) (gms.) (cm.) Initial | After gr. 
1 AwO 4.19 491 30.71 3.4 4.0 
2 Aw /5 4.10 400 26.77 4.6 5.3 
3 Aw /10 3.78 399 27.00 5.8 4.4 
4 Aw 1/ 2.60 338 24.63 3.35 4.4 
5 Aw 3/ 2.22 328 22.08 3.15 3.6 
6 AwNa 3.83 468 30.10 3.45 3.8 
di AwM 4.65 485 29 .23 5.4 4.0 
8 BwO 5.22 469 32.96 6.6 7.2 
9 Bw /5 4.90 466 32.84 7.4 7.6 
10 Bw /10 4.65 424 32.04 8.6 8.2 
11 Bw 1/ 5.38 491 32.06 6.4 5: 
12 Bw 5/ 5.85 472 31.33 5.2 6.8 
13 Bw 10/ .95 174 12.26 2.8 3.8 
14 BwK, /10 5.13 466 35.55 10 1.2 
15 BwCa 5.70 539 34.23 T 6.6 
16 CwO 4.82 465 29 .12 4.2 6.4 
17 Cw /5 4.17 401 24.78 6.4 7.0 
18 Cw /20 2.25 301 18.85 310 1.2 
19 Cw 1/ 4.05 403 26.50 3.6 6.4 
20 Cw 5/ 2.47 296 20.85 3.2 5.2 
21 CwNa 4.50 441 28.72 4.2 6.6 
houses at the same time no particular effort was made to con- 
trol accurately the conditions of growth. The following general 
conditions were decided upon: (1) Moist high temperature, (11) 
moist low temperature, and (111) dry high temperature. These 
conditions are relative, of course, and all supported good growth. 
‘“ Moist” in the sense here used simply means that by frequent 
sprinkling of walls and floors the humidity was raised above that 
of the usual greenhouse compartment. However, in the case 
of those cultures placed under conditions of high moisture and 
high temperature there was also necessary a slight degree of 
shade. This caused the plants to grow up rather quickly. As 
a result of this rapid growth in this section of the series it was 
determined to take down all cultures after about 15 days except 
those placed under the conditions referred to as moist, low 
