Angles of Inclination . 
319 
TABLE III. 
Showing angles attained on the klinostat after prolonged 
forced stimulation . 
Species . 
Tempera- 
ture, . 
Period of 
stimulation. 
Time of 
observa- 
tion. 
Angles attained. 
From 90°. 
Av. 
From 1 3 5 0 . 
Av. 
Vicia 
Faba 
2 2° 
5 hrs. 
30 min. 
90, 90, 30, 90, 90, 60 
90,45, 70,90, 90 
25! hrs. 
45,30, 45,12, 50, 15 
33 
4°, 5°, 35, 80 , 95 
60 
Vicia 
Faba 
Q\ 
0 
5 hrs. 
5 min. 
40, 30, 30, 0, 30 
45, 20,45,15,50 
19 hrs. 
15, o,i 5 ,-i 5 *, 15 
30, 30, 30,0,-25* 
24 hrs. 
15, 0, 0,-15*, 10 
5 
30, 30,30, 0,-10* 
18 
Lupinus 
albus 
23*5° 
4 hrs. 
10 min. 
0, 70, 70, 80, 60 
45,30,45, 0,45 
12 hrs. 
0, 30, 30, 15, 20 
55,4°, 30,15,55 
24 hrs. 
0,30,3°, 0, 0 
12 
45,45,30, 0,45 
33 
Lupinus 
albus 
23° 
4! hrs. 
25 min. 
30, 30, 45, 60, 60 
60,60, 10, 10,45 
20 hrs. 
30, 30, 0, 60, 40 
75,10, 0, 0,45 
36 hrs. 
15, 10, 0, 10, 10 
34 
45, °, 0, 0, r 5 
26 
In the experiments made by Czapek there are no details given 
from which we can judge of the similarity of behaviour of his primary 
roots. From the few like tests recorded in the present paper we may, 
however, infer that Czapek s results were correspondingly irregular. 
B. Relative Intensity of Response at Equal Angles 
ABOVE AND BELOW THE HORIZONTAL. 
When Sachs 1 and Stone 2 state that the geotropic response of primary 
roots and stems is approximately proportional to the cosine of the angle 
of inclination during stimulation, the deduction is that equal angles of 
inclination above and below the horizontal will cause equal geotropic 
reactions. Czapek 3 contests this conclusion, stating that for roots all 
angles of inclination above the horizontal cause stronger curvatures than 
equal angles below ; while for stems all inclinations below cause stronger 
curves than equal angles above the horizontal. The method employed 
to obtain these results was, however, the objectionable one used to find 
the angle for greatest geotropic effect. The experiments giving the best 
evidence for Czapek’s conclusion are to my mind those of Miss Pertz 4 on 
1 Ueber das Wachsthum der Haupt- und Nebenwurzeln. Arbeit, bot, Inst. Wiirzb., i, 1873, 
p. 454. 
3 ‘ Geotropic Experiments.’ Bot. Gazette, xxix, 1900, p. 136. 
3 Untersuchung iiber Geotropismus. Jahrb. f. wiss. Bot, xxvii, 1895, p. 283. 
4 1 On the Gravitation Stimulus in Relation to Position/ Annals of Bot, xiii, 1899, p. 620. 
