2 hours 1 hour ', hour | Control 
— 25 22 Bl 
1.7 LY 1.8 15 
7 Aa | — — 2.3 
Much more distinct differences oecur when transverse and longi- 
tudinal gravitational stimuli are applied simultaneously. A slight 
modification of Miss Risz’ procedure enables us to demonstrate also 
the influence of the longitudinal component, when the latter has a 
negative value. With this object two boxes are placed parallel to 
the vertical axis of the centrifuge so that the seedlings in one box 
have their apices turned towards the axis, in the other away from 
it. If now such a revolution-velocity is given to the axis as to apply 
to the seedlings a force mg. then the longitudinal component for 
the first box is + mg. and for the second — mg. Furthermore gravity 
acts on the seedlings at the same time. After centrifuging the boxes 
were again placed in their original position. A box which for the 
same length of time had been horizontal, served as control, since 
in this ease the longitudinal component is 0. 
With a stimulation of 30 minutes the curvatures were 40 minutes 
after its cessation : 
2.9 1.6 0.2 
3.4 1.5 0.3 
ST La ie ep 0.9 
If a unilateral light-stimulus is applied after an omnilateral gravi- 
tational stimulus, then similar differences can be observed. 
For this the boxes are again placed on the centrifuge, whose axis 
After 30 minutes centrifuging the seedlings 
are illuminated during 6 seconds with an intensity of 10 M.C. The 
this time is horizontal. 
control box, which remained in its ordinary position, was naturally 
subjected to the same conditions as the seedlings on the centrifuge, 
which had their apices pointing towards the axis. In both eases the 
longitudinal component was + mg. 
