3 1 8 New combe, — Geo tropic Response at Various 
about one centimetre in length, and were open at both ends, the tapering 
end having but a small pore, and the growing root pushing the glass tube 
forward. The glass tubes were placed over the root-tips, and the roots, 
always in two sets, laid the one set at 90° the other at 135 0 from the 
position of stable equilibrium. The glass tubes lay on a plane support 
below, so that their weight did not rest on the roots. The seedlings were 
so placed that during revolution when the curves came the curves were 
parallel with the vertical plate of the klinostat. The following table 
is so constructed as to show changes in the angles of roots as the ex- 
periment progressed, and to show variation among the members of the 
same set of seedlings. The third column shows the period of stimulation 
while the roots were covered with glass tubes. The fourth column gives 
the time of observation after the glass tubes were removed. The fifth 
and seventh columns show the position of individual roots at two or three 
periods during the experiment ; all of the numbers in the same vertical row 
in any one experiment give the angles for the same root. The sixth and 
eighth columns give the average angles at the observation nearest 24 hours. 
The four numbers marked e * ’ indicate original angles reversed. The angles 
as given are all for the place of the original curvature. The subsequent 
curves nearer the apex of the roots are not indicated. 
An inspection of the following table shows such an individual variation 
on the part of the roots that the whole method must appear unsatisfactory. 
It is true that three of the four experiments give average results favouring 
the position of 135 0 ; but the fourth experiment reverses this result. More- 
over, in each experiment of five roots there are at least two roots from 
the position of 90° that, after many hours’ rotation, exceed in their angles 
the two smallest from 135°. As worthy of note in the behaviour not shown 
in the table it may be said that roots kept in the forced positions in glass 
tubes usually tend to reduce their original angles after a few hours’ stay 
on the klinostat, and even continue to reduce the angles after the apex 
of the angle has passed beyond the region of the so-called elongating zone. 
In the last experiment, for example, given in the table, several of the root- 
tips after 20 hours were 1 5 mm. beyond the angles ; yet the angles were 
reduced during the ensuing 1 6 hours. 
