62 PENHALLOW ON MECHANISM 
maximum temperature had passed. The time of the greatest movement was from 3.50 to 
7.10 p.m. on a decreasing temperature, and within three degrees of the lowest phase of the 
thermal wave. The times of least movement were from 1.45 to 3.50 p.m., and from 7 p.m. 
to the close of observations. As in the preceding case, there was, in this, a marked distinc- 
tion between the waves of more rapid diurnal, and those of slower nocturnal movement— 
the time of division being 7 p.m. 
The tendril commenced its nutations with a dextrorse movement, and in its entire 
activity manifested a greater equality between right and. left motion, than in even the last 
case. The dextrorse movement was 166.10 cm.; the sinistrorse 161.7 cm., and the ratio, 
therefore, 1: 0.97. At the commencement of observations, the sun was bright, and the 
temperature high. The vitality of the plant was much depressed, and the action slow— 
all the parts drooping from excessive transpiration. This continued until 4 p.m., during 
which time there were slow waves. At 4 o’clock, the plant revived, the leaves became 
erect, and the normal condition and activity were once more restored. From that time 
until sunset, the waves of greatest movement occurred. The sky was clear until after 
midnight, but slow waves continued throughout the remainder of the night, with a 
slight acceleration just after sunrise. : 
Tendril No. 7 a.—Observations commenced Aug. 16th, at 9 o’clock, a.m, and were con- 
tinued for ten consecutive hours. The total distance covered, during that time, was 227.1 
cm., or at the rate of 0.88 cm. per minute. The time of most rapid movement was from 
5 to 5.20 p.m., when the tip moved at the rate of 0.92 cm., per minute. This occurred 
just at the outset of a rapid decline in temperature, and six hours after the maximum of 
temperature had passed. The time of greatest movement was from 3.15 p.m. to the close 
of the observations at seven o’clock, co-incident with a rapid decline in temperature. 
The time of least movement was from 1.42 to 2.25 p.m.; the tip moving at the rate 
of 0.53 em. per minute. “This was during high temperature, but one hour and forty-two 
minutes after the maximum had passed. The waves of least motion were found to extend 
from 9 a.m. until 3.15 p.m., with a marked retardation towards the latter hour. These 
waves were coincident with the greatest heat wave, the greatest retardation of motion 
occurring just after the maximum temperature had passed. 
The experiment commenced with the sky clear and the plant in active condition. As 
the heat increased, however, its effect upon the plant was noticed, and at 12 o’clock, with 
the mercury at 34.4° C., the leaves drooped, and the whole plant was in a very flaccid 
condition. During this time, the waves of slowest motion occurred. This condition 
continued until, with considerable fall in temperature during the afternoon, the normal 
tension and activity of the plant were restored, when the waves of greatest activity 
were noted. The entire dextrorse movement was 92.90 em.; the sinistrorse 134.20 cm. 
and the ratio as 1: 1.44. 
Tendril No. 7b, c.—This was the same as the preceding, observations upon which 
were discontinued during the night, but resumed on the morning of the 17th at 8 o’clock, 
and carried over a period of seven hours and fifty minutes. The entire movement during 
this time was 94.40 cm., giving an average rate per minute of 0.205 cm. Most rapid 
movement was at the rate of 0.555 cm. per minute, and occurred from 8 to 8.15 a.m., at 
