64 PENHALLOW ON MECHANISM 
until the close of observations. The entire dextrorse action was 103.50 cm.; the 
sinistrorse 121.50 cm., and the ratio, therefore, as 1 : 1.17. 
Tendril No. 8 c.—Observations upon the tendril were resumed on the 17th of August, 
at 5 o’clock p.m., and extended over fifteen hours. Apparently, on account of its age, 
and the time of observation, the entire movements were slow, amounting in the whole 
period to only 159.0 cm., thus giving an average rate per minute of 0.176 cm. 
The greatest movement was from 7.12 to 7.28 pm., at the rate of 0.65 cm. per 
minute. The waves of most rapid movement were from 5 to 7.30 p.m., with a slight 
acceleration in the morning. Least movement was found from 2.30 to 3 p.m., at 
the rate of 0.023 cm. per minute, occurring at the time of minimum temperature. The 
extreme variation of temperature during the time of observation was only 2 C. A light 
rain fell during the greater part of the time, and heavy clouds obscured the sky the 
remainder. The dextrorse movement was 117.6 cm.; the sinistrorse 41.40 cm., and the 
ratio as 1: 0.35. 
Tendril No. 9.—The last tendril experimented upon was taken August 17th, at 6 
o'clock p.m. It was in the last stages of movement, and exhibited the least horizontal 
range. The whole length of movement was 191.30 cm.; the time sixteen hours and 
forty minutes, and the consequent average rate per minute was 0.191 cm. | 
The greatest movement was from 7 to 7.06 a.m., at the rate of 2.17 cm. per minute. 
This occurred from 9.30 to 10.00 p.m., at the rate of 0.02 cm. per minute. The waves of 
slowest motion were found from 6 p.m. until 5 am. The temperature varied only three 
degrees during the entire time of observation. From the commencement until 10 o’clock 
pm. light rain fell and the sky was entirely overcast until the close of observations. At 
5 a.m., there was a cool east wind, with a very large amount of moisture in the air, and 
the plant was in a very active condition. At the close of observations, heavy rain com- 
menced to fall. The total dextrorse motion was 160.40 cm.; the sinistrorse 30.90 cm. ; 
and the ratio as 1: 0.181. 
GENERAL SUMMARY. 
AVERAGE RATE OF MOVEMENT.—From a total of 436 distinct observations upon the 
motion of the tendril under all conditions of temperature and humidity, it is reasonably 
safe to assume that the average rate of movement deduced from them, will represent with 
approximate accuracy, the true normal rate of movement under all the ordinary conditions 
of growth. This rate we find to be 0.316 cm. per minute. 
Maximum RATE OF MOVEMENT.—By reference to the accompanying table, it will be 
seen that the maximum rates vary very widely, and also. in the same tendril, that they 
usually occur in waves, as in 5a, 56, ¢, etc. 
