66 PENHALLOW ON MECHANISM 
humidity; of all the remainder, when the sky was clear and the sun bright. The rates 
of movement in the four tendrils just mentioned were respectively 2.06, 0.65, 2.6 and 2.17 
em., and were attained when, owing to the humidity of the air, transpiration was not 
very active. Tendrils 2, 5, 4, 5 a, Ta, b and 8a gave respectively 1.76, 3.55, 0.85, 1.44, 
0.92, 0.555 and 1.2 as the maximum of motion. These rates were all reached while 
transpiration was excessive, and the effect of this upon the plants so great that all the 
leaves, flowers and buds were drooping. Tendrils 5 b,e and 6 a,b, in which the highest 
maxima were reached, gave respectively 4.55 and 6.50. em., but these rates were reached 
under conditions of active, though not excessive, transpiration, clear sky and bright sun, 
and while the plant was in a normally active condition, as shown by the erect leaves and 
fine healthy color of all the parts. 
Minimum RATE oF MoyeMENT.—Of the thirteen minimum movements recorded, we 
find that five occurred between sunset and midnight, two between midnight and sunrise, 
three between 10 a.m. and 1 p.m., and three between 1 and 4 pm. We further find that 
four occurred during a minimum temperature ; four just before the maximum; two just 
after, and three at the very time of maximum. 
As in our previous division, taking the figures obtained for 6 a, b, 3, 5b,c, 1, 8c and 9 
as representing the true minima for the entire movement of each tendril, we find 
the average temperature at which these movements occurred to be 22.9° C., while the 
average temperature for the whole thirteen is found to be 25.8° C. The remaining seven 
movements of greater rapidity were found under the influence of an average temperature 
of 28.2° C. The following table will show the connection between temperature and rate 
of movement, as just explained :— 


Maximum movements............. 13 | 26.5° Mean Temperature. 
Minimum res e cesse 13 25 BRIE # 
Maximum fe (a) rapid..... 6 | PAG ES ce 
a si (B) Slow TRANS ts se 
Minimum 3 (a) slow. .... 6 | 22-95 eS 
: a (b) rapid..... 7 | BoP “ 
| 

From this it will appear that a higher temperature is favorable to the more rapid 
movements, to a greater activity of the whole plant. 
Referring to the atmospheric conditions, it is found that tendrils 6 a, b and 1 gave 
their minima of movement during pleasant weather, while the plant was apparently in 
an active condition. The rates per minute were .047 and 0.21 cm. respectively. Ten- 
drils 7b, 9,5b,c and 8 gave 0.08, 0.02, 0.043 and 0.013 cm. respectively, during a time 
of great moisture and even rain; 8¢ gave 0.025 em., during the time of a heavy fog and 
cold east wind. The remainder, 4, 7a, 2, 8b,8 a and 5a, gave respectively 0.031, 0.058, 
0.18, 0.10, 0.166 and 0.13 cm., at a time when transpiration was excessive, as shown by 
shown by the drooping leaves and terminals, and always during a very bright sun. 
DEXTRORSE AND SINISTRORSE MovemeEnts.—The circumnutations of the tendril tip 
