a ea 
— > R.CooL. 
1904] DARWIN: MOVEMENTS OF STOMATA 103 
Exp. 79.—There was either no effect on the temperature, or when an effect 
was produced it was the reverse of the leaf-effect, z. ¢., the artifi- 
cial leaf became relatively cooler in darkness, warmer in light. 
Exp. 86.—No definite effect on the temperature-curve. 
Exp. 89.—The effect of alternate light and darkness was perceptible, and 
was of the same character as in the case of leaves, z. ¢., darkness 
produced a relative rise of the temperature of the artificial 
leaf, But the curve as a whole is strikingly different from 
a leaf-curve, both in the slight amplitude and the slow occur- 
rence of temperature change. 
Exp. 96.—Four alternate observations of light and darkness produced no 
visible effect on the relative temperature. 
From these experiments I conclude that alternations of light 
and darkness do not produce alternations in the temperature of 
a layer of wet linen. This being so, we may, I think, accept 
the obvious explanation that the temperature changes pro- 
duced in a living leaf are simply due to opening and closing of 
the stomata. 
J 
a8 
" 
e 
N 
Baanensas 
eel Titi 
REECE 
Aging eeR Le 
rLEREP Erie 
11-7 A.M, 
1:0 D.-+ 
tar DE Beay. 
Bane 
255 DE! | | 
11-69.L. 
Fic. 14. 
EXPERIMENT 62, fig. 1g. March 27,1900. NARCISSUS. 
The leaf on bulb R, an artificial leaf on B; therefore, an R-cool rise in 
the curve means an opening of the stomata. 
The diagram shows the times at which the illumination was 
