1881. ] Botany. 387 
openings of the bottle and allowed to remain there until the small 
hermometer remained constant at about the temperature of the sur- 
sounding water. The weighing cork was then quickly changed for 
the one attached to the grass leaf. After leaving the grass leaf in the 
test-tube for half an hour, the weighing cork was put in place 
again, and the test-tube weighed, care being taken to remove 
completely all the external moisture. The following table em- 
braces the results. The weights are given in grams and decimals, 
and the temperatures in degrees of Fahrenheit’s thermometer. 
The same leaf was used in all the experiments, excepting Nos. 
. and 17. The observations were continued through several 
ays. 
| 
Light. Temperature. ae hah eg Mog gt 0 ag 
(Sunshine 5. ..6 cases 45-52 25.8700 25.8853 0.0153 
2 heee nee os 41-45 25.8670 25.8814 | 0.0144 
3 ite ee ek. 45 25.8665 25.8780 | 0.0115 
4 te ee eee 50 25.8650 25.8739 0089 
5 ie wae kaede 43-48 25.8619 25.8713 ° 
6 eee UsG 48 25.8619 25.8763 0.0144 
7 erp enee 43-48 25.8615 25.8723 0.0108 
8 ee ewevees es 68-72 25.8605 25.8703 
Pe ay eres Re 95 25.8308 25.54 0.0152 
To |Diffused light...... 41 2 895 25.87 
xg where ere 59 25.8632 25.8655 0.0023 
12 ess Meelis 59 25.8627 25.8643 0,0016 
13 |Leaf in darkness... 41 25.8667 25.8688 0,0021 
14 |Whole plant in dark- 
uit 61 25.861 25.8615 eet 
15 |Whole plant in dark- : : “ 
MESS bows cute ces 61 25.861 25.8619 0.0004 
 tehine. ......... 93 aaah rot 5036 0.0628 
17 |\Darkness,.......... 95-97 20.4402 20.4420 0.0018 
A careful study of the foregoing table shows that the leaf in- 
variably lost more water in sunshine than in darkness. The 
a vital on 
A pine splinter from a board was now cut into about the size 
and form of a grass leaf, and after being soaked in water until 
