80 
squares were at once taken to an air bath and dried at a tem- 
perature of 100° C. until no further loss of weight took Place, 
The same thing was repeated at 12 with the leaflets, which 
had remained on the plant after 7 o’clock A separate experi: 
ment in which the leaflets on both sides of the petiole were 
taken off at the same time, and afterward dried and weighed, 
proved the absolute reliableness of this method, the weights 
arrived at for both sides showing a difference which is nothing 
to the difference caused by the influence of continued insola- : 
tion. In this way numerous weighings were undertaken , which 
may guarantee the correctness of the figures given by and by. 
The other plant was Delima sarmentosa; it has simple leaves, 
also glittering but tough, even somewhat brittle, with a ve 
nation strongly protruding from the back. In this case to 
squares were cut out of the exact middle, but since it is m | 
possible to find leaves as closely corresponding to each other as 
the leaflets of a compound leaf, special care was required 
Therefore in the first place a definite kind of leaf was in evéely 
ease selected, one that was full grown and judging from the 
colour, not too old. If now for instance at 8 a. m. square’ 
were taken from 4 leaves of this description, the same proces 
was repeated at 12 with similar ones. A check-experim 
showed that in this way great mistakes were avoided To make 
assurance double sure, I added up the results of several expel 
iments, and calculated from their sum the average weight 
one square Meter of leaf at different periods of the day. 
Between 6.10 and 7.10 a. m. 1 M.? weighs 83.34 gt 
11.45a.m.and12.35p.m.  , e 
~ 3.30 p. m. and 5.30 p. m. : ; 82.08 gt 
A simple calculation shows that between the morning howl 
and noon every M.* has gained 1.27 gr. It is evident also that 
the weight grows rapidly smaller so as to fall down to ti 
morning weight in the afternoon. This result exactly com 
1) 83.34 is the average of 7 observations, 90.33 of 6, and 82.08 of 9 om 
tions. The leaves cnt at 4 were generally taken from the westside, but the ® 
was Often clouded at this time. 
