IN A SATURATED ATMOSPHERE. 805 
Epilobium hirsutum (continued). 
ight in 
bien " Loss per cent. | Temp. (W. & D). 
July 21st. o 
8 A.M. 2:480 1:98 615 
3 P.M. 2:460 079 62 
10.30 p.m. 2:460 x 0:00 62 
July 22nd. 
5.30 p.m. 2:850 447 63 
July 23rd. 
9 A.M. 2:850 x 0:00 62 
2 P.M. 2:300 2°12 64 
Between 6 p.m. one day and 8 a.m. on the following day, the 
plants very frequently either lost nothing (*), or else they gained 
weight (t). 
The author of ‘How Plants Feed’ says :—“ Knop found in 
one instance that a Portulaca, standing overnight in a bell-glass 
with moistened sides, did not lose, but gained weight, some dew 
having gathered on the foliage " (p. 87). That plants, especially 
when at all * wilted,” to use the American term, can absorb dew 
and rain has been abundantly proved by Boucicault * and by 
myself t. 
In carefully examining the specimens, of course through the 
glass jar, I could not detect that the gain was in consequence 
of any visible dew upon the surface. Indeed,the amount gained 
in each case is so minute, that it could only be detected by very 
careful weighing ; but the fact that the gains all occurred during 
the evenings and nights, when the temperature fell, while the 
losses only occurred by day, are sufficient to indicate the occur- 
rence as an undoubted fact; and while Knop only recorded it as 
an isolated instance, the above table establishes the property of 
gain as a law. 
* Annales de Chimie et de Physique, Mars 1878. 
t Journ. Linn. Soc., Bot. vol. xvii. p. 313. 
