171 
but afterwards became yellow ; those in red light 
appeared green, and preserved a tinge of that colour ; 
those in violet light were quite green, and their co- 
lour augmented with their age ; while those raised 
in obscurity possessed no verdure at all *. 
437. These experiments were repeated on French 
beans, and with results nearly similar. In propor- 
tion as the plants grew in height, in different kinds 
of light, the number and size of their leaves diminish- 
ed. In the free air and light, the leaves of beans, 
shooting out of the earth, became green in a day or 
two, according to the intensity of the light ; those 
leaves which received light through water, had a 
deeper green colour ; those in violet light acquired 
a deep green, approaching to blackness ; those grow- 
ing in red light were also green, but less so than na- 
tural leaves. In all these experiments, more or less 
light was reflected by the fluids employed, or inter- 
cepted in its transmission through them. If, there- 
fore, the effects produced come near to those which 
attend the action of entire light, it must, says M. Se- 
nebier, be owing less to the intensity of illumination, 
than to the quality of the illuminating ray. Hence, 
when the violet ray renders plants as green at least 
as entire light, this cannot arise from its power of illu- 
mination ; for this ray is only a part of entire light, and 
is, besides, transmitted through a glass vessel, and 
through the fluid which that vessel contains. But 
the violet light, which thus acts on the colour, does 
not equally act on the growth and development of 
the plant ; whence it is concluded, by M. Senebier, 
* Mem. Phvs. Chim. t. ii. p. 55. et sea. 
