194 SOME OBSERVATIONS ON THE FLASHES OF LIGHT FROM FLOWERS. 
on ; these singular scintillations were shown to her father and other philosophers, 
and Mr. Wilcke, a celebrated electrician, believed them to be electric. Vide Lin. 
Spec. Plantar. 490 ; Swedish Acts for the Year 1762 ; Pulteneys View of Linnceus, 
page 220. Nor is this more wonderful than that the electric eel and torpedo should 
give voluntary shocks of electricity ; and in this plant perhaps, as in those animals, 
it may be a mode of defence, by which it harasses or destroys the night-flying 
insects which infest it, and probably it may emit the same sparks during the day, 
which must be then invisible. This curious subject deserves further investigation. 
The ceasing to shine of this plant after twilight might induce one to conceive that 
it absorbed and emitted light like the Bolognian Phosphorus, or calcined oyster 
shell. The light of the evening, at the same distance from noon, is much greater, 
as I have repeatedly observed, than the light of the morning ; this is owing, as I 
suppose, to the phosphorescent quality of almost all bodies in a greater or less 
degree, which thus absorb light during the sunshine, and continue to emit it again 
for some time afterwards, though not in such quantity as to produce apparent 
scintillations." 
On the same subject Darwin has an additional note in the same volume, page 
182. " In Sweden a very curious phenomenon has been observed on certain 
flowers, by M. Haggren, Lecturer on Natural History. One evening he perceived 
a faint flash of light repeatedly dart from a marigold ; surprised at such an uncommon 
appearance, he resolved to examine it with attention, and to be assured that it was 
no deception of the eye, he placed a man near him, with orders to make a signal at 
the moment when he observed the light. They both saw it constantly at the same 
moment. The light was most brilliant in marigolds of an orange colour, but scarcely 
visible in pale ones. 
" The flash was frequently on the same flower two or three times in quick suc- 
cession, but more commonly at intervals of several minutes ; and when several 
flowers in the same place emitted their light together, it could be observed at a con- 
siderable distance. 
" This phenomenon was remarked in the months of July and August, at sunset, 
and for half an hour after, when the atmosphere was clear ; but after a rainy day, or 
when the air was loaded with vapours, nothing of it was seen. 
" The following flowers emitted flashes, more or less vivid, in this order : — 1. The 
marigold {Calendula officinalis) ; 2. Garden Nasturtium (Tropwolum majus) ; 3. 
Orange Lily (Lilium hulbiferwm) ; 4. African Marigold ( Tagetes patula et erecta). 
Sometimes it was also observed on the Sun-flowers (Helianthus annuus) ; but 
bright yellow, or flame colour, seemed in general necessary for the production of 
this light, for it was never seen on the flowers of any other colour. 
" To discover whether some little insects, or phosphoric worms, might not be the 
cause of it, the flowers were carefully examined, even with a microscope, without 
any such being found. From the rapidity of the flash, and other circumstances, it 
might be conjectured that there is something of electricity in this phenomenon. It 
is well known, that when the pistil of a flower is impregnated, the pollen bursts away 
by its elasticity, with which electricity may be combined. But M. Haggren, after 
