HISTORICAL NOTES. 179 
hind, and believed in the old opinion of Beccaria, 
Heinrich, at Nuremberg, and Pearsall, in London, 
supported the ideas of Dessaignes. Becquerel 
and Biot have the merit of having first studied 
the influence of transparent screens of different 
substances (glass, quartz, calcareous spar, etc.) in 
promoting or extinguishing phosphorescent leht 
produced by insolation. Their experiments were 
repeated recently by Professor Henry, of Phila- 
delphia. The action of coloured glasses upon this 
phenomenon had already been investigated by 
Wilson and Beccaria. 
I shall not repeat here what I have stated in 
other parts of this work concerning the discovery 
of plant-phosphorescence and of light-emitting 
animals. 
For the benefit of those who might desire to 
consult some of the more important and original 
documents relating to the subject of phospho- 
rescence, I have determined to give, in an Ap- 
pendix to this work, their titles, and the dates of 
their publication. 
As we have already seen, the light emitted by 
flowers is thought to be owing to electricity ; but 
as for that which is evolved from Fungz, such as the 
Agaric of the olive, the Rhizomorpha, etc., no idea 
has been formed of the direct cause of the lumi- 
nous phenomenon. 
According to Matteucci, Roberts, and De 
