174 PHOSPHORESCENCE. 
In 1686, Tachard, an ecclesiastic, in order to 
explain the phosphorescence of the sea, stated 
that the waters of the ocean absorbed the hight of 
the sun by day and emitted it again at night. 
The distinguished philosopher Robert Boyle, who 
lived at this period, believed that the light of 
the waves was owing to friction. He imagined 
that the atmosphere rubbed against the water of 
the sea by the rotation of the earth, and that 
this friction had for direct effect the emission of 
a certain amount of caloric and ight. We have 
already seen that Boyle endeavoured also, by 
numerous and ingenious experiments, to account 
for the phosphorescence of rotten wood, flesh, etc. 
Later still, we find that Mayer reproduces the 
old opinion of Tachard ; and Beccaria affirms that 
the solar-phosphorus, or Bologna stone, ‘‘ absorbs 
light, and emits it some time afterwards.” Bec- 
caria thought he had observed that this substance, 
when submitted to coloured light from red, yellow, 
blue, and green glasses, shone in the dark with a 
red, yellow, blue, or green hght. But this was 
afterwards distinctly denied by Wilson in England, 
Zanetti and Algerotti in Italy, by Dufay in France, 
and by Grosser of Vienna. 
In 1797, Brugnatelli published a singular opi- 
nion in the ‘Annali di Chimica.’ He believed 
that the phosphorescence of the Lampyride, or 
clowworms, was owing to a peculiar physiological 
