C 28 3 
III. Experiments and Observations on the Production of Light 
from different Bodies , by Heat and by Attrition . By Mr . 
Thomas Wedgwood ; communicated by Sir Joseph Banks, 
Bart. P. R. S. 
Read December 22, 1791. 
Before I begin to state the experiments which are the sub- 
ject of this Paper, it may not perhaps be improper to give a 
very compendious history of the discoveries which have already 
been made relative to phosphoric bodies ; omitting, however, 
the electrical phosphori, and such as are evidently consumed or 
decomposed in the emission of their light, as these are well 
known, and are too numerous and important to be slightly 
noticed. 
Pliny was well acquainted with the luminous appearance 
of rotten wood, and of the eyes of dead fish. From this time 
I find nothing relative to the phosphor ism of bodies, till the be- 
ginning of the sixteenth century, when Benvenuto Cellini, 
in his Art of Jewellery, mentions his having seen a carbuncle 
shine in the dark like coals nearly burnt out ; and relates a 
story of a coloured carbuncle having been found in a vineyard 
near Rome, by its shining in the night. About the year 1639, 
Vincenzo Cascariolo, of Bologna, discovered, by accident, 
that when a certain stone found in that neighbourhood was 
