XXV. Letter from Mr. John Baptist Beccaria, of Turin, F. R. S., to Mr. J. Canton, F.R.S., on his New Phosphorus receiving Several Colours, and only Emitting the Same. From the Latin, p. 212. (1771)

The Philosophical Transactions of the Royal Society of London, For their commencement, in 1665, to the year 1800: Abridged, with notes and biographic illustrations by Charles Hutton, LL.D. F.R.S. George Shaw, M.D. F.R.S. F.L.S. Richard Pearson, M.D. F.S.A. VOL XIII From 1770 to 1776. London: Printed by and for C. And R. Baldwin, New Bridge-Street, Blackfriars. 1809Mr. B. made several cylindrical boxes of thin iron plates, black withinside; and covered with a lid; in which was inserted a glass of any colour different from that of the box. Into every box he put similar bits of the phosphorus. These inclosed bits were exposed to the sun altogether; then taking the boxes into the dark, and opening them, he saw that the piece of phosphorus was green, which was imbued with the light through the green glass; but red, through the red glass; and yellow, through the yellow glass: that is, it appears by this experiment that the phosphorus emits not only the light imbibed, but each its own light also.