on the Light emitted from various Bodies. 423 
water; and they all descended, very luminous, from the top to 
the bottom, some quickly and others slowly, according to their 
gravity, making a very pleasing experiment. 
Exper. 4. A large wooden bowl, about 12 inches wide, was 
next filled with water heated to about 110°, and then a quan- 
tity of illuminated phosphorus, partly in the form of powder, 
and partly in pieces of different magnitudes, was scattered over 
the whole surface of the water ; all which pieces fell, with in- 
creased splendour, to the bottom, where they preserved their 
light for some time* 
II. The imbibed Light is extinguished by a great Degree of 
Heat. 
Exper. 5. Some fragments of the phosphorus, rendered lu- 
minous, were exposed to a greater degree of heat, namely, by 
casting them into a tin vessel containing two pints of boiling 
water. They flashed with increased light, as soon as they came 
in contact with the water, fell precipitately to the bottom, in a 
lucid state, and then were gradually extinguished. 
Exper. 6 . In which the degree of heat was still increased. 
A small bar of iron, of about an inch square, was made red-hot, 
and laid horizontally in the laboratory, until, by cooling, it nearly 
ceased to shine. Some pieces of illuminated phosphorus were 
then put upon it in succession, and the light, in a moment, 
glowed with uncommon lustre, but was quickly after totally 
extinguished.* 
• Solar light, when received merely on a piece of white paper, may also be rendered 
more luminous by heat, and then extinguished by it, as appears from an experiment 
made by the late Mr, B. Wilson, whose book on phosphori I had not seen before 
this Paper was drawn up. 
