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Phosphorescence. 
PRESIDENTIAL ADDRESS DELIVERED OCT. 22ND, 1903, 
By Cuas, Gro, Marruews, F.1.C., F.C.S. 
es NCD te property in living and non-living 
things of bearing or showing light which has not its origin in 
the ordinary sources of light, e.g., the burning of combustible sub- 
stances, or that state of a heated body known as Incandescence. 
I purpose first speaking of Phosphorescence rather generally, 
then (a) Phosphorescence amongst living things, and to a less 
extent, (b) Phosphorescence amongst non-living things. 
When we come to enquire as to the circumstances and cases 
under and in which phosphorescence has been noted, we find our- 
selves, it seems to me, in a field of surprising wealth and variety. 
I will enumerate some of these, adding such remarks as the subject 
may seem to justify. 
1, Spontaneous phosphorescence, as shown by the Firefly and 
Glow-worm in all their varieties, and by various other living things, 
especially those pertaining to the sea; phosphorus; radium and its 
congeners. * 
Note experiments towards the close of the paper. 
