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Art. XVII.- — On a Singular luminous property of Wood, ^c. 
steeped in Solutions of Lime and Magnesia. 
About the middle of last summer, Mr Cameron of Glas- 
gow, (the inventor of the ingenious method of making crucibles, 
described in our last number,) brought me some pieces of wood 
that had been steeped in oxymuriate of lime, the common 
bleaching powder of Mr Tennant, and mentioned to me, that 
he had observed a singular luminous property in the white sub« 
stance which remained after burning the wood. In order to 
observe this appearance, the end of the piece of wood is heldln 
the flame of a candle till it is completely burnt. A sort of 
white substance is left at the end of the wood, and when this 
substance is held in the outer part of the flame of the candle, it 
exhibits a brilliant dazzling light, not much, if at all, inferior to 
that which arises from the deflagration of charcoal by the action 
of galvanism. When bits of woods of diflerent kinds were 
steeped in the oxymuriate of lime, they gave the same results, 
only the harder woods seemed to produce a more satisfactory 
effect than the softer kinds. 
By submitting the whole substance to the action of the blow- 
pipe, I found that the intensity of the light was greatly increased, 
but the white substance was generally driven away by the blast. 
Upon shewing this experiment to Mr Sivright of Megget- 
land, he conjectured that the white residue of the burnt wood 
consisted of particles of lime in a minute state of division, and 
we found upon trial, that it was soluble in nitric acid. Dr 
Fyfe, to whom I gave a portion of the ashes, found them to be 
pure lime, and also ascertained that wood acquired the same 
property by being steeped in solutions of the salts of that earth, 
or in lime-water. I obtained a similar result by steeping the 
wood in a solution of sulphate of magnesia ; but no effect was 
produced when it was steeped in a solution of hydrate of barytes. 
The calcareous residue was highly phosphorescent, when thrown 
upon a hot iron, but the magnesian residue exhibited no symp- 
toms of phosphorescence. 
The sight of these experiments naturally suggests the idea, 
which occurred also to Mr Cameron, tliat SMch a brilliant light. 
