55^ Of Things relating to Chyrnittryj&c. Part IV.' 
prefents a bright Rofy hugh. As the Sun approaches the 
Meridian, it advances to a higher and more firey Com- 
plexion, like that of a red hot Iron. A little after Sun-fet, 
declines to a pale wan colour, like Chalk., or rather Mother 
of Pearl. 
Expos'd, faith he, to the light of a Candle, or flaming 
Fagot, it receives a pale Luminous colour, as from the 
Sun towards fetting. But being expos'd for a confiderable 
time to the mod clear Moonfliine that I have feen m Lon- 
don, I could not perceive it to become Luminous in the 
leaft. 
It hath been kept, faith he, in the Vacuum of my Great 
and Noble Patron, the Honourable Mr. Boyle called Vacu- 
um Boyle anum, and by his Highnefs Prince Rupert and Him- 
felf obferv'd, for above four or five months, without any 
diminution of its fhining property. 
He adds, That he hath lately found a way to affix this 
Shining Matter to Glafs, whereby fome not unpleafing 
Experiments may be made. Thus far Dr. Slare. 
As to his Ingenious Conjectures of the Subject and 
Caufe of Light in this Phofphorus .* becaufe he hathdefired 
my Opinion, I (hall therefore fubjoyn it in a few lines. 
As to the firft, What it is which gives the Light : It 
feems hard to fay, Whether it be the Cretaceous Salt, the 
Nitrous Salt, or fome Igneous Particles incorporated with 
them in the Operation ? It is plain, That one way or other, 
they do all concur to produce it. 
As to the Queftion, How thefe Particles give light? It 
fhould firft be ftated, What Light is 5 Whether it be a 
Body? Which, though much difputed, yet in ftri& fpeak- 
ing, is an abfurd Queftion $ all one, as to ask, Whether a 
Quality, be a Body ? But the meaning of the Queftion is, 
or ought to be, Whether there be any Body in Nature, 
which is the peculiar fubject of Light, or metonymically 
may be called Light ? Or whether more Bodies than one, 
may fucceffively be the immediate fubjecl thereof ? If fo, 
Whether it be any other Adjunct befides Motion ? If only 
Motion, Whether as there is one peculiar Motion, at leaft 
for a Mufical found, fo another for Light ? And in regard 
' there are fome Experiments which feem to favour each of 
thefe Queftions i fuch an Anfwer fhould be given as will 
cor- 
