I know not, _Pyrophilus_, whether it be worth while to acquaint you with
the ways that came into my Thoughts, whereby in some measure to explicate
the first of the mention'd ways of making a Green; for I have sometimes
Conjectur'd, that the mixture of the Bise and the Orpiment produc'd a Green
by so altering the Superficial Asperity, which each of those Ingredients
had apart, that the Light Incident on the mixture was Reflected with
differing Shades, as to Quantity, or Order, or both, from those of either
of the Ingredients, and such as the Light is wont to be Modify'd with, when
it Reflects from Grass, or Leaves, or some of those other Bodies that we
are wont to call Green. And sometimes too I have doubted, whether the
produced Green might not be partly at least deriv'd from this, That the
Beams that Rebound from the Corpuscles of the Orpiment, giving one kind of
stroak upon the _Retina_, whose Perception we call Yellow, and the Beams
Reflected from the Corpuscles of the Bise, giving another stroak upon the
same _Retina_, like to Objects that are Blew, the Contiguity and Minuteness
of these Corpuscles may make the Appulse of the Reflected Light fall upon
the _Retina_ within so narrow a Compass, that the part they Beat upon being
but as it were a Physical point, they may give a Compounded stroak, which
may consequently exhibit a Compounded and new Kind of Sensation, as we see
that two Strings of a Musical Instrument being struck together, making two
Noises that arrive at the Ear at the same time as to Sense, yield a Sound
differing from either of them, and as it were Compounded of both; Insomuch
that if they be Discordantly ton'd, though each of them struck apart would
yield a Pleasing Sound, yet being struck together they make but a Harsh and
troublesome Noise. But this not being so fit a place to prosecute
Speculations, I shall not insist, neither upon these Conjectures nor any
others, which the Experiment we have been mentioning may have suggested to
me. And I shall leave it to you, _Pyrophilus_, to derive what Instruction
you can from comparing together the Various ways whereby a Yellow and a