In many ways high alchemy is the science of light.
We see light as the first being emerging from the Void in Genesis.
One should understand this, not as the narrow band/spectrum of visible light alone,
but as the entire electro-magnetic spectrum. Light is also infrared, ultraviolet, x-ray, gamma, hertzian...
"Oh Lord my God, Thou coverest Thyself with light as if a garment" - Psalm 104:2
In quantum physics, photons are the carriers of light. These, again, represent a certain frequency
of the EM spectrum/Ouroboros. Photons are a mercury of sorts, the way electrons communicate.
In mythology and alchemy and various religions, there is placed much importance on light -
the light of Gnosticism, of Kabbalah, the Lucifer, the Phosphorus...
Alchemy stresses the significance of colors in the work, and colors are light.
In The Alchemical Manuscripts series, "The Betty Story", we see a green light having mysterious
effects on alcohol.
Schwaller claimed that the secret manuscript which Champagne found was about colors.
Newton, the alchemist, also studied gravity, magnetism, optics, light...
Manfred Junius makes it a point to mention three types of tartar according to their relation to light.
And we know that one of the things that separates alchemy from chemistry lies in exposing the
matter to the rays of the sun and the moon.
So I just want to remind that when considering alchemy, one should contemplate this light.
Here is an interesting link to Karl von Eckarthausen's "Catechism"