I
White light carries its colours within.
One quiet beam enters the glass; distinct intervals depart in measured succession.
The Order of Light
II
Refraction is a measured departure.
The angle changes by degree, making difference visible without ornament or conjecture.
III
Each band earns its proper place.
Seven pigments hold their order, from the warm edge of red to the deepest blue.
IV
Observation becomes common language.
A ray diagram gives the eye, the instrument, and the reader one account of the fact.