In its highest purity it always carries with it the nature of brightness, and has a serene, gay, softly exciting character.

How the chemical yellow develops itself in and upon the white, has been circumstantially described in its proper place. In prismatic experiments it extends itself alone and widely in the light space, and while the two poles remain separated from each other, before it mixes with blue to produce green it is to be seen in its utmost purity and beauty. It appears on the slightest mitigation of light, whether by semi-transparent mediums or faint reflection from white surfaces.