2, will readily bring to the mind of the reader the relation of these one to another, and their intensities in the different parts of a decomposed sunbeam.
The various points of the solar spectrum are represented in the order in which they occur between A, and B, this exhibits the limits of the Newtonian spectrum, corresponding with Fig.1.

Sir John Herschel and Seebeck have shown that there exists, beyond the violet, a faint violet light, or rather a lavender to b, to which gradually becomes colorless; similarly, red light exists beyond the assigned limits of the red ray to a.

The greatest amount of actinic power is shown at E opposite the violet; hence this color "exerts" the greatest amount of influence in the formation of the photographic image.
(Blue paper and blue color have been somewhat extensively used by our Daguerreotype operators in their operating rooms and skylights, in order to facilitate the operation in the camera.

I fancy, however, that this plan cannot be productive of as much good as thought by some, from the fact, that the light falling upon the subject, and then reflected into the camera, is, coming through colorless glass, not affected by such rays as may be reflected from the walls of the operating room; and even if it were so, I conceive that it would be injurious, by destroying the harmony of shadows which might otherwise occur.) The greatest amount of white light is at C; the yellow contains less of the chemical power than any other portion of the solar spectrum.

It has been found that the most intense heat is at the extreme red, b.
Artificial lights differ in their color; the white light of burning charcoal, which is the principal light from candles, oil and gas, contains three rays--red, yellow, and blue.