Light and Color.

Scientific American 15, 23.12.1854

The great Author of the Universe . He who said, "Let there be light, and the light was," has empoyed colors adorning the various productions of his power and wisdom, and for giving pleasure to his more intelligent creatures. Earth and man were expressly created for one another, and a benificent God has caused the general aspect of the world around us to be in harmony with our physical and mental constitution. The heart swells with emotion in gazing upon the crimson sky of sunset, and the blue vault above, when the sentinel stars come out at night and look down upon us from their nightly watchtowers. The colors of field and forest are imprinted with the siget mark of their Author, and the soul of man made in that Maker's image, drinks in pleasure in beholding them. The red bird, dancing from bush to bush, and the butterfly from flower to flower, charm us with the beauty of their plumage; and the flowers themselves, from the modest daisy to the stately dahlia, thrill us with delight, How pungent the truth "Man shall not live by bread alone." Music charms the soul through the sense of ear; sweet perfumes through the sense of smell, and clors through the sense of sight. In all ages, man in every rank and condition of life has endeavored to imitate nature in her profusion of beauty, and from this passion the art of dyeing originated. Strange as it may appear, however, (and this shows the peculiar relationship of the immaterial within, with the universe without,) colors have no material existence; "What," one may say, "has the rose no color, and is the purple of the violet a delusion?" It is even so; color does not exist in these objects, but in the light which is reflected from them.

By examining any object through a glass prism, it will be found that it appears apparreled in the most gorgeous colors. Every leaf of a tree or shrub, green though it may be to the naked eye, then appears clothed in azure, scarlet, and gold. Color exists (if quality may be said to have an existence) in light. A beam of light is composed of three differently colored rays, red, blue and yellow. According to Newton, a beam of light contained seven colors, and this theory was entertained by philosophers until about 1823, but not by practical dyers, who knew better. Red, blue, and yellow are now called "the primary colors," and all others are a mixture of these three, or any two of them, in different proportions. The celebrated Euler is the author of the true theory of colors.

Rejecting Newton's views, he conceived light to be propagate like sound, by a vibratory notion, and that "the different degree of velocity with which those vibrations successively reached the organs of vision, occasioned the sensations or perceptions  of the different colors." We have quoted these words from a volume of Dr. Bancroft, published in London in 1794, sixty years ago. Bancroft is the earliest English writer on dyeing with which we are acquainted; he rejected Euler's theory for Newton's, as did all subsequent writers until within a very few years. The great discoveries which have recently been made in light confirm the deductions of Euler, and his theory is now embraced by the most scientific men of the day. It is not known to men of science, that every part of nature is in a state of molecular motion, so subtle as in most cases to defy itself by its effects. It is only when those vibrations (like sound) grow strong and frequent, that they become perceptible to the senses in the form of light and heat. The spectrum (the colors of a ray of light decomposed by a prism of glass) appears, on a casual examination, to be merely a series of hues, beginning with red, brightening into yellow, and fading away from violet into darkness. But when examined scientifically, it is found that those hues are produced by a series of vibrations of the broken beams of light, the strongest and slowest of which are least refracted, and form red; and  the feeblest and most refracted the deep blue.

The human eye must be so constructed as to appreciate these vibrations of light, or it will be color-blind, as was the famous Dr. Dalton, author of the atomic theory, who could not, by its color, distinguish a cherry from the green leaf of the tree. It is the same with some persons respecting music, their ears cannot appreciate either tune or harmony. A ray of light has different properties. The red ray is termed the calorific, the yellow the luminous, and the blue the chemical or actinic. The red ray developes heat, the blue chemical, and the yellow neutral qualities, of which the daguerreotypist takes advantage, by employing yellow drapery in his room when he wants a very dark back ground for his picture, and uses blue glass when he wishes his plate to be acted upon rapidly. The rays of light also exhibit electric properties, both positive and negative, and Sir Jas. Ross, at the late meeting of the British Association for the Advancement of Science, asserted, that he had seen a beam of light in the Arctic regions make the magnet oscillate five degreet. The calorific and chemical rays of light explain the phenomena of fish and flesh meat decomposing so rapidly under the  influence of moonlight, The heat rays of the sun are absorbed by the moon, while the feebler but more rapidly vibrating rays of blue are reflected, and bring to the earth a certain amount of illumination, combined with a strong chemical influence, which, in tropical eliminates especially, exert such an active decomposing force upon fish exposed to their influence.

By mixing the different rays - red, blue, and yellow - (Which constitutes the art of coloring) as much diversity of shade is produced to the eye, as by blending the vibrations of the atmosphere in producing every variety of musical tunes. Red and blue mixed togerher make crimson, purple, violet, lilac and maroon, according to the proportions of the mixture. Blue and yellow form every variety of green shades. Red and yellow form scarlet, orange, salmon, buff. Black is a combination of all the three colors, and so is white; the former nullifies the vibrations of the sunbeam, the latter exhibits those vibrations unbroken in number and velocity. As light is produced by vibrations, (about which there can be no question now,) and also all the colors of the spectrum, and as these colors are electric, the conclusion is that there is a subtle medium pervading all space, according to the theory of Descartes - for to produce vibrations there must be something to vibrate.

Some of these views will be new to the most of our readers, and are intended to form a necessary introduction to a series of articles on the Art of Dyeing. We intended to have commenced these four weeks ago, but owing to some articles on another subject having been continued from week to week, until the last, we have delayed until now; after this they will be continued regularly, and be of a thorough practical character, useful for the workshop and family.