The light produced by wax and tallow candles, and by oil and gas under combustion, is yellow in color ; this is the reason why we can scarcely distinguish between blue and green colors at night by artificial illumination. A correspondent of the London Mechanics' Magazine makes an inquiry regarding the possibility of obtaining artificial white light, by making it pass through a series of glasses tinted according to the prismatic spectrum, neglecting the yellow ray, of course. A very great improvement in the color of the artificial light could easily be effected by employing globes or shades of a very faint purple color. Purple is composed of the red and blue rays of the spectrum, which, properly combined with the yellow ray, produce white.
This article was originally published with the title "Artificial White Light"