Phenomena of light.

Scientific American 39, 19.6.1847

Light holds a most intimate connection with all the other sciences both in its constitution and operations, and must ultimately attain a most important rank among the sciences and repay back to them what it has received from them. Many of the phenomena of light are only to be explained by reference to the hydro-dynamic principles. The relation of the laws of light, acoustics and music are most astonishing in their resemblance. The phenomena called polarised light presents philosophers with the most delicate instruments for ascertaining the constitution of bodies. It is an optical law that all transparent bodies become colored when they are formed into plates attenuated beyond certain limits, and moreover, that the particular colors, which under these circumstances they show, are dependant upon the degree of attenuation. It was thus that Newton determined that the thickness of the thinnest part of a soap bubble when colors are first visible is no more than 1-25,000 of an inch, and that before it bursts it attenuates to 1-4,000,000 of an inch; and by the same means that we know that the transparent wings of some insects are not more than 1-100,000 of an inch in thickness.