IV. On the blue colour of the sky, the polarization of skylight, and on the polarization of light by cloudy matter generally

Abstract

Since the communication of my brief abstract “On a new Series of Chemical Reactions produced by Light,” the experiments upon this subject have been continued, and the number of the substances thus acted on considerably augmented. New relations have also been established between mixed vapours when subjected to the action of light. I now beg to draw the attention of the Royal Society to two questions glanced at incidentally in the abstract referred to,—the blue colour of the sky, and the polarization of skylight. Reserving the historic treatment of the subject for a more fitting occasion, I would merely mention now that these questions constitute, in the opinion of our most eminent authorities, the two great standing enigmas of meteorology. Indeed it was the interest manifested in them by Sir John Herschel, in a letter of singular speculative power, that caused me to enter upon the consideration of these questions so soon.