Note 104 — Chapter VII
Reading edition
On the Polarization of the Chemical Rays of Light: by John Sutherland, M.D., in which the author refers to the following experiment of M. J. E. Bérard—“I received the chemical rays directed into the plane of the meridian on an unsilvered glass, under an incidence of 35° 61'. The rays reflected by the first glass were received upon a second, under the same incidence. I found that when this was turned towards the south, the muriate of silver exposed to the invisible rays which it reflected was darkened in less than half an hour; whereas, when it was turned towards the west, the muriate of silver exposed in the place where the rays ought to have been reflected, was not darkened, although it was left exposed for two hours. It is consequently to be presumed that the chemical rays can undergo double refraction in traversing certain diaphanous bodies; and lastly, we may say that they enjoy the same physical properties as light in general.”—Philosophical Magazine, vol. xx.
Dr. Leeson has stated that Daguerreotype pictures can be taken more readily under the influence of polarized light, than by ordinary radiation.