Color of Snow.

Scientific American 21, 12.2.1848

It has been found that the colors of bodies depend very much, if not entirely upon the arrangement of their particles by which they reflect this or that kind of rays of light. Some experiments of Dr. Brewster of Edinburgh, prove this. He took a piece of polished steel and by beating it to a different degree of temperature, different colors are exhibited and by making slight cuts on its surface, some of them curved or waved &c., he also was enabled to exhibit different colors in consequence of the light being reflected at different angles and of course different rays striking the eye. In regard to the color of snow, we believe that in our latitude it is of a brilliant white color. But in higher latitudes it has been seen of a red color. This at first astonished Parry and his companions, who discovered it in the arctic regions. After a close examination it was found that the red color was occasioned by a foreign substance mingled with it, and which, on further examination, was found to be a very minute vegetable, something like some of the mosses or mould. Indeed, it might with propriety be said to be mouldy snow.

Capt. Parry observes that the arctic mountains, on which he observed the red snow, are about six hundred feet high, and extended eight miles in length. The depth to which the color penetrated has been variously stated by different observers. Some found that it descended many feet beneath the surface, while others never ascertained that it spread beyond one or two inches.

There is no reason to suppose says he, that the coloring matter itself as well as the snow, is a meteorlogical product, although Humboldt certainly mentions a shower of red hail which fell at Paramo, in South America.

Ei kommentteja :