Note A — THE STORM-CLOUD OF THE NINETEENTH CENTURY.

In speaking, at p. 11 of the first lecture, of the limits of depth in the rose-color cast on snow, I ought to have noted the greater strength of the tint possible under the light of the tropics. The following passage, in Mr. Cunningham's 'Natural History of the Strait of Magellan,' is to me of the greatest interest, because of the beautiful effect described as seen on the occasion of his visit to "the small town of Santa Rosa," (near Valparaiso.) "The day, though clear, had not been sunny, so that, although the snowy heights of the Andes had been distinctly visible throughout the greater part of our journey, they had not been illuminated by the rays of the sun. But now, as we turned the corner of a street, the chain of the Cordillera suddenly burst on our gaze in such a blaze of splendor that it almost seemed as if the windows of heaven had been opened for a moment, permitting a flood of crimson light to stream forth upon the snow. The sight was so unexpected, and so transcendently magnificent, that a breathless silence fell upon us for a few moments, while even the driver stopped his horses. This deep red glow lasted for three or four minutes, and then rapidly faded into that lovely rosy hue so characteristic of snow at sunset among the Alps."