I went to the room opposite to watch the sunrise, for I had observed in the diary that the appearance of the sun would not be for a few minutes. There were streaks of light in the east above the horizon, but no colour was visible. That hectic flush--slight, yet well marked--which was deepening in the western heavens, had no counterpart in the east, except the colourless light which marked the wintry sun's near approach. As soon as the sun's rays shot up into the eastern clouds, and his orb appeared above the horizon, the western sky paled, the colour left it, as if ashamed of its assumed glory. A foreglow like that I have very rarely seen, and its existence was a puzzle to me till I studied Dr. Aitken's explanation of the afterglows after sunset. I had never come across any description of a foreglow; and, of course, across no explanation of the curious phenomenon. The western heavens were coloured with fairly bright roseate hues, while the eastern horizon was only silvery bright before the sun rose; whereas, after the sun appeared and coloured the eastern hills and clouds, the western sky resumed its leaden grey and colourless appearance. Why was that? What is the explanation? I have not space enough to repeat the explanation given already in the last chapter of the glorious phenomenon of the afterglow. But the explanation is similar. Before sunrise, the rays of the sun are reflected by dust-particles in the zenith to the western clouds. The colouring is intensified by the frozen water-vapour on these particles in the west. One thing I carefully noted. Ere mid-day, snow began to fall, and for some days a severe snow-storm kept us indoors. Then, at any rate, the foreglow betokened a coming storm. It was, like a rainbow in a summer morning, a decided warning of the approaching wet weather. CHAPTER XX THE RAINBOW The poet Wordsworth rapturously exclaimed-- "My heart leaps up when I behold A rainbow in the sky." And old and young have always been enchanted with the beautiful phenomenon. How glorious is the parti-coloured girdle which, on an April morning or September evening, is cast o'er mountain, tower, and town, or even mirrored in the ocean's depths! No colours are so vividly bright as when this triumphal arch bespans a dark nimbus: then it unfolds them in due prismatic proportion, "running from the red to where the violet fades into the sky." A plain description of the formation of the rainbow is not very easily given, but a short sketch may be useful. Beautiful as is the ethereal bow, "born of the shower and colour'd by the sun," yet the marvellous effect is more exquisitely intensified in its gorgeous display when the hand of science points out the path in which the sun's rays, from above the western horizon, fall on the watery cloud, indicating fine weather--"the shepherd's delight."