ON Sunday, January 8, upon leaving the house at half-past four in the afternoon, I observed that the clouds were suffused with a kind of pink or lurid coppery tinge, a sort of angry sunset tint spread over the whole sky. The clouds were of the stratus type which is common in a winter anticyclone, but were moving or rather driving with a swiftness quite unusual under such conditions. The barometer was very high and rising rapidly; but during the afternoon there were several violent and noisy gusts of wind almost amounting to squalls, though during the greater part of the day the atmosphere was still almost to stagnation. The air was mild and intensely humid, and everything was dripping with moisture. In fact the weather was in many particulars the opposite of what we expect during the prevalence of an anticyclone. The diffused sunset effects were quite unlike anything I ever remember to have witnessed before. The gas-lamps had just been lit, and the flames not only appeared of a greenish tint, but seemed to be inclosed in green glass. Several persons stopped me in the street and inquired what it all meant, and one acquaintance said, “What is going to happen?” In the green tint of the gas there is, of course, some suggestion of a colour complementary to the strange red glow which seemed to pervade the atmosphere. But in the absence of all, even the most rudimentary, knowledge of the subject, I should be glad if you or some of your readers can explain the cause to me and to others who witnessed the unaccustomed phenomenon.