WHILE in a rowing-boat on the ocean during a sultry afternoon this summer I observed a very peculiar series of refraction phenomena that seem worth describing. A thunderstorm was brewing in the north-east far enough away so that the thunder was just audible. There was no sunshine. The wind had dropped and the sea was gently undulating. A small steamer was passing westward some three miles distant. When I first saw her she was almost hull down (apparently). In a few minutes she loomed up so that the forecastle was high, although the midship section was normal. A little later the cabins disappeared entirely and all one could see was an unbroken line of black hull, the funnel and the masts. Next she again appeared hull down, only to emerge with complete hull and upperworks. Then once more she seemed to sink so that her deck was awash. These changes took place as one gazed at the boat and were most startling. The hull seemed slightly longer at the time when only the deck showed but this may have been imagination on the part of the observer.