ON Thursday, August 16, while R.M.S. Norham Castle was in lat. 2° 20′ N., long. 13° 58′ W., a phenomenon entirely new, at least to the officers and passengers on board, appeared at 11 a.m., and lasted until 12.30 p.m. This consisted of a complete rainbow round the sun, when nearly and at the zenith, having an inner diameter—taken by Capt. Winchester, R N. R.—of 43° 08′. The day was bright and warm, with a slight haze above. The rainbow appeared to crown the whole of the upper dome of the sky, and to possess all the normal colours, only very slightly dimmed. Whether connected with this appearance or not I cannot say, but the next two days were squally, with heavy rains.