A type of corona discharge observed on ships under conditions approaching those of an electrical storm. The charge in the atmosphere induces a charge on the masts and other elevated structures. The result of this is a corona discharge which causes a spectacular glow around these points. This effect was accentuated by the contours of early sailing vessels, which usually had several masts and much rigging. The display thus created under darkened conditions was quite striking. The effect was not understood through much of that era and led to much superstition on the part of sailors.