In the Cardiff coal-mines an interesting plant is found, which emits so brilliant a light, that the men have been able to “see their hands by it,” and was visible at a distance of sixty feet. Mr. Worthington Smith, who is an authority for this, observed the same phenomenon in _Polyporus sulfureus_. While various theories have been recorded as to the physiological cause of the light in cryptogams, and many writers give the most careful details of the structure of the luminous parts, we are unable to go a step farther to explain the cause of the light which appears to be a combustion, but does not consume. CHAPTER XVIII. PHANTOMS. Phosphorescent light plays an important part in the composition of ghosts and phantoms; and the number of persons who believe that certain phenomena exist which cannot be explained by well-known natural laws is somewhat surprising. Some years ago I was introduced to a gentleman who was a firm believer in a modern Flying Dutchman. His house was upon a beautiful little bay, and from the piazza, he informed me that, more than once, he had seen a phantom ship. Sometimes it beat up the bay, the white sails showing distinctly at night. Again it was seen coming in directly against the wind, now appearing in one place, then in another, as fickle as the wind itself. On every other subject he was sane, and of more than ordinary intelligence; but some electric phenomenon or emanations from schools of fishes, together with a vivid imagination, had produced the phantom ship, which in his mind was a reality. Many well remember the excitement occasioned around one of the New-York markets a number of years ago, by the appearance of a mysterious light. A fish-dealer’s assistant, who had occasion to enter the market late one evening, observed an unusual light there; and being an ignorant, superstitious fellow, he rushed out of the building and into a neighboring store, stating excitedly that the ghost of a former market-man was hovering about his old stand. A number of persons returned with him to the market, and there saw a light, a dull yellowish gleam, about six feet in length, proceeding apparently from some body lying in a recumbent position. The crowd pressed in, and found the ghost to be a large piece of fish that had become phosphorescent.