Page:Popular Science Monthly Volume 49.djvu/592

572 seem, however, to have lingered round the wells, for it was occasionally necessary in the middle ages to forbid devotions of certain kinds about them. Afterward the reverence for the wells and such practices as bathing crippled children in them and using the water to cure sore eyes, were regarded as papistical. They were supposed to cure illness and madness; if properly interrogated, to reveal the future; and, upon the simple condition of dropping a pin or a piece of money into the water, to secure good fortune to the worshiper. There are still, it is said, wells at the bottom of which pins may be seen. In Portugal, according to Mr. Oswald Crawfurd, the wells are supposed to be haunted by Moorish maidens.

Light-bearing Cephalopods.—An animal of the cuttlefish family, described by Henri Coupin and M. Joubin as Histioteuthis Bonnetliana, of bright rose color, has bright red membranes connecting the tentacles, and on the surface of its body yellow and blue spots of various sizes, with a bright point in the middle. These spots, according to Verany, shine while the animal is alive, but lose their glow after it is dead. They consist of a black cup, wide open at the top, with a large convex lens within the opening forming a kind of cover to it. Another round opening serves as a sort of frame to a second lens. A section lengthwise of the organ discloses a parabolic mirror and the two lenses arranged perpendicularly to each other, the whole forming a sort of black cylindrical lantern closed above by a large lens, which casts a light upward, and in front by another lens throwing it out horizontally. Another cephalopod, colored pale blue or violet, so like the sea as to be hardly visible, found in fine weather on the surface of the Mediterranean—the Chiroteuthis, a poor swimmer—is provided with special organs in the form of nets that are always spread to attract and capture its food of smaller animals. A series of intensely black vesicles may be perceived on its ventral arms, separated by little transparent suckers armed with a circle of sharp teeth. These vesicles are formed externally of concentric lamellæ and internally of a transparent vesicle, the contents of which have strong refracting powers. While the animal is living, light is decomposed by the concentric lamellæ, and the organs are thereby made iridescent with a silvery metallic luster. Smaller animals are attracted by the glitter of these organs, and are then seized by the suckers, which are kept on guard by the side of them. The suckers of the larger tentacles are incapable by their structure of seizing prey, but are helped, as in the case of these vesicles, by a combination of lure and snare, the lure consisting of highly colored vesicles or chromatosperes, and the snare of a network of waving, anastomosed lamellæ which issues from the cup and spreads itself around as a net. The animal swims slowly along, shaking its tentacles around itself, stretching them out and bending them back so as to keep out in the water around it innumerable lines to catch the little animals as they pass and hold them as if in the jaws of a pincers. A third type of hunting organs in this animal is that of special suckers at the ends of the tentacular arms, each containing a black organ forming a lure, with a well-developed sucker at the end.

A Theory of Sheet Lightning.—In his paper on thunderstorms in India, Prof. Michie Smith says that sheet lightning is seen at Madras every evening for six months, always near the horizon and directed toward the southwest. The time of occurrence varies from day to day, but is always toward evening, and generally not later than nine o'clock. The phenomenon is not a reflection of distant lightning flashes, but consists of an actual discharge of electricity from cloud to cloud or between two portions of the same cloud, and it takes place in the upper portions of low-lying clouds. When morning lightning occurs, its direction is northeast, hence the lightning is always to be looked for in the regions of still air where the land and sea breezes meet. The time of occurrence depends on the hour when the sea breeze sets in, the display being about three hours later than this. Cumulus clouds rise together in pairs and the discharge takes place between them, sometimes possibly within them. The author thinks the electrical conditions of the clouds may be accounted for by the fact that the sea breeze is moist and dusty, while the land breeze is dry and dusty. The presence of dust in the