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POPULAR SCIENCE MONTHLY. 



seem, however, to have lingered round the 

 wells, for it was occasionally necessary in 

 the middle ages to forbid devotions of cer- 

 tain kinds about them. Afterward the rever- 

 ence for the wells and such practices as bath- 

 ing crippled children in them and using the 

 water to cure sore eyes, were regarded as pa- 

 pistical. They were supposed to cure illness 

 and madness ; if properly interrogated, to re- 

 veal the future ; and, upon the simple condi- 

 tion 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 Craw- 

 furd, 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 Hisiioteiithis Bon- 

 netliana, 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 biight 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 ar- 

 ranged 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 an- 

 other lens throwing it out horizontally. An- 

 other cephalopod, colored pale blue or vio- 

 let, so like the sea as to be hardly visible, 

 found in fine weather on the surface of the 

 Mediterranean — the CJdroteuthis, 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 vesi- 

 cles 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 lamellje 

 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 lamella?, 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 con- 

 sisting of highly colored vesicles or chroma- 

 tosperes, and the snare of a network of wav- 

 ing, anastomosed lamellse 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 or- 

 gan forming a lure, with a well-developed 

 sucker at the end. 



A Tbeory of Sheet Lightning. — In his 



paper on thunderstorms in India, Prof. Mi- 

 chie 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 even- 

 ing, and generally not later than nine o'clock. 

 The phenomenon is not a reflection of dis- 

 tant 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 por- 

 tions of low-lying clouds. When morning 

 lightning occurs, its direction is northeast, 

 hence the Ughtning is always to be looked 

 for in the regions of still air where the land 

 and sea breezes meet. The time of occur- 

 rence 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 elec- 

 trical conditions of the clouds may be ac- 

 counted 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 



