POPULAR SCIENCE MONTHLY.
necessary except the oil container. The mantles are of special form, being somewhat shorter and apparently broader than those used for coal-gas burners, and the mesh of the material is more open. It is claimed that the lamp will give a fifty-candle light, with rather less than one third the oil consumption customary with a burner of the ordinary type having equal illuminating power. The air blast, which is necessary for converting the luminous flame into a heating one, is secured by the use of an unusually long chimney. The adjusting of the flame to its proper height is effected by the ordinary rack mechanism operating on the wick case and wick. If the flame is too high it begins to "sing," and this serves as a ready means for regulating it. It is stated that the complete apparatus, with spare gallery and cap, is sold retail at about $2.40, and can be fitted to any type of lamp having a fourteen-line cylindrical burner.
Chemistry of a Silk Jacket.—Dr. T. L. Phipson has recently had occasion to analyze a piece of black dress silk of medium quality, at the request of a lady who wished to ascertain its value. The results are curious. The material contained a large quantity of substance that was not silk at all, being considerably "weighted." It would not burn with flame, but smoldered away like tinder and left a large amount of ash, the principal ingredient of which was oxide of tin. The precise composition was: Water, 11·43 parts; ash (mostly oxide of tin and silica), 14·30; real silk, 28·14; organic matters, etc., not silk, 46·13; in all, 100 parts; nitrogen, 4·76 parts. Respecting the tin, the author observes that he has examined specimens of poor tin ore from Cornwall that did not contain more tin than this material for a lady's blouse; "and I at once realized the fact that the silk dresses worn by the ladies we see daily parading in Regent Street and Bond Street, taken together, would represent a Cornish mine of very fair quality." The analysis brought to light the fact that the durability of a piece of silk can be determined by this method. The probable life—that is, the length of time before it would become "utterly shabby, greasy-looking, and showing the threads"—was estimated by a milliner at about three months. It is said, however, that the public prefer the cheap products that get shabby so soon because the fashions change so rapidly that it would be useless to buy silk of better quality.
A Primitive Maya Jewsharp.—Mr. M. H. Saville gives the following interesting information in a recent note in the American Anthropologist: The ancient forms of musical instruments known to have been used in Yucatan have been almost entirely superseded by those introduced since the Spanish conquest. In some of the interior pueblos the tunkul, or ancient wooden drum, is still used on feast days. "During the winter of 1890-'91, while engaged in explorations at the cave of Loltun, we employed a number of Mayas who came from small villages in the interior remote from Spanish influences. Their evenings were passed in singing plaintive melodies in their native tongue, accompanied by a primitive form of stringed instrument which I have never seen described. It was called hool, and consisted of a piece of ropelike vine (ohil) stretched between the two ends of a pliable stick, making a bow about two feet long. One end of this bow is placed near the face, about one third of the distance from the end, so that the mouth covers but does not touch the string, forming a resonator. Between the string and bow a piece of wood is placed in such a manner that it may be pressed against the string or relaxed at will. The tones are produced by tapping on the string, and somewhat resemble those made in playing a jewsharp, but are more agreeable to the ear. Variation of tone was produced by varying the pressure of the stick upon the string and also by the opening or partial closing the mouth. The music is weird and not unpleasing."
The Jesup Expedition.—The object of the Jesup expedition to the North Pacific, as explained by Prof. F. W. Putnam in the British Association, is to study the question of the supposed Asiatic origin of the ancient American peoples. The whole cost of the expedition is to be paid by Mr. Morris K. Jesup. A thorough and careful exploration will be made of both sides of the Pacific Ocean north of the Columbia River in America