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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 con- 

 sumption 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 un- 

 usually 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 gal- 

 lery 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 qual- 

 ity, 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, 

 1 1 -43 parts ; ash (mostly oxide of tin and 

 silica), 14-30 ; real silk, 28*14 ; organic mat- 

 ters, 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 ma- 

 terial 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 be- 

 fore it would become " utterly shabby, greasy- 

 looking, and showing the threads " was es- 

 timated 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 Ameri- 

 can 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 win- 

 ter of 1890-'91, while engaged in explora- 

 tions at the cave of Loltun, we employed a 

 number of Mayas who came from small vil- 

 lages in the interior remote from Spanish in- 

 fluences. 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 (phil) 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. Be- 

 tween 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 agree- 

 able to the ear. Variation of tone was pro- 

 duced 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 Jesnp 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 ex- 

 pedition 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 



