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THE POPULAR SCIENCE MONTHLY. 



be warned of the presence of the snake, 

 and would probably be induced to give it 

 abundant space. Doubtless, by this means, 

 the snakes have been saved from many a 

 rude tread by bear or wolf or panther that 

 would have been unpleasant to them, and 

 might have involved them in a fight in 

 which they had everything to lose and noth- 

 ing to gain. 



Mineral Fibers. — Mr. C. V. Boys, de- 

 scribing in the Physical Society in London 

 " The Production, Preparation, and Proper- 

 ties of the Finest Fibers," said that in pro- 

 ducing very fine glass-fibers, he found it 

 best to use very small quantities at high 

 temperatures, with a velocity of separation 

 as great as possible. In the last point, the 

 best results are given by a cross-bow and 

 straw arrow, to the tail of which a thin rod 

 of the substance to be drawn is cemented. 

 By this means, fibers of glass less than 

 ■\T5hr<s of an inch in diameter can be made. 

 The author had also experimented on many 

 minerals, with more or less success. Ruby, 

 sapphire, and fluor-spar could not well be 

 drawn into fibers, but quartz, augite, and 

 feldspar gave very satisfactory results. Gar- 

 net, when treated at low temperatures, 

 yielded fibers exhibiting the most beautiful 

 colors. From quartz, fibers less than i-rriAjcny 

 of an inch in diameter had been obtained. 

 The thread can not be drawn directly from 

 the crystal, but the latter has to be slowly 

 heated, fused, and cast in a thin rod. 

 Quartz-fiber seems to be free from the tor- 

 sional fatigue so evident in glass and me- 

 tallic fibers, and is therefore valuable for 

 instruments requiring torsional control. The 

 tenacity of such fibers is about fifty tons on 

 the square inch. 



Photographing Birds.— Dr. R. W. Shu- 

 feldt suggests, in " The Auk," to ornitholo- 

 gists that they may find a portable photo- 

 graphic outfit of advantage in their studies. 

 He finds that by the use of the instantaneous 

 shutter, birds may be photographed in near- 

 ly all of their positions. " Out here on the 

 prairies we will often find an old stump or 

 Btalk upon which a dozen or fifteen species 

 of birds will alight during seven or eight 

 hours, on almost any day suitable to use the 

 camera upon them. Now, all we have to 



do is properly to set up our instrument near- 

 this point, conceal it in such a way as not 

 to alarm the birds, focus it sharply upon the 

 perch where they alight, place .on your 

 ' snap-shutter,' and fix it with a string, and 

 then remove yourself far enough away to 

 pull it when you have a suVjjcct sitting to 

 your liking. Birds that you have wounded 

 but slightly may be photographed under 

 the most favorable circumstances ; they 

 may also be taken sitting on their nests ; 

 in actual flight, however swift; in pursuit 

 of their food ; in leading about their young ; 

 indeed, the list is almost an endless one. 

 Rookeries also offer admirable subjects, 

 and a splendid field is open at those won- 

 derful resorts of water-birds in such places 

 as the Bahamas or the Alaskan coasts." 



NOTES. 



The Leander 5rcCormick Observatory 

 of the University of Virginia, Professor Or- 

 mond Stone, director, devoted much atten- 

 tion last year to the nebula of Orion, in 

 which the director believes that the princi- 

 pal changes going on are of brightness. 

 Besides thessj, three hundred and fifty-one 

 observations of miscellaneous nebulas have 

 been made, resulting in a large number of 

 sketches, and in the discovery of two hun- 

 dred and seventy nebula; which are supposed 

 not to have been hitherto detected. A work- 

 ing-list of all known nebula? north of thirty 

 degrees south declination, which are as 

 bright as the fourteenth magnitude, has 

 been made to aid in the determination of 

 nebular motions. Three independent pub- 

 lications have been issued, and six articles 

 published in astronomical periodicals. 



The recent Manchester meeting of the 

 British Association appears to have been 

 one of the most successful that was ever 

 held. It was said, at the close of the pro- 

 ceedings, that Manchester l:ad surpassed all 

 other places visited by the Association, alike 

 in the numbers attending, the amount re- 

 ceived in subscriptions, and the amount 

 which the Association in its turn was ena- 

 bled to vote for scientific research. 



A COMMITTEE was appointed by the Chem- 

 ical Section of tlie British Association, at 

 the Manchester meeting, 1887, to inquire 

 into and report upon the methods adopts 

 ed for teaching chemistry in the various 

 schools. It consists of the representatives 

 of the universities and colleges, schools and 

 technical institutions in which chemistry is 

 taught. This action was taken after ex- 

 pressions of dissatisfaction in a discussion 



