Page:Popular Science Monthly Volume 32.djvu/444

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430
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 nothing to gain.

 

Mineral Fibers.—Mr. C. V. Boys, describing in the Physical Society in London "The Production, Preparation, and Properties of the Finest Fibers," said that in producing 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. Cy this means, fibers of glass less than 110000 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. Garnet, when treated at low temperatures, yielded fibers exhibiting the most beautiful colors. From quartz, fibers less than 1100000 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 torsional fatigue so evident in glass and metallic 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. Shufeldt suggests, in "The Auk," to ornithologists that they may find a portable photographic outfit of advantage in their studies. He finds that by the use of the instantaneous shutter, birds may be photographed in nearly all of their positions. "Out here on the prairies we will often find an old stump or stalk 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 subject 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 wonderful resorts of water-birds in such places as the Bahamas or the Alaskan coasts."

 


NOTES.

The Leander McCormick Observatory of the University of Virginia, Professor Ormond Stone, director, devoted much attention last year to the nebula of Orion, in which the director believes that the principal changes going on are of brightness. Besides these, three hundred and fifty-one observations of miscellaneous nebulæ have been made, resulting in a large number of sketches, and in the discovery of two hundred and seventy nebulæ which are supposed not to have been hitherto detected. A working-list of all known nebulæ 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 publications 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 proceedings, that Manchester had surpassed all other places visited by the Association, alike in the numbers attending, the amount received in subscriptions, and the amount which the Association in its turn was enabled to vote for scientific research.

A committee was appointed by the Chemical Section of the British Association, at the Manchester meeting, 1887, to inquire into and report upon the methods adopted 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 expressions of dissatisfaction in a discussion