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SCIENCE NOTES & NEWS.

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SCIENCE NOTES & NEWS. WHERE ARE METEORITES BORN? Speculation as to the origin of the meteoric stones and irons that occasionally fall from the sky has a peculiar charm for the imagi- nation. The density of these bodies and the great size of some of them constitute argu- ments in favour of the view that they must have been ejected from some massive body in space, such as the sun or a star. In discus- sing the peculiar meteorites which fell some years ago at Brenham, Kansas, Dr. O. W. Huntington suggests that we may infer, from their composition, from what part of the heavenly body that ejected them they came. The heavy metallic meteorites, called side- rites, may plausibly be supposed to have come from the deeper parts of a star; the light, stony ones, called aerolites, from the super- ficial layers; and the rare" pallasites," like the Brenham meteorites, which are inter- mediate in composition, from the transitional zone between the outer crust and the dense •interior nucleus. NEW FACTS ABOUT \rIWEtOPS. The velocity of falling ~opg has been "measured by Professor ScmnKlfc with an ap- paratus consisting essentially of two hori- zontal plates of sheet zinc attached to the ends of a vertical shaft about 8in. long. A sector of the tipper and A disc was cut -out and the lower disc v. ed with filter paper strewn with eosin powder. The appara- tus was set into uniform c o 1 and exposed to the rain. The only drops that can reach the lower disc are those which have fallen through the open sector of the upper disc. Meanwhile the /-use 1 ia -vi -o that the wet sector of the lower case is not vertically under the open scocter of the 11 (Esc, but is displaced throve 1 a ends on the velocity of the The size of the drop can be cut r c.i.ys Science Sift- .ings, from the size of the c-rccilir nn which it makes on the pr-spared paper. In this way the diameters and velocities of more than 3,300 raindrops were determined. The dia- meters ranged from 3'5 to 0*4 millimeters (0T4in. to 0"018in.), and the velocities from 7"4 to 1*8 meters (24-3ft. to 509ft.) per second. THE ZODIACAL LIGHT. An interesting result won by the applica- tion of the cumulative principle of photo- graphy has been the record of the spectrum of the Zodiacal light. This is a faint glow wliich may be seen to cover a large area of the heavens, sloping up from the horizon in the evening sky after the sun has set in the spring months of the year or before the sun rises in the autumn. What is the precise cause of the Zodiacal light is uncertain. The cause of the Zodiacal light is uncertain. The generally received opinion is that it is due to sunlight reflected from minute particles of matter surrounding the sun. If this be the case, the SPECTRUM SHOULD BE THE SAME as that of sunlight, but hitherto the existence of the Fraimhofer lines has not been proved. If the presence of the solar absorption lines could be definitely shown, the hypothesis would be converted into a certainty. Obser- vations taken at Lick by Dr. Fath, and car- ried on at Mount Wilson, have gone a con- siderable way towards settling this point. But, remarks a writer in the Manchester Guardian, the difficulties have been enor- mous. As the light is of sufficient brightness fo, less than an hour preceding dawn, the ex- posure must be cumulative. In the early at- tempts an exposure of six hours was secured on seven mornings. This has been increased to twelve hours, and ^XTRAOKDINARY PRECATTTIONS HAVE BEEN to prevent any sky I J t or abnormal dawn affecting the plates. a he spectrum seen on developing is small and faint, but two ab- sorption lines can be seen with certainty, and have lbeen identified as the line G and a blend of the two lines Ti and re. There is no "indication of bright lines, so that, so far as spec bra of such low dispersion and resolving power can be trusted, there is good evidence to suppose that the Zodiacal light, is due to .-reflected sunlight. VALUE OF BLACK DIAMONDS. The term black diavnonds is sometimes jokingly applied to ordinary coal which we burn in our furnaces; but the real black diamonds of commerce are .among the most unique mineral products of the world, and they serve a purpose in the industrial world that makes them of great value. The black diamonds are pure carbon, and yet in no out- ward appearance resemble the diamonds which we are i cc v id to wear as orna- ments. They an 11 itly harder than the crystal or gem a ds, and, in fact, about the hardest si rv known. Black cFa- monds or carbons, remarks the Scientific American, are among the greatest curiosities of the mineral kingdom. Tiiev are without \4?rystalline form, and are found in irregular pieces ranging in size from half a carat up to three, four, and five hundred carats. They -are dark grey, black, or brownish in colour, and opaque. The real diamond of the jewel- -lery trade is also pure carbon, but trans- lucent and crystalline in form. Two objects so alike in composition could not be found so -opposite in appearance as these two forms of I ■■carbon. Another peculiar thing about the black diamonds is that they are found ONLY IN ON3 LOCALITY IN THE WORLD. "They come from a very small section of Brtizi.1, not more than 225 miles in area. Out- side of this limited territory no pure black diamonds have ever been found. In the Brazilian black-diamond ^fields the natives dive in the river bed.s for them, and recover them from the gravel and washings of the rivers. What peculiar freak of nature caused the of the black diamonds in this section' of the world, and nowhere else is one of the mysteries which science has failed to explain. None of them has been found in the great Kimberley diamond regions, where the crystal diamonds have for so long been mined, and no fine s:>cei marts of the diamond .I i have been found in the Brazilian black- diamond fields. The whole origin of tji-e bitek diamonds is, tiie-refore, a soientuic. enigma. Naturally the question is raised, OF WHAT TJSS IS A BLACK DIAMOND? No one would care to wear one of these dia- monds, which resembles a piece of coal more than a real diamond. ISieverthe.laES, the binck ■ •diamonds serve a most important and useful Junction in the industrial world. This pure black carbon is not only harder tnan the real diamond, but tougher and not so brittle as the gem. Cousequontly it is of great value for many mechanical purposes, and pirticu- larly for boring with uiamond drills. In uia- mond drilling' the tips of the drills are studded with carbon or 'black diamonds, and when the bores are deep the pressure is so great that the gem diamonds would be crashed in the process. But the carbon resists this continued pressure, and slowly eats down into the rocks. The fear that the supply of black diamonds may some day give out and paralyse the diamond drilling industry has stimulated prospectors to systematic searcii for new deposits, but so far they have not been successful. On the other hand, scientists have been making a close study of the chemi- cal conditions which have produced the black diamonds-; but tl-i,r m,-tn,,ifacture is appa- rently about as difficult as-the making of gem diamonds. It is possible under certain con- ditions to make either, r;t in sizes suSL- cieub to be of any commercial value.

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