The American Journal of Science, المجلدات 161-162J.D. & E.S. Dana, 1901 |
المحتوى
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طبعات أخرى - عرض جميع المقتطفات
عبارات ومصطلحات مألوفة
acid Amphicyon angles appears beds bolometer cæsium calaverite calculated carbon cells cent character circle coil color condenser containing copper corresponding Creodonts crystals curve cusp Cynodictis density described determined developed diameter distance effect electric Eocene epidote equator experiments figure foramen formation gases genus Geological given glaucophane glaucophane schists heat hydrogen increase iron laccolith length less limestone liquid lower magnetic manganese marcasite Marsupials material measured metallic meteorite method mineral molar nearly observed obtained occur oxalate oxide oxygen phosphorus plate portion position posterior precipitate premolar present pressure probably protractor pyrite quartz rays region rock salt sandstones schist SCI.-FOURTH SERIES sectorial seen shales shonkinite solution species specimen spectrum stereographic projection strains stress structure sulphuric surface sylvanite temperature thickness tion transverse tube Uintacyon upper Viverravus volume Vulpavus wire
مقاطع مشهورة
الصفحة 332 - The custody, maintenance, and development of the national standards of measurement, and the provision of means and methods for making measurements consistent with those standards, including the comparison of standards used in scientific investigations, engineering, manufacturing, commerce, and educational institutions with the standards adopted or recognized by the Government.
الصفحة 332 - That the functions of the bureau shall consist in the custody of the standards; the comparison of the standards used in scientific investigations, engineering, manufacturing, commerce, and educational institutions with the standards adopted or recognized by the Government; the construction, when necessary, of standards, their multiples and subdivisions; the testing and calibration of standard measuring apparatus; the solution of problems which arise in connection with standards; the determination...
الصفحة 155 - Leyden jar in the circuit, while it more or less completely obliterates the second spectrum of hydrogen, also has a similar effect on the greater part of these other rays of, as yet, unknown origin. The violet and ultra-violet part of the spectrum seems to rival in strength that of the red and yellow rays, -if we may judge of it by the intensity of its impressions on photographic plates.
الصفحة 155 - ... the question of the aurora and the nature of the upper air. On passing electric discharges through the tubes containing the most volatile of the atmospheric gases, they glow with a bright orange light, which is especially marked at the negative pole. The spectroscope shows that this light consists, in the visible part of the spectrum, chiefly of a succession of strong rays in the red, orange, and yellow, attributed to hydrogen, helium, and neon. Besides these, a vast number of rays, generally...
الصفحة 155 - This shows conclusively that hydrogen in sensible proportion exists in the earth's atmosphere, and if the earth cannot retain hydrogen or originate it, then there must be a continued accession of hydrogen to the atmosphere (from interplanetary space), and we can hardly resist the conclusion that a similar transfer of other gases also must take place. The tubes containing the residue of atmospheric gases uncondensed at the temperature of liquid hydrogen we have examined spectroscppically.
الصفحة 170 - Contributions to the Tertiary fauna of Florida, with especial reference to the silex beds of Tampa and the Pliocene beds of the Caloosahatchie River, including a complete revision of the generic groups treated of and their American Tertiary species.
الصفحة 156 - ... impeded by the double refraction of the calc spar. As the light of the negative pole only was required, the electric discharge was made continuously in one direction only, with the result that the hydrogen lines grew fainter in each successive photograph, and soon disappeared altogether. Along with the ultra-violet rays, the less refrangible rays of hydrogen also disappeared, so that no trace of the C or F line could be seen, nor yet of the second spectrum, so long as the current passed in the...
الصفحة 171 - On some additional or imperfectly understood fossils from the Cretaceous rocks of Queen Charlotte Islands, with a revised list of the species from these rocks.
الصفحة 156 - In the spectrum of this gas the rays of helium are dominant, decidedly stronger than those of neon, although the latter are very bright. In the spectrum of the residue of atmospheric air, the proportion of helium to neon seems reversed, for in this the yellow neon line is as much more brilliant than the yellow helium line as the latter is the more brilliant in the spectrum of Bath gas. All the prominent lines in the spectrum of the volatile residue of Bath gas were also in that of the residue of...
الصفحة 157 - This is too large by an amount which considerably exceeds the probable errors of observation, and we are forced to conclude that the nebular material is either absent from our tubes, or does not show itself under the treatment to which it has been subjected. Although the residual gases of the atmosphere, uncondensed at the temperature of liquid hydrogen, do not show the nebular lines, we found that another tube gave a ray very close indeed to the principal green nebular ray. This tube had been filled...