Lick Observatory Bulletins, Volume 5

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Lick Observatory, University of California, 1910
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Page 154 - That these lines were not produced by the portion of the Earth's atmosphere through which the light of Mars had passed was shown by the absence of similar lines in the spectrum of the Moon, which at the time of observation had a smaller altitude than Mars.
Page 154 - B and a, and the adjacent lines of the solar spectrum. On February 14, faint lines were seen on both sides of Fraunhofer's D. The lines on the more refrangible side of D were stronger than the less refrangible lines. These lines occupy positions in the spectrum apparently coincident with groups of lines which make their appearance when the Sun's light traverses the lower strata of the atmosphere, and which are therefore supposed to be produced by the absorption of gases or vapours existing in our...
Page 15 - The bolometrlc observations at Flint Island were designed to test the inferences above referred to and to measure more definitely the quantity and quality of the coronal radiation. Apparatus. — A concave mirror of 50 centimeters diameter and only 100 centimeters focus, mounted equatorially and driven by a clock, served to produce a very intense image of the corona. A small guiding telescope was attached to the mirror frame so that the observer might point toward any desired object. In the focus...
Page 154 - C, at about one-fourth of the distance from C to B. As a similar line is not found in this position in the solar spectrum, the line in the spectrum of Mars may be accepted as an indication of absorption by the planet, and probably by the atmosphere which surrounds it.
Page 153 - Martian and lunar spectra, as observed at small zenith distances through a minimum of water vapor, is that the quantity of any water vapor existing in the equatorial atmosphere of Mars at the time these observations were made was too slight to be detected by present spectrographic methods.
Page 16 - Transmissibility 0.90 0.01 0.04 0.10 0.20 0.41 0.66 0.80 0.9 0.92 By interposing this absorbing screen the proportion of the observed radiation which lay in the infrared spectrum could be roughly determined. Various trials made on Flint Island showed that ordinary sunrays comprised from 29 to 37 per cent. of rays transmissible by this screen, depending on the humidity of the air and the altitude of the Sun ; whereas sky-rays had only about 20 to 25 per cent. of transmissible rays. Moon-brightness...
Page 156 - The results of these observations are as follows: First. — The spectra of Mars and our Moon, observed under favorable and identical circumstances, seem to be identical in every respect. The atmospheric and aqueous vapor bands which were observed in both spectra appear to be produced wholly by the elements of the Earth's atmosphere. The observations, therefore, furnish no evidence whatever of a Martian atmosphere containing aqueous vapor. Second. — The observations do not prove that Mars has no...
Page 16 - Island on the beach at about 12 meters distance from the galvanometers used for observing the indications of the bolometer. Two galvanometers were provided, exactly alike in resistance and general construction, and arranged so that if at the last moment any accident should happen to one, the observer might pass at once to the...
Page 16 - The opening of this shatter, therefore, exposed the central part of the bolometer to such rays as are transmissible by glass. Between the shutter and the glass plate, and close to the latter, was a special screen composed of a thin stratum of asphaltum varnish laid on one side of a plane parallel glass plate 3 millimeters thick. This screen was held out of the beam by a spring, except when designedly interposed. Its property, when used, was to cut off nearly all the visible part of the radiation,...
Page 16 - A glass plate three millimeters thick was fixed close to the bolometer, between it and the mirror, so that the radiation examined was thereby limited to wave-lengths less than about 3*1.

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