Publications of the Astronomical Society of the Pacific, Volume 18

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Astronomical Society of the Pacific., 1906
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Page 218 - VIII. Fall of chimneys ; cracks in the walls of buildings. IX. Partial or total destruction of some buildings. X. Great disasters; overturning of rocks; fissures in the surface of the earth; mountain slides.
Page 118 - While I must leave to others an estimate of the importance of these conclusions, it seems to me that they have a very direct bearing on many, if not all, questions concerning the cosmogony. If, for example, the spiral is the form normally assumed by a contracting nebulous mass, the idea at once suggests itself that the solar system has been evolved from a spiral nebula, while the photographs show that the spiral nebula is not, as a rule, characterized by the simplicity attributed to the contracting...
Page 254 - Report of the Astronomer Royal to the Board of Visitors of the Royal Observatory, Greenwich, read at the Annual Visitation of the Royal Observatory, 1860, June 2; and Address of the Astronomer Royal to the Board of Visitors, 1860, May 12.
Page 64 - The total range of speed is but three one hundredths of a kilometer per second. An observer favorably situated in another system, provided with instruments enabling him to measure speeds with absolute accuracy, could detect this variation, and in time say that our sun is attended by planets. At present, terrestrial observers have not the power to measure such minute variations. As the accuracy attainable improves with experience, the proportional number of spectroscopic binaries discovered will undoubtedly...
Page 264 - BY GEORGE E. HALE, WALTER S. ADAMS, AND HENRY G. GALE In considering the characteristic features of the spectra of sunspots, three points especially attract attention: 1. The fact that certain lines in the spectrum of a given element are strengthened, while others are weakened; the remainder of the lines being unaffected. 2. The inclusion of all the strengthened lines within the visible spectrum, none of them occurring in the ultra-violet, and their predominance in the red, yellow, and green. 3....
Page 119 - ... directed in somewhat changing courses, and would be pulsatory in character, resulting in rather irregular and somewhat divided arms, and in a knotty distribution of the ejected matter along the arms. These knots must probably be more or less rotatory from inequalities of projection. It is thus conceived that a spiral nebula, having two dominant arms, opposite one another, each knotty from irregular pulsations, and rotatory, the knots probably also rotatory, and attended by subordinate knots and...
Page 198 - Earth's crust with a velocity of some 14km of which I shall speak presently, and communicate a sort of stress to the superincumbent surface layer of the Earth's crust in the region about the observing station; the latter being, in consequence, thrown into its own proper vibrations. In fact, the preliminary...
Page 74 - ... Sun above the horizon proved to be a very important factor, so that the focus changed much more rapidly near noon than early in the morning. From the outset, the advantages of observing the Sun during the early morning hours had been apparent. In view of the difficulties that were being experienced, this point was again carefully investigated, and it was soon found that with the Snow telescope the finest definition is to be expected about one hour after sunrise. At this time the mountain is but...
Page 120 - In the particular case of the solar nebula it is assumed (1) that the central mass was relatively very great; (2) that the knots were very irregular in size and placed at irregular distances from the center; and (3) that the nebulous portion was very small relative to the central mass and probably large relative to the knots.
Page 195 - The preliminary tremor, which consists of vibrations of small amplitude and of comparatively short period, is divided into the earlier portion or the first preliminary tremor, and the later portion or the second preliminary tremor. Commencement of the latter is market! by an increa.se of the amplitude, and, in many cases, also by the appearance of slow undulations. The principal portion...

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