Advanced PhysiographyJ. Hughes & Company, 1893 - 277 pages |
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angle angular appear asteroids astronomers atmosphere attraction average axis bodies calculated cause celestial celestial pole centre circle comet crust density depth determined diameter direction disc earth earth's orbit eccentricity ecliptic equator equatorial equinox fact feet Fraunhofer lines full moon gravity heat hence horizon hydrogen inches inclination increase Jupiter known latitude length lens libration longitude luminous lunar Mars mass mean distance measured Mercury meridian meteorites miles minor planets moon moon's motion move nebulæ Neptune nodes object observations occur parallax passes perihelion period photosphere planet poles portion position prism produced radius rays refraction represent retrograde motion revolution revolving round right ascension ring rise rotation round the sun satellite Saturn seen semi-major axis sidereal Sidereal Months sidereal period Sirius solar spectra spectroscope spectrum sphere spots stars sun-spots sun's surface swarms of meteorites synodic synodic period telescope temperature tides Uranus vapours variation varies Venus
Popular passages
Page 47 - Mercury will be represented by a grain of mustard seed, on the circumference of a circle 1 64 feet in diameter for its orbit; Venus a pea, on a circle 284 feet in diameter ; the Earth also a pea, on a circle of 430 feet; Mars a rather large pin's head, on a circle of 654 feet...
Page 9 - When a ray of light passes from one medium to another, it is refracted so that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities in the two media.
Page 81 - Change of motion is proportional to the impressed force, and takes place in the direction of the straight line in which the force acts.
Page 198 - the stars of our firmament, instead of being scattered in all directions indifferently through space, form a stratum of which the thickness is small in comparison with its length and breadth, and in which the earth occupies a place somewhere about the middle of its thickness, and near the point where it subdivides into two principal laminae, inclined at a small angle to each other.
Page 84 - The radius vector (line joining the centre of the sun with the centre of the planet) of each planet sweeps over equal areas in equal times. 3. The squares of the periodic times (the periods of complete revolution round the sun) of two planets are proportional to the cubes of their mean distances from the sun.
Page 81 - Every body perseveres in its state of rest or of moving uniformly in a straight line, except in so far as it is made to change that state by external forces.
Page 131 - This result, it seems to me, is absolutely conclusive against the supposition that terrestrial magnetic storms are due to magnetic action of the sun ; or to any kind of dynamical action taking place within the sun, or in connexion with hurricanes in his atmosphere, or anywhere near the sun outside.
Page 167 - The result of these observations may be thus briefly stated. As we pass from minimum to maximum, the lines of the chemical elements gradually disappear from among those most widened, their places being taken by lines of which at present we have no terrestrial representatives. Or, to put the result another way — at the...
Page 253 - Aluminium Antimony Argon Arsenic Barium Beryllium Bismuth Boron Bromine Cadmium Caesium Calcium Carbon Cerium Chlorine Chromium Cobalt Copper...
Page 216 - ... due to gravity. II. The spectra of all bodies depend upon the heat of the meteorites, produced by collisions, and the average space between the meteorites in the swarm, or in the case of consolidated swarms upon the time which has elapsed since complete vaporization.