A Treatise on Astronomy: Illustrated with Maps and PlatesE. Hunt & Company, 1837 - 288 pages |
Common terms and phrases
altitude amount angle angular distance apogee apparent diameter apparent magnitude ascertained astronomers attraction called cause celestial pole celestial sphere centre of gravity circle comet consequently constellation cresent declination degrees described difference Digits eclipsed direction earth earth's axis earth's orbit earth's shadow earth's surface east ecliptic limit equal equator equinoctial evident explain fig FIGURE greater greatest heavenly body heavens hemisphere Herschel horizon illustrated by fig increases Jupiter latitude latter length less libration light longitude lunar eclipse magnitude mean solar meridian miles months moon moon's disc moon's orbit moving nearly nebulæ node north pole obliquity observed parallax pass perigee period plane Planisphere position precession radius represent retrograde retrograde motion revolve right ascension rising rotation Saturn seen side sidereal sidereal day solar days solar eclipse stars stationary sun's supposed synodic revolution take place tides tion variation velocity Venus vernal equinox visible zenith
Popular passages
Page 142 - Aries the Ram, Taurus the Bull, Gemini the Twins, Cancer the Crab, Leo the Lion, Virgo the Virgin, Libra the Balance, Scorpio the Scorpion, Sagittarius the Archer, Capricornus the Goat, Aquarius the Waterbearer, and Pisces the Fishes...
Page 163 - On the other hand, in the regions beneath the dark side, a solar eclipse of fifteen years in duration, under their shadow, must afford (to our ideas) an inhospitable asylum to animated beings, ill compensated by the faint light of the satellites. But we shall do wrong to judge of the fitness or unfitness of their condition from what we see around us, when, perhaps, the very combinations which convey to our minds only images of horror, may be in reality theatres of the most striking and glorious displays...
Page 165 - 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; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across...
Page 20 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.
Page 228 - In the solitude of the seas, we hail a star as a friend from whom we have long been separated. Among the Portuguese and the Spaniards peculiar motives seem to increase this feeling; a religious sentiment attaches them to a constellation, the form of which recalls the sign of the faith planted by their ancestors in the deserts of the New World.
Page 228 - It has been observed at what hour of the night, in different seasons, the Cross of the South is erect or inclined. It is a time-piece that advances very regularly near four minutes a day, and no other group of stars exhibits, to the naked eye, an observation of time so easily made.
Page 248 - Thus a yellow colour predominating in the light of the brighter star, that of the less bright one in the same field of view will appear blue ; while, if the tint of the brighter star verge to crimson, that of the other will exhibit a tendency to green — or even appear as a vivid green, under favourable circumstances.
Page 54 - If from any point without a circle two straight lines be drawn, one of which cuts the circle, and the other touches it ; the rectangle contained by the whole line which cuts the circle, and the part of it without the circle, shall be equal to the square of the line which touches it.
Page 165 - ... 430 feet; Mars a rather large pin's head, on a circle of 654 feet; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across; Saturn a small orange, on a circle of four-fifths of a mile...
Page 248 - In such instances, the larger star is usually of a ruddy or orange hue, while the smaller one appears blue or green, probably in virtue of that general law of optics, which provides, that when the retina is under the influence of excitement by any bright, coloured light ; feebler lights, which seen alone would produce no sensation but of whiteness, shall for the time appear coloured with the tint complementary to that of the brighter.