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altitude angle appear astronomers atmosphere axis azimuth called celestial celestial sphere circle clock comet conjunction constellation degree diameter disk distance diurnal revolution double stars earth earth's orbit ecliptic equal equator equinox exhibit figure fixed stars force full moon globe gravity greater heavenly bodies heavens Hence Herschel horizon hour inferior conjunction inferior planets instrument Jupiter latitude learner light longitude lunar lunar eclipse magnitude measure Mercury meridian miles moon moon's move nearer nearly nebulae node oblique observations opposite orbit parallax parallel passing perihelion period planetary pole quantity of matter refraction represented respect revolve right ascension ring satellites Saturn seen shadow side sidereal sidereal day solar system space spectator sphere spots sun and moon sun's superior conjunction superior planets supposed surface tail tance telescope tide-wave tides tion Uranus velocity Venus visible west to east zenith Zodiac Zodiacal Light
Page 198 - ... 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 of beneficent contrivance.
Page 193 - ... and less strongly marked than those of Jupiter, and owing, doubtless, to a similar cause. That the ring is a solid opake substance is shown by its throwing its shadow on the body of the planet, on the side nearest the sun, and on the other side receiving that of the body, as shown in the figure.
Page 138 - As the sun and earth are both situated in the plane of the ecliptic, if the moon also revolved around the earth in this plane, we should have a solar eclipse at every new moon, and a lunar eclipse at every full...
Page 99 - THIRD LAW. — The squares of the periodical times are as the cubes of the mean distances from the sun. The periodical time of a body is the time it takes to complete its orbit, in its revolution about the sun. Thus the earth's periodic time is one year, and that of the planet Jupiter about twelve years.
Page 49 - Every year whose number is not divisible by 4 without remainder, consists of 365 days ; every year which is so divisible, but is not divisible by 100, of 366 ; every year divisible by 100, but not by 400, again of 365 ; and every year divisible by 400, again of 366.
Page 146 - In any year, the number of eclipses of both luminaries cannot be less than two, nor more than seven. The most usual number is four, and it is very rare to have more than six.
Page 62 - AB is a telescope mounted on a horizontal axis and capable of two motions, one in altitude parallel to the circle abc, and the other in azimuth parallel to EFG. Hence it can be easily brought to bear upon any object. At m, under the eye glass of the telescope, is a small mirror placed at an angle of 45°...
Page 198 - The rings of Saturn must present a magnificent spectacle from those regions of the planet which lie above their enlightened sides, as vast arches spanning the sky from horizon to horizon, and holding an invariable situation among the stars.
Page 47 - The most ancient nations determined the number of days in the year by means of the stylus, a perpendicular rod which casts its shadow on a smooth plane bearing a meridian line. The time when the shadow was shortest, would indicate the day of the Summer solstice ; and the number of days which elapsed, until the shadow returned to the same length again, would show the number of days in the year. This was found to be three hundred and sixty-five whole days, and accordingly, this period was adopted for...
Page 116 - ... existence of the inhabitants of our planet. An author, who has reflected much on subjects of this kind, reasons as follows : " A navigator who approaches within a certain distance of a small island, although he perceives no human being upon it, can judge with certainty that it is inhabited, if he perceives human habitations, villages, corn-fields, or other traces of cultivation. In like manner, if we could perceive changes or operations in the moon, which could be "traced to the agency of intelligent...