Astronomy |
From inside the book
Page vi
... Diameter . - Its Paral- lax , Distance , and real Diameter . - First Approximation to its Orbit . - An Ellipse about the Earth in the Focus . - Its Excentricity and Inclina- tion . - Motion of the Nodes of its Orbit . - Occultations ...
... Diameter . - Its Paral- lax , Distance , and real Diameter . - First Approximation to its Orbit . - An Ellipse about the Earth in the Focus . - Its Excentricity and Inclina- tion . - Motion of the Nodes of its Orbit . - Occultations ...
Page 16
... diameter , measured with an instrument called the dip sector , is the same ( except under some singular atmospheric circumstances , which produce a temporary distortion of the outline ) , in whatever direc- tion the measure is taken ...
... diameter , measured with an instrument called the dip sector , is the same ( except under some singular atmospheric circumstances , which produce a temporary distortion of the outline ) , in whatever direc- tion the measure is taken ...
Page 17
... diameter . Leaving , at present , out of consideration the effect of refraction in the air below M , of which more hereafter , and which always tends , in some degree , to increase that angle , or render it more obtuse , this is the ...
... diameter . Leaving , at present , out of consideration the effect of refraction in the air below M , of which more hereafter , and which always tends , in some degree , to increase that angle , or render it more obtuse , this is the ...
Page 18
... diameter of the earth diminishes , being nowhere so great as 180 ° , or two right angles , but falling short of it by some sensible quantity , and that more and more the higher we ascend . The figure exhibits three states or stages of ...
... diameter of the earth diminishes , being nowhere so great as 180 ° , or two right angles , but falling short of it by some sensible quantity , and that more and more the higher we ascend . The figure exhibits three states or stages of ...
Page 21
... diameter bears the same proportion to the distance of the visible horizon from the eye as that dis- tance does to the height of the eye above the sea level . When the stations are unequal in height the problem is a little more ...
... diameter bears the same proportion to the distance of the visible horizon from the eye as that dis- tance does to the height of the eye above the sea level . When the stations are unequal in height the problem is a little more ...
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Common terms and phrases
action altitude amount angle angular angular velocity appear arise ascertained astronomical atmosphere attraction axis body calculation called cause celestial CHAP circle clock comet degree described determined deviation diameter difference direction disc distance disturbing force diurnal motion double stars earth earth's surface ecliptic effect ellipse equal equator equinoctial equinox error exact exactly excentricity fixed globe gravity heavens heliocentric hemisphere horizon inclination inequality instance instrument interval Jupiter latitude latter law of Kepler length less light longitude lunar magnitude mass mean measure meridian moon moon's nearly nodes nutation object observed orbit parallax perihelion period planet planetary pole portion position precession produce proportion reckoned refraction respect retrograde revolution revolving right ascension ring rotation round satellites Saturn seen sidereal sidereal period situation solar spectator sphere spherical stars station sun's suppose synodical period telescope tion triangle Uranus variation velocity visible whole zenith
Popular passages
Page 204 - Aries, Taurus, Gemini, Cancer,, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces.
Page 236 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Page 287 - 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 394 - This earth ? reciprocal, if land be there, Fields and inhabitants. Her spots thou seest As clouds, and clouds may rain, and rain produce Fruits in her soften'd soil, for some to eat Allotted there ; and other suns, perhaps, With their attendant moons, thou wilt descry, Communicating male and female light, Which two great sexes animate the world, Stored in each orb, perhaps, with some that live...
Page 211 - the sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth. By its heat are produced all winds, and those disturbances in the electric equilibrium of the atmosphere which give rise to the phenomena of lightning, and probably also to those of terrestrial magnetism and the aurora.
Page 353 - ... of the spherical shell, which form the bases of both the cones, or pyramids, be similar and equally inclined to their axes. Therefore their areas will be to each other as the squares of their distances from the common apex. Therefore their attractions on it will be equal, because the attraction is as the attracting matter directly, and the square of its distance inversely. "Now, these attractions act in opposite directions, and, therefore, counteract each other. Therefore, the point is in equilibrium...
Page 232 - ... it is certain that the conception of some more real and intimate connection is quite as strongly impressed upon the human mind as that of the existence of an external world — the vindication of whose reality has (strange to say) been regarded as an achievement of no common merit in the annals of this branch of philosophy. It is our own immediate consciousness of effort, when we exert force to put matter in motion, or to oppose and neutralize force, which gives us this internal conviction of...
Page 230 - The consequence must be absolute aridity below the vertical sun, constant accretion of hoar frost in the opposite region, and, perhaps, a narrow zone of running water at the borders of the enlightened hemisphere.' It is possible, then, that evaporation on the one hand, and condensation on the other, may to a certain extent preserve an equilibrium of temperature, and mitigate the extreme severity of both climates...
Page 395 - 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 162 - Of course we do not here speak of those uncouth figures and outlines of men and monsters, which are usually scribbled over celestial globes and maps, and serve, in a rude and barbarous way, to enable us to talk of groups of stars, or districts in the heavens, by names which, though absurd or puerile in their origin, have obtained a currency from which it would be difficult to dislodge them. In so far as they have really (as some have) any slight resemblance to the figures called up in imagination...