Outlines of astronomy |
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Page xxi
... the law of gravity . Actual dimensions of comets . Periodical return of several . Halley's Other ancient comets probably periodic . Encke's comet- comet . Biela's - Faye's - Lexell's - De Vico's - Brorsen's CONTENTS . xxi.
... the law of gravity . Actual dimensions of comets . Periodical return of several . Halley's Other ancient comets probably periodic . Encke's comet- comet . Biela's - Faye's - Lexell's - De Vico's - Brorsen's CONTENTS . xxi.
Page xxiii
... Actual dimensions of their orbits . menon of complementary colours . Sanguine stars . Proper motion of the stars . Partly accounted for by a real motion of the Sun. Situa- tion of the solar apex . Agreement of southern and northern ...
... Actual dimensions of their orbits . menon of complementary colours . Sanguine stars . Proper motion of the stars . Partly accounted for by a real motion of the Sun. Situa- tion of the solar apex . Agreement of southern and northern ...
Page 3
... actual progress ; inasmuch as he will find it at once easier and more satisfactory to pursue from the outset a straight and definite path , than to be constantly stepping aside , involving himself in perplexities and circuits , which ...
... actual progress ; inasmuch as he will find it at once easier and more satisfactory to pursue from the outset a straight and definite path , than to be constantly stepping aside , involving himself in perplexities and circuits , which ...
Page 21
... actual size of the earth itself : and , in fact , were it not for the effect of refraction , by which we are enabled to see in some small degree round the interposed segment ( as will be hereafter explained ) , this would be a tolerably ...
... actual size of the earth itself : and , in fact , were it not for the effect of refraction , by which we are enabled to see in some small degree round the interposed segment ( as will be hereafter explained ) , this would be a tolerably ...
Page 32
... actual material atoms of the air itself . To understand how this takes place , we must recollect , that it is not only by the direct light of a luminous object that we see , but that whatever portion of its light which would not ...
... actual material atoms of the air itself . To understand how this takes place , we must recollect , that it is not only by the direct light of a luminous object that we see , but that whatever portion of its light which would not ...
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Common terms and phrases
61 Cygni amount angle angular appear apsides ascertained astronomers attraction axis bright calculation celestial Centauri circle comet Cygni described diameter difference direction disc distance disturbing force Ditto diurnal diurnal motion double stars earth ecliptic effect epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity greater heavens hemisphere horizon inclination increase instance interval Julian period Jupiter latitude latter length less light longitude lunar magnitude mass mean measure meridian micrometrical moon moon's nearly nebula node normal force nutation object observed orbit Orionis parallax parallel perihelion period perturbations phænomena phænomenon planet planetary pole portion position precisely proper motion proportion reckoned refraction remarkable respect result revolution right ascension rotation round satellites Saturn seen sidereal sidereal day situation solar solar apex sphere spherical station sun's suppose surface syzygies tangential force telescope tion Uranus variation velocity visible whole
Popular passages
Page 241 - Aries, Taurus, Gemini, Cancer,, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces.
Page 294 - 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 351 - 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 259 - 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 terrestrial action and the aurora.
Page 353 - As to getting correct notions on this subject by drawing circles on paper or, still worse, from those very childish toys called orreries, it is out of the question.
Page 58 - Ocean, the first thing which strikes us is, that, the north-east and south-east monsoons, which are found the one on the north and the other on...
Page 285 - 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 xxv - ... adverse to notions he may have previously formed for himself, or taken up, without examination, on the credit of others. Such an effort is, in fact, a commencement of that intellectual discipline which forms one of the most important ends of all science. It is the first movement of approach...
Page 353 - 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...