Outlines of Astronomy |
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Page 18
... appears to every one , until he has understood and weighed the proofs to the contrary , the most positive evidence of his ... appear only as stars somewhat brighter than the rest , are to him spacious , elaborate , and habitable worlds ...
... appears to every one , until he has understood and weighed the proofs to the contrary , the most positive evidence of his ... appear only as stars somewhat brighter than the rest , are to him spacious , elaborate , and habitable worlds ...
Page 18
... appear to untaught eyes round bodies of no very considerable size , become enlarged in his imagi- nation into vast globes , - the one approaching in magnitude to the earth itself , the other immensely surpassing it . The planets , which ...
... appear to untaught eyes round bodies of no very considerable size , become enlarged in his imagi- nation into vast globes , - the one approaching in magnitude to the earth itself , the other immensely surpassing it . The planets , which ...
Page 37
... appear otherwise situated than they would to the same spectator , had the atmosphere no existence . It thus produces a false impression respecting their places , which must be rectified by ascer- taining the amount and direction of the ...
... appear otherwise situated than they would to the same spectator , had the atmosphere no existence . It thus produces a false impression respecting their places , which must be rectified by ascer- taining the amount and direction of the ...
Page 38
... appear more elevated above the horizon A H , when seen through the refracting atmosphere , than it would appear were there no such atmosphere . Since , however , the disposition of the strata is the same in all directions around A , the ...
... appear more elevated above the horizon A H , when seen through the refracting atmosphere , than it would appear were there no such atmosphere . Since , however , the disposition of the strata is the same in all directions around A , the ...
Page 40
... appear more elevated by it above their true directions than those at a high altitude . 3dly . The rate of its increase is nearly in proportion to the tangent of the apparent angular distance of the object from the zenith . But this rule ...
... appear more elevated by it above their true directions than those at a high altitude . 3dly . The rate of its increase is nearly in proportion to the tangent of the apparent angular distance of the object from the zenith . But this rule ...
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Common terms and phrases
altitude amount angle angular appear apsides ascertained astronomers axis bright calculation celestial centre circle comet curve described diameter difference direction disc distance disturbed body disturbing force diurnal diurnal motion double stars earth ecliptic effect elements ellipse epoch equal equator equinoctial equinox error exact excentricity fixed globe gravity greater heavens heliocentric horizon inclination increase inequality instance instrument interval Jupiter latitude latter less light longitude lunar magnitude mass mean measure meridian moon moon's motion nearly nebula node normal force nutation object observed orbit parallax parallel perigee perihelion period perpendicular perturbations planet planetary pole portion position precession proper motions proportion recede recess reckoned refraction remarkable respect result revolution right ascension rotation round satellites Saturn seen sidereal sidereal day sidereal period situation solar sphere spherical stars station sun's suppose syzygies tangential force telescope tion Uranus variation velocity visible whole zenith
Popular passages
Page 211 - ... of those great deposits of dynamical efficiency which are laid up for human use in our coal strata. By them the waters of the sea are made to circulate in vapour through the air, and irrigate the land, producing springs and rivers.
Page 568 - William Youatt. A new edition, with numerous illustrations ; together with a General History of the Horse ; a Dissertation on the American Trotting Horse; how trained and jockeyed; an Account of his Remarkable Performances; and an Essay on the Ass and the Mule.
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 terrestrial action and the aurora.
Page 6 - Manual of Ancient History, from the Remotest Times to the Overthrow of the Western Empire, AD 476.
Page 281 - 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 298 - ... the earth. And since it is an observed fact, that even those larger comets which have presented the appearance of a nucleus have yet exhibited no phases, though we cannot doubt that they shine by the reflected solar light, it follows that even these can only be regarded as great masses of thin vapour, susceptible of being penetrated through their whole substance by the sunbeams, and reflecting them alike from their interior parts and from their surfaces.
Page 204 - Ingens macula in sole conspiciebatur, cujus diam eter= s'ji "diam. solis. uniformly bright. Its ground is finely mottled with an appearance of minute, dark dots, or pores, which, when attentively watched, are found to be in a constant state of change. There is nothing which represents so faithfully this appearance as the slow subsidence of some flocculent chemical precipitates in a transparent fluid, when viewed perpendicularly from above...
Page 526 - 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 166 - This remarkable belt has maintained, from the earliest ages, the same relative situation among the stars ; and, when examined through powerful telescopes, is found (wonderful to relate ! ) to consist entirely of stars scattered by millions, like glittering dust, on. the black ground of the general heavens.
Page 210 - ... may, nevertheless, be in a state of most intense ignition. It does not, however, follow of necessity that it must be so. The contrary is at least physically possible. A perfectly reflective canopy would effectually defend it from the radiation of the luminous regions above its atmosphere, and no heat would be conducted downwards through a gaseous medium increasing rapidly in density. That the penumbral clouds are highly reflective, the fact of their visibility in such a situation can leave no...