Library of Useful Knowledge: Natural philosophy, Τόμος 31834 |
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Σελίδα 64
... method ex- plained in page 59 , of determining parallax and refraction , we have shewn how the parallax would affect the value of Et , as compared with ET , on the supposition that s was the apparent place of the body , depressed by ...
... method ex- plained in page 59 , of determining parallax and refraction , we have shewn how the parallax would affect the value of Et , as compared with ET , on the supposition that s was the apparent place of the body , depressed by ...
Σελίδα 69
... method therefore seems to give but an inaccurate mode of estimating the elements in question . We may however estimate in this manner their mean value . If we suppose the dura- tion of an actual revolution of the moon , her periodic ...
... method therefore seems to give but an inaccurate mode of estimating the elements in question . We may however estimate in this manner their mean value . If we suppose the dura- tion of an actual revolution of the moon , her periodic ...
Σελίδα 115
... methods of ascertaining the elements in ques- tion ; but for the present it is sufficient to have explained the possibility of ascertaining them ; and that sufficiently appears from the method above pointed out . The same method may ...
... methods of ascertaining the elements in ques- tion ; but for the present it is sufficient to have explained the possibility of ascertaining them ; and that sufficiently appears from the method above pointed out . The same method may ...
Σελίδα 116
... method above explained is a very easy one of obtaining the length of a particular revolution . It may , however , happen , and it will be found to be the case , that this period is not always the same , though its variations are not con ...
... method above explained is a very easy one of obtaining the length of a particular revolution . It may , however , happen , and it will be found to be the case , that this period is not always the same , though its variations are not con ...
Σελίδα 119
... method of ascertaining the periodic time , on the supposition of cir- cular motion . The expressions , also , will be correct as to the mean synodic and periodic times , even in the case of elliptic motion . * It is at present , how ...
... method of ascertaining the periodic time , on the supposition of cir- cular motion . The expressions , also , will be correct as to the mean synodic and periodic times , even in the case of elliptic motion . * It is at present , how ...
Άλλες εκδόσεις - Προβολή όλων
Συχνά εμφανιζόμενοι όροι και φράσεις
aberration altitude angle apogee apparent diameter appear ascer ascertained astronomers axis calculated called centre circle comet consequently corresponding course declination deduced degree determined direction diurnal motion ecliptic elevation equal equator equinox excentricity fixed stars given greater greatest heavenly bodies heavens Hipparchus horizon hour angle inferior planet instance Jupiter Kepler known latitude latter length less longitude lunar mean anomaly measured meridian method moon moon's nearly node nutation observed orbit parallax parallel passing perigee perihelion period perpendicular planet pole position precession proportion Ptolemy quantity radius refraction remarkable represent respect retrograde motion revolution revolve right ascension rotation round the earth round the sun satellites seen side sidereal sine solar solstice South sphere spherical sun's supposed supposition Surya Siddhanta synodic period tables tance tion triangle true tude variation velocity whole zenith distance
Δημοφιλή αποσπάσματα
Σελίδα 54 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.
Σελίδα 18 - ... invisible. These animals are of a great variety of shapes and sizes, and in such prodigious numbers, that, in a short time, the whole surface of the rock appears to be alive and in motion. The most common...
Σελίδα 137 - D'Alembert, was the Precession of the equinoxes and the Nutation of the earth's axis, according to the theory of gravitation.
Σελίδα 15 - The lowest and most level parts of the earth, when penetrated to a very great depth, exhibit nothing but horizontal strata composed of various substances, and containing almost all of them innumerable marine productions. Similar strata, with the same kind of productions, compose the hills even to a great height. Sometimes the shells are so numerous as to constitute the entire body of the stratum. They are almost...
Σελίδα 18 - The examination of a coral reef during the different stages of one tide, is particularly interesting. When the tide has left it for some time it becomes dry, and appears to be a compact rock, exceedingly hard and ragged ; but...
Σελίδα 2 - Scotland was divided into two provinces — the one on the north, and the other on...
Σελίδα 169 - ... the squares of the periodic times are as the cubes of the distances from the common centre, the centripetal forces will be inversely as the squares of the distances.
Σελίδα 3 - ... they pass rapidly along the surface of the sea, and continue a quarter of an hour or more before they disappear. A notion has been entertained that they are very dangerous to shipping, owing to the descent, at the instant of their breaking, of a large body of water sufficient to sink a ship ; but this does not appear to be the case, for the water descends only in the form of heavy rain.
Σελίδα 15 - On the barren flank of a rock grows a tree with coriaceous and dry leaves. Its large woody roots can scarcely penetrate into the stone. For several months of the year, not a single shower moistens its foliage. Its branches appear dead and dried; but when the trunk is pierced, there flows from it a sweet and nourishing milk. It is at the rising of the sun that this vegetable fountain is most abundant. The blacks and natives are then seen hastening from all quarters, furnished with large bowls to receive...
Σελίδα 3 - Whirlwinds sometimes arisfi from winds blowing among lofty and precipitous mountains, the form of which influences their direction, and occasions gusts to descend with a spiral or whirling motion. They are frequently, however, caused by two winds meeting each other at an angle, and then turning upon a centre. When two winds thus encounter one another, any cloud which happens to be between them is of course condensed and turned rapidly round ; and all substances sufficiently light are carried up into...