A Compendious System of Natural Philosophy: With Notes Containing the Mathematical Demonstrations, and Some Occasional Remakrs. In Four Parts ...S. Harding, 1745 - Astronomy |
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Common terms and phrases
Aftronomers alfo alſo Angle Angles of Incidence appear Atmoſphere Axis becauſe Cafe called Caufe cauſe Center central Force Chap Circle Colours Comet confequently convex Courſe decreaſes defcribe Degree Diameter diftinguiſhed diminiſhed Diſtance Earth Ecliptic Ellipfe equal Equator Equinoctial faid fall fame farther fecond feem feen feven feveral fhall fhew fhewn fhould fince firft firſt fmall Focus of parallel fome fometimes ftill fuch fuppofe Glafs Globe greateſt Heavens Hemiſphere Horizon Hour Hyperbola Image incident Rays increaſes inferior Planets itſelf Jupiter laft lefs Lemma Light Line Meaſure Meridian Moon Motion move muſt nearer Nodes Number obferved Object Obliquity oppofite Orbit paffes paffing Parabola Parallax parallel Rays perpendicular Place Planets Point Poles Propofition Proportion Quadratures Reaſon reflected Rays Refraction reprefent retaining Power revolving Body rifing round Saturn ſhall ſmall Spectator Square Stars Sun's Surface Syzygies Teleſcope thefe themſelves theſe thofe thoſe Velocity Weft whofe
Popular passages
Page 184 - Romans also reckoned their hours after this manner : as do the Turks at this - day. This kind of hours...
Page 105 - Center is C. Let DE be the reflected Ray of the incident one RD, produce ED to F, and through R draw the Line RH parallel to FE till it meets CD produced in H. Then will the Angle RHD be...
Page 181 - Eye-glafTes, where the Rays which form the extreme Parts of the Image are brought together in order to enter the Pupil of the Eye, as explained above. It is apparent alfo, that the nearer the Eye is placed to the Eye-glafs of this Telefcope, the larger is the Area feen through it ; for, being placed clofe to the Glafs, as in the Figure, it admits Rays that come from A and B, the Extremities of the Objed, which it could not if it was placed farther off.
Page 129 - ... fubtenfe common to them both. From this propofition it follows; that, were the eye clofe to the furface at K, the real and apparent objeft would be feen under equal angles (for the real objeft appears from that place under the fame angle that the image does, as will be...
Page 124 - I its focus of parallel rays, and c its centre. Through A and B, the extremities of the object, draw the lines...
Page 125 - В : if therefore an object be fuppofed to be fituated beyond the centre in IM, the image of it will be formed in AB between that and the focus of parallel rays, will be lefs than the object, and inverted. 5. If the middle of the object be placed in the centre of convexity of the reflecting...
Page 115 - Let them converge in the lines RB and SF proceeding towards X, a point between the focus of parallel rays and the centre ; their angles of incidence will then be...
Page 102 - C be the centre of convexity ; suppose HE to be the reflected ray of the oblique incident one DH proceeding as from F, a point in the line AB produced. Through the point H draw the line...
Page 114 - M, the focus of parallel rays ; then, as the parallel rays AF and EB were reflected into the lines FM and BM (by Prop, ii.), thefe rays will now on the contrary be reflected into them.
Page 184 - Mars, and so the twenty-second will fall to Saturn again; and therefore the twenty-third to Jupiter, and the last to Mars; so that on the first hour of the next day it will fall to the Sun to preside ; and by the like...