A Compendious System of Natural Philosophy: With Notes, Containing the Mathematical Demonstrations, and Some Occasional Remarks: in Four Parts, Volume 2Sam. Harding, 1753 |
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Aftronomers alfo alſo Angle Angles of Incidence appear Atmoſphere Axis becauſe Cafe called Caufe cauſe Center central Force Chap Circle Colours Comet confequently convex decreaſes defcribe Degree Diameter diminiſhed Diſtance diſtinguiſhed Earth Ecliptic equal Equator Equinoctial faid fall fame farther fecond feem feen feven 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 paſs perpendicular Place Planet Point Poles Propofition Proportion Quadratures Reaſon reflected Rays Refraction reprefent retaining Power revolving Body rifing round Saturn ſeen ſhall ſmall Spectator Square Stars Sun's ſuppoſed Surface Syzygies Teleſcope thefe themſelves theſe thofe thoſe Velocity Weft whofe
Popular passages
Page 122 - AG, be a pencil of rays flowing from A. These rays, proceeding from a point beyond the focus of parallel rays, will after reflection converge towards some point on the opposite side...
Page 179 - Eye-glalTes, 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...
Page 103 - Fig. 2. rays incident, the one perpendicularly, the ether obliquely, on the concave surface BH, whose centre of concavity is C. Let BF and HF be the reflected rays meeting each other in F ; this will be the middle point between B and C. For drawing through C the perpendicular CH, the angles DHC and FHC, being the angles of incidence and reflection, will be equal, to the former of which the angle HCF is equal, as alternate ; and therefore the triangle CtH is isosceles.
Page 162 - ... substance. The quickness of these vibrations depending on the elasticity of the medium, (as the quickness of the vibrations in the air, which propagate sound, depend solely on the elasticity of the air, and not upon the quickness of those in the sounding body) the motion of the particles of it may be quicker than that of the rays; and therefore when a ray, at the instant it impinges upon any surface, is in that part of a vibration of this...
Page 129 - ... therefore, when the eye is nearer to the image than that point, the image will fubtend a larger angle at it than the objeft...
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 180 - 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...
Page 181 - This telescope may be made to magnify in any given degree, provided it be of a sufficient length. For, the greater the focal distance of the object-glass, the less may be the focal distance of the eye-glass ; though not directly in proportion. Thus, an object-glass of 10 i.ECT.
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...