STARGAZING: PAST AND PRESENT.CHAPTER I.the dawn of stargazing.Some sciences are of yesterday; others stretch far back into the youth of time. Among these there is one of the beginniDgs of which we have lost all trace, so coeval was it with the commencement of man's history; and that science is the one of which we have to trace the instrumental developments.Although our chief task is to enlarge upon the modern, it will not be well, indeed it is impossible, to neglect the old, because, if for no other reason, the welding of old and new has been so perfect, the conquest of the unknown so gradual.The best course therefore will be to distribute the different fields of thought and work into something like marked divisions, and to commence by dividing the whole time during which man has been observing the heavens into two periods, which we will call the Pre-telescopic and the Telescopic Ages. The work of the Pre-telescopic age of course includes all the early observations made by tTable of Contents CONTENTS; BOOK I THE PRE-TELESCOPIC AGE; CHAP PAGE; I-The Dawn of Stargazing 1; II-The First Instruments 1G; III-HlPPARCHUS AND ptolemy 25; IV-Tycho Brahe 37; BOOK IT THE TELESCOPE; V-The Refraction of Light 55; VI-The Refractor 73; VII-The Reflection of Light 90; VIII- The Reflector 100; IX-Eyepieces 109; X-Production of Lenses and Specula 117; XL-The "Optick Tube" 139; XII-The Modern Telescope 152viii; CONTENTS; BOOK 111 TIME AND SPACE MEASURERS; CHAP PAGE; XIII-The Clock and Chronometer 175; XIV-Circle Reading 211; XV-The Micrometer 218; BOOK IV; MODERN MERIDIONAL OBSERVATIONS; XVI-The Transit Circle 233; XVII-The Transit Clock and Chronograph 253; XVIII-" Greenwich Time," and the Use Made of It 271; XIX-Other Instruments Used in Astronomy of Precision 284; BOOK V; THE EQUATORIAL; XX-Various Methods of Mounting Large Telescopes 293; XXI-The Adjustments of the Equatoria