W. H. M. CHRISTIE, ASTRONOMER ROYAL 121 THE ASTRONOMER ROYAL'S HOUSE 127 THE COURTYARD 130 PLAN OF OBSERVATORY AT PRESENT TIME 134 THE GREAT CLOCK AND PORTER'S LODGE 147 THE CHRONOGRAPH 158 THE TIME-DESK 164 HARRISON'S CHRONOMETER 165 THE CHRONOMETER ROOM 167 THE CHRONOMETER OVEN 171 THE TRANSIT PAVILION 174 'LOST IN THE BIRKENHEAD' 179 THE TRANSIT CIRCLE 189 THE MURAL CIRCLE 195 AIRY'S ALTAZIMUTH 208 NEW ALTAZIMUTH BUILDING 211 THE NEW ALTAZIMUTH 213 THE NEW OBSERVATORY AS SEEN FROM FLAMSTEED'S OBSERVATORY 219 THE SELF-REGISTERING THERMOMETERS 235 THE ANEMOMETER ROOM, NORTH-WEST TURRET 240 THE ANEMOMETER TRACE 243 MAGNETIC PAVILION--EXTERIOR 246 MAGNETIC PAVILION--INTERIOR 248 THE DALLMEYER PHOTO-HELIOGRAPH 254 PHOTOGRAPH OF A GROUP OF SUN-SPOTS 259 THE GREAT NEBULA IN ORION 269 THE HALF-PRISM SPECTROSCOPE ON THE SOUTH-EAST EQUATORIAL 273 THE WORKSHOP 276 THE 30-INCH REFLECTOR WITH THE NEW SPECTROSCOPE ATTACHED 278 'CHART PLATE' OF THE PLEIADES 286 THE CONTROL PENDULUM AND THE BASE OF THE THOMPSON TELESCOPE 289 THE ASTROGRAPHIC TELESCOPE 291 THE DRIVING CLOCK OF THE ASTROGRAPHIC TELESCOPE 294 THE THOMPSON TELESCOPE IN THE NEW DOME 297 THE NEBULÆ OF THE PLEIADES 300 DOUBLE-STAR OBSERVATION WITH THE SOUTH-EAST EQUATORIAL 308 THE SOUTH-EAST DOME WITH THE SHUTTER OPEN 314 [Illustration: GENERAL VIEW OF THE OBSERVATORY BUILDINGS FROM THE NEW DOME. (_From a photograph by Mr. Lacey._)] THE ROYAL OBSERVATORY GREENWICH CHAPTER I INTRODUCTION I had parted from a friend one day just as he met an acquaintance of his to whom I was unknown. 'Who is that?' said the newcomer, referring to me. My friend replied that I was an astronomer from Greenwich Observatory. 'Indeed; and what does he do there?'