257

THE PHASES OF THE MOON 262

THE COURSE OF THE SUN THROUGH THE TWELVE SIGNS 264

THE NORTHERN CONSTELLATIONS 265

THE SOUTHERN CONSTELLATIONS 267

ASTROLOGY AND WEATHER PROGNOSTICS 269

THE ANALEMMA AND ITS APPLICATIONS 270

SUNDIALS AND WATER CLOCKS 273

BOOK X

INTRODUCTION 281

MACHINES AND IMPLEMENTS 283

HOISTING MACHINES 285

THE ELEMENTS OF MOTION 290

ENGINES FOR RAISING WATER 293

WATER WHEELS AND WATER MILLS 294

THE WATER SCREW 295

THE PUMP OF CTESIBIUS 297

THE WATER ORGAN 299

THE HODOMETER 301

CATAPULTS OR SCORPIONES 303

BALLISTAE 305

THE STRINGING AND TUNING OF CATAPULTS 308

SIEGE MACHINES 309

THE TORTOISE 311

HEGETOR'S TORTOISE 312

MEASURES OF DEFENCE 315

NOTE ON SCAMILLI IMPARES 320

INDEX 321

LIST OF ILLUSTRATIONS

CARYATIDES FROM TREASURY OF CNIDIANS, DELPHI 6

CARYATIDES OF ERECHTHEUM, ATHENS 6

CARYATID IN VILLA ALBANI, ROME 6

CARYATIDES 7

PERSIANS 9

CONSTRUCTION OF CITY WALLS