Although, and indeed because, these inquiries are still incomplete, I now bring together some of the notes I have collected, as they may induce other inquirers to go on with the work. Some of the results already obtained have been communicated to the Royal Society, and others have appeared in articles published in _Nature_, but only a small percentage of the monuments available has so far been examined. Further observations are required in order that the hypothesis set forth in this book may be rejected or confirmed. In the observations made at Stonehenge referred to in Chapter VII. I had the inestimable advantage of the collaboration of the late Mr. Penrose. Our work there would not have been possible without the sympathetic assistance of Sir Edmund Antrobus, Bart.; Colonel Duncan A. Johnston, R.E., Director-General of the Ordnance Survey, also was good enough on several occasions to furnish us with much valuable information which is referred to in its place. Messrs. Howard Payn and Fowler skilfully and zealously helped in the observations and computations. To all these I am glad to take this opportunity of expressing my obligations. With regard to the other monuments besides Stonehenge, I have to tender my thanks to the following gentlemen for most valuable local assistance:-- Brittany--Lieut. de Vaisseau Devoir. Stenness--Mr. Spence. Stanton Drew--Professor Lloyd Morgan, Mr. Morrow, and Mr. Dymond. The Hurlers, and the Merry Maidens--the Right Hon. Viscount Falmouth, Capt. Henderson, Mr. Horton Bolitho and Mr. Wallis. Tregaseal--Mr. Horton Bolitho and Mr. Thomas. The Dartmoor Avenues--Mr. Worth. The following have helped me in many ways, among them with advice and criticism:--Principal Rhys, Dr. Wallis Budge, Dr. J. G. Frazer, and Mr. A. L. Lewis. The assistance so generously afforded in the case of Stonehenge by Colonel Johnston, R.E., in furnishing me with accurate azimuths was continued for the monuments subsequently investigated till his retirement. To his successor, Colonel R. C. Hellard, R.E., I am already under deep obligations. For the use of some of the Illustrations my thanks are due to the Royal Society, the Society of Antiquaries, the Royal Institute of British Architects, Messrs. Macmillan, and Mr. John Murray. I have to thank Mr. Rolston, F.R.A.S., one of my staff, for assistance in the computations involved. NORMAN LOCKYER. SOLAR PHYSICS OBSERVATORY, _17th May, 1906_. CONTENTS PAGE PREFACE v CHAPTER I. INTRODUCTORY 1 II. THE ASTRONOMICAL DIVISIONS OF THE YEAR 12 III. THE AGRICULTURAL DIVISIONS OF THE YEAR 17 IV. THE VARIOUS NEW-YEAR DAYS 25