Note 1 — PREFACE.

My lectures, given in November, 1890, were printed in Nature, April-July, 1891, under the title "On some Points in the Early History of Astronomy," with the following note:—"From shorthand notes of a course of lectures to working men delivered at the Museum of Practical Geology, Jermyn Street, in November, 1890. The notes were revised by me at Aswân during the month of January. I have found, since my return from Egypt in March, that part of the subject-matter of the lectures had been previously discussed by Professor Nissen, who has employed the same materials as myself. To him, therefore, so far as I at present know, belongs the credit of having first made the suggestion that ancient temples were oriented on an astronomical basis. His articles are to be found in the Rheinisches Museum für Philologie, 1885."