I wish to record my debt to Dr. Stanley Smith, some time Reader in Palaeontology in the University of Bristol, who first attracted my attention to the problems of ancient mineralogy. When he died in 1955 we were engaged on work which had led us on occasion to discuss certain passages in Books XXXVI and XXXVII. Where I have summarized his views on such passages in my notes, I have added his name. It gives me pleasure to be able to pay this tribute, however small, to a distinguished scientist.

I wish also to thank Dr. F. C. Phillips of the University of Bristol, who has patiently answered my questions about gemstones, Dr. John Harris of Christ Church, Oxford, who has generously provided me with a wide range of information concerning Ancient Egypt, and Professor W. Beare of the University of Bristol, who has kindly read the proofs. I should mention, however, that I alone must bear the responsibility for the errors that remain in spite of their help.