additions, which may be rendered necessary by the progress of discovery.
The numbers are of course as purely arbitrary and relative as those
of the different thermometrical systems, but they afford a convenient
system of arrangement. The products of the prehistoric Egyptians are, so
to speak, distributed on a conventional plan over a scale numbered from
30 to 80, 30 representing the beginning and 80 the close of the term,
so far as its close has as yet been ascertained. It is probable that
"sequence-date 80" more or less accurately marks the beginning of the
dynastic or historical period.

This hypothetically chronological classification is, as has been said,
due to Prof. Petrie, and has been adopted by Mr. Randall-Maclver and
other students of prehistoric Egypt in their work. [*_El Amra and
Abydos_, Egypt Exploration Fund, 1902.] To Prof. Petrie then is due the
credit of systematizing the study of Egyptian prehistoric antiquities;
but the further credit of having _discovered_ these antiquities
themselves and settled their date belongs not to him but to the
distinguished French archæologist, M. J. de Morgan, who was for several
years director of the museum at Giza, and is now chief of the French
archæological delegation in Persia, which has made of late years so many
important discoveries. The proof of the prehistoric date of this class
of antiquities was given, not by Prof. Petrie after his excavations at
Dendera in 1897-8, but by M. de Morgan in his volume, _Recherches sur
les Origines de l'Égypte: l'Âge de la Pierre et les Métaux_, published
in 1895-6. In this book the true chronological position of the
prehistoric antiquities was pointed out, and the existence of an
Egyptian Stone Age finally decided. M. de Morgan's work was based on
careful study of the results of excavations carried on for several years
by the Egyptian government in various parts of Egypt, in the course
of which a large number of cemeteries of the primitive type had been