Temples, Tombs & Hieroglyphs_ A Popular History of Ancient Egypt - Barbara Mertz [7]
Having established the earlier and later types of this particular pottery class, which he called “W,” Petrie had the beginning of a chronological sequence. Now he could begin to tie in the other pottery classes that were found in company with the wavy-handled examples. Some of the graves that contained wavy-handled pots also had pottery of a class that Petrie designated “L,” for “late,” because it continued in use up to historic times. This gave him a terminal point, since the examples of the “L” type that occurred in First Dynasty graves could be dated. In all Petrie worked with nine classes of prehistoric pottery. Besides the “L” and “W” classes he had a blacktopped red group (B), a red-polished (P), a rough (R), and others. Not all the graves contained all nine classes of pottery, but each grave contained at least two; if a grave did not have more than one class, it was useless for a comparative methodology, and Petrie did not include it within his corpus of examples.
Through correlation with the wavy-handled types Petrie was able to work out sequence patterns for the other classes of pottery. Of course, the chronological developments of various classes had to be consistent. For example, let us assume that subtypes 9–12 of wavy-handled pottery are consistently found with subtypes 1–3 of the red-polished ware. Then subtypes 4–6 of the red-polished ware cannot occur with the wavy-handled subtypes of an earlier date—subtypes 1–9. If they do, then something is wrong with the internal arrangement of one class or the other—or both. This is a very simplified example of the sort of cross-check Petrie had to make with nine different classes of pottery and seven hundred graves. And he had no computer! The logical processes involved are not especially profound, but the scope of the material is so broad that one’s imagination reels in considering it.
However, this was precisely the sort of problem at which Petrie excelled; as a recorder of multitudinous details, he was probably without a peer among archaeologists. He gave numbers to all the subtypes within his nine classes and wrote the numbers on his index slips, one slip for each grave. Having transformed his pots into mathematical symbols, he could juggle bits of paper rather than objects; we can picture him hovering over a big table spread with an intellectual meal of seven hundred index slips, rushing from one side of the table to the other in order to find the right spot for a particular slip, and feasting his eyes on a particularly consistent arrangement, like a gourmet at a seven-(or seven-hundred-) course dinner.
In the end, Petrie had a series of grave groups whose pottery formed a consistent and logical pattern. The pottery classes overlapped in time, naturally; one category might be in its last stages of development before another category came on the scene, and the oldest class might have vanished altogether before the latest one appeared. Yet the overlapping of classes was continuous, and there was never a point at which a comparative method, involving at least two types, could not be applied. Petrie had forced his scattered graves into a sequence, and the numbers he assigned to the grave groups were called “sequence dates,” for they had