Some matters, however, point to a stage which passed away soon after. The sign for a seal is not a scarab, or a ring, but a cylinder of jasper, set in gold ends, and turning on a pin attached to a necklace of stone beads. Cylinders are often met with in early times, but died out of use almost entirely by the eighteenth dynasty. This points to a connection with Babylonia in early times. The numerals are all derived from various lengths of rope; pointing to an original reckoning on knotted ropes, as in many other countries. And some suggestion of the original home of Egyptian culture near the sea, is made by the signs for water being all black or dark blue-green. This is a colour that no one living on the muddy Nile would ever associate with water; rather should we suppose it to have originated from the clear waters of the Red Sea. Another glimpse of the prehistoric age in Egypt is afforded by the burials at Medum. The later people always buried at full length, and with some provision for the body, such as food, head-rests, &c. Such burials are found among the nobles at Medum. But most of the people there buried in a contracted form, nose and knees, or at least with the thigh bent square with the body and heels drawn up. And moreover, no food-vessels or other objects are put in. Yet there was no mere indifference shown; the bodies are in deep well tombs, often placed in large wooden boxes, which must have been valuable in Egypt, and always lying with the head to the north, facing the east. Here is clearly a total difference in beliefs, and probably also in race. We know that two races, the aquiline-nosed and the snouty, can be distinguished in early times; and it seems that the aborigines used the contracted burial, and the dynastic race the extended burial, which--with its customs--soon became the national mode. Is it likely that the bulk of the people should have resisted this change for some 800 years, and then have suddenly adopted it in two or three generations? Does not this rapid adoption of the upper-class custom, between the beginning of the fourth dynasty and the immediately succeeding times, suggest that the dynastic race did not enter Egypt till shortly before we find their monuments? At least, the notion that the stages preceding the known monuments should be sought outside of Egypt, and that this is the explanation of the dearth of objects before the fourth dynasty, is strengthened by the change of custom and belief which we then find.