THE EGYPTIAN SUDAN convince the visitor that their foundations are rarely well laid, and that in consequence some of their walls have " settled " so deeply at the corners that whole sides and ends have fallen out.

Besides this, the stones used for the lintels of the doors and for the roofs were not well chosen in the first instance, and the damage caused by "' weathering " has been considerable. Another cause of the ruined state of many of the chapels is the wind, which, blowing fiercely from the north, and being laden with sand, acts upon the stones in their corners like a sand-blast, and erodes them deeply. It is important to mention these details, otherwise misconception may arise in some minds as to the true causes which have contributed to the ruin of some of the chapels and their surrounding walls.

So soon as I began to go about among the pyramids it became evident that it was impossible to make accurate measurements of them, because the lower parts of the sides of all were buried in the loose stones which had fallen, or had been thrown down from their tops, and in masses of loose rubble. I checked the measurements given by Cailliaud and Hoskins, and though many appear to have been arrived at by guesswork, they are sufficientl}' correct for all practical purposes. Nearly all the pyramids are oriented a little to the south of east, but with very few exceptions the angles of orientation are all different. It is clear, in my opinion, that all were oriented to the same celestial body, and that the differences in orientation corresponded to the changes in position of that body. The pyramids throughout the S<idan seem to me to prove beyond doubt the truth of Sir Norman Lockyer's theory of orientation as propounded in his " Dawn of Astronomy," but no group so clearly makes it manifest as that which I was then examining, partly because of the semi-circular arrangement of the pyramids, and partly because of their large number.

Passing over the narrow valley which divides the two groups of pyramids, I found that the southern group was as instructive as the northern one, and it was interesting to note how careful the builders of the pyramids had been to arrange each in such a way that its shrine should receive the light directly into it from the celestial object.

Returning to the northern group, and proceeding along the foot 276 4 i