Hi Wayne.

The King's

"Probably the base of the chamber was the part most carefully adjusted and set out; and hence the original value of the cubit used can be most accurately recovered from that part. The four sides there yield a mean value of 20.632 ± .004, and this is certainly the best determination of the cubit that we can hope for from the Great Pyramid."

Summary of Chambers - Kings/Queens.

The passage widths are so short and variable that little value can be placed on them, especially as they depend on the builder's and not on the mason's work. The lengths of the passages are very accurate data, but being only single measures, are of less importance than are chambers, in which a length is often repeated in the working. The chamber dimensions are rather variable, particularly in the Subterranean and Antechamber, and none of the above data are equal in quality to the King's Chamber dimensions. If a strictly weighted p 179 mean be taken it yields 20.620 ± .004; but taking the King's Chamber alone, as being the best datum by far, it nevertheless contracts upwards, so that it is hardly justifiable to adopt a larger result than 20.620 ± .005.

Chapter 20. Section 136

I remarked on this in a previous thread where I suggested that 20.620 +/- .005 was more a chamber standard (Kings and Queens) rather than a pyramid standard. The wording above which amplifies this is " in which a length is often repeated in the working"

The sub is left out of this for obvious reasons.

Petrie knew that repetitive work in cubits was much more likely to yield good results. The King's he knew full well was shaken out of true and although he compensated for it, to the best of his ability, the figure 20.632 +/- .004, is a little suspect at best. The summary in chapter 20 might seem contradictory to that of chapter 7 but I think it fair to say that it's the more acceptable, especially when so many other sources have the 20.62 figure in print.

Ironically the 440 base number of Khufu calls for a cubit length shorter than both the afore mentioned. The 20.632 +/.004 cubit would considerably stretch the imagination.

Anyway if we maximize one and minimize the other there is only .003 inch difference, which just goes to show that when we convert imperial to royal using either .620 or .632 we should adopt two sets of values.

Petrie often seems to be contradictory so at times we have to decide whether to juggle or not.