Continues from Part 1.
The second lemma needs to be deduced from reading these pages from chapter two of Christopher Milbourne’s Illustrated History of Magic published in 1975. (Dear publisher: please treat this as free advertising for your wonderful book.). Yes it’s all relevant, and it starts off with a story about Khufu. Click to enlarge for easier reading.
According to the historians, the cubit is an ancient measure based on the length of the arm plus hand, like this:
where the normal cubit is 6 palms long, and the Royal Cubit 7 palms long. Well, that’s one explanation of the origin. The other is that they got it from the gods, a long long time ago.
Now there are several problems with the common cubit as shown above. In the first place, it’s generally accepted as being 17.6 or 18 inches long. That’s 44.7 to 45.7 cm.