Yes I have the book, have read it and know how the average of 7 stops was determined.
Each edition of The Theory of the Photographic Process is different enough (at least in the sensitometry and tone reproduction sections) that it's worth reading or owning each one. The first edition has the distinction of Loyd Jones editing the section on sensitometry and writing the chapter on the theory of tone reproduction. It was published in 1942, which was just after Jones seminal papers, so it contains the most detailed summary of those papers.
Bill, you should have shown the "Willow Pond" image. It was used extensively as an example in Jones' papers and became kind of famous. When I was writing a short article on Jones for a magazine (not published), I called Kodak to see if they could track down a copy. At that point Kodak no longer had an archivist so the attempt was futile. I did; however, get a photograph of Jones.