I have Graham Webb's two books: "The Disc Musical Box Handbook"
published in 1971 and the second version, "The Musical Box Handbook
- Volume 2 - Disc Boxes," published in 1984.  The early book shows
a 24-1/2" Polyphon scale starting with the lowest notes tuned to
B-flat on both combs, yet the latter book shows the lowest notes on
both combs tuned to a G.  Can anyone explain?

Thanks,
Mark Poole