I’m about halfway through part 4—not much left to do, but I won’t be able to finish today.
One of the things that stumped me and now the copy editor are references in the letters to things called “Barbinettes.” No idea what those are, but I’m guessing some kind of dried fruit, since they often are mentioned along with “rum soakers.” I wasn’t sure how to spell “Barbinette” either, but having gone over the scans very carefully, I think that’s the spelling—he capitalizes the “B” consistently, which is about the only consistent usage of capitalization you’re likely to see in those letters.