James Oswald published at least a dozen booklets, mostly with around 30 pages of tunes including variations, in the 1770s and 1780s. They weren't actually dated, and historians have estimated the dates from various clues from many sources. His terminology is a bit confused with both the original booklets and the two (known) combined collections of 6 of them into one book are called "volumes". See https://hummingadifferenttune.blogspot.com/2014/10/james-oswalds-caledonian-pocket.html for an idea of the mess these collections present for archivers.
Scanned images of the full set appeared on the National Library of Scotland's site (www.nls.uk) in 2018, and by 2020, archive.org had a subset that includes the original 12 books. I took on the project of transcribing them to ABC notation, to make the material more widely available. The more historically included may want to visit nls.uk or archive.org, and get your own copy of the originals.
One bit of oddity is that Volume 2 appeared online (nls.uk and archive.org) before Volume 1, and their organization is a bit different. Volume 1 contains the first 6 "books", complete with title pages and the original page numbers (1 thru 36 or so), plus a set of 6 indexes at the end. Volume 2 contains only a single title page, followed by a combined semi-alphabetical index, then the tune pages (1-162). The original books 7-12 are labelled in handwriting, but otherwise Vol.2 has no indication of the original 6 booklets' boundaries. This structure is mirrored in the subdirectories here, with the CPC directory containing CPCv1 and CPCvv2. CPCv1 has subdirectories CPCv1/Book01 thru CPCv1/Book06 which contain the tunes in those books, while CPCv2 contains all the tunes from the originasl Books 7-12, with the page numbers 1-162 used in the single-tune file names.
Each tune has been transcribed in a separate file. These can be combined into larger files by various software, depending on how you are using them. For the 1st volume, the pages aren't consequitively numbered; they start over at page 1 for each of the 6 books. There are fewer than 100 pages in each book, so the convention adopted here is to use file names of the form 1BPPN_Tune_Title.abc, where B is the book number (1-6), PP is the page number (01-36), and N is the tune counter for the page. Some tunes are across two pages; they are numbered on their first page, with the first full tune on the next page counted as tune 1. For the 2nd volume, the single-tune file names have a simpler naming convention, since the pages were renumbered for the collection. There are more than 99 numbered pages, so the file names are of the form 2PPPN_Tune_Title.abc, where PPP is the page number, N is the tune number on the page, '_' is a separator, and Tune_Title is the title with '_' for spaces and mixed capitalization that follows the modern practice of major words capitalized. Initial articles are not capitalized, which makes it easy for software to alphabetize by simply ignoring all characters before the first upper-case letter. This naming scheme produces the same tune order as the book, and can be useful with a lot of music software. A few tunes have -V1.abc or -V2.abc at the end of the file name. These are tunes with two transcriptions, for versions 1.* and 2.* of the ABC notation. These deal with things like occasional double "voices" in some measures, or dynamic markings not implemented in ABC 1.*, etc. There aren't many instances where ABC 2 features are needed, and they can usually be approximated easily in ABC 1, but when they occur, the -V2.abc file is the most accurate transcription. For these tunes, the '_' between the number and the title is changed to '-' for V1 tunes and '=' for V2 tunes. This was done to make recognizing them simpler in the Makefiles.
This collection was published before I and J had stabilized as different letters. The index has a single 'I' section that has a mix of titles starting with I or J. Sometimes 'J' is used where 'I' would be in the modern spelling, and the appropriate modern letter is transcribed.
This collection is somewhat inconsistent in its repeat notation. It seems to mostly use :||: as a single token meaning "Repeat the previous", but sometimes has thick double bars without the dots. These cases are transcribed as-is, as nearly as ABC allows. There is also common use of ... :||: ... :||: which is usually transcribed as |: ... :: ... :|, which is the modern notation for "Repeat all the strains." The initial |: is usually omitted when there's an initial "pickup" (anacrucis), but included if the tune starts on a downbeat. This is sometimes suggested as a good approach, partly to help software determine which initial notes are significant, and also useful for multi-note beginnings to emphasize where the downbeat is.
(In Oct 2019, I finally noticed that I hadn't increased the year in the Z: fields, which were all dated 2018. So I wrote a little script that rewrote all the dates in the files 2061*.abc throuth 2110*.abc, which were transcribed from March to October 2019. Sorry 'bout that. This has been an on-and-off project, worked on during various periods with sufficient free time. ;-)
-- John Chambers