Hi C
These formulae were published regularly by the British Journal of Photography, in their Photographic Almanac's. They are the various developers etc required for processing Dufaycolor.
The Dufay process goes back to 1908 and was still in use whe I first held a camera
On first appearance the formulae might appear to be of no modern use, Dufaycolor was an additive system, but because it used a B&W emulsion the formulae could easily be adapted for reversal processing of modern B&W film.
I'm fairly sure there's a chapter about Dufay colour in D.A. Spencer's "Colour Photography, possibly with colour example.
At some stage I'll post them on APUG.
Ian