Soaking the cotton rope in saltpetre (potassium nitrate) would seem to make it into what's called a slow match http://en.wikipedia.org/wiki/Slow_match . I don't think it's necessary and I don't think the Aussie original did, it might produce better results but I've no idea about extinguishing it though. Having a little search there's a post on British Blades which is basically just about a piece of copper tube and cord, the tube protects the charred end of the rope making it easier to catch sparks the next time you use it. http://www.britishblades.com/forums/showthread.php?t=7726 That looks useful, rather than the full kit Ray used (which to be fair to Ray he was just trying out what the old Aussie explorer was using).