I would guess some original carved circular "button" applied decorations have be removed. Differences in the finish are evident within and without the circles.
My guess is that the scribed line inside the purfling is simply decorative and was original, having been scribed using the purfling channel as a guide before the purfling strips were added.
I seems that the dark center wood of the purfling may be made up of two pieces. If so, would that aid in determining the origin of the instrument? Or is that method too common/widespread?
If memory serves, I seem to recall that Peter Christian Paulsen, Danish maker who immigrated to Chicago about 1882, was contracted to make violins for the Mills Novelty Company for use in their Violano mechanical playing machines.
Rue, they're both two-toned. I bet they came from the same place? Looks like someone stripped the tops, but didn't want to deal with doing the intricate bases. Sorry, can't help with the id.
Violadamlore- This is a very difficult to understand explanation of what/where the "delta" is; I doubt that it resolved Derek Law's question. Can you give it another "go"?
My admittedly untrained eye tells me someone put a horrendous replacement neck/head on an otherwise decent box, and finished the whole with a terrible black "antiqueing" treatment.
Possibly recent high sales are a result of the current inflationary trend- folks are investing more in physical items which tend to hold value, rather than leave money in the stock market or banks where it is steadily losing value.
I believe this is actually 4-ply purfling, with all plys made equal width. Two white center plys were used to achieve a wider white "center" purfling. The technique was used because it was easier/faster to make all purfling strips the same width.
Perhaps of more interest might be the purfling. Use of the double white center strips could point to certain regional origins, and even possibly particular makers if not "schools". Do you know the origin or maker of this cello?