There is an active discussion in the European Pocket Watches Forum. It was made during one of the periods when Ingold was working in Paris. It is in a Henry Wing Jr. style display case and is from the collection of Oscar T. Lang, who was the famous collector that Chapter 21 is named for. It has some features in common with the watches made by the British Clock and Watch Co., which was probably the first to attempt an interchangeable design machine made watch. The forum discussion about this watch is What do Ingold watches look like?