The case style is called a half-hunter, or Demi-hunter. The front cover has blue vitreous enamel Roman numerals over a guilloche background. The case appears to be made of 18-karat gold based on the stamping inside the rear cover. The movement (mechanism) is of Swiss origin, key-wound, key set. I don’t think the case is Swiss. A Swiss case would likely be marked .750 (decimal equivalent of 18 karat). Otherwise, the case would be marked with an image of Helvétia, the Swiss standard mark for 18-karat gold. The movement has a cylinder escapement and has (possibly) up to perhaps 10 or 11 ruby jewels. The watch likely dates from the fourth quarter of the 19th century. The greatest value would be to your family. The more desire there would be in the market place, the higher the market value would be. This watch would be of little value as a collectible, so the value would most likely be the melt value of the case. It would be next to impossible to determine the maker of the case or the movement. The decoration on the case back contains a monogram, it would appear, and the decoration was all done by a hand engraver. The front cover can be opened by pressing the button in the middle of the pendant on the edge of the case. The dial is of white vitreous enamel, likely with black vitreous enamel Roman numerals.
Interesting that the balance cock with the regulator is marked FAST and SLOW. Being Swiss, I would expect the makings would be ADVANCE and RETARD. During the era when this watch was made, the Swiss were not a major exporter of watches. But this one was likely made for an English speaking market. But not likely for England because the markings in the case back are not consistent with the markings as would be found in a Swiss watch sold in the English market.
Consider printing this information and keeping it with the watch. Now that you know about the watch and its family history,,it should be worth more to you.
