This 1904 Seth Thomas open-face 18-size Model 8 pocket watch was manufactured with a nickel finished 3/4 plate, 7 jewels, and it is non-adjusted. The movement is stem-wound and lever set, with a Breguet hair spring, slotted hairspring stud, and plain/simple regulator. Its serial number is 700001, and its grade is Seth Thomas numbered grade 36. The movement is signed Seth Thomas Thomaston, Conn. There is no serial number stamped on the top plate. This was the first (see explanation below) Seth Thomas New Eagle Model 8 pocket watch produced. Model 8 serial numbers started at 700001 and concluded at 2593000.

The movement presents with an 18-size Seth Thomas #1216 Roman dial with a ring minute track and black five-minute marginals, fitted with Seth Thomas #1281 blued spade hands 18-size.

The movement is cased in an 18-size open-face Wessell Metal (silver plated) pocket watch case with hinged back and bezel, serial number 209729. This appears to be the original case for the movement.

     A single numeral “1” has been documented in three canonical control locations:

Internal factory numbers:

• Back of the top plate between the plates, visible between the 35 and 40-minute position.

• Underside of the balance bridge (the usual “last-five” spot).

• Underside rim of the balance wheel (scribed).

• On Old Eagle Model 6 and Model 7, the last-five digits were stamped beside the banking pins; where this Model 8 shows a numeral “1” in that same legacy location.

• Later Model 8s moved the last-five digits stamp under the 3rd-wheel pivot

  Most economical identification:

• The Model 8 serial block begins at 700001.

• With internal control “00001” (placeholders omitted “1”) and no conflicting marks, the simplest, evidence-conserving reading is that this movement is the first in the Model 8 block: 700001.

  Winding-Bridge Construction as a Dating Tool

  The winding-bridge on this movement is the clamp type, identical in structure to the ones used in Model 6, comparison example serial 597683 in this collection.
  Seth Thomas shifted to a solid block winding bridge beginning somewhere between serial numbers 715597 and 731396.

  Movement Markings Are Consistent with Model 8 Style 1

• There were three styles of standard movement markings used on Seth Thomas Model 8 pocket watches.

  The standard movement markings on the open-face Model 8 movements started out exactly where open-face Model 6 left off, with the signature “Seth Thomas Thomaston, Conn.” inscribed around the lower 180 degrees of the perimeter. The signature presents in some variation of an Old English Text font. The movement serial number is located to the left of center below the cutout for the balance wheel and “SAFETY PINION” is inscribed to the right of center below the cutout in a Serif Caps font. Serial number 783931 is the highest serial number utilizing this marking format for which photographic documentation is available on the Pocket Watch Database. Aside from this movement not having a serial number located to the left of center below the cutout for the balance wheel, or anywhere else, the movement markings on this movement are consistent with Model 8 Style 1.

  Top Plate Reverse Surface – Observed Engraving Residuals

• This image documents the reverse surface of the top plate removed from the unidentified early Seth Thomas Model 8 movement. The photograph was taken under raking illumination to reveal subsurface relief features.

• The most notable anomaly is a faint, reversed impression of text corresponding to the front-side engravings (“Seth Thomas, Thomaston, Conn.” and the floral damaskeening pattern). These reverse impressions are characteristic of deeply cut, die-engraved plates and confirm that the top surface was engraved and damaskeened prior to final finishing.

• More significantly, below the mainspring recess and slightly to the right of the plate’s center, there is a ghost marking consistent with a partially effaced “JEWELS” inscription. This marking does not appear on the front face of the plate and is not part of any known Model 8 production engraving pattern. According to ChatGPT its presence strongly suggests that the plate was initially machined or engraved using pre-standardized master dies that included jewel-count text, later polished away during rework or prototype refinement.

• According to ChatGPT this evidence supports the hypothesis that the movement represents a toolroom or first-series prototype, bridging the late Model 6 production and the introduction of the Model 8 series. The combination of (1) missing serial number on the top plate, (2) early-style clamp-type winding bridge, and (3) residual engraving traces together point to an origin near the beginning of the Model 8 production block—possibly serial 700001, or the pre-serial pilot piece used for setup and inspection.