The Old Century line was the cheapest the company offered and there is some evidence that these models were on the drawing board from the very beginning. Very little effort was made to dress up these 7-jewel gilt or nickel movements with stamped parts and flat hairsprings. They were to be a workingman's piece, retailing for $1.90 in the 1904 catalog. None were marked Seth Thomas; all of the company's output in the Century Series were made up of named grades.
Totals for the Old Century models are not known, and they weren't in production for very long. No full serial numbers have been reported other than the three numbers stamped under the dial, but it's doubtful that more than 100,000 were made. Every 7-jewel watch used bushings for the gear train, regulators were simple inboard and nearly all were pendant-set as the company tried unsuccessfully to compete with the growing trend of cheap dollar watches.
The first printed record of the Century model was the 1904 catalog, in which all thirteen of the company's 18-size models were listed, even though some of them had already been discontinued. The year that their lowest-grade watch was introduced is not known, why Seth Thomas dropped the Old Century line, or when.
The New Century design differed from the Old Century line in plate cuts only. It's not clear why the company retired one in favor of the other, since there is little mechanical difference between the two models, but the watches were the lowest grades the factory had to offer. None were marked Seth Thomas; all of the company's output in the Century lines were made up of named grades. Novelty watches with fake glass jewels appeared for the very first time, and it became clear that the end was at hand.
Total production for both of the New Century models is around a little over a third of a million, counting roughly 300,000 of the open-face M12 and about 80,000 of the hunting M13.
The Model 12
All reported examples occupy an uninterrupted block between SN 1,000,001 and 1,301,000 with matching porcelain dials. Nearly all had only 7 jewels, although some runs of the Republic had a higher jewel count of 15 with two-tone plates and its own special embossed dial.
The Model 13
All examples fall between SN 1,700,001 and 1,780,000, and named grades were the only ones being produced, including novelty "railroad" grades such as Trainmen's Special, Sentinel and RR Special. The Republic grade again was notable as the only one with the higher count of 15 jewels.
Again, the first printed record of the Century model being offered for retail was the 1904 catalog, but it's ambiguous and doesn't state whether it's the Old or New line, nor is there a photograph to make it obvious. The last catalog listing is 1909, but given how cheaply they were made it's likely they continued to the end.
All of the Models 10 to 13 movements turned out by the factory were named grades; evidently none were marked Seth Thomas on the plates. There were quite a few named grades overall throughout all the models but only a dozen or so were used exclusively on the Century Series. So far all of the reported examples carry matching dials, and some, like the Wyoming and the Toronado, are fairly rare.
Three of the named grades within the New Century line - the Engine Special, the Sentinel, and the Trainmen's Special - were standard 7-jewel movements with glass cap jewels over the pivots and the barrel that served no purpose. The micro-regulator on the balance cock was functional in adjusting the rate. The Trainmen's Special came with two fake "counts" of either 17 or 23 jewels, but again these were for looks only and did not affect the accuracy in any way. There were similar grades in the 6-size watches, such as the Countess Janet.
The Republic grade was offered in both 6-size and 18-size, and was apparently a special grade within the Model 12/13 run because it had higher jewel counts, came in a variety of finishes, and had its own special patterned (embossed) dial.
There were plenty of named grades to accompany the factory-numbered ones.
Click here for the entire alphabetical list, along with models and jewel counts.