Elgin Grade 70, Transitional

This is a "transitional" pocketwatch movement.  It is key-wind, from the back, like older models, but it also works in cases that have winding arbor.  Note the square arbor in the neck of the case, and the square hole in the movement.

For the most part, American watch companies never made watch cases.

In those days, the customer would select a movement and a case separately at the point of retail.  Even though the winding/setting moving parts were often part of the case, like on this one, the two businesses achieved a remarkable level of standardization of movements and case configurations, so that they mixed and matched quite well.

This example is an 18 size watch, lever-set, 15 jewels, made about 1874.

It's been having an issue with "over-banking".  It takes a lot of tweaking and testing to get past that.