I agree with syl in that I do not think this is Waltham. If it was Waltham it would date to 1876-77 by the serial number and would be marked on the face and on the movement. If you look at the movement of an 1877 Waltham watch, the finish work is like night and day in comparison. Watchmakers took great pride in their finish work and you will see a lot of engine turning and engraving (including their name) on their movements. The movement and finish on this unmarked watch looks pretty plain although there is some engine turning visible on one plate. The crown over the 18 on the inside cover is most likely the mark of the case maker and not the watch movement maker. I would guess this is foreign in manufacture (English, Swiss, or French). If you are in a large city, I would ask an old, established jeweler (not Kay or Goodman, etc.) about old watchmakers or collectors in your area that could look at it in person. There might be some marks or hallmarks you are overlooking. It looks like it needs a good cleaning to run.