Elgin Grade 55

Here are a few detail images of an Elgin grade 55. It's an early 18 size, 7 jewel, Mat Laflin model, made about 1868. 

This movement has an extra narrow tangential lever. It is highly polish and even beveled along the long sides. They didn't do that very much, this is a special one.

Many grade 55s are found with solid balance wheels. But the balance on this watch is a typical split style, with screws.