Here is a super cool little cuff or hat engineer button. Very, very early, and rare, possibly 1810-1820. Worn by the Corps Of engineers. The front showing very fine details, depicts the flying spread wing eagle holding in its beak a scroll with the word "Essayons", a bastion with embrasures in the distance, surrounded by water. Has the rising sun in lower left. Single line border. The back is the neat part, has the full integral shank, slightly bent with the raised backmark, and outer ring and double inner rings. Showing split line mold lines with offset connections in the middle. This cuff size button differs in the die pattern slightly from the coat size and may have been used only for them

This button most likely started out as a blank planchat, imported to this country and then the front stamped. The back then was stamped using a split mold that folded around the shank, and then stamped, which resulted in this misalignment.
Backmark: ""SCOVILLS.WATERBURY."rm (15.2mm)
Ref: Albert - UNLISTED