PAT’D DEC-28-1880 “Patent” back marks are especially valuable as they pin down the manufacture date for a particular kind of button, such as this late 19th century black glass.
Relatively few antique glass buttons have back marks. By using this dating clue, you can make assumptions as to age for other black glass buttons similar in shank and artistic face design.
Click to see the full patent description.
Explore more button related patents at the National Button Society (Button Country) website.
