Chinese export Canton Ware warming plate, early 19th century.
Slightly octagonal, it measures 9.75 inches across to reservoirs x 2.25 inches tall.
Presents with Catalog number incised on verso (please see photo)….seems to be permanent and suggests piece was de-accessioned from a museum or private collection.
“Canton" ware was mass-produced at Canton after the American Revolution, as an export ware to America. It is sometimes referred to as "Ballast ware" for the low cost and huge amounts shipped (sometimes as ballast) of this porcelain.