Plate Warmer Made With Old Sheffield Plate Early 1800's

Old Sheffield Plate is a highly sought after and valuable antique due to its age and special creation.  Old Sheffield plate was actually made by accident by Thomas Boulsover in 1745 when he bonded silver with copper.  Eventually a new method was invented whereby copper was sandwiched between silver and rolled into a thin sheet which was meticulously worked into a piece of tableware.  The edges are often plain, there is no trim.  Sometimes they are bent over.  Sometimes the bottom of an item was covered with tin, explaining why it would be black, other times more silver. 

This plate warmer was made in England in the Old Sheffield Plate technique in the early 1800's making it very special and unique.  The top piece lifts off and hot water is poured inside.  Then the top piece becomes hot and whatever is on top is also heated, either plates or a single dish of food.  Wonderful!  Piece is in very good condition for something this old.  8.5" wide not including handles