This is one of those postcards where we feel obliged to tell you who’s who.  Sir Benjamin Thompson, Count Rumford, was an American-born British physicist and inventor whose challenges to established physical theory were part of the 19th-century revolution in thermodynamics.  (He was born in Woburn in 1753.)  (No, we didn’t know either.)  Unused old, undivided back card.  Grade: 1