This is beautiful old antique sterling silver lidded mustard pot that is missing its spoon.

The pot weighs about 270.5 grams (including the black (or cobalt) glass inside liner.

The lid is monogrammed with letters, possibly "JAY" ?.

The underside of the lid is hallmarked with a poissant (Lion) and "O" and "RE" ?

The base is hallmarked "RE" over "EB" ?, with a poissant, a letter "O", a person's profile (George III ?), and some other symbol.

The inside glass liner, black or cobalt in color is stuck to the inside and I could not remove it.  The glass is also chipped at one end, but the edges are not sharp and the glass still functions properly.  Otherwise the silver pot is in nice condition with a properly functioning lid hinge.

The base has a beautifully gadrooned top section.  It measures about 4 1/2" long (including the handle, by about 2 5/8" wide, by about 3" tall to the top of the finial.

A really nice old mustard pot with terrific patina !!

Could be from a famous silversmith?