How do I identify the date of my silver jug?

You look for the stamped assay office hallmarks on the underside or exterior wall of the vessel. Each letter stamp corresponds to a specific year and city where the piece was tested and verified.

Are these jugs safe to use for hot gravy?

Solid sterling silver conducts heat rapidly, making these vessels effective at maintaining the temperature of warm liquids. Pouring hot gravy or melted butter into the boat presents no structural harm to the metal.

Why do some sauce boats come in pairs?

Large formal dining tables in the eighteenth and nineteenth centuries required balanced placement of condiments at opposite ends. Silversmiths created matching pairs to satisfy the symmetry demanded by grand hosting customs.