Old Berlin Castle Punch

This is from the Rhine district.

Dissolve two pounds of sugar in a quart of water. Place in granite saucepan and bring to a boil, then reduce the heat and add 2 bottles Rhine wine, keeping below the boiling point. Soak a lump of sugar in brandy and ignite it, holding it in a spoon over the pan. Then slowly pour a pint of good rum over the burning sugar and into the pan. Serve piping hot.