Two book covers

Two oblong silver tablets, each with a curved short side; the curved sides each with three drilled holes; the outsides of the tablets decorated with leaf- and strapwork: curved acanthus tendrils, twining around sticks towards the short sides; on the edges of the short sides, a shell is used as the main decorative motif; in the middle of each tablet, a "calendarium perpetuum" is fastened, taking the shape of rotating discs with the names, days and symbols of the months, the courses of the sun, moon and stars etc.; on one tablet, there are two discs on top of each other; the other one has the goldsmith's signature "Ioh : Mettel . fecit et sculps : A. Gotha : 1732" on its back; on top of this signature, "F.VERMEULEN" was later added in irregular letters (probably the owner's name).