Cracked. Reads: "I H 1774" Marked three times: "MZ"
Front and back hounds are heavy wooden members of the running gear. Each is configured into a "wishbone" shape whose "prongs" are attached to front or rear axle. Thus, this iron is likely a hound band that encircles and secures the hounds where they are joined to the coupling pole that runs front to back. (These wooden members are part of what we now call the chassis.)
Cast silver wax holder in shape of a small walnut. Identical halves of nut are attached at one end and partially open at the other. Interior is filled with beeswax for drawing thread through, and multiple score marks are evident in wax. Hanging ring at fixed end.