Peculiar rolling parallel ruler. Approximately half of a hollow wooden tube, with a brass plate screwed onto, and covering, each end. The wooden roll bar fits in the tube, protruding slightly above the horizontal, and is attached to the inside of the brass plates by a rivet at each end. All wood is varnished in a dark color.
Inscription/Sig.
"E WOLFF & SON-LONDON" on roll bar. "HEYER'S PATENT" on end plate.
