Watch and clock escapements;
A technical manual on watch and clock escapements issued by The Keystone, Philadelphia, 1904, for working horologists and apprentices learning to draw and adjust escape wheels, pallets and balances. Line engravings show lever and cylinder escapements in plan and section, with dotted construction arcs, lettered reference points and hatched metal, usable as diagram ornament, compass-geometry motifs and toothed-wheel silhouettes.
