Rule, Slide

Object ID
M972.54.1 a-b
Vessel Equipment - General, Navigation
cardboard; fabric
a) Rectangular laminated cardboard power and speed calculating rule, 34.1 cm by 9.2 cm by 0.5 cm. Sliding rules in central portion on both front and back. White, with black lettering and numbering indicating measurements, increments, and instructions for use and calculations.
b) Black fabric-covered cardboard case, 34.2 cm by 9.4 cm by 0.7 cm. Open at one end with semicircular cuts to allow fingers to grasp the rule.