Triangular 24-Inch Engineering Scale (30579641960)
Summary
Cartographers used this tool to take linear measurements from maps and scale diagrams. If two of its six available scales matched those of a map original and desired copy, the tool could be used to accurately make a scaled copy.
Tags
cia
central intelligence agency
map drawing instruments
intelligence
maps
ultra high resolution
high resolution
technical drawing
Date
09/11/2016
Source
Triangular 24-Inch Engineering Scale
Link
Copyright info
Public Domain