Portable Perspective Sketcher (Hehr-o-graph),
ENGINEER BOARD FORT BELVOIR VA
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The portable perspective sketcher Hehr-o-graph designed by the Special Devices Division Bureau of Aeronautics, U. S. Navy, has been examined and tested to determine the limitations, adaptability, and possible use of such an instrument as a standard item of issue to Army and Base Topographic Battalions.
- Cartography and Aerial Photography