Identification of Aircraft by Rockwell Test
This is a 1930 technical note from the Aeronautical Research Council series, issued by NASA's Technical Reports Server, documenting test equipment for aircraft identification by Rockwell hardness testing. The three pages show photographs of machines, fixtures and gauges for engineers and metallurgists. A designer could draw on these pages for their plain, documentary look: grey halftone photographs of workshop machinery set in stacked frames with small printed figure captions.
