BRL P.G. 54, Photogrammetry Slide Rule

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Country of manufacture: England,            Date of manufacture: ____
Overall length: 33.1 cm,          Width: 4.5 cm,           Weight: 97.4 gms
Materials: Plastic stators and slide, adjustable metal end braces
Cursor: 3.6 X 5.6 X 0.9 cms; metal runners holding plastic lens, adjustable; lines = single line front and back
Scales: 12, including some specialized on back
Front: S&T, A [ B, S, T, C ] D
Back: Ground size (feet) [ Image Size (mm), Image Size (feet), Focal Length (inches) ] Altitude (feet)
Gauge Marks: [ C (1128), ρ'' (2063), π, ρ' (3438), C₁ (3568) ]
Condition: C4-C5 (Minimal to Normal signs of use)
Came with: Original black hinged wooden case, instruction aheet entitled, "The Photogrammetric Slide Rule"

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