Perrygraf Feild's Hydraulic Calculator, based on the Manning Formula

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Country of manufacture: USA,            Date of manufacture: >= 1950
Dimensions: 16 x 17 cm,      Weight: 22.6 gms
Materials: cardboard
Scales: numerous, specialty
Front
Back
Condition: C4-C5 (Minimal to Normal Signs of Use)
Came with: Paper sleeve, labelled "Feild's Hydraulic Calculator for Gravity Flow in Pipes"

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