Pair of Keuffel & Esser Surveying Tools

Pair of mid-20th century surveying tools by Keuffel & Esser Co. (drafting instrument and supplies company founded in 1867 by two German immigrants); one WW2 era Cooke Radio Slide Rule, model #4139, designed in mid-1930’s by Nelson M. Cooke of the Navy’s Radio Materiel School (first electronics training facility of America’s military organizations), measures 21.5” x 1.75” x 2”, mounted on iron stands, does not include carrying case; one Keuffel & Esser vintage Abney Level designed for measuring slope, circa 1950s, includes dark blue leather carrying case inscribed K&E, level measures 6.25” x 2.5” inside a leather carrying case measuring 7.5” x 3.5”.
Condition Report: Both in generally good aesthetic condition, slide rule plastic center and slides are fully functional with some various light stains and surface scratches consistent with age; abney level functionality unknown