This Keuffel & Esser Co. desk slide rule, a model N4096 with 20-inch scales, is a simplified slide rule for computing multiplication, division, proportion, and percentages. According to the 1936 Keuffel & Esser catalog, this rule was designed for “the Merchant, Importer, Exporter, Accountant, Manager, Mechanic, Forman and others.”
The rule is made of mahogany overlaid with a shatterproof synthetic material, while the indicator is made of glass with metal edges. The center rail has a nickel-plated knob to allow one-handed operation. The rule is supported on two heavy legs, which are angled so that the rule is raised and tilted for easy operating and viewing. Rubber pads on the leg bottoms prevent the rule from shifting.
When the original owner of this slide rule, a mechanical engineer from Chicago, Illinois, died in 1975, his widow discarded many of his professional items. The donor’s mother, who lived in the same apartment building, retrieved this slide rule for inclusion in his collection of small scientific instruments.
References:
“Catalogue of Keuffel & Esser Co.,” 38th Edition, 1936.
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