DescriptionPolyphase (Mannheim) Slide Rule 4053-3, 10 inch, made by Keuffel & Esser Co., New York and Hoboken, no date, circa 1914-1915. Mahogany laminated with engine divided white celluloid scales; printed table of equivalents laminated to back; all glass cursor (indicator) with metal cursor blocks. With: original leather covered slipcase imprinted in gold; printed instruction sheet (catalogued separately as archives 2009.006.0229.01; best image with that record, but areference image is with this record.) Front of stator near center engraved in red: Keuffel & Esser Co. NY | Pat. June 5, 1900 Front scales marked at right: A, B, CI, C, D (model no. <4053-3> in red at left edge) Front scales with slide inverted and marked at right: A, S, [L], T, D Scale, bottom edge: [K] Top edge is beveled and has laminated English measure rule. No serial number called for, but production lot number is stamped on end of stator and slide: 188. Cursor has recess on bottom block for indication using K scale. Back of top cursor block stamped: Pat.Appl'For. Printed instructional insert; printed one side on cardstock 1-5/16" x 10-5/8" wide: "How to Adjust the K & E Patent Slide Rule." Illustration and text on using the screws on the back to achieve the proper tension so the slide will stay in place. Dating of this item was done from information on the Clark McCoy website (2009) and comparison to images of slide rules available there. K&E had their main office and factories in Hoboken during the period when this item was made.