Description"Ever-There" 4098 slide rule, 5 inch, advertising special, made by Keuffel & Esser Company, N.Y. (Hoboken, N.J.), no date, circa 1931-1936. White Xylonite (white celluloid), 5" (6" overall length); engine divided in black and red; engraved on back "Pacific Pump Works"; transparent "frameless" xylonite indicator. Serial number 18360. With: smooth leather sheath gilt stamped "Pacific Pump Works." Hand-engraved on stator beneath slide: Dr. R.E. Humphreys. Front scales: A B CI C D K Scales on reverse of slide: S L T (note slide does not invert; see detail end view) Back has a 13 centimeter ruler and 5 inch ruler. The 4098, a pocket polyphase slide rule (a small version of the 4053), was apparently introduced in 1931; replaced as the 4098A in 1936. Imaged is page 48 from a 1934 price list for the 37th edition catalog of 1927 noting it as product added since the edition was first issued. K&E main offices and factory were in Hoboken when this item was made.