Pickett N3-ES Duplex Slide Rule

This ten-inch aluminum duplex linear slide rule is coated with Pickett's distinctive "eye saver" yellow coloring. The magnifying indicator is made of nylon (the "N" in the model number) with white plastic sides. The front top of the base has two extended square root scales and K and A scales. The front bottom of the base has D, DI, and three extended cube root scales. The front of the slide has B, ST, S, two extended T, CI, and C scales. The left of the slide is marked: PickETT (/) MODEL N 3-ES (/) POWER LOG EXPONENTIAL (/) LOG LOG DUAL BASE. The right of the slide is marked: ALL METAL (/) SLIDE RULES (/) PickETT (/) MADE IN U.S.A. The red printing on the front of the rule has faded considerably.

The back top of the base has LL0, LL1, and DF scales. The back bottom of the base has D, LL2, and LL3 scales. The back of the slide has CF, CIF, Ln, L, CI, and C scales. The left of the slide is marked: COPYRIGHT 1960© (/) PATENT APPLIED FOR. The right of the slide bears the third Pickett logo on the instrument. The burgundy leather case is partially lined with blue velvet to protect the magnifier and has another logo (in gold) below the slot for the case's flap. The back of the case has a ring on the back for a belt strap, but the strap is missing.

This example of Model N3 was owned and used by the mathematician and theoretical computer scientist, Harley Flanders. It is identical to 1980.0097.01 except for its color and magnifying indicator. Pickett switched from glass to nylon indicators in 1958 and used this logo from 1964 to 1975. Pickett also moved from Alhambra, Calif., to Santa Barbara, Calif., in 1964. The mention on the instrument of a patent application may refer to a patent for a case issued to John W. Pickett in 1960. Pickett was the son of company founder Ross C. Pickett and served as president from 1957 to 1967. For early company history, see 1979.0601.02.

References: Peter M. Hopp, "Slide Rule Scales," Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 285–287; International Slide Rule Museum, "Pickett All-Metal Slide Rules," http://sliderulemuseum.com/SR_Dates.htm#Pickett; John W. Pickett, "Slide Rule Case" (U.S. Patent D187,632 issued April 5, 1960).

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