Pickett N3-ES Duplex Slide Rule

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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).
Currently not on view
date made
ca 1965
date received
Flanders, Harley
Pickett Industries
place made
United States: California, Santa Barbara
Physical Description
aluminum (overall material)
plastic (cursor material)
leather (case material)
cloth (case material)
overall: 32.5 cm x 8.2 cm x 5 cm; 12 25/32 in x 3 7/32 in x 1 31/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Harley Flanders
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History


"For your information Pickett claimed that their N3ES was painted in 5,600 angstrom yellow-green ... which happens to be at the peak point of human visibility. I still have mine and its original factory leather belt sheath. I would like to sell it to a worthy collector and buy a graphing scientific calculator. When I was in college there were no electronic calculators of any kind. Personal comuters only existed in science fiction novels. The university did however have an IBM 360 mainframe computer. I submitted my FORTRAN program in the form of one punched card per line of code. I put it in the submission window before noon with a rubber band and my name as well as my department (engineering) wrapped around the cards. I picked up the line printer produced text printout graph the next day at noon. I usually had to submit it several times in order to eliminate the bugs in the code. My Uncle was a mechanical engineer in Florida. I visited his office and found that the only calculating machine they had was a multi-column (rows of buttons) electric adding machine that had + - X and divide functions. He said it was "state of the art. " We now have personal computers that fit in one hand ... and are interfaced wirelessly to the Internet ... which was not even conceived back then. COUNT YOUR BLESSINGS!!!"

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