From the Westford Academy exhibit
The 12" polyphase slide rule made was by Keuffel & Esser Co., and was sometimes called a "slip stick." It has a patent date of June 5, 1900. According to the International Slide Rule Museum, this was an analogue calculating device ("computer"), which was invented over 300 years ago. It utilized logarithmic scales to aid in calculations, but could not be used for linear measurements. The slide rule's use declined in the 20th century with the advent of modern calculators and computers. Starting in 2017, the Westford Public schools began to issue ultra-potable Chromebooks to high school students.
The slide rule was donated by Deborah Stein-Sharpe in 2008 as part of the Atwood-Millett collection.