This mahogany wood 10” slide rule with scales on the front (K, A, B, T, ST, S, D, and DI) and back (DF, CF, CIF, CI, C, D, and L) was more expensive than the plastic, one-sided models. Keuffel & Esser produced this model from 1939 to 1955. This slide rule belonged to Dr. Harry Blum, a mathematician who worked at the NIH Laboratory of Statistical and Mathematical Methodology in the Division of Computer Research and Technology from 1967 to 1982. During his career, Blum collaborated on a variety of projects involving the use of biologic measurements to create formulas for shape modeling; one such project focused on invariant shapes found in adult mandibles and their use in analyzing genetic and environmental differences in growing lab mice. [10.0010.001]
The 4081 family of slide rules were the most lucrative products for Keuffel & Esser from the 1940s to 1960s. The 4081-3, shown here, has extended trigonometric scales with decimal divisions, and it was manufactured some time after 1953. It is made of wood and glass, rather than plastic, which would soon become ubiquitous. This slide rule was used by Dr. Michael Potter (1924–2013), who won the Lasker Award for medical research for his work on understanding tumors and the immune system. He worked for over 50 years at the NIH National Cancer Institute, studying how tumors in plasma cells, called plasmacytomas, are produced, and developed strains of mice still used in research around the world. [13.0017.001]
The “ES” in this slide rule’s model number means “eye saver yellow” and the “N” means “new,” with an improved cursor design and square corners. In addition to exponential, trigonometric, and square root scales, it also had double logarithmic and natural log scales. Pickett Inc. dropped the Eckel name in 1949–50, but the logo dates from 1958–1962, so the date of this slide rule is uncertain. Marketing research enabled Pickett Inc. to target slide rules to particular demographics based on the number of scales and price. Because this rule was one of the most expensive that the company sold, it was clearly intended for use by skilled professionals. Indeed, this slide rule was used by Dr. Joseph E. Rall (1920–2008), who served as scientific director of NIAMD and NIDDK before becoming the first deputy director of NIH Intramural Research. For more about Rall, read the NIH Catalyst article. [11.0003.024]
