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Wang Laboratories, Inc. Calculator, Model 450-1, c. 1972

Each of the four models of the Wang series 400 calculators incorporated functions particularly suited for a specific discipline. The Model 450-1 Calculator was designated as “Basic Scientific.” The 450-1 could be programmed by use of the numeric keypad and a set of special function keys whose location brings to mind the function keys found on today’s PCs. Programs could alternatively be loaded by use of an optional device that read punched or mark-sense cards. The specialized functions that especially suited the Wang 450-1 for general scientific applications, what Wang called “personality,” was provided by a plug-in discipline-specific circuit board containing read only memory (ROM) programs. Results from calculations were provided on a Panaflex display atop the keyboard comprised of a series of twelve neon bulbs with filaments, portions of which could form numerals from 1 to 9 as well as 0. The Model 450-1 Wang Calculator was actually quite expensive: when first introduced in 1972 it cost $1,300, or almost $7,400 in 2012 dollars.

This calculator was used by Dr. Earl Stadtman (1919–2008), recipient of the 1979 National Medal of Science for his work on anaerobic bacteria and enzymology, during his years of work as the chief of the Laboratory of Biochemistry at NHLBI. 

Hewlett Packard HP-35 calculator, c. 1973

The HP-35 was the first pocket-sized scientific calculator, allowing scientists to abandon their slide rules for good. Named for its 35 keys, the HP-35 was the first scientific pocket calculator when it was introduced in 1972. The development of metal-oxide-semiconductor integrated circuits in the early 1970s made it possible to shrink the technology necessary for complicated calculations—at a price. Due to the high cost of the new circuits, the HP-35 debuted at a steep $395, but that didn’t prevent 100,000 units from being sold during its first year in production. In addition to its cutting edge circuits, the HP-35 also used new Light Emitting Diodes (LEDs) in its screen. 

Prior to the release of the HP-35, pocket calculators could perform only the four basic arithmetic functions, and slide rules were used for exponential and trigonometric functions. The HP-35 was able to reduce calculation times by almost 80%, effectively making the slide rule obsolete. In recognition of its revolutionary effect on the work of scientists and engineers everywhere, the HP-35 was awarded the IEEE Milestone in Electrical Engineering and Computing award in 2009. This particular calculator was used by Dr. Michael Channing, then a radiochemist, then later the group chief of the Radiopharmaceutical Production and Quality Control group in the Positron Emission Tomography department in the NIH Clinical Center. [06.0007.001]

Texas Instruments SR-51A Calculator, c. 1975

The Hewlett Packard HP 35, launched in 1972, is generally recognized as the first portable scientific calculator. But Texas Instruments, home of the invention of integrated circuits, launched its reply to the HP 35, the SR 50, in early 1975. As it was expensive to produce, it was soon replaced by the SR 51, which incorporated some cost-saving modifications. The liquid crystal display in the SR 50, for example, was replaced by a smaller CD bar behind a magnifier bubble. The SR 51A was promoted as a scientific-financial calculator in recognition of the higher mathematical capability. The SR 51A was capable of performing both trigonometric and statistical operations. The keyboard contained 20 keys for performing arithmetic, and an additional 15 keys are devoted to higher mathematical functions. The calculator was also equipped with a random number generator. The SR51A, like its counterpart the HP 35, has been credited with ending the long dominance of the slide rule for technical calculations. This model of calculator was introduced in June 1975 for $224.95. The “A” in the model number means that it was identical to the SR-51 model except it had no inner rigid keyboard frame, LED display, or bubble-lens magnifier, making it a cheaper high-end calculator. This calculator was used by Dr. Marshall Nirenberg, who won the Nobel Prize for breaking the genetic code. [10.0001.004]

Hewlett Packard (HP) 41C Programmable Calculator, c. 1979

By adding an alpha key to enable the keyboard to go between the alpha and normal keyboard modes, this calculator made inputting programs and functions easier. Functions could also be typed in with the “User” key and assigned to a specific key. The 41C also increased the amount of memory available in its predecessor, which could also be expanded with memory modules. The card reader had a translator for programs written for the HP 67. Hewlett Packard made the 41C from 1979 to 1985. This calculator pictured here belonged to Dr. Kenneth J. Rothman, founding editor of the journal Epidemiology. Rothman was working at the NIH National Cancer Institute in 1979 when he co-authored ”Epidemiologic Analysis with a Programmable Calculator” with Dr. John D. Boice, Jr. Later editions of the book [13.0013.002] referred specifically to this calculator model.

Casio SL-300V Pocket Calculator, c 1980s

The Casio SL-300V was a typical example of the sizeable number of compact calculators that came on the market in the 1980s from different manufacturers.  The 24-button keyboard on this calculator from Casio included numerals in addition to keys for functions. The keyboard also included a separate key for turning the calculator ON and another for turning it OFF. If left unattended while ON, the machine saved power by automatically shutting down in less than 10 minutes. The calculator had a limited memory, though: all entries and results were lost when the unit was shut down.  The Casio SL-300V was a light-powered machine with a prominent photocell located in the top-right corner of face. A hearing aid-type 1.5 volt battery served as backup power for use when there is not enough light to provide operating power. Entries and results were shown on a large 8-digit liquid crystal display. First introduced in the early 1980s, the Casio SL300 and its later variants are still listed for sale in 2014. This calculator pictured her belonged to Ruth Kirschstein, who did important research on the polio vaccine and was the first female director of an NIH institute (NIGMS), NIH deputy director, and NIH acting director. 

TI-66 Programmable Calculator, c. 1983

With its 170 engineering and statistical functions, the TI-66 calculator was an indispensable piece of equipment for researchers such as Dr. Howard Nash, NIMH. State-of-the-art technology when it was introduced in 1983, the TI-66’s landscape orientation of the customary 14 arithmetic keys as well as an additional 28 keys for mathematical operations and programming distinguished this machine from its competitors.  The TI-66 could be programmed to perform up to 512 steps. Programs could be written on the keyboard or loaded from a magnetic card; user-written programs could also be copied onto those magnetic cards for later use. TI also provided an optional thermal printer that could be controlled by the calculator keyboard.
Although it was a Texas Instruments (TI) product, it was built by Toshiba from Toshiba components — a collaboration to challenge Hewlett Packard’s successful HP-41 calculator. Hewlett Packard and TI each had introduced a programmable calculator in 1972, the HP-65 and TI-52, respectively. Each of these calculators incorporated a small motor for passing the card by a reading device; however, the dimensions of the HP and TI programming cards were quite different. In 1977, TI introduced the TI-59, a calculator with increased ROM (read-only memory), which could be further enhanced by a plug-in ROM module. The TI-66 further improved the design, offering more programmable steps and more memory in a smaller package. Howard Nash used this calculator pictured here in his research on the molecular neurobiological basis of general anesthetic action.

Radio Shack Ten Digit Scientific Calculator, EC-4030, c. 1988

The Radio Shack EC-4030 electronic calculator, introduced in 1988, was somewhat of a latecomer to this field. This portable calculator, as noted by the term “Scientific” on the nameplate, was designed for handling more complex mathematics in addition to simple arithmetic. The capacity of this device resembled that of the HP 35 from Hewlett Packard and the Texas Instruments SR 50, both of which became available in the early 1970s. Advances in the design and manufacture of chips since the 1970s arguably resulted in decreasing the cost of components used for the EC-4030. Like its predecessors, the EC-4030 featured a keyboard with 42 keys. Twelve of those keys are numerals and the arithmetic operations. The remaining keys are dedicated mathematical functions such as the trigonometric functions and logarithms. Results of calculations are shown on a ten-digit liquid crystal display above the keyboard. This calculator pictured here was used by Dr. Ichiji Tasaki, NIMH, who introduced the giant squid axon as a system for studying nerve conduction and pioneered the use of dyes that fluoresce upon exposure to electrical stimulation. His research career spanned nearly 70 years. 

“Dual Power” Pocket Calculator, c 1990s

The “Dual Power” label on the face of this calculator from an unknown manufacturer in Taiwan, as well as the presence of a solar cell, indicates that this machine incorporated a battery that takes over when there is insufficient light. While the 24-button keyboard was typical for this class of calculators, the use of round key labels for numerals and arithmetic operations was unusual and set these apart from other functions represented by rectangular buttons. Like other small calculators, data entry and results of calculations are shown on a liquid crystal display. This calculator belonged to Dr. Ruth Kirschstein and was likely acquired as part of a promotional giveaway, due to its lack of branding. 

Sharp Elsimate EL-326M Pocket Calculator, c. 1995

Introduced in 1995, this Sharp pocket calculator has seven functions, 24 keys, and an LCD display for people with low vision. It is powered by a solar cell. This variant of the popular EL-326 product line came with an attached cardboard and plastic case. A very similar model, the EL-326S, is still available. This calculator pictured here was used by Dr. Ira Levin, former scientific director of NIDDK. 

Book: "Epidemiologic Analysis with a Programmable Calculator," 1979

Starting in the mid-1970s, the development of programmable pocket calculators meant that an epidemiologist could work anywhere and at any time, which is especially important in fieldwork. But would the epidemiologist know how to use the calculator?   Even after the basic operations of the calculator were mastered, would the person remember all the calculations required for different analytical equations?  

Drs. Kenneth J. Rothman and John D. Boice, Jr. sought to help the technologically and mathematically challenged epidemiologist, introducing their 1979 book Epidemiologic Analysis with a Programmable Calculator by stating:

"Our purpose in writing this book is to present a collection of pocket calculator programs developed to handle the range of analyses that most epidemiologists face routinely....Before the advent of moderately priced programmable pocket calculators, complicated numerical calculations could be accomplished only by relying upon a sizable computer or upon a willingness to plow through tedious computations, recording intermediate results along the way. The disadvantages of the large computer are inaccessibility and expense. The pencil and paper approach is often frustrating and unreliable....In the past, the most appropriate analytic procedures for epidemiologic data have often not been applied either because they were too complicated for routine use or not widely known among epidemiologists."

 Some of the equations in the book, which includes those for case control studies and cohort (follow-up) studies, are used today and some are not published anywhere else.  While geared specifically for the Hewlett Packard HP67 calculator, later editions of the book encompassed the HP41, 41C, and 41CV. You can see an HP 41C in our collection elsewhere on this page. 

Rothman and Boice worked at the Environmental Epidemiology Branch of the National Cancer Institute.

Donated by the National Cancer Institute Library