Our Lovely World

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Tom Thumb adds !

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Tom Thumb is a character of English folklore. The History of Tom Thumb was published in 1621, and was the first fairy tale printed in English. Tom is no bigger than his father’s thumb, and his adventures include being swallowed by a cow, tangling with giants, and becoming a favourite of King Arthur.   Apparently Tom Thumb was good at calculating too.

When I was at High School, I was awarded the Honour Certificate for being the best History student in Year 12.  I love to think about the origin or source of things, and about history.

I bought a beautiful working Tom Thumb adding machine / slide adder in mint condition, together with stylus, case and instructions from the Vintage and Mod Shop on Etsy !!

Did you know that Blaise Pascal, noted mathematician, thinker, and scientist, built the first mechanical adding machine in 1642 based on a design described by Hero of Alexandria (2AD) to add up the distance a carriage travelled?

Charles Babbage produced the difference engine by 1822 to perform routine mathematical operations automatically. In 1833, Babbage ceased working on the difference engine because he had a better idea. His new idea was to build an “analytical engine.” The analytical engine was a real parallel decimal computer which would operate on words of 50 decimals and was able to store 1000 such numbers. The machine would include a number of built-in operations such as conditional control, which allowed the instructions for the machine to be executed in a specific order rather than in numerical order. The instructions for the machine were to be stored on punched cards, similar to those used on a Jacquard loom.

Source  http://lecture.eingang.org/conditional.html

A step toward automated computation was the introduction of punched cards, which were first successfully used in connection with computing in 1890 by Herman Hollerith working for the U.S. Census Bureau. He developed a device which could automatically read census information which had been punched onto card. Surprisingly, he did not get the idea from the work of Babbage, but rather from watching a train conductor punch tickets. As a result of his invention, reading errors were consequently greatly reduced, work flow was increased, and, more important, stacks of punched cards could be used as an accessible memory store of almost unlimited capacity; furthermore, different problems could be stored on different batches of cards and worked on as needed.

Hollerith’s tabulator became so successful that he started his own firm to market the device; this company eventually became International Business Machines (IBM).

Read more about binary calculation and the Turing machine, and other fascinating information at –


Eighty years before Jack Kilby invented the first electronic pocket calculator, J.L. Troncet of France invented in 1888 an adding device / adding machine, or slide adder called the Arithmographe. This device was based in a set of sliding digits embedded in a cardboard frame and built into a notebook. Troncet’s invention became so popular that the term troncet was usually applied to refer to this type of device.

The basic principle used in Troncet’s adding device was not new, it was already used by the Additionneur of Claude Perrault (1613-1688) in 1685, by C. Caze in 1720, and improved by Kummer in 1847. According to Robert Otnes [3], in the United States, S.S. Young patented a slide adder in 1849, G.B. Fowler patented one in 1863, which was improved in 1890 and sold under the name The Universal Adding Machine. Then, C.E. Locke patented one in 1901.

These devices were inspired by the Abacus. Beads and strings were replaced by slide bars with notches or holes moving inside a flat case. Notches were accessible through a slot. The slot had digits marked on its side. Digits were also marked on one part of the slide and hidden by the body of the case, except for one which was displayed through a small window in the display. One slide was used for each relative position in a number.

Early implementations had the slides arranged horizontally. Troncet arranged them vertically to facilitate its use as a hand-held device. Addition was performed by pushing down the slide, with the help of a stylus, a number of notches equal to the digit to be added. At the top, the slot bent to the left and then one unit down, allowing the stylus to be moved to the left and then down while displacing the left slide by one unit when the result exceeded 9. This rudimentary but practical carry mechanism was the improvement made by Kummer in 1847.

Troncets were made in Germany, USA and several Asian countries with a wide range of features. They were cheap and became so popular that some were still used when electronic pocket calculators took their place in the 70’s.

In Germany,  Addiator was a manufacturer of high quality slide adders. Addiators became so popular that they became synonymous of slide adders of Troncets. Typical Addiator’s models were: Addiator Standard (1920), Maximator (1925), Duplex (1950) and Arithma (1960).

Some examples of slide adders are: Addiator, Addifix, Addimax, Correntator, Exactus, Produx, German, Kingson, Groesbeck, Locke, Fowler, Universal, Bair, Rapid Computer, Arithstyle, Dilworth, Calculator, Ve-Po-Ad, Omega, Omega Rechner, Addimult (Tower,) Kalkometer, Magic-Brain, Midget, MBC Pocket, Tasco, Valiant, Vanguard, Windsor and Wolverine.

SOURCE:   http://www.xnumber.com/history_pages/history2.htm

Wait, what about little Tom Thumb?

My research has uncovered the Western Stamping company of Jackson, Michigan produced an Add-em calculator Adding machine in 1950, under the brand name Tom Thumb.  The USA was the closest rival to Germany for the variety of slide adders made. However it was unsurpassed in the field of dial adders in the twentieth century.   I am happy to have found my little Tom Thumb slide adder was also made by this company.

See:   http://www.mathsinstruments.me.uk/page27.html    which says this about my calculator –

“Tom Thumb Adding Machine”, Western Stamping Co, Jackson, Michigan
8 slides, 9 digit display
5.5 x 3.3 inches
Steel & plastic
With red/clear vinyl wallet, metal stylus with plastic ends, and instructions
This is identical to the later type of Baby Calculator, seen above, except for the printing on the face plate and the type of case.

I already have a Baby Calculator and a thin Arithma Addiator.   Here are more photos of my Tom Thumb which I WILL be using !!

You can visit  Vintage and Mod Shop  for amazing affordable vintage items – it’s easy and safe to use Etsy.

I can vouch for the friendliness and professional service of Mallory, the New York store owner of Vintage and Mod Shop, whom will help you with your every need in a timely manner.







Author: Star Wise

Bookaholic and Peace-aholic, and Animal lover, I try to spread peace and fairness for all, and appreciation of, and proper use of the wonderful world we live in. Mitakuye Oyasin - we are all related.

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