An adding machine is a type of mechanical calculator originally designed for bookkeeping, often tailored to specific currencies. They were common office equipment throughout the twentieth century but were gradually replaced by electronic calculators in the 1970s and personal computers from the mid-1980s. The mechanical calculator traces back to inventors like Blaise Pascal and Wilhelm Schickard in 1642, who developed machines for addition, subtraction, and basic multiplication and division. Later advances included Thomas de Colmar's simplified arithmometer in 1851, and the widespread adoption triggered by Dorr E. Felt’s comptometer and Burroughs’ commercial machines in the late 19th century.
Operation
To add a new list of numbers and arrive at a total, the user was first required to "ZERO" the machine. Then, to add sets of numbers, the user was required to press numbered keys on a keyboard, which would remain depressed (rather than immediately rebound like the keys of a computer keyboard or typewriter or the buttons of a typical modern machine). The user would then pull the crank, which caused the numbers to be shown on the rotary wheels, and the keys to be released (i.e. to pop back up) in preparation for the next input. To add, for example, the amounts of 30.72 and 4.49 (which, in adding machine terms, on a decimal adding machine is 3,072 plus 449 "decimal units"), the following process took place: Press the 3 key in the column fourth from the right (multiples of one thousand), the 7 key in the column second from right (multiples of ten) and the 2 key in the rightmost column (multiples of 1). Pull the crank. The rotary wheels now showed 3072. Press the 4 key in the third column from the right, the 4 key in the second column from right, and the 9 key in the rightmost column. Pull the crank. The rotary wheels now show a running 'total' of 3521 which, when interpreted using the decimal currency colour-coding of the key columns, equates to 35.21. Keyboards typically did not have or need 0 (zero) keys; one simply did not press any key in the column containing a zero. Trailing zeros (those to the right of a number), were there by default because when a machine was zeroed, all numbers visible on the rotary wheels were reset to zero.
Subtraction was impossible, except by adding the complement of a number (for instance, subtract 2.50 by adding 9,997.50).
Multiplication was a simple process of keying in the numbers zero or more columns to the left and repeating the "addition" process. For example, to multiply 34.72 by 102, key in 3472, pull crank, repeat once more. Wheels show 6944. Now key in 347200 = 3472x100 (3472 in columns 3 to 6 from the right, and nothing in columns 1 and 2 from the right), pull crank. Wheels now show 354144, or 3,541.44. To multiply by 102, 3 additions are required. To multiply by any number, the number of additions required is the sum of its digits.
A later adding machine, called the comptometer, did not require that a crank be pulled to add. Numbers were input simply by pressing keys. The machine was thus driven by finger power. Multiplication was similar to that on the adding machine, but users would "form" up their fingers over the keys to be pressed and press them down the multiple of times required. Using the above example, four fingers would be used to press down twice on the 3 (fourth column), 4 (third column), 7 (second column) and 2 (first column) keys. That finger shape would then move left two columns and press once. Usually a small crank near the wheels would be used to zero them. Subtraction was possible by adding complementary numbers; keys would also carry a smaller, complementary digit to help the user form complementary numbers. Division was also possible by putting the dividend to the left end and performing repeated subtractions by using the complementary method.3
Some adding machines were electromechanical – an old-style mechanism, but driven by electric power.
Some "ten-key" machines had input of numbers as on a modern calculator – 30.72 was input as 3, 0, 7, 2. These machines could subtract as well as add. Some could multiply and divide, although including these operations made the machine more complex. Those that could multiply, used a form of the old adding machine multiplication method. Using the previous example of multiplying 34.72 by 102, the amount was keyed in, then the 2 key in the "multiplication" key column was pressed. The machine cycled twice, then tabulated the adding mechanism below the keyboard one column to the right. The number keys remained locked down on the keyboard. The user now pressed the multiplication 0 key which caused tabulation of the adding mechanism one more column to the right, but did not cycle the machine. Now the user pressed the multiplication 1 key. The machine cycled once. To see the total the user was required to press a Total key and the machine would print the result on a paper tape, release the locked down keys, reset the adding mechanism to zero and tabulate it back to its home position.
Modern adding machines are like simple calculators. They often have a different input system, though.
| To figure this out | Type this on the adding machine |
|---|---|
| 2+17+5=? | 2 + 17 + 5 + T |
| 19-7=? | 19 + 7 - T |
| 38-24+10=? | 38 + 24 - 10 + T |
| 7×6=? | 7 × 6 = |
| 18/3=? | 18 ÷ 3 = |
| (1.99×3)+(.79×8)+(4.29×6)=? | 1.99 × 3 = + .79 × 8 = + 4.29 × 6 = + T |
Burroughs's calculating machine
William Seward Burroughs received a patent for his adding machine on August 25, 1888. He was a founder of American Arithmometer Company, which became Burroughs Corporation and evolved to produce electronic billing machines and mainframes, and eventually merged with Sperry to form Unisys. The grandson of the inventor of the adding machine is Beat author William S. Burroughs; a collection of his essays is called The Adding Machine.
See also
Notes
Sources
- Marguin, Jean (1994). Histoire des instruments et machines à calculer, trois siècles de mécanique pensante 1642–1942 (in French). Hermann. ISBN 978-2-7056-6166-3.
- Taton, René (1963). Le calcul mécanique. Que sais-je ? n° 367 (in French). Presses universitaires de France. pp. 20–28.
Further reading
- Chase, George C. "History of mechanical computing machinery." Proceedings of the 1952 ACM national meeting . 1952. online
- Couffignal, L. "Calculating Machines: Their Principles and Evolution." In: B. Randell, B. (ed) The Origins of Digital Computers. Texts and Monographs in Computer Science (Springer, Berlin, Heidelberg, 1982). https://doi.org/10.1007/978-3-642-61812-3_10
- Eleje, Lydia I., et al. "Utilization of Adding Machine by Students’ of Secondary School: The Impact on their Critical Thinking Skills According to their Teachers Perception." Journal of Theoretical and Empirical Studies in Education 10.1 (2025): 217-234. online, teachers at 62 schools in Nigeria.
- Kistermann, Friedrich W. "Blaise Pascal's adding machine: new findings and conclusions." IEEE Annals of the History of Computing 20.1 (1998): 69-76. DOI: 10.1109/85.646211
- Locke, L. Leland. "The history of modern calculating machines, an American contribution." The American Mathematical Monthly 31.9 (1924): 422-429. online
- Morar, Florin-Stefan. "Reinventing machines: the transmission history of the Leibniz calculator." The British Journal for the History of Science 48.1 (2015): 123-146.
- Price, Derek De Solla. "A history of calculating machines." Ieee Micro 4.1 (1984): 22-52.
- Wilkes, M. V. "Automatic calculating machines." Journal of the Royal Society of Arts 100.4862 (1951): 56-90. online
External links
- Media related to Adding machines at Wikimedia Commons
References
see things-that-count.net and in particular, Schickard versus Pascal - an empty debate? Archived April 8, 2014, at the Wayback Machine http://things-that-count.net ↩
J.A.V. Turck, Origin of modern calculating machines, The western society of engineers, 1921, p. 143 ↩
Easy Instructions for Operation the Controlled Key Comptometer http://www.ed-thelen.org/comp-hist/Comptometer-instructions.html ↩