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The Macaroni Box Computer

When taking a math class, students often take their calculators for granted. The calculator is an engineering marvel that has been passed off as nominal. This was not so in 1885 when the first device resembling a calculator was produced. It is know as the comptometer, or the “macaroni box computer.”

It all began in the early 1880’s with a young machinist from Chicago named Dorr Felt. One day at work, he noticed how a planer could cut various depths due to a ratcheting mechanism. This concept gave him the idea he needed to design one of the first calculating machines. Soon after, he had a wooden model of his creation. It was made from rubber bands, skewers, strings, stapes and a macaroni box. This was the first comptometer, know as the “macaroni box computer” (The Computer of Dorr Felt).

The “macaroni box” comptometer could add, subtract, multiply (through repeated adding) and divide (through repeated subtraction). Later models could also find square roots. It did these operations via a mechanical mechanism. There were anywhere from 80 to 200 keys on the comptometer. When a key was pressed, it would advance a set of gears. These gears would spin a device that would store numbers, know as the accumulator. Stored numbers allowed the comptometer to “remember” numbers and do mathematic operations. Added on to later models was an error control mechanism that prevented errors, such as partially pressed keys (Mackay).

This piece of machinery is very important in the advancement of business, notably accounting. First off, it was designed to add and subtract more numbers faster than any accountant could. Felt knew that at the time the average accountant could carry four digits in mental calculation. To make a market for his product, Felt designed his comptometer to carry on average 12 digits. The comptometer was not a simple device though, and it led to the development of a new job, the comptometer operator. The comptometer operator was trained to take advantage of the biggest two advantages of the comptometer, speed and accuracy. The speed was due to the key driven operation while the accuracy of the comptometer was due to the basic design of the mechanism (Wolff). Jobs that used to take tedious hand calculation could now be performed quickly and with confidence. During the reign of the comptometer, not many adding machines could come close to the speed of the Felt comptometer. While other adding machines could handle around 120 strokes per minute, the Felt comptometer could handle as many as 500 strokes per minute. It is easy to see why this comptometer advanced the accounting world (The Computer of Dorr Felt).

Stemming from the early success of his comptometer, Felt soon made a business deal with Robert Tarrant, in 1887. Tarrant was the owner of a machine shop and foundry. Together, Felt and Tarrant established the Felt and Tarrant Manufacturing Company. This company continued to produce comptometers until 1914 when Felt and Tarrant went their separate ways. Felt continued on the path of the comptometer while Tarrant began to pursue the comptograph, basically a comptometer with a print output. Felt’s company continued to profit until the 1960’s, when it began to be replaced by companies producing more efficient and smaller electric machines. (The Computer of Dorr Felt).

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Works Cited

"The Computer of Dorr Felt." History of Computers. Ed. Georgi Dalakov. N.p., 18 May 2012. Web. 22 May 2012. <http://history-computer.com/sources.html>.

Mackay, Ray. "Memorised Description of Comptometer's ® Mechanism." Mechanical Calculators - Articles. N.p., 27 Dec. 1997. Web. 23 May 2012. <http://www.xnumber.com/xnumber/comptometer.htm>.

Wolff, John. "Felt & Tarrant - The Comptometer." John Wolff's Web Museum. N.p., 15 May 2012. Web. 23 May 2012. <http://home.vicnet.net.au/~wolff/calculators/Comptometer/FT.htm>.