In early 19th century Europe, the painstaking work of sum calculation drove innovation in mechanical aids. Visionaries experimented with movable number strips controlled by pointers to essentially automate the steps required for addition. While the pioneering abbaque rhabdologique of Claude Perrault and nouvelle machine arithmétique of César Caze hinted at the possibilities, they had limitations – chiefly, no ability to carry numbers between columns. By the 1840s, tinkerers were racing to perfect designs to unleash the full potential of mechanical calculation.
The State of Play for Adders – And Lingering Gaps
In 1846, a gifted German musician named Heinrich Kummer found himself immersed in this race while working in St. Petersburg, Russia. Surrounded by Russian scientists sharing new arithmetic aids, he noted the recent iteration by Chaim Zelig Slonimski allowed carries. However, its construction was quite complex for users. Kummer became convinced he could build something both functionally and physically simpler.
As Kummer embarked on his work, most mechanical adding machines remained restricted to three or four digits numbers. And none had achieved widespread adoption outside scientist circles given difficult user interfaces. A breakthrough was needed to unlock the power of automated addition for common use.
Pioneering Adding Machines
| Inventor | Device | Year | Features | Limitations |
|---|---|---|---|---|
| Claude Perrault | Abaaque rhabdologique | c1670 | Movable number strips | No carry capacity |
| César Caze | Nouvelle machine arithmétique | c1700 | Metal number slides | No carry capacity |
| Chaim Slonimski | Slonimski adder | 1845 | Allowed carries | Complex to use |
Eureka! Kummer‘s Elegant Adder
Kummer evaluated contemporaneous adding machines and determined the core barriers to adoption were size, ease of use and carry function. By September 1846, he had crafted a working wooden prototype of his own compact, portable design implementing carries through an ingenious dual slide system. Numbers 0-9 marked one set of brass strips on which calculations were set using a pointer. The breakthrough was a second set of slides with extending teeth. When a column‘s sum exceeded 10, its tooth engaged the neighboring column, incrementing it by 1 for the carry.
Famed Russian mathematician Mikhail Ostrogradsky examined Kummer‘s model and was deeply impressed, noting:
"Its simplicity and convenience exceed anything previously devised."
Equally important was its diminutive size – just 40 x 8.5 x 11 cm. Compared to bulkier contemporary adding machines, Kummer‘s could fit in a coat pocket…and arithmetic could now travel anywhere too!
An Adding Machine For The Masses
Kummer secured Russian and international patents for his machine in 1847. Workshops in Moscow commenced manufacturing the model, now dubbed the Kummer Adding Machine. By the 1870s between 10,000 – 20,000 units were selling annually across Europe. Over a dozen variants emerged over the decades at factories in Russia, France, Austria and Germany.
The adder became a common sight in offices performing commercial and financial transactions. Its intuitive interface meant usage was no longer limited to mathematical elites. Calculating sums was suddenly open to the masses.
Even with the advent of electricity in the early 1900s, the reign of the Kummer Adding Machine continued. Why? Users appreciated its reliability, portability and no power dependency compared to electromechanical counterparts. While adding machines grew more advanced, manufacturers retained Kummer‘s key tenet – numerical slides. These manual workhorses lasted nearly 130 years until electronic pocket calculators fully outmoded them in the 1970s.
Legacy of a Humble Genius
The longevity of Kummer‘s basic concept is a testament to its ingenuity. By creatively addressing key weaknesses of prior art, his compact, carry-enabled adder transformed addition from an onerous undertaking into a trivial exercise. His timing, coming just before the dawn of the Industrial Revolution, exponentially increased productivity across Europe.
While not as famous as computing pioneers Charles Babbage or Ada Lovelace, Heinrich Kummer proved one of the most influential engineers of automatic calculation. The advent of his Adding Machine in 1846 unlocked arithmetic for the people…and his elegant design ushered addition into the modern age. Whenever you reach for a calculator, take a moment to recognize this humble musical genius who made numbers work for humanity.
