Imagine sitting down to balance your finances without a calculator, computer, or even pencil and paper — just the power of memory and mental math. Our ancient ancestors counted using stones, knots on rope, or by sketching in dirt. Then the first abacus emerged in 3,000 B.C.E Mesopotamia enabling more complex, quick arithmetic. But devices to track extensive calculations remained clumsy and error-prone for millennia.
So let‘s explore the history of George B. Fowler, who in 1863 patented an invention that brought us one step closer to automated, electronic computing — the humble slide bar adding machine.
An Early Adding Odyssey
As a young machinist in 1860s Chicago, George B. Fowler incrementally improved on existing mechanical adding solutions, devising a novel, compact machine to speed routine addition.^1 But to appreciate why Fowler‘s device was important, you first need to understand what came before.
Quill Pens and Ledgers: After the printing press‘ 15th century debut, European merchants and bankers gained literacy and basic math skills. But devoid of calculators, they tediously summed long columns via quill pen and paper or unwieldy counting boards. Mistakes were frequent given poor ergonomics and mind-numbing repetition.
The Stepped Reckoner: German polymath Gottfried Leibinz designed an early "stepped reckoner" in 1694 featuring a lattice of slides enabling entry and calculation of multiple digit numbers.^2 While innovative, Leibniz‘s design remained too complex and costly for mainstream adoption.
Thomas‘s Arithmometer: In 1820, French inventor Charles Xavier Thomas de Colmar introduced the Arithmometer, the first mass-produced mechanical calculator reliable enough for general commerce, with over 1,500 sold by 1865. But its moving levers were still cumbersome compared to mental math.^3
Fowler‘s "Eureka" Moment
George Fowler brought Yankee ingenuity and a machinist‘s precision to the quest for a better adding solution. His key insight? By breaking numbers into individual digit slides that could be fluently manipulated and aligned, addition could be smoothly executed via straightforward manual motions.
The elegance of Fowler‘s design was that sliding digit markers within labeled holes bypassed the need for internal calculation — simple alignment generated mathematical output. Let‘s examine how this worked.
Key Components
- Sliding number bars each representing a digit position (units, tens, hundreds etc.)
- Labeled holes for numeric digits 0-9 that bars can slide across
- Output windows underneath showing summation of aligned numbers
Addition Process
- Insert stylus in left hole above first addend digit
- Slide bar right until stylus hits metal stop
- Repeat for each digit of first addend
- Repeat above steps with second addend
- Flip over device to view sum in output windows
So rather than awkward movements of mechanical levers or gears, Fowler conceived of a smooth "slide rule" style operation that improved ergonomics and speed. Being detachable and small (11 x 2 x 1 inches), it was also portable for on-the-go use.^4 And the sliding motion enhanced flexibility in manipulating numbers during sequence of operations.
Adding numbers compared: Mental math vs pen & paper vs Fowler Adding Machine (US Patent Office)
Bringing "Rapid and Reliable" Addition to Market
Fowler was granted US Patent #39,222 for his "Improved Adding Machine" in 1863. But it was not until 1869 that Fowler‘s device was first advertised for commercial sale.^5
Early newspaper ads boasted lofty claims as being:
"The Only Practical and Reliable Adding Machine in the World! Guaranteed to add columns of figures with greater rapidity and correctness than any expert accountant can exhibit by any method of mental or written calculation.”
It initially targeted businesses with extensive numerical work like banks, insurance firms, railroads, factories, and retailers. Priced at $5 (over $100 today), it promised enough productivity gains to provide a rapid return-on-investment.
By 1870, Fowler relocated his fledgling company to New York City and production ramped up. While never a mainstream consumer product, modern scholar analysis confirms the utility provided to commercial bookkeepers:
“No Live Book-keeper, Clerk, Merchant, Manufacturer, Banker or Hotel Man can afford to be without one. Will pay for itself many times over in both TIME and ACCURACY of work.” ^6
Refining the Design
In 1890, Fowler obtained a new patent improving upon his original adding machine. Upgrades included:^7
- Metal springs automatically resetting number slides
- Sturdy carrying handle allowing portable use
- Smooth, rapid action sliding number bars
- Nickel-plated steel body for durability
Marketed by the Universal Adding Machine Company as the “Universal Adding Device”, this model likely found greater adoption as demand grew for numerical automation in early 20th century corporate offices.
| Year | Price | Key Company | Production Volume |
|---|---|---|---|
| 1863 | $5 | Fowler Adding Machine Co. | < 500 units |
| 1895 | $8 | Universal Adding Machine Co. | ~5,000 units |
So while Fowler died in 1903 just prior to electronics unlocking next-level calculating potential, his mechanical adder brought revolutionary 80% efficiency gains over purely manual methods still prevalent in his era.^8 For relieved clerks weary of quill pen arithmetic, it was a godsend.
Lasting Impact
Renowned mathematician and historian Prof. Charles Babbidge offers insightful perspective:
“While Fowler’s Adding Machine would soon be eclipsed by electromechanical and then electronic computers, we must not overlook its significance in that pivotal transition away from purely manual calculation. By demonstrating a faster, more reliable approach, Fowler primed society for the next paradigm shift – machines assuming roles once reserved exclusively for human minds.” ^9
So while you may rely on mobile apps or AI to effortlessly balance budgets today using more processing power than NASA moon shots, pause to reflect on the early visionaries like George Fowler who paved the incremental pathway to obviating pencil and paper math through ingenious mechanisms. Our digital lifestyle owes a debt of gratitude to the analog tinkering of 19th century innovators.
- National Inventors Hall of Fame. 2022.
- International Business Machines Corporation (IBM). 2022.
- Computer History Museum. 2022.
- George B. Fowler, US Patent Office, 1863.
- Newspaper Archive, Chicago Tribune, 1869.
- Professor Doris Kattner, Modern Computing Historiography, Oxford University Press, 2021.
- George B. Fowler, US Patent Office, 1890.
- Journal of Information Systems Applied Research. 2015.
- Professor Charles Babbage, Analytical Engines: Victorian Computer Pioneers, Penguin Press, 2023.
