Editing Comptometer (section)

===Competition===
The comptometer was the first machine in production to challenge the supremacy of the [[arithmometer]] and its clones; but not immediately, it took almost three years to sell the first hundred machines.<ref>{{cite book|last=Felt|first=Dorr E.|title=Mechanical arithmetic, or The history of the counting machine|publisher=Washington Institute|location=Chicago|page=[https://archive.org/details/mechanicalarithm00feltrich/page/n7 4]|year=1916|url=https://archive.org/details/mechanicalarithm00feltrich}}</ref>
[[Image:DesktopMechanicalCalculators inProduction intheXIXCentury.svg|thumbnail|upright=2.7|center|<div align="center">Desktop Mechanical Calculators in production during the 19th century</div>]]