How William Burroughs Invented the First Practical Adding Machine

An 1888 patent for a mechanical calculating machine that used a system of levers and gears to perform accurate arithmetic operations.

What it covers

This patent describes a mechanical device designed to perform mathematical calculations through a system of interconnected keys, levers, and rotating gear wheels. When a user presses a key, it moves a specific lever that rotates a gear by a set amount corresponding to the number pressed. The machine uses a carry mechanism to transfer values from one decimal column to the next, ensuring that addition is performed correctly across multiple digits.

What it doesn't cover

• —Does not cover electronic or digital computation methods.
• —Does not cover software-based calculators or algorithms.
• —Does not cover devices that rely on electricity or batteries for power.
• —Does not cover non-mechanical input methods like touchscreens or voice.

The clever bit

The invention introduced a reliable carry mechanism that allowed the machine to handle complex multi-digit addition without the user needing to manually track overflows between columns.

Why it matters

This invention was a cornerstone of the modern office. It transformed how businesses handled accounting by replacing error-prone manual ledger work with a reliable, repeatable mechanical process.

Real-world examples

• 1.Burroughs adding machines used in early 20th-century banks
• 2.Mechanical accounting registers
• 3.Early office bookkeeping hardware