
thumb|upright=1.2|Model ST (1930s) thumb|upright=1.2|Prototype of the first all-electronic desktop calculator marketed by of the United Kingdom|UK
thumb|upright=1.2|Model ST (1930s) thumb|upright=1.2|Prototype of the first all-electronic desktop calculator marketed by of the United Kingdom|UK
The comptometer was the first commercially successful key-driven mechanical calculator, patented in the United States by Dorr Felt in 1887.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).