Invented by Leonardo Torres in 1920, the Torres calculating machine is a machine that solves essential addition, subtraction, multiplication, and division problems using a simple manner. It was a ...

National 3000 automatic bookkeeping calculating machine no 101364 42-BT, by National Cash Register Company Limited, England, 1935-1945. This machine was formerly the property of Dr. L J Comrie FRS.

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This fully automatic, non-printing ...