Check the listing for details. Antique Calculator/adding Machine By Brunsviga .midget Patent 1906.1910. Listed at 210.00 USD. The Antique Calculator by Brunsviga, known as the "midget" model and patented in 1906 and 1910, also with name grimme, natalis & co. It is in great condition with key .lt is a prized collectible for those interested in vintage technology and mathematical history. This compact and intricate device would have been a marvel of precision and craftsmanship for its time, offering users a unique blend of functionality and aesthetic appeal. With its historical significance and patent dates, this calculator by Brunsviga holds a special place in the world of antique and collectible items.