This Hatfield adder was invented by Aaron L. Hatfield of Lewisburg, PA. Patent no.11,729 was issued to Aaron on September 26, 1854. The Hatfield was a circular adding machine consisting of 3 concentric brass discs with a brass lever mounted to a wood paddle. A paper-label instruction sheet was glued to the rear.

 

There were two version produced though both operated similarly. The first version was produced by the W. O. Hickok Mfg. Co. of Harrisburg, PA. As for the later versions, as the inscription on the machine reads, Aaron Hatfield was both "inventor and manufacturer" of the adder which was done in his hometown..

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Hart's Mercantile Computing Machine was a similarly-functioning, paddle-mounted device.

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Have one for sale? Please email me at Antikey.Chop@gmail.com or call +1 860 729 2252

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