On 2 December 1879 William Briggs (1813-1887), a farmer and miller of Stoughton, Massachusetts, received a patent for an arithmetical calculator (see US patent Nr. 222126). The patent model of the device (up to 1880, the US Patent Office required inventors to submit a model with their patent application) is still preserved in the National Museum of American History, Washington, D.C. (see the image below). In his patent application Briggs mentioned previous patents of Strode (US Patent Nr. 74170), Hudson (Nr. 45829), and Parmelee (Nr. 99226).
The calculator of William Briggs (he called it quick and sure reckoner) is a wood, metal and paper device with overall measurements: 2.2 cm x 15 cm x 15.4 cm.
The calculator of William Briggs is an adder with a square wooden frame. On top is a piece of paper printed with the numbers from 1 to 100 and a rotating tin disc. The disc has 100 holes and is covered with another piece of paper, with the digits from 1 to 100 printed around the edge. Atop this disc is a second, smaller wooden stellated wheel (disc) with 10 serrations around the edge.
The carry mechanism is implemented by means of a fixed metal arm that reaches over the 100 discs on the outside paper. This arm advances the smaller disc at every rotation of the larger disc.
Briggs suggested that further wheels could be introduced to indicate thousands, ten thousands, etc., but he didn’t include these wheels on the simple wooden and paper model he sent to the US Patent Office.