Thomas Strode (1810–1880), a storekeeper and farmer from Coatesville, Chester county, Pennsylvania, was a holder of three patents for calculating devices: US patent №30264 from 1860 for an adding machine (calculator), similar to Calculating Clock of Schickard and Pascaline of Blaise Pascal, and two patents for circular stylus-operated adding machines (patents №49168 from 1865 and №74170 from 1868).
The adding machine from the first patent of Strode is a pin-operated device with four (or more) wheels. Each of the wheels is provided with ten teeth and a carrying tooth (of course, the leftmost wheel doesn’t have a carrying tooth). Numbers are entered into the device by inserting a pin into the circular plate of the corresponding wheel and rotating until the pin strikes the connecting strip. There is no zeroing mechanism provided, so the wheels must be zeroed manually.
The last patent of Strode (US74170) is for a circular stylus-operated adding device, the patent model of which survived to our time, and is kept in the collection of the National Museum of American History, Washington D.C. (see the lower image).
It is a wood, paper, and metal device, with overall measurements: 1.8 cm x 16.7 cm x 26 cm.
The outer edge of the paddle is divided clockwise into marked in ink 100 parts. Five concentric metal discs (held together in the middle by a screw) are atop the paddle, each one slightly smaller than the one below.
The first disc above the paddle has 100 holes around the edge and rotates. The second disc is fixed, with the numbers from 1 to 97 marked in pen counterclockwise around the edge (a few higher digits are hidden). The third disc is toothed, and has the numbers from 1 to 100 around its edge, inside the teeth. The fourth disc covers the third one, with one notch that reveals a number on the toothed disc. The fourth disc also has 100 holes around its edge. Just inside these holes is the fifth, top disc. It also is divided into 100 parts around the edge, marked in pen from 1 to 50 going counterclockwise on the right side, and from 1 to 47 going clockwise around the left side (a few divisions are unmarked).
The first disc is intended to represent sums of numbers up to 100 (cents), and to carry a term to advance the third disc, which represents hundreds (dollars). The smallest disc can be used as a guide in adding or subtracting hundreds.
Biography of Thomas Strode
Thomas T. Strode was born on 11 February 1810, in Coatesville, Chester county, Pennsylvania. He was the second child of William Strode (26 Dec. 1782—25 Dec. 1851), a farmer, son of Richard Strode and Ruth (Shields) Strode, and Elizabeth Strode (7 Jan. 1787—1 Apr. 1861). He had an elder brother, Richard (1808-1848), and a younger brother and five sisters—Elizabeth (b. 1818), Ruthanna (b. 1820), David James (1822–1848), Mary Ann (b. 1825), Hannah (1830-1856), and Caroline (1833-1883).
Thomas T. Strode was an heir 6th generation of the early settler George Strode (1654–1698), a grocer from Millbrook, Hampshire, England, who emigrated to the New World about 1682 with his family, and settled in Chester County, Pennsylvania. Many generations Strodes left their mark around West Chester. Strode’s Mill, a property of Strodes from 1737 until 1878 is still preserved and is part of Strode’s Mill Historic District, a national historic district located in East Bradford Township. Besides Strode’s Mill (see the nearby photo), Strode’s Mill Historic District includes Strode Farm, Strode’s Pork Products plant, and other buildings.
Thomas Strode worked as a storekeeper and farmer around Coatesville (in some of the patents he was specified as living in Mortonville, a hamlet near Coatesville). He must have been a very inventive man, because, besides the three above-mentioned patents for calculating devices, he took out five other US patents—two patents for calendar clocks (US30166 and US49169), a machine for boring holes (US8569), an excavator (US152882), and grain winnower and weigher (US8763).
Thomas T. Strode died on 19 March 1880, in Mortonville, Pennsylvania.