Hart's Mercantile Computing Machine
date: label: date made
content: 1878
name: label: patentee
content: Hart, William
label: maker
content: Scovill Manufacturing Company
notes: label: Description
content: The instrument consists of three concentric brass discs, a brass marker, a steel stop, and a wooden handle (instrument must be removed from box to find handle). Each brass disc has the numbers from 0 to 99 stamped around the edge. The two inner discs both have a circle of 100 holes just outside the numbers. The inner holes are used to add the last two digits of a number by rotation. Any hundreds value in the sum carries to the second set of holes, which are used to add hundreds and thousands places.
label: Description
content: The machine is in a cylindrical wooden case with cover.
label: Description
content: According to the Kirksville [Missouri] Democrat for August 2, 1888, by then Hart had sold 3500 of these devices and “he lately ordered one thousand more.”
label: Description
content: References: U.S. Patent #199289
label: Description
content: P. Kidwell, "Adders Made and Used in the United States," <I>Rittenhouse</I>, 1994, 8:78-96.
label: Description
content: <I>Kirksville [Missouri] Democrat</I>, August 2, 1888.
label: Location
content: Currently not on view
place: label: place made
content: United States: Connecticut, Waterbury
label: place patented
content: United States: Missouri, Kirksville
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Adder
label: See more items in
content: Science & Mathematics
creditLine: label: Credit Line
content: Gift of Mrs. Robert T. Kerr
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1993.0510.01
label: accession number
content: 1993.0510
label: catalog number
content: 1993.0510.01
objectType: label: Object Name
content: adder with carry
physicalDescription: label: Physical Description
content: steel (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: wood (overall material)
label: Measurements
content: overall: 5.5 cm x 13.5 cm x 13.5 cm; 2 5/32 in x 5 5/16 in x 5 5/16 in