Adders Using Rods

From antiquity, mathematicians have known that one can represent numbers by lengths. To find the sum of two numbers, one can use two rulers that slide next to one another, assuming the rulers are long enough. In 1700, the Frenchman Claude Perrault suggested that one could represent each digit in numbers to be summed by a separate sliding stick. Another Frenchman, C. de Caze, actually built such an instrument.

The Smithsonian collections include several models of adders submitted to the United States Patent Office. Some of these represented numbers by the length of movable rods. Another rod-type adder, invented by Clarence E. Locke of Kensett, Iowa, was the first American-made adder to sell successfully for several years.

This wooden patent model for an adder has a frame that holds seven strips of wood. Each strip has 19 holes on it. The ten right holes are numbered from 0 to 9. The nine remaining holes are unnumbered, but the wood is colored green.
Description
This wooden patent model for an adder has a frame that holds seven strips of wood. Each strip has 19 holes on it. The ten right holes are numbered from 0 to 9. The nine remaining holes are unnumbered, but the wood is colored green. To the sides of each strip, the numbers 1 to 9 are written on the frame. The left part of the strip is covered by an upper piece on the frame.
Samuel S. Young of Eaton, Ohio, took out three patents for computing devices. This is the patent model for the first. The later ones were a rule for calculating interest, patented September 2, 1851 (U.S. patent 8323), and an arithmetical proof rule, patented October 26, 1858 (U.S. patent 21921).
The U.S. Census for 1850 indicates that S. S.Young of Eaton, Ohio, was 40 years old that year, and living with his wife and two children. His occupation is given as “gardener.” Apparently by 1860 he had moved to the nearby town of Washington and is listed as a “horticulturalist” by profession.
References: Samuel S. Young, Calculating-Machine, U.S. Patent, No. 6602, issued July 24, 1849.
Robert Otnes, “Sliding Bar Calculators,” ETCetera, #11, June, 1990, p. 6.
P. Kidwell, “Adders Made and Used in the United States,” Rittenhouse, May, 1994, p. 80.
Location
Currently not on view
date made
1849
patentee
Young, Samuel S.
maker
Young, Samuel S.
ID Number
MA.252680
catalog number
252680
accession number
49064
Some 19th-century Americans earned their keep as inventors and patent agents. One of them was George B. Fowler, inventor of this adder.This U.S. patent model has a wooden frame with slots for eight sliding bars.
Description
Some 19th-century Americans earned their keep as inventors and patent agents. One of them was George B. Fowler, inventor of this adder.
This U.S. patent model has a wooden frame with slots for eight sliding bars. The frame is covered on the left and the right with black zinc plates. These hold the bars in place and also fold over the left and right edges of the device to form the sides. Each bar has a series of regularly spaced holes. The wooden pieces that form the slots are stamped from right to left 1 to 9. Numbers are entered by moving the bars from left to right. Totals are visible on the back of the device. There is no carry mechanism.
According to U.S. Census records, Fowler was born in Long Island in about 1834 or 1835. In 1863, when he patented this device, he listed himself as a resident of Chicago, Illinois. By 1864 he had settled in New York City, and at the end of the decade he was a patent agent in Brooklyn.
This small adder, patented July 14, 1863, was the subject of Fowler’s first patent (#39222). He went on to patent a variety of other devices, including a clothes and hat hook (#40923, December 15, 1863), wood-splitters (#53289, March 20, 1866), a game-box for ten-pins (#107030, September 6, 1870), a wagon-jack (#113285, April 4, 1871), an eggbeater and mixer (#256310, April 11, 1882), a picture cord and hook hanger (#357312, February 8, 1887), and an improved version of his adder (#432266, July 15, 1890).
Production models of Fowler’s instrument survive. Fowler charged $5.00 for the adder. He garnered testimonials from lumber dealers, bookkeepers, and insurance companies, and publicized the instrument in at least one circular and in Scientific American. Correspondence from 1863 suggests that Fowler hoped to find agents who would pay substantial sums to market his machine, but there is no indication that this occurred.
References: U.S. Patent 39,222, July 14, 1863.
Robert B. Otnes, “Sliding Bar Calculators,” ETCetera, #11, June, 1990, p. 7.
P. Kidwell, “Adders Made and Used in the United States,” Rittenhouse, May, 1994, p. 80.
Location
Currently not on view
date made
1863
patentee
Fowler, George B.
maker
Fowler, George B.
ID Number
MA.252688
catalog number
252688
accession number
49064
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa in 1892.
Description
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa in 1892. Locke worked for a time as a civil engineer in Minnesota, and then joined his father operating a lumberyard in Kensett, Iowa.
This version of the device has a metal base with grooves for nine sliding metal rods that move crosswise. Each rod represents a digit of a number being added. Protruding knobs on the rods represent different numerals. The rods are held in place by metal covers, painted black, that extend over the right and left thirds of the instrument. When the device is in zero position, all the rods are in their rightmost position. Numbers are entered by sliding rods to the left, and the result appears in numbers immediately to the left of the cover on the right. The rods are color-coded to distinguish units of money. They lock when depressed, so that they will not slide if the instrument is tilted.
The locking mechanism, the color-coded rods, and the oval shape of the knobs on the rods are all improvements featured in Locke’s second calculating machine patent, taken out in 1905. This patent is not listed on the instrument. There is no carry mechanism. The instrument sits in a wooden box with no lid. The base of it is covered with red cloth.
The instrument is marked on the right cover: C.E. LOCKE (/) MFG. Co. It is also marked: KENSETT, IOWA. [/] U.S.A. It is marked on the left cover: THE (/) LOCKE (/) ADDER. It is also marked: PATENTED DEC. 24. 1901. This example came to the Smithsonian from the collection of Felt & Tarrant Manufacturing Company (later Victor Comptometer Corporation).
References: C. E. Locke, “Calculating Machine,” U.S. Patent 689680, December 24, 1901.
C. E. Locke, “Calculating Machine,” U.S. Patent 779088, January 3, 1905.
Robert Otnes, “Sliding Bar Calculators,” ETCetera #11 (June 1990): pp. 6-8.
P. Kidwell, “Adders Made and Used in the United States,” Rittenhouse, 8, (1994): pp. 78-96.
Location
Currently not on view
date made
1901
maker
C. E. Locke Manufacturing Company
ID Number
MA.323619
catalog number
323619
accession number
250163
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945), a native of Edgerton, Wisconsin, who graduated from Cornell College in Mt. Vernon, Iowa, in 1892.
Description
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945), a native of Edgerton, Wisconsin, who graduated from Cornell College in Mt. Vernon, Iowa, in 1892. Locke worked for a time as a civil engineer in Minnesota, and then joined his father in operating a lumberyard in Kensett, Iowa.
This early version of the device has a wooden base with grooves for nine sliding metal rods that move crosswise. Each rod represents a digit of a number being added. Protruding knobs on the rods represent different numerals. The rods are held in place by a metal cover that extends over about a third of the right top, and by a metal bracket on the left side. When the device is in zero position, all the rods are in their rightmost position. Numbers are entered by sliding rods to the left, and the result appears in numbers immediately to the left of the metal cover. There is no carry mechanism. The cover is brown, not black or silver-colored as in later Locke adders.
The instrument is marked on the cover: C.E. LOCKE (/) MFG. Co. It is also marked: KENSETT, IOWA. [/] U.S.A. This example came to the Smithsonian from the collection of Felt & Tarrant Manufacturing Company (later Victor Comptometer Corporation).
References: Robert Otnes, “Sliding Bar Calculators,” ETCetera #11 (June 1990): pp. 6-8.
P. Kidwell, “Adders made and Used in the United States,” Rittenhouse, 8, (1994): pp. 78-96.
Location
Currently not on view
date made
1901
maker
C. E. Locke Manufacturing Company
ID Number
MA.323620
catalog number
323620
accession number
250163
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa, in 1892.
Description
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa, in 1892. Locke worked for a time as a civil engineer in Minnesota, and then joined his father operating a lumber yard in Kensett, Iowa.
This version of the device has a metal base with grooves for nine sliding metal rods that move crosswise. Each rod represents a digit of a number being added. Protruding knobs on the rods represent different numerals. The rods are held in place by bronze-colored metal covers that extend over the right and left thirds of the instrument. When the device is in zero position, all the rods are in their rightmost position.
Numbers are entered by sliding rods to the left, and the result appears in numbers immediately to the left of the cover on the right. The rods are color-coded to distinguish units of money. They lock when depressed, so that they will not slide if the instrument is tilted. The locking mechanism, the color-coded rods, and the oval shape of the knobs on the rods are all improvements featured in Locke’s second calculating machine patent, taken out in 1905. There is no carry mechanism. The base of is covered with green cloth.
The instrument is marked on the right cover: C. E. LOCKE (/) MFG. Co. It also is marked: KENSETT, IOWA. [/] U.S.A. It is marked on the left cover: THE (/) LOCKE (/) ADDER. It also is marked: PATENTED DEC. 24. 1901 (/) JAN. 3 1905. This example came to the Smithsonian from the collection of L. Leland Locke.
The instrument resembles MA.323619, but it has green rather than red cloth on the bottom and has no surrounding wooden box. Also compare to MA.321327.
References: C. E. Locke, “Calculating Machine,” U.S. Patent 689680, December 24, 1901.
C. E. Locke, “Calculating Machine,” U.S. Patent 779088, January 3, 1905.
Robert Otnes, “Sliding Bar Calculators,” ETCetera #11 (June 1990): pp. 6-8.
P. Kidwell, “Adders Made and Used in the United States,” Rittenhouse, 8, (1994): pp. 78-96.
Location
Currently not on view
date made
1905
maker
C. E. Locke Manufacturing Company
ID Number
MA.155183.29
catalog number
155183.29
accession number
155183
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa, in 1892.
Description
The first American-made adder to enjoy modest commercial success was developed by Clarence E. Locke (1865-1945). A native of Edgerton, Wisconsin, he graduated from Cornell College in Mt. Vernon, Iowa, in 1892. Locke worked for a time as a civil engineer in Minnesota, and then joined his father operating a lumberyard in Kensett, Iowa.
This version of the device has a metal base with grooves for nine sliding metal rods that move crosswise. Each rod represents a digit of a number being added. Protruding knobs on the rods represent different numerals. The rods are held in place by bronze-colored metal covers that extend over the right and left thirds of the instrument. When the device is in zero position, all the rods are in their rightmost position.
Numbers are entered by sliding rods to the left, and the result appears in numbers immediately to the left of the cover on the right. The rods are color-coded to distinguish units of money. They lock when depressed, so that they will not slide if the instrument is tilted. The locking mechanism, the color-coded rods, and the oval shape of the knobs on the rods are all improvements featured in Locke’s second calculating machine patent, taken out in 1905. There is no carry mechanism. The base of it is covered with green cloth.
The instrument is marked on the right cover: C.E. LOCKE (/) MFG. Co. It is also marked: KENSETT, IOWA. [/] U.S.A. It is marked on the left cover: THE (/) LOCKE (/) ADDER. It is also marked: PATENTED DEC. 24. 1901 (/) JAN. 3 1905. The instrument fits in a cardboard case covered with black cloth.
According to the donor, the example of the Locke adder was given to him by the retiring operator of a country milk receiving station for a dairy. The operator used it to determine the total number of pounds of milk received each day at the station.
References: C. E. Locke, “Calculating Machine,” U.S. Patent 689680, December 24, 1901.
C. E. Locke, “Calculating Machine,” U.S. Patent 779088, January 3, 1905.
Robert Otnes, “Sliding Bar Calculators,” ETCetera #11 (June 1990): pp. 6-8.
P. Kidwell, “Adders made and Used in the United States,” Rittenhouse, 8, (1994): pp. 78-96.
Accession file, for advertising brochure and history of the instrument.
Location
Currently not on view
date made
1905
maker
C. E. Locke Manufacturing Company
ID Number
MA.321327
catalog number
321327
accession number
243137

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.