Holman Adding Machine

Holman Adding Machine

<< >>
This round metal patent model for an adder with carry has a cylindrical case that contains two concentric rotating rings, each with the digits from 0 to 99 engraved evenly around the edge. The outer, lower ring, with digits representing hundreds, is slightly larger than the other ring. Atop these is a metal disc with two adjacent windows, which make it possible to see the digits on the discs below. On top of this disc is a flat ring with four spokes that hold it together. This ring is the size of the lower ring. This ring also has 100 divisions around the outside, which are engraved with numbers. There is a window at 1 that allows one to see the disc below. This spoke has a small knob for rotating it.
Rotating this ring so that a number on it is opposite a stop projecting over the ring adds the number to the total already indicated. When the inner ring advances past 99, there is a carry to the outer ring. There is also a knob on the bottom of the machine for advancing or zeroing the hundreds ring, as well as a strap for carrying it.
According to the 1870 US Census, Calvin J. Holman, age 39 (hence born about 1831) was a Massachusetts native who was living in Sylvania Township, Lucas County, Ohio. He was the proprietor of a mill, and had substantial holdings in real estate. Also in the household were his wife, Adelia, (age 35) and children Della (16), Delvin (14), and James (11). Holman is also listed in the 1880 Census as living in Toledo and working in “spring manufacture.” Living with him were Adelia, a daughter Emma S., 23 years old and born in Pennsylvania, a son Delvin J. (21), born in Wisconsin, and a son James H. (20), also born in Wisconsin.
In addition to this adding machine, Holman patented several inventions closely related to milling. These included an improved sawing machine (U.S. patent 40837, granted December 8, 1863) and a machine for sawing staves (U.S. Patent 51,896, granted January 2, 1866), both to Calvin J. Holman of Oshkosh, Winnebago County, Wisconsin. Calvin J. Holman of Chicago was granted U.S. Patent 72639 (December 24, 1867) for a machine for sawing barrel heads. On May 29, 1877 he was granted a patent (#191428) for an improvement in vehicle springs, which may have led to his work in spring manufacture. There are several later patents granted to Calvin J. Holman or Calvin James Holman of Chicago, which also may be associated with this inventor. No record of him was found in either the 1860 or the 1900 U.S. Census.
Reference: U.S. Patent 153826, August 4, 1874.
Currently not on view
Object Name
adder with carry
Object Type
Patent Model
date made
Holman, Calvin J.
Holman, Calvin J.
place made
United States: Ohio, Toledo
place patented
United States: Ohio, Toledo
Physical Description
brass (overall material)
cloth (overall material)
overall: 8 cm x 15.6 cm x 15.6 cm; 3 5/32 in x 6 5/32 in x 6 5/32 in
ID Number
accession number
catalog number
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
Nominate this object for photography.   

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.


Add a comment about this object