Alonzo Johnson, a machinist from Springfield, Mass., is a holder of two US patents for calculating devices: patent Nr. 73732 from 28 Jan. 1868 and patent Nr. 85229 from 22 Dec. 1868). The first patent was granted to Alonzo Johnson and James Loomis as co-inventor (James A. Loomis (29 Dec 1812-9 Aug 1892) was a machinist and wheelwright from Springfield, Mass.). The patent models of both devices (up to 1880, the US Patent Office required inventors to submit a model with their patent application) are still preserved in the National Museum of American History, Washington, D. C. (see the images below).
The first calculating device, patented by Johnson and Loomis (with Charles Gifford of Gardiner, Maine, as assignee), was used to add numbers up to 99. It was manufactured by James Loomis and Henry Conkey, another machinist from Springfield. It was a brass and steel device with overall measurements: 4.3 cm x 18 cm x 18 cm.
The device is painted black on the reverse side and has a green paper label glued with directions for use. It has also a support attached to the back so that it can sit at an angle.
The adder consists of two concentric brass discs, one rotating inside the other. The rim of the outer disc has the numbers from 0 to 99 engraved around its edge. The inner disc has 100 small holes marked evenly around its edge, which are also numbered 0 to 99. Two steel arms pivot at the center of the inner disc. The longer arm has a pin on the underside that fits into the holes and a small knob on the upper side so that it can be rotated. A protruding pin set at 0 in the outer circle stops the motion of this arm.
The device has a carry mechanism. When the total on the inner disc exceeds 99, the smaller arm advances one digit, indicating hundreds. Hundreds cannot be entered directly. Sums of up to 9999 can be indicated.
The second calculating machine of Alonzo Johnson is essentially an improved version of the first. It was a brass, wood and steel device with overall measurements: 16.5 cm x 18.5 cm x 18.5 cm, used to add numbers up to 99.
This adder of Johnson also has as its base two concentric brass discs, one rotating inside the other. Again, the rim of the outer disc has the numbers from 0 to 99 engraved around its edge. The inner disc has 100 small holes (also are numbered 0 to 99) marked around its edge. Two steel arms pivot at the center of the disc. The longer arm has a pin on the underside that fits into the holes and a small knob on the upper side so that it can be rotated. A protruding pin set at 0 in the outer circle stops the motion of the arm.
The carry mechanism of the device is implemented by means of a smaller arm, which advances one digit, indicating hundreds, when the total on the inner disc exceeds 99. The number of hundreds entered appears in a window in a small disc that is on top of three relatively small gears concentric to the large discs. Hundreds cannot be entered directly. The adder has a big handle that projects from the center of the back.
Biography of Alonzo Johnson
Alonzo Johnson Johnson was born on 12 February 1828, in Bangor, Maine, the son of Lovisa (Underwood) Johnson (26 Oct. 1805-20 April 1835) and Cicero Dolliver Johnson (17 July 1800-30 Nov. 1884).
Dolliver Johnson from Bradford, Vermont, (a son of Joseph Johnson (1765-1827) and Betsey Beckford (1768-1854)) was a railroad engineer at Boston & Worcester Railroad, then a superintendent of locomotive power on the Fitchburg Railroad, and finally associated with the Illinois Central at Duluth, Wis. Dolliver Johnson (a Charter Member of Mount Tabor Masonic Lodge) was also a good mechanic, machinist and farmer. Alonzo had two younger native brothers: James Underwood Johnson (b. 1831) and George Henry Johnson (born and died in 1835), and another brother and two sisters from the second marriage of his father (after the early death of his first wife Lovisa in 1835, Dolliver Johnson married to Lucretia Abbot, on 17 October 1837).
Alonzo Johnson obviously inherited the engineering talents of his father, and became an imaginative man and very good machinist, because besides the above-mentioned patents for calculators, he is the holder of eight more patents for: nut lock (pat. US188055), spindle fastener (US203160), machine for slitting lock nuts (US231492), car brakes (US235152 and US247830), card cutter (US241372), sash fastener (US256144), and gumming device (US397798).
On 27 Oct. 1850 Alonzo Johnson married to Sarah E. Sinclair (b. 13 Dec. 1827 – died 1902) at Canton, Mass. They had three children: Melissa H. (b. 16 June 1854), Charles B. (b. 16 March 1857 – died 1919), and Laura Lovisa (b. 7 Nov. 1858).
Alonzo Johnson died in 1905 in Springfield, Mass., and was buried in the local Oak Grove Cemetery.