Early Life and Education
William Henry Hart was born in 1829 in New York state. Not much is known about his childhood or early education, but census records show that as an adult he lived in Maysville, Wisconsin. There he married a woman named Elizabeth Davidson from Pennsylvania in 1850, when Hart would have been around 21 years old.
The couple started a family, ultimately having eight children: Emma Delilah, Rosalie, Henry, Sarah Sadie, twins Lawrence and Clarence, Volney, and Waren. According to census data, Hart supported his household through work as a watchmaker and jewelry store owner. By 1867 when their son Lawrence was a year old, the Harts relocated to Kirksville, Missouri. This is where William Henry Hart would spend much of his inventive career.
Career as a Jeweler and Watchmaker
Once settled in Kirksville, Hart wasted no time establishing himself professionally. He opened his own jewelry store on the main town square doing business as W. Hart Jeweler. Being an entrepreneurial sort, Hart even made an unsuccessful run for city council in 1874.
The following year Hart entered into a partnership with one Albert Dutcher, likely to access more investment capital for his store. However by 1880 he had sold his interest to Dutcher and transitioned into watchmaking full time. Likely his exposure to the intricate gears and mechanics of timepieces inspired some of Hart‘s later inventions.
Ill health compelled Hart to spend more time outdoors around this period. But by 1886 he felt well enough to return to the jewelry trade via the firm Hart & Miller. Later he owned a store named Hart’s Jewelry outright. Tragically in 1890 this establishment burned down in a fire that took the life of his son Volney and left William Hart himself with severe injuries.
Remarkably by 1892 Hart had recovered enough to open yet another shop with his remaining son Lawrence, called Hart & Son, which specialized in watches and jewelry. His son would go on to become an early osteopathic physician. Clearly William Henry Hart was adaptable and determined when faced with personal and professional challenges. But it is his side interest as a serial inventor, rather than retail business, for which he is best remembered today.
A Prolific Inventor and Tinkerer
William Henry Hart had a mechanically creative mind, as evidenced by the over thirteen patents he held for various contraptions and devices. He likely developed many of these innovations while running his jewelry stores, needing tools and equipment for delicate watch repairs.
Unfortunately it seems that only one of Hart‘s patented concepts ever made it into commercial production – the calculating machine that bore his name. Others like graphaphone reproducers, clock escapements, hammers, and jewel setting tools probably never progressed past the design phase.
Nonetheless, the range of technical problems Hart attempted to solve is impressive and speaks to his relentless experimentation. He surely had a well equipped workshop both at home and his places of business to tinker with all these novel ideas. It‘s as an ingenious inventor rather than tradesman where Hart made his lasting impact.
Hart‘s Important Calculating Machine Invention
Hart‘s most famous creation is no doubt the Hart‘s Mercantile Computing Machine, for which he obtained US patent #199,289 in January of 1878. The key motivation behind this mechanical calculator was to speed up the accounting operations needed by virtually every merchandising or retail business of the era.
Manually computing large volumes of transactions, interest, payroll, etc. occupied huge chunks of a store owner‘s time in the 19th century. So there was strong demand for a fast yet affordable calculating aide not relying solely on the human memory. Hart‘s computing machine brilliantly fit this niche.
It consisted of three stacked brass discs or rings marked with numeric digits zero through nine. Each disc was nested inside the other and could be independently rotated to dial in numbers. The disks were turned by a long handle which incorporated a pointer to set the various digits of the multiplicands.
Mechanically connecting the rotating discs were a series of concentric shafts and gears. These enabled numbers set on each disc to be carried over and accumulated in appropriate columns. So a merchant could readily perform operations like addition, subtraction, multiplication in their head or on paper – but then simply dial in the values and turn the handle to derive sums, differences, products, etc.
A key innovation Hart introduced was an automatic "hundreds carry" mechanism constructed from watch-like components. This feature enabled his machine to tally totals up to 9,999 accurately, eliminating human errors. Based on separate reports, Hart sold between 3,000 to 5,000 computing machines from 1878 onwards, indicating substantial commercial success.
Hart‘s Mercantile Computing Machine helped pave the way for cheap and efficient mechanical calculators used well into the 20th century. Even as electronics and then computers replaced purely mechanical approaches, Hart deserves credit as an early computing pioneer attempting to reduce the laborious nature of numerical work.
Involvement with the Spiritualist Movement
In addition to Hart‘s retail and invention careers, he also nurtured a passion for spiritualism later in life. In 1884 Hart and his wife Elizabeth were two of the original incorporators of the Spiritual and Liberal Association in Kirksville.
This organization centered around the belief that spirits of deceased people could communicate with and even physically manifest themselves to the living. Séances, mystical predictions and ghost sightings were central activities, quite in vogue during the late 1800s. How deeply Hart actually believed in psychic mediums versus just intellectual curiosity is unknown.
Nonetheless, his involvement shows dimensions beyond career and commerce. The Spiritual and Liberal Association also promoted progressive social causes like abolitionism, women’s rights, health reforms and liberal activism. So participation offered opportunities to discuss contemporary issues and politics too.
Later Years and Passing in Mexico
After 44 years of marriage, misfortune struck again when Hart’s wife Elizabeth died in January 1894. Perhaps this combined with memories of his burned down store and deceased son encouraged Hart to make a dramatic life change. Not long afterwards, he departed Kirksville permanently and immigrated across the border to Mexico.
At the time, Los Mochis in the state of Sinaloa was being established by American settlers as a utopian socialist community. Two of William Henry Hart’s adult children Henry and Rosalie had already relocated there, probably influencing his destination choice. Sadly just three years after arriving, Hart himself passed away in Los Mochis on April 2, 1907 at 78 years old.
He left behind an impressive professional and creative legacy, over a dozen patented inventions covering a diversity of applications, and advancement of 19th century computing aids that benefitted family businesses across America. While the Spiritual and Liberal Association likely dissolved long ago, inventor William Henry Hart’s impact persists indirectly whenever we reach for a calculator to simplify routine arithmetic.
