John Mauchly – Complete Biography, History, and Inventions

John Mauchly

John Mauchly – Complete Biography, History, and Inventions

Key Points

  • John’s aptitude for physics was apparent in his youth when he not only installed bells and resolved electrical issues for his neighbors, but also excelled at Mathematics and Physics.
  • His brilliant mind earned him the Engineering Scholarship of the State of Maryland. In 1925, he enrolled at Johns Hopkins University, to study Electrical Engineering.
  • In 1941 John worked with Eckert on trajectory tables for artillery shells. Both men also designed the first computers BINAC and UNIVAC.
John Mauchly
John Mauchly

Who Was John Mauchly?

John William Mauchly was an American physicist who designed the ENIAC. ENIAC is popularly regarded as the first general-purpose electronic digital computer. John completed ENIAC’s design alongside J. Presper Eckert. His other design includes BINAC, UNIVAC I, and EDVAC.

John Mauchly worked collaboratively with J. Presper Eckert; they both started the first computer company in the United States, the Eckert–Mauchly Computer Corporation (EMCC) while pioneering multiple fundamental computer concepts, such as programming languages, stored programs, and subroutines. Their works influenced an explosion of computer development in the late 1940s worldwide.

Quick Facts

Full Name
John Mauchly
August 30, 1907
January 8, 1980
  • IEEE Emanuel R. Piore Award
  • Harold Pender Award
  • Harry H. Goode Memorial Award
Place of Birth
Cincinnati, Ohio
Fields of Expertise
Ursinus College, University of Pennsylvania
ENIAC, UNIVAC, Mauchly’s sphericity test

Early Life

John William Mauchly was born on 30 August 1907, in Cincinnati, Ohio, to the family of Sebastian J. and Rachel Scheidemantel Mauchly. His father, Sebastian Mauchly, was a high-school science teacher, who went on to receive his Ph.D. in physics from the University of Cincinnati.

When John Mauchly was eight (8), his father received an appointment as a chief physicist at the Carnegie Institute of Washington, D.C., in the newly established Department of Terrestrial Magnetism. This position, and his apparatus, enabled John’s father to discover the diurnal variation in the Earth’s magnetic field, a discovery for which he secured a considerable reputation.

John’s mother, Rachel Mauchly, was also a strong woman, who enjoyed the gay lifestyle of the 1920s. She had attended the regular meetings of the local Women’s Club, hosted some of its luncheons, and held informal hen parties with her new friends and social acquaintances. She worked hard to cultivate her son’s interests, arranging for his obligatory piano lessons, chiding him for his penmanship, and saving up for the annual family vacation out at the Jersey shore.

His father’s occupation afforded John a decent education, beginning with his schooling at the McKinley Technical High School in downtown Washington. Yet in grade school, John Mauchly demonstrated his talent in construction and earned money installing electric bells in place of mechanical bells.

For instance, when neighbors had trouble with their wiring, they called John Mauchly. He earned near-perfect scores in high school, was a whiz at math and physics, and was editor of the school paper his senior year (1925).

Still, in balancing his school work with tennis matches and walks through the woods, or one of Edgar Allen Poe’s ghost stories read in the dark among friends, Mauchly led a reasonably comfortable existence as an upper-middle-class youth. His academic achievements brought him the Engineering Scholarship of the State of Maryland, which enabled him to enroll at Johns Hopkins University in the fall of 1925, for an undergraduate program in Electrical Engineering.

During his freshman year at Johns Hopkins University, John complained to his father about the General Engineering course, which attempted to provide a more theoretical foundation for engineering. Sadly, by the end of his second year, he began to feel that engineering was too mundane.

In 1927, John Mauchly used a special provision that allowed outstanding students to enroll directly in a Ph.D. program before completing their undergraduate degrees and transferring to the graduate physics program of the university.

Unfortunately, John’s father passed away on Christmas Eve of 1928, which somewhat aggravate the family crisis. However, thankfully, a few scholarships permitted him to continue with his studies after his father’s death. John Mauchly submitted his dissertation on “The Third Positive Group of Carbon Monoxide Bands” to the faculty of Johns Hopkins University in 1932.


Phase 1

After his father’s death, John Mauchly eventually accepted a teaching position in physics at Ursinus College, a small, liberal arts college located on the outskirts of Philadelphia, where he taught introductory physics courses.

However, the circumstances at Ursinus did not suit the research interests to which he had been thoroughly conditioned. Physics itself was changing, and by the 1930s the leading laboratories in the country were equipped with accelerators, spectrometers, and other instruments beyond the resources of many state universities, let alone an individual professor working at a liberal arts college.

John made multiple attempts to develop analog electronic instruments suitable for specific lines of research. He also discovered a wealth of meteorological data, which by the 1930s were being collected from field stations located all around the globe. Such data were available in tabular form and were transportable to an isolated researcher. Their analysis, however, required extensive calculations.

John Mauchly actually sought more generally to improve calculating instruments, thinking as much about the needs of his students as his own research. This preoccupation with making calculations quicker and easier led him toward calculating machines.

John purchased a second-hand Marchant calculator to carry out the calculation of molecular energy levels that could be extracted from meteorological data.

Phase 2

John Mauchly decided to take up a position as a temporary assistant physicist and computer at the Carnegie Institution’s Department of Terrestrial Magnetism during the summer of 1936. He accepted a position as a glorified human-computer, working for his father’s former supervisor.

At the end of the third summer, John had submitted his work for publication in the Journal of Terrestrial Magnetism and Atmospheric Electricity; although it was rejected, particularly for relying on a relatively short period of data analysis.

This caused John to think about finding a means of performing a greater volume of computation. He first turned to the resources offered by the National Youth Administration, a Depression-era agency that allowed him to hire students to work as human computers. Simultaneously, John turned to mechanical solutions. One aspect of this was his decision to examine tabulating machines, a machine that was used to routinely compute statistics in the social sciences.

This new interest alongside his encounter with John Atanasoff eventually in 1941 led John to the Moore School of Electrical Engineering, part of the University of Pennsylvania. The Moore School stood at the heart of a strong regional electrical industry that had grown with the popularity of radio, telephony, and other electronic technologies.

With the prospects of war looming, the military began to seek young engineers trained to operate the electronic weapons and communications systems that were becoming an increasing part of U.S. armaments. The Moore School stepped forward to accept a contract from the U.S. Army to teach a special ten-week course on Electrical Engineering for Defense Industries directed to students with a degree in mathematics or physics.

Consequently, John Mauchly agreed to study electrical engineering at the Moore School, despite having the opportunity to take up a defense training job at another college with bigger pay. It was there he met Eckert and they began their famous collaboration.

The Moore School had already developed one of the most advanced electro-mechanical computational devices in the world, the differential analyzer. The differential analyzer was a mechanical analog computer designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration.
At the beginning of the war, the United States Army had awarded the school a contract to compute the tables of trajectories for artillery shells. Both John and Eckert became deeply involved in this project, which, in turn, increased his interests in electronic computation and ultimately to the creation of ENIAC

What is John Mauchly known for?

Invention 1

John Mauchly and Eckert resigned from the Moore Engineering School in 1947 and began their own corporation, the Eckert and Mauchly Computer Corporation. Later on, they developed the computers BINAC and UNIVAC, wherein Eckert catered to the engineering functions, and John ran the business.

However, neither John nor Eckert were brilliant businessmen, causing them to run into financial troubles, and in 1950 they sold their company along with their computer patents to Remington Rand.

Sperry Rand later bought out Remington. John Mauchly worked for Remington and Sperry until 1959 when he left to form his own consulting corporation, Mauchly Associates. In 1968, he founded a second computer consulting corporation, which he called Dynatrend.

Mauchly leaning over UNIVAC console
John Mauchly leaning over the UNIVAC console

Invention 2

Despite his family, business, and court problems, we can safely say that John Mauchly had a successful career. Whatever the various turns in his life, he designed and oversaw the development of the first large-scale general-purpose electronic computer. He created a start-up venture which he eventually sold at a profit to the company that went on to manufacture his computer. His work as a consultant was also successful.

John Mauchly: Marriage, Divorce, Children, and Personal Life


John Mauchly got married twice. He married his first wife, Mary Augusta Walzl, a mathematician, in 1930. On 7 February 1948, John married one of the programmers on the ENIAC, Kathleen R. McNulty.


John Mauchly had two (2) children with his first wife: a son, James, born 1935, and a daughter, Sidney, born 1939. Unfortunately in September 1946, while they were swimming in the Atlantic, Mary was swept out to sea and drowned. He had five more children with his second wife, Kathleen, four daughters, and a son.


John lost his father on Christmas Eve of 1928. Also, unfortunately, in September 1946, while they were swimming in the Atlantic, Mary, his first daughter was swept out to sea and drowned.

John Mauchly technically suffered all his life from a hereditary genetic disease called hemorrhagic telangiectasia, which caused anemia, bloody noses, and internal bleeding, among other symptoms. In his later life, he had to carry around oxygen to breathe properly. He died on January 8, 1980, of complications from an infection.

John Mauchly: Awards and Achievements

Award 1

Mauchly received a few academic recognition for his contributions. This includes the Potts Medal of the Franklin Institute in 1949, the John Scott Award in 1961, and the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.

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Frequently Asked Questions

Who was John Mauchly?

John William Mauchly was an American physicist who designed the ENIAC. ENIAC is popularly regarded as the first general-purpose electronic digital computer. John completed ENIAC’s design alongside J. Presper Eckert. His other design includes BINAC, UNIVAC I, and EDVAC.

What else did John Mauchly invent aside from the ENIAC?


How did John Mauchly invent his electronic computer?

At the beginning of the war, the United States Army had awarded the The Moore School a contract to compute the tables of trajectories for artillery shells. Both John and Eckert became deeply involved in this project, which, in turn, increased his interests in electronic computation and ultimately to the creation of ENIAC.

When was John Mauchly born?

August 30, 1907

When did John Mauchly die?

January 8, 1980.

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