John W. Mauchly
1907-1980

Physicist, Inventor, Computer Pioneer
Level 2 biography
Fast Facts
John W. Mauchly [pronounced mawk-lee] was a physicist. With J.Presper Eckert, he developed the first multi-purpose computer, known as ENIAC. The two also developed a number of other computers, including UNIVAC.
Born August 30, 1907 in Cincinnati, Ohio
Married 1. Mary Walzl
2. Kathleen McNulty
Children: 7
Died January 8, 1980 in Ambler, Pa.
Level 2 biography
Fast Facts
John W. Mauchly [pronounced mawk-lee] was a physicist. With J.Presper Eckert, he developed the first multi-purpose computer, known as ENIAC. The two also developed a number of other computers, including UNIVAC.
Born August 30, 1907 in Cincinnati, Ohio
Married 1. Mary Walzl
2. Kathleen McNulty
Children: 7
Died January 8, 1980 in Ambler, Pa.
Early Life
John William Mauchly was born in Cincinnati, Ohio. He was born on August 30, 1907. His father was Sebastian J. Mauchly. His mother’s name was Rachel. John’s father was a scientist. His field was physics. John was interested in science, too. He was fascinated by electricity. When he was five years old, he built a flashlight. In 1913 John’s father got a new job. The Carnegie Institute in Washington D.C. hired him. They asked him to study the earth’s magnetism. The family moved to Chevy Chase, Maryland. John’s father was often away from home. Sometimes he had to go on sea journeys on research ships. He studied the weather.
Like many children, John liked to read after it was time to go to sleep. He did not want his mother to catch him with his light on. He invented a way to make his light turn off when his mother came up the stairs. When she went downstairs again, the light would go back on.
John went to school at the McKinley Technical High School. It was a very good school. It was located in downtown Washington. His family lived comfortably. John liked to play tennis. He walked in the woods. He liked to read Poe’s ghost stories with friends. Once as an April Fool’s joke he tinkered with the doorbell to their house. He fixed it so that anyone ringing it would get a slight electric shock. John was a normal teenager. But in some ways he was very meticulous. He kept a careful diary, which he called his “Daily Record.” He wrote down how much sleep he’d had each night.
While John was in high school, his father became sick. His illness was chronic, which means it would not go away. Mr. Mauchly would not slow down. He would not take care of himself. He worked long hours on his scientific work. This made his illness worse. By the time John started college his parents had moved to the Jersey Shore. They were trying to help his father get better.
Studying at Johns Hopkins University
John was an excellent student. In 1925 he won the Engineering Scholarship of the State of Maryland. He used it to enter Johns Hopkins University. He studied electrical engineering, because that is what the scholarship was for. John did not really like his major subject. Johns Hopkins had a special program for excellent students. They could skip over the rest of their undergraduate work and enroll directly in the doctorate program. John did this in 1927. He entered the graduate Physics program.
John’s father died in 1928, around Christmas time. John did not have to stop going to school. He had scholarships that paid his way. In 1930 John married Mary Walzl.
In 1932 John finished his studies. He wrote a dissertation. It was called “The Third Positive Group of Carbon Monoxide Bands.” He was awarded his PhD [doctorate] in Physics.
Finding a Place to Work
When John finished school, many people were out of work. It was the time in history we call the Depression. It was hard for new scientists to find work. John’s interest and study was in molecular spectroscopy. A few years before that had been a hot topic. Now interest in it was fading. John applied to a number of places that did research. He even applied to Carnegie, where his father had worked. None of them wanted him.
Finally John got a job. Ursinus College hired him. He taught beginning Physics courses. John wanted to do research as well. Ursinus was not a large school. It did not have spectrometers or accelerators. John had to make do with what he had.
John became interested in weather data. His father had studied weather. Now weather information was being collected all around the world. He could get the information in the form of tables. He was interested in analyzing these tables. He studied the variations in the ion density of the ionosphere during the day. He worked for two summers at the Department of Terrestrial Magnetism. This was part of the Carnegie Institute in Washington D. C. John’s studies took a long time. For each set of numbers that he studied, he had to do many calculations. John studied one month’s worth of figures. He wrote a paper on what he had learned. Experts rejected it. They said his study needed to be of a longer period of time. A month was not enough. But to study a longer period would involve a massive number of calculations.
John very much wanted a way to speed up his calculations. He was interested in creating some kind of electronic calculating machine. He spent two years experimenting with digital circuitry. He built a switch that would flip-flop to record 1’s and 0’s. The best results came with using vacuum tubes to run the machinery. John couldn’t afford vacuum tubes. He used neon tubes instead. They were cheaper. The problem was that they didn’t work as well. John was frustrated.
A Chance to Study at Moore School of Electrical Engineering
One day John got a letter from the Moore School of Electrical Engineering in Philadelphia. The school had a new program. They had been commissioned by the army to find people who had degrees in math or physics. The school was to select some of these people. They were to teach them about the army’s new weapons and communications systems. That way, if there were another war, there would be people who knew how they worked. The letter asked if John had any students who might be interested in the program. John was interested himself! He enrolled in 1941. He was overqualified, with his doctorate in physics, but he went anyway.
John took the course. He found it easy. The lab instructor was named J. Presper Eckert. After John finished his class work, he and Pres Eckert had time to talk. John told Pres about his idea for a computer. The two men talked about it many times.
John William Mauchly was born in Cincinnati, Ohio. He was born on August 30, 1907. His father was Sebastian J. Mauchly. His mother’s name was Rachel. John’s father was a scientist. His field was physics. John was interested in science, too. He was fascinated by electricity. When he was five years old, he built a flashlight. In 1913 John’s father got a new job. The Carnegie Institute in Washington D.C. hired him. They asked him to study the earth’s magnetism. The family moved to Chevy Chase, Maryland. John’s father was often away from home. Sometimes he had to go on sea journeys on research ships. He studied the weather.
Like many children, John liked to read after it was time to go to sleep. He did not want his mother to catch him with his light on. He invented a way to make his light turn off when his mother came up the stairs. When she went downstairs again, the light would go back on.
John went to school at the McKinley Technical High School. It was a very good school. It was located in downtown Washington. His family lived comfortably. John liked to play tennis. He walked in the woods. He liked to read Poe’s ghost stories with friends. Once as an April Fool’s joke he tinkered with the doorbell to their house. He fixed it so that anyone ringing it would get a slight electric shock. John was a normal teenager. But in some ways he was very meticulous. He kept a careful diary, which he called his “Daily Record.” He wrote down how much sleep he’d had each night.
While John was in high school, his father became sick. His illness was chronic, which means it would not go away. Mr. Mauchly would not slow down. He would not take care of himself. He worked long hours on his scientific work. This made his illness worse. By the time John started college his parents had moved to the Jersey Shore. They were trying to help his father get better.
Studying at Johns Hopkins University
John was an excellent student. In 1925 he won the Engineering Scholarship of the State of Maryland. He used it to enter Johns Hopkins University. He studied electrical engineering, because that is what the scholarship was for. John did not really like his major subject. Johns Hopkins had a special program for excellent students. They could skip over the rest of their undergraduate work and enroll directly in the doctorate program. John did this in 1927. He entered the graduate Physics program.
John’s father died in 1928, around Christmas time. John did not have to stop going to school. He had scholarships that paid his way. In 1930 John married Mary Walzl.
In 1932 John finished his studies. He wrote a dissertation. It was called “The Third Positive Group of Carbon Monoxide Bands.” He was awarded his PhD [doctorate] in Physics.
Finding a Place to Work
When John finished school, many people were out of work. It was the time in history we call the Depression. It was hard for new scientists to find work. John’s interest and study was in molecular spectroscopy. A few years before that had been a hot topic. Now interest in it was fading. John applied to a number of places that did research. He even applied to Carnegie, where his father had worked. None of them wanted him.
Finally John got a job. Ursinus College hired him. He taught beginning Physics courses. John wanted to do research as well. Ursinus was not a large school. It did not have spectrometers or accelerators. John had to make do with what he had.
John became interested in weather data. His father had studied weather. Now weather information was being collected all around the world. He could get the information in the form of tables. He was interested in analyzing these tables. He studied the variations in the ion density of the ionosphere during the day. He worked for two summers at the Department of Terrestrial Magnetism. This was part of the Carnegie Institute in Washington D. C. John’s studies took a long time. For each set of numbers that he studied, he had to do many calculations. John studied one month’s worth of figures. He wrote a paper on what he had learned. Experts rejected it. They said his study needed to be of a longer period of time. A month was not enough. But to study a longer period would involve a massive number of calculations.
John very much wanted a way to speed up his calculations. He was interested in creating some kind of electronic calculating machine. He spent two years experimenting with digital circuitry. He built a switch that would flip-flop to record 1’s and 0’s. The best results came with using vacuum tubes to run the machinery. John couldn’t afford vacuum tubes. He used neon tubes instead. They were cheaper. The problem was that they didn’t work as well. John was frustrated.
A Chance to Study at Moore School of Electrical Engineering
One day John got a letter from the Moore School of Electrical Engineering in Philadelphia. The school had a new program. They had been commissioned by the army to find people who had degrees in math or physics. The school was to select some of these people. They were to teach them about the army’s new weapons and communications systems. That way, if there were another war, there would be people who knew how they worked. The letter asked if John had any students who might be interested in the program. John was interested himself! He enrolled in 1941. He was overqualified, with his doctorate in physics, but he went anyway.
John took the course. He found it easy. The lab instructor was named J. Presper Eckert. After John finished his class work, he and Pres Eckert had time to talk. John told Pres about his idea for a computer. The two men talked about it many times.
Moore School and the War Effort
Moore School was involved in several projects. One had to do with artillery. The army was producing new weapons. They wanted to know how far these weapons would shoot their missiles and bombs at various angles. This is called measuring the trajectory. They set up the Ballistics Research Laboratory [BRL]. It consisted of a group of skilled women who sat with desktop calculating machines and figured out all of the numbers for firing tables. Even though the women worked hard all day, they could not keep up with the number of calculations that needed to be done. There was always a backlog of work. John Goes to Work for Moore
Some of the regular professors were doing war research. Someone had to teach their classes. Moore needed to hire more teachers. After his summer course, Moore hired John as an adjunct professor. He taught some basic electrical engineering courses. He also was assigned to a U.S. Army Signal Corps project, to study radar. His job was to calculate antenna radiation patterns. He used a team of mathematicians (mostly women) to do the calculations. In addition, he studied cryptography in his spare time. All of this gave him lots of practice with complicated calculations.
ENIAC
John continued to work on the idea of a computing device. He visited Professor John V. Atanasoff in Iowa in 1941. Professor Atanasoff and his helper, Clifford Berry, were also working on making a machine to do calculations. Theirs was called the ABC [Atanasoff-Berry Computer.] It was complex, but it was designed to do just one job.
In 1942 John wrote a memo. He outlined the idea for a large-scale digital electronic computer. It would be able to do many types of calculations. He wrote the memo carefully to get the maximum interest. He said the computer could:
In 1943 Lt. Herman Goldstine read the memo. He was part of the Ballistics Research Laboratory. He had a doctorate in mathematics. He knew that a computer such as John suggested could solve his calculations backlog problem. Goldstone encouraged Moore and the Ordnance Department to support the project. The army funded the building of the computer. It was a secret, so it had a secret name. It was called Project PX. John’s friend J. Presper Eckert was the chief engineer of the project. Officially John was only a consultant to the project. In reality he worked very closely with Eckert and others.
Building a computer was not easy. It took 2 ½ years. It cost the army about $500,000.00. There were many problems. But at last on February 14, 1946 the new computer was ready to go. It was called ENIAC. This stood for Electronic Integrator And Computer.
Moore School was involved in several projects. One had to do with artillery. The army was producing new weapons. They wanted to know how far these weapons would shoot their missiles and bombs at various angles. This is called measuring the trajectory. They set up the Ballistics Research Laboratory [BRL]. It consisted of a group of skilled women who sat with desktop calculating machines and figured out all of the numbers for firing tables. Even though the women worked hard all day, they could not keep up with the number of calculations that needed to be done. There was always a backlog of work. John Goes to Work for Moore
Some of the regular professors were doing war research. Someone had to teach their classes. Moore needed to hire more teachers. After his summer course, Moore hired John as an adjunct professor. He taught some basic electrical engineering courses. He also was assigned to a U.S. Army Signal Corps project, to study radar. His job was to calculate antenna radiation patterns. He used a team of mathematicians (mostly women) to do the calculations. In addition, he studied cryptography in his spare time. All of this gave him lots of practice with complicated calculations.
ENIAC
John continued to work on the idea of a computing device. He visited Professor John V. Atanasoff in Iowa in 1941. Professor Atanasoff and his helper, Clifford Berry, were also working on making a machine to do calculations. Theirs was called the ABC [Atanasoff-Berry Computer.] It was complex, but it was designed to do just one job.
In 1942 John wrote a memo. He outlined the idea for a large-scale digital electronic computer. It would be able to do many types of calculations. He wrote the memo carefully to get the maximum interest. He said the computer could:
- Do ballistics calculations
- Show how good Moore was in the field of engineering.
- Serve as a general-purpose digital computer. [It could measure more than just ballistics: it would be good for weather analysis and cryptography as well.]
In 1943 Lt. Herman Goldstine read the memo. He was part of the Ballistics Research Laboratory. He had a doctorate in mathematics. He knew that a computer such as John suggested could solve his calculations backlog problem. Goldstone encouraged Moore and the Ordnance Department to support the project. The army funded the building of the computer. It was a secret, so it had a secret name. It was called Project PX. John’s friend J. Presper Eckert was the chief engineer of the project. Officially John was only a consultant to the project. In reality he worked very closely with Eckert and others.
Building a computer was not easy. It took 2 ½ years. It cost the army about $500,000.00. There were many problems. But at last on February 14, 1946 the new computer was ready to go. It was called ENIAC. This stood for Electronic Integrator And Computer.
The army had been interested in ENIAC for the ballistics calculations. They had used ENIAC to do some of the calculations for the hydrogen bomb. Now the war was over. They did not need to do the trajectory calculations any more. Since ENIAC was multi-purpose, it was not a waste of money. The army could use it for other things. Right away they had a new use for ENIAC. It could work on the calculations for the atomic bomb, being developed at Los Alamos. ENIAC was very good, but John and his friend Pres Eckert knew that they could do better. They worked on upgrading ENIAC.
Starting a Business
John and Pres Eckert had developed ENIAC at a university. Usually the university doesn’t allow you to apply for a patent if you’ve done the work in their laboratories. But this project was funded by the military, so it wasn’t really the university’s property. The two men were allowed to file for a patent. It was granted. Then after the war the university tightened up its patent policy, and asked John and Pres to give their patent rights to the university. After doing all the work to get the patent, they would not give it up. They resigned on March 31, 1946.
The two men started their own business. It was called the Electronic Control Company. It was located in downtown Philadelphia. They still had ideas for making a better computer. John’s part of the job was to find ways in which computers could be used. Pres had the job of designing and building the new machine. John was able to get a contract from the Census Bureau. While working on this, in December 1948, they changed the name of the company to the Eckert-Mauchly Computer Corporation.
Personal milestones
In the summer of 1946 John’s wife Mary was swimming at the New Jersey Shore. She drowned. Some years later John married Kathleen McNulty. She had been one of the women who performed the many calculations during the war.
UNIVAC
John and Pres developed a better computer. They named it UNIVAC. This stood for Universal Automatic Computer. UNIVAC was a huge success. It had some new features. It used magnetic tape instead of punch cards. The census bureau used it to tabulate their figures. John had told them that it would save them money. It did. They liked another feature even better. It was fast. Other groups found uses for it.
One group interested in UNIVAC was the news media. In 1952 there was a Presidential election. Adlai Stevenson was the favorite. His opponent was Dwight D. Eisenhower. All of the opinion polls said that Stevenson would win. CBS News fed data into UNIVAC. It predicted that Eisenhower would win, by many votes. UNIVAC was right! Other companies began building computers.
Selling the Business
Even though John and Pres worked hard, they could not make their business pay. The computer business was so new that it was hard to predict how much something would cost. They were great scientists. They were not great businessmen. Finally they sold the company to Remington Rand. John continued to work for Remington Rand. He was to be an advisor. John was not happy in this job. He didn’t think he was asked for much advice.
John left Remington Rand in 1959 and started his own company. It was called Mauchly Associates. He worked as a consultant. He advised businesses and industries. He started another company in the 1960’s. This one was called Dynatrend.
Later Life
Eventually John Mauchly moved to the Philadelphia suburbs. He settled in Ambler, Pa. John had heart surgery on January 8, 1980. He died during the surgery. He was 72 years old.
Was John Mauchly really the inventor of the computer?
Some people say that credit for the computer should go to Professor Atanasoff. He designed a computing device before John and Pres Eckert did. But Professor Atanasoff’s machine never worked very well. The computer that John and Pres developed worked on a large scale, was dependable, and did many functions. Most complicated inventions are the result of lots of peoples’ ideas. Probably no one person can take credit for the computer.
Reading Level 5.9. Images of Mauchly and Eckert from U.S. Department of Energy. Images of ENIAC courtesy of ushistory.org
Starting a Business
John and Pres Eckert had developed ENIAC at a university. Usually the university doesn’t allow you to apply for a patent if you’ve done the work in their laboratories. But this project was funded by the military, so it wasn’t really the university’s property. The two men were allowed to file for a patent. It was granted. Then after the war the university tightened up its patent policy, and asked John and Pres to give their patent rights to the university. After doing all the work to get the patent, they would not give it up. They resigned on March 31, 1946.
The two men started their own business. It was called the Electronic Control Company. It was located in downtown Philadelphia. They still had ideas for making a better computer. John’s part of the job was to find ways in which computers could be used. Pres had the job of designing and building the new machine. John was able to get a contract from the Census Bureau. While working on this, in December 1948, they changed the name of the company to the Eckert-Mauchly Computer Corporation.
Personal milestones
In the summer of 1946 John’s wife Mary was swimming at the New Jersey Shore. She drowned. Some years later John married Kathleen McNulty. She had been one of the women who performed the many calculations during the war.
UNIVAC
John and Pres developed a better computer. They named it UNIVAC. This stood for Universal Automatic Computer. UNIVAC was a huge success. It had some new features. It used magnetic tape instead of punch cards. The census bureau used it to tabulate their figures. John had told them that it would save them money. It did. They liked another feature even better. It was fast. Other groups found uses for it.
One group interested in UNIVAC was the news media. In 1952 there was a Presidential election. Adlai Stevenson was the favorite. His opponent was Dwight D. Eisenhower. All of the opinion polls said that Stevenson would win. CBS News fed data into UNIVAC. It predicted that Eisenhower would win, by many votes. UNIVAC was right! Other companies began building computers.
Selling the Business
Even though John and Pres worked hard, they could not make their business pay. The computer business was so new that it was hard to predict how much something would cost. They were great scientists. They were not great businessmen. Finally they sold the company to Remington Rand. John continued to work for Remington Rand. He was to be an advisor. John was not happy in this job. He didn’t think he was asked for much advice.
John left Remington Rand in 1959 and started his own company. It was called Mauchly Associates. He worked as a consultant. He advised businesses and industries. He started another company in the 1960’s. This one was called Dynatrend.
Later Life
Eventually John Mauchly moved to the Philadelphia suburbs. He settled in Ambler, Pa. John had heart surgery on January 8, 1980. He died during the surgery. He was 72 years old.
Was John Mauchly really the inventor of the computer?
Some people say that credit for the computer should go to Professor Atanasoff. He designed a computing device before John and Pres Eckert did. But Professor Atanasoff’s machine never worked very well. The computer that John and Pres developed worked on a large scale, was dependable, and did many functions. Most complicated inventions are the result of lots of peoples’ ideas. Probably no one person can take credit for the computer.
Reading Level 5.9. Images of Mauchly and Eckert from U.S. Department of Energy. Images of ENIAC courtesy of ushistory.org