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Photos courtesy of the Mauchly and Bartik families, United States Army, Library of Congress

Facts amid the fiction

The Eniac Six

While it was fun to dig up old comic books and learn about Fantomah, Magician From Mars, and Black Cat, I was even more excited to read about the real-life women of early computers, the ENIAC Six, and imagine them joining the fight against evil with the superheroes. Because the skills they demonstrated during the war made them superheroes of sorts too.

During WWII, only men were allowed to fight in the Armed Forces, so as they went overseas to battlefronts, women were tapped to enter the workforce. And they did it in large numbers and in a variety of important roles. We’ve come to know the familiar posters for “Rosie the Riveter” and “Wendy the Welder,” who encouraged women to work in shipyards and munitions plants. But there were many women who took on more daring positions as pilots, code crackers, and even “human computers.”

As computers, they used mechanical desk calculators to work through challenging mathematical equations. The answers to these calculations were then compiled into tables and turned into books, which soldiers used during combat. The tables helped soldiers increase their accuracy as they aimed artillery weapons through rain, high winds, and other factors that might affect a shell’s trajectory toward a target.


Now these sorts of calculations are done instantly using computer technology, but during WWII, it took human computers sometimes thirty hours to calculate a single trajectory. For them, math was a powerful weapon. And it was something they were good at. “I loved it and found it fun and easy to do,” recalled one of the ENIAC Six, Kathleen “Kay” McNulty Mauchly Antonelli, about her interest in mathematics.


“I didn’t want to teach. I just wanted to do the math puzzles.”

Kay McNulty graduated in 1942 with a degree in mathematics. And with the war just getting underway, she saw a world of job possibilities open up for women like her who had a passion for math. “About 2 weeks after I graduated . . . there was an ad in the Philadelphia paper saying, ‘Looking for women math majors.’ ” The job they were asked to do? Serve as “computers.”

Kay wasn’t the only woman to answer the ad—hundreds of women did. But six special mathematicians—Kay McNulty and her friend from math classes Frances Bilas Spence, Jean Jennings Bartik, Ruth Lichterman Teitelbaum, Frances “Betty” Snyder Holberton, and Marlyn Wescoff Meltzer—were asked to use their remarkable math skills in service to a top-secret, massive new calculator called the ENIAC.

“We knew this calculator was being built at the Moore School,” wrote Kay, “but nobody talked to us about it, and we really had no idea what it looked like. I never went into the PX [Project X] room because it was classified ‘Confidential’ with signs saying that no one without clearance was allowed in the room.”

The ENIAC, which is considered the world’s first digital, general-purpose computer, was created by John Presper “Pres” Eckert Jr. and John W. Mauchly to speed up the time it took to solve complicated math problems. It could work a thousand times faster than human computers. Through cables, switches, and vacuum tubes set in specific sequences, the machine answered questions in seconds. But the trick was arranging it all just right.

With no instructions or manual to guide them, the ENIAC Six had to figure out on their own how to get the machine to do what they wanted. And so with every pattern they set up, they wrote down the precise steps, then unplugged the cables and moved them to another spot. Soon they were doing something that had never been done before: programming!

It was not until 1997 until Kay, Jean, Fran, Marlyn, Betty, and Ruth received the honors they deserved, when all six of them were inducted into the Women in Technology International Hall of Fame. Just like the superheroes in comic books, the ENIAC Six used their superpowers with math to perform remarkable, even heroic deeds.

“I think she would think that you don't need superpowers,” reflected Jean’s son, Tim Bartik, on his mother’s barrier-breaking role, “you just need to focus on your dreams and goals, be persistent, and follow through and complete the task at hand.”

If Jean could give any advice to young girls today, Tim figured it would be direct and to the point: 


"She'd say, ‘Go for it. Why let the men have all the fun?’ "

While The League of Secret Heroes series is a work of fantasy fiction, it is inspired by a variety of World War II figures, organizations, and historical moments. What follows is some of the factual information that appears in CAPE, MASK, and BOOTS.

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My Grandfather

I've always been fascinated with learning about the ENIAC machine because my own grandfather, Bill Nolan, worked on it. During WWII he moonlighted after hours from his day job at Bell Telephone Co. on the ENIAC. The work was so secret, he didn't even tell his family about it. My mother and her siblings learned about it after the war.

Room Twelve
During World War I, British Naval Intelligence was made up of a collection of code-crackers driven to break German codes. They were housed in Room 40 in the Old Building of the Admiralty of the British Navy, and as their success grew, “Room 40” eventually came to stand for naval intelligence, the secrecy around it, the undercover work, and their impressive achievements. With this in mind for Cape, I called the secret intelligence operation “Room Twelve” as an echo to Britain’s Room 40.


Spy Tricks

Spies employed fascinating tricks during World War II—from hanging laundry in a way that signaled or spelled out a clue to marking up newspapers and leaving them in seemingly casual spots, like a bench or table, for other designated spies to receive. And many spies went to great lengths to make sure nobody was following them, entering buildings by one door and quickly leaving by another or jumping on a train in one direction and then jumping off to catch one going the opposite way. Here are a few other interesting examples of spy tricks from history:


  • Explosive rats: With the intention of blowing up important enemy sites, spies and saboteurs would stuff dead rats with explosives and place them around factories or other key locations. When factory workers came across the rodents, they might toss them into a trash fire to get rid of them. Once in the fire, the dynamite-stuffed rats would explode, damaging the factory and harming anyone nearby.


  • Invisible ink: Secret messages are nothing new, and they can be traced back to the earliest civilizations. While there are high-tech chemical formulas for mixing invisible ink, you can keep it simple by using milk or even lemon juice. To write a note like Emmett’s secret message to Josie, simply dip a cotton swab in milk, write your note on a blank sheet of paper, then let it dry. To uncover the invisible message, hold the dry paper over a flame—but not too close or it will burn! (Make sure to have an adult with you to supervise.)


Learn more about spies and spy tricks at the International Spy Museum in Washington, D.C.

Alyce Hall & the Women Computers

From 1942-46, hundreds of women mathematicians took on jobs as “computers” to calculate ballistics tables for missiles and guns used by American and Allied soldiers overseas. Among them was Alyce Hall (at far left in photo), one of only two African American women allowed to take part in the University of Pennsylvania project. A story has it that when a celebratory dinner was planned for the computers, Alyce wasn’t going to be able to attend. The reason? The restaurant the organizers had chosen for the big event wouldn’t serve blacks. As soon as the other computers found out, they moved restaurants so Alyce could join them. Her sister, Alma, was also a mathematician and computer during the war years.


Alyce’s story demonstrates how racism at home in the United States was another painful battlefront for African Americans during World War II.


The Halls weren’t the only sisters who were computers. Identical twins Doris and Shirley Blumberg were both math whizzes who served as ballistics experts during the war.


Learn more about barrier-breaking women in computing at Kathy Kleiman's remarkably researched and informative ENIAC Programmers Project and
at  Top Secret Rosies: The Female Computers of World War II.

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