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Thomas Edison's Eccentric Job Interview Questions: A Cheat Sheet

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Hulton-Deutsch Collection/CORBIS

Thomas Edison had an encyclopedic memory, and by the early 1920s, he had become increasingly frustrated by the fact that college graduates applying to work for him didn’t have a wealth of knowledge comparable to his own. To test the mental mettle of incoming job seekers, he administered to each a series of 150 questions, tailored to the position for which they were applying. Some were specific to the industry, while others were mysterious. Masons, for instance, needed to know who assassinated President Lincoln.

Others were topical (In what cities are hats and shoes made?) and are now outdated (What telescope is largest in the world?). But just in case the Edison Quiz fad ever returns, here’s a cheat sheet to help you master some of the finer points. Good luck!

Who was Francis Marion?
An officer in the Revolutionary War, often cited as being the father of guerilla warfare. His skill at clandestinely moving troops by dressing drably and utilizing swamp paths earned him the nickname “Old Swamp Fox.”

Where is the River Volga?
Oh, the longest river in Europe? Russia, of course.

Who invented logarithms?
Scottish mathematician and ruff-wearer John Napier, in the mid 1600s. He also combined the work of Italian mathematician Fibonacci and Ottoman genius-of-all-trades Matrakç? Nasuh to invent the awesomely named “Napier’s Bones,” an abacus-like system of numbered rods that transform multiplication, division, and exponents into simple addition and subtraction.

What is the first line in The Aeneid?

Arms, and the man I sing, who, forced by fate
And haughty Juno’s unrelenting hate
Expelled and exiled, left the Trojan shore:
Long labors, both by sea and land, he bore;
And in the doubtful war, before he won
The Latin realm and built the destined town,
His banished gods restored to rights divine,
And settled sure succession in his line;
From whence the race of Alban fathers come,
And the long glories of majestic Rome.
-- Virgil, and translated by John Dryden.

Note: The colon after “shore” is disputed, so we include the entire first stanza for good measure. Playwright George Bernard Shaw would have correctly answered this one, as evidenced by the title of his 1894 play Arms and the Man.

What war material did Chile export to the Allies during the War?
Sodium nitrate, which was used to manufacture gunpowder, and made Chile very rich. Nitratine appeared there in such large deposits, the mineral is also known as Chile saltpeter.

A question tailored to cabinetmakers: Who was the Roman emperor when Jesus Christ was born?
Caesar Augustus, Sept. 23, 63 BC—Aug. 19, 14 AD.

Where is the Sargasso Sea?
The only “sea” to be entirely surrounded by water, the Sargasso is actually an elliptical patch of the North Atlantic, near Bermuda. The water in this area is relatively calm and thick with seaweed (sargassum weed, actually), trapped there by the surrounding currents: the Canary Current at the northeast, the Northern Equatorial Current along the south, and the Gulf Stream on the northwest.

Because of the Sargasso’s relatively low precipitation, high evaporation, light winds, warm temperatures and high salinity, scientists used to think it was a sort of oceanic desert; they knew aquatic creatures made their habitat in the sargassum, but thought the water wasn’t hospitable to plankton. More recently, however, mysterious plankton blooms suggest that the area is “far more productive than we could explain...” according to Dennis McGillicuddy, oceanographer and leader on the Eddies Dynamics, Mixing, Export, and Species composition (EDDIES) project. Put that in your pipe, Edison.

Of what is brass made?
Brass is an alloy of zinc and copper. Humans started making brass as early as the Neolithic era, though ancient texts often use the term brass when they mean bronze – an alloy of copper and tin.

Who was Leonidas?
The military king of ancient Sparta who heroically led a mere 300 men in the battle against massive Persian forces in the battle of Thermopylae. Sure, he had some help from other Greeks, but the 300 thing is his legacy. So much so, he’s now most famous for being the guy who yells “This! Is! Spartaaaa!”

Who discovered the X-ray?
The obvious answer to this question is Wilhelm Röntgen, who, in 1895, famously noted the effects of a mysterious new kind of ray that appeared as a byproduct of his experiments with Crookes tubes. He called his discovery the “X ray,” to indicate its yet unknown properties, then went on to take a widely publicized X-ray print of the bones of his wife’s hand, and eventually won a Nobel prize in 1901 for his achievements. However, several other physicists made similar discoveries while experimenting with Crookes tubes around the same time. Among them: Nikola Tesla, Edison’s well-known rival. Edison had himself experimented with X-rays for a time, and was certainly aware of the variations in the X-ray origin story among his colleagues. This question suggests an eagerness to promote his preferred version.

Where do we get shellac?
You probably know shellac as a term commonly applied to wood varnish, which is actually a combination of alcohol and the naturally occurring thermoplastic resin also called shellac. But did you know the latter shellac is produced and secreted by the lac insect (Laccifer lacca), a type of scale bug somewhat related to aphids and cicadas? Proper shellac is also used commercially in products like sealing wax, hairspray, and even cake glazes and anti-caking agents in candy. Vegans beware.

Why is cast iron called Pig Iron?
Modern-day metal workers would argue that cast iron and pig iron are not exactly the same thing, but what Edison probably meant by pig iron was the raw material used in making iron and steel. Back in the day, pig iron was melted into casts that resembled baby piglets suckling from their mother. Likewise, iron workers used to call the iron in the adjoining lateral channel “the sow.”

Who was Bessemer and what did he do?
Henry Bessemer invented the Bessemer process, which revolutionized mass production of steel. From pig iron. See? We’re learning!

Pencils Down!

Of the well over 500 young men who took Edison’s test, only about 35 passed to his satisfaction (a score of 90% or higher). When several disgruntled rejects complained to the press, Edison refused to release his questions and answers, so the public had to rely largely on the memory of his “victims” for the complete list. Magazines subsequently began running “Edison pop quizzes,” and rival employers -- fancying themselves as exclusive as Edison -- began conducting employment quizzes of their own. Edison’s scientific conclusions on the subject?

“Only 2% of the people think, as I gather from my questionnaire.”

What's the most bizarre question you've been asked in an interview? Has the Sargasso Sea come up?

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Library of Congress
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10 Facts About the Tomb of the Unknown Soldier
May 29, 2017
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Library of Congress

On Veterans Day, 1921, President Warren G. Harding presided over an interment ceremony at Arlington National Cemetery for an unknown soldier who died during World War I. Since then, three more soldiers have been added to the Tomb of the Unknowns (also known as the Tomb of the Unknown Soldier) memorial—and one has been disinterred. Below, a few things you might not know about the historic site and the rituals that surround it.

1. THERE WERE FOUR UNKNOWN SOLDIER CANDIDATES FOR THE WWI CRYPT. 

Wikimedia Commons // Public Domain

To ensure a truly random selection, four unknown soldiers were exhumed from four different WWI American cemeteries in France. U.S. Army Sgt. Edward F. Younger, who was wounded in combat and received the Distinguished Service Medal, was chosen to select a soldier for burial at the Tomb of the Unknowns in Arlington. After the four identical caskets were lined up for his inspection, Younger chose the third casket from the left by placing a spray of white roses on it. The chosen soldier was transported to the U.S. on the USS Olympia, while the other three were reburied at Meuse Argonne American Cemetery in France.

2. SIMILARLY, TWO UNKNOWN SOLDIERS WERE SELECTED AS POTENTIAL REPRESENTATIVES OF WWII.

One had served in the European Theater and the other served in the Pacific Theater. The Navy’s only active-duty Medal of Honor recipient, Hospitalman 1st Class William R. Charette, chose one of the identical caskets to go on to Arlington. The other was given a burial at sea.

3. THERE WERE FOUR POTENTIAL KOREAN WAR REPRESENTATIVES.

WikimediaCommons // Public Domain

The soldiers were disinterred from the National Cemetery of the Pacific in Hawaii. This time, Army Master Sgt. Ned Lyle was the one to choose the casket. Along with the unknown soldier from WWII, the unknown Korean War soldier lay in the Capitol Rotunda from May 28 to May 30, 1958.

4. THE VIETNAM WAR UNKNOWN WAS SELECTED ON MAY 17, 1984.

Medal of Honor recipient U.S. Marine Corps Sgt. Maj. Allan Jay Kellogg, Jr., selected the Vietnam War representative during a ceremony at Pearl Harbor.

5. BUT THE VIETNAM VETERAN WASN'T UNKNOWN FOR LONG.

Wikipedia // Public Domain

Thanks to advances in mitochondrial DNA testing, scientists were eventually able to identify the remains of the Vietnam War soldier. On May 14, 1998, the remains were exhumed and tested, revealing the “unknown” soldier to be Air Force 1st Lt. Michael Joseph Blassie (pictured). Blassie was shot down near An Loc, Vietnam, in 1972. After his identification, Blassie’s family had him moved to Jefferson Barracks National Cemetery in St. Louis. Instead of adding another unknown soldier to the Vietnam War crypt, the crypt cover has been replaced with one bearing the inscription, “Honoring and Keeping Faith with America’s Missing Servicemen, 1958-1975.”

6. THE MARBLE SCULPTORS ARE RESPONSIBLE FOR MANY OTHER U.S. MONUMENTS. 

The Tomb was designed by architect Lorimer Rich and sculptor Thomas Hudson Jones, but the actual carving was done by the Piccirilli Brothers. Even if you don’t know them, you know their work: The brothers carved the 19-foot statue of Abraham Lincoln for the Lincoln Memorial, the lions outside of the New York Public Library, the Maine Monument in Central Park, the DuPont Circle Fountain in D.C., and much more.

7. THE TOMB HAS BEEN GUARDED 24/7 SINCE 1937. 

Tomb Guards come from the 3rd U.S. Infantry Regiment "The Old Guard". Serving the U.S. since 1784, the Old Guard is the oldest active infantry unit in the military. They keep watch over the memorial every minute of every day, including when the cemetery is closed and in inclement weather.

8. BECOMING A TOMB GUARD IS INCREDIBLY DIFFICULT.

Members of the Old Guard must apply for the position. If chosen, the applicant goes through an intense training period, in which they must pass tests on weapons, ceremonial steps, cadence, military bearing, uniform preparation, and orders. Although military members are known for their neat uniforms, it’s said that the Tomb Guards have the highest standards of them all. A knowledge test quizzes applicants on their memorization—including punctuation—of 35 pages on the history of the Tomb. Once they’re selected, Guards “walk the mat” in front of the Tomb for anywhere from 30 minutes to two hours, depending on the time of year and time of day. They work in 24-hour shifts, however, and when they aren’t walking the mat, they’re in the living quarters beneath it. This gives the sentinels time to complete training and prepare their uniforms, which can take up to eight hours.

9. THE HONOR IS ALSO INCREDIBLY RARE.

The Tomb Guard badge is the least awarded badge in the Army, and the second least awarded badge in the overall military. (The first is the astronaut badge.) Tomb Guards are held to the highest standards of behavior, and can have their badge taken away for any action on or off duty that could bring disrespect to the Tomb. And that’s for the entire lifetime of the Tomb Guard, even well after his or her guarding duty is over. For the record, it seems that Tomb Guards are rarely female—only three women have held the post.

10. THE STEPS THE GUARDS PERFORM HAVE SPECIFIC MEANING.

Everything the guards do is a series of 21, which alludes to the 21-gun salute. According to TombGuard.org:

The Sentinel does not execute an about face, rather they stop on the 21st step, then turn and face the Tomb for 21 seconds. They then turn to face back down the mat, change the weapon to the outside shoulder, mentally count off 21 seconds, then step off for another 21 step walk down the mat. They face the Tomb at each end of the 21 step walk for 21 seconds. The Sentinel then repeats this over and over until the Guard Change ceremony begins.

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