All Together Now

When London’s Millennium Bridge opened in 2000, it began to sway unexpectedly under the footsteps of the inaugural crowds. The danger of vibration in bridges was well known — the Albert Bridge (below) still bears a sign dating from 1873 that warns soldiers to break step while crossing. But the Millennium Bridge revealed a new phenomenon: As the pedestrians felt the bridge swing beneath them, they altered their movements to maintain their balance and began to sway together in step. This increased the amplitude of the bridge’s oscillations, a factor called synchronous lateral excitation.

The bridge was closed on opening day and underwent $9 million in repairs to increase its damping. It reopened in February 2002 and is now free of vibration, but it’s still known affectionately as the “wobbly bridge.”
Image: Wikimedia Commons

The Photophone

Alexander Graham Bell believed that his greatest achievement was the photophone, a device that could transmit speech on a beam of light. The speaker’s voice would strike the back of a mirror, modulating a reflected ray. When the ray reached the receiver the process was reversed, producing sound waves.

“I have heard articulate speech by sunlight!” Bell wrote to his father in 1880. “I have heard a ray of the sun laugh and cough and sing! … I have been able to hear a shadow and I have even perceived by ear the passage of a cloud across the sun’s disk. You are the grandfather of the Photophone and I want to share my delight at my success.”

Bell hoped the invention might supplant expensive telephone lines, but it proved too vulnerable to weather conditions and fell by the wayside. That didn’t surprise the New York Times, which wrote in an editorial, “Until [the public] sees a man going through the streets with a coil of No. 12 sunbeams on his shoulder, and suspending them from pole to pole, there will be a general feeling that there is something about Professor Bell’s photophone which places a tremendous strain on human credulity.”

“Bike Keeps Family in Stitches”

Carrying four persons and a sewing machine, the world’s weirdest bicycle recently had a tryout in Chicago, Ill. The two-story vehicle, known as the ‘Goofybike,’ is the creation of Charles Steinlauf. It carries the whole Steinlauf family. The inventor rides at the top and guides the contraption by means of a huge automobile steering wheel. Mrs. Steinlauf sits below, operating a sewing machine, while her son pedals behind and her daughter rides on the handlebars in front. When the odd vehicle is at rest, the projecting legs of the sewing machine prevent the lofty cycle from tipping over.

Popular Science, October 1939

The Spirit Battery

When the electric telegraph was making its appearance in the 1840s, it was strangely easy to confuse it with spiritualism: Both were uncanny means of talking with absent people through systems of symbols. In a bid for legitimacy, spiritualists appealed to the principles of “electrical science.” In his 1853 book The Present Age and Inner Life, Andrew Jackson Davis proposed a “spirit battery” by which a medium could improve her contact with the spirit world by asking her guests to hold a magnetic rope whose ends were dipped in water-filled buckets made of copper and zinc:

The males and females (the positive and negative principles) are placed alternately; as so many zinc and copper plates in the construction of magnetic batteries. The medium or media have places assigned them on either side of the junction whereat the rope is crossed, the ends terminating each in a pail or jar of cold water. … But these new things should be added. The copper wire should terminate in, or be clasped to, a zinc plate; the steel wire should, in the same manner, be attached to a copper plate. These plates should be dodecahedral, or cut with twelve angles or sides, because, by means of the points, the volume of terrestrial electricity is greatly augmented, and its accumulation is also, by the same means, accelerated, which the circle requires for a rudimental aura (or atmosphere) through which spirits can approach and act upon material bodies.

“We are negative to our guardian spirits; they are positive to us,” Davis wrote. “The whole mystery is illustrated by the workings of the common magnetic telegraph. The principles involved are identical.”

Alarming bonus factoid: When Samuel Morse appeared before Congress in 1838 to seek funding for an experimental telegraph line, some congressmen introduced amendments that would provide funds for research on mesmerism as well. The committee chair wrote, “It would require a scientific analysis to determine how far the magnetism of mesmerism was analogous to the magnetism to be employed in telegraphs.” When the bill came to a vote, 70 congressmen left their seats; many hoped “to avoid spending the public money for a machine they could not understand.”

(From Jeffrey Sconce, Haunted Media: Electronic Presence from Telegraphy to Television, 2000.)


The job of creating voices for Munchkins and Winkies in The Wizard of Oz fell to vocal arranger Ken Darby. “In those days we didn’t have the technical facilities we have now, like speeding up tape,” he said. “I had to figure out how to make the Munchkins sound high-pitched”:

I worked it out mathematically, using a metronome. Then I went to the head of the sound department, Doug Shearer. I told him that if we could record at sixty feet per minute instead of the normal ninety feet per minute and if we sang at a slower pace in a different key, when we played it back at ninety it should sound right. He said there was no way to do that because we didn’t have a variable-speed recorder. Then he said he would try to manufacture a new gear for the sound-recording machine. And it worked. I had the singers sing very slowly and distinctly so the words would be clear when we played it back at a faster speed. Ding … Dong … the … witch … is … dead. When we played it back, it was a perfect one-fourth higher.

“None of the midgets did any of the singing. None of them could carry a tune.”

(From Aljean Harmetz, The Making of The Wizard of Oz, 1977.)

Working Smarter

In 1947 two Harvard undergraduates, William Burkhart and Theodore Kalin, built a primitive machine for doing propositional logic. They had been taking a course in symbolic logic with Willard Van Orman Quine and were tired of solving problems with pencil and paper, so they set about making a machine that would do their homework automatically.

The result of their $150 investment was a small machine that could handle problems involving up to 12 terms in the propositional calculus. The “Kalin-Burkhart machine” marks a milestone in the development of logic machines, but working in the machine’s language is so laborious that using a pencil is faster.

“It is interesting to note that when certain types of paradoxes are fed to the Kalin-Burkhart machine it goes into an oscillating phase, switching rapidly back and forth from true to false,” noted Martin Gardner in Logic Machines and Diagrams (1958). “In a letter to Burkhart in 1947 Kalin described one such example and concluded, ‘This may be a version of Russell’s paradox. Anyway, it makes a hell of a racket.'”


An epic contest from the Annual Green Fair and South West Scythe Festival in Somerset, U.K., June 2010.

One commenter wrote, “Now we know why Death carries a Scythe, not a brushcutter.”

Words Without Language
Image: Wikimedia Commons

In contemporary secretary schools, training emphasizes the inhibition of reading for meaning while typing, on the assumption that such reading will hinder high-speed performance. Some support for this assumption derives from the introspections of champion speed typists, who report that they seldom recall the meaning from the source material incidentally.

— William E. Cooper, Cognitive Aspects of Skilled Typewriting, 2012

We don’t even know the keyboard. A 2013 study at Vanderbilt asked 100 subjects to take a short typing test; they were then shown a blank QWERTY keyboard and given 80 seconds to label the keys. On average they typed at 72 words per minute with 94 percent accuracy but could correctly label only 15 letters on a blank keyboard.

“This demonstrates that we’re capable of doing extremely complicated things without knowing explicitly what we are doing,” said graduate student Kristy Snyder.

It had formerly been believed that typing starts as a conscious process that becomes unconscious with repetition. But it appears that typists never memorize the key locations in the first place.

“It appears that not only don’t we know much about what we are doing, but we can’t know it because we don’t consciously learn how to do it in the first place,” said psychologist Gordon Logan.

(Kristy M. Snyder et al., “What Skilled Typists Don’t Know About the QWERTY Keyboard,” Attention, Perception, & Psychophysics 76:1 [January 2014], 162-171.)

Tight Squeeze

Above: From Paris, 1927: a novelty car that can “sidle” into parking spaces.

Below: Someone was actually working on this in the 1950s (thanks, Martin):

A related puzzle from The Chicken From Minsk, Yuri B. Chernyak’s 1995 collection of math and physics problems: Why is it easier to parallel-park a (conventional) car by backing into the space rather than pulling in directly?

Click for Answer

Helping Hand
Image: Flickr

This Victorian artificial arm and hand is in the collection of the London Science Museum. “The arm is amazingly versatile,” writes Ben Russell in Robots (2017). “The elbow can be locked in several positions, and the fingers articulated using a brass button in the wrist. It is also heavily decorated in the neo-Gothic style. Rather than being covered up, this arm would be out on view, making its wearer a true man-machine.”
Image: Flickr