Redefining the kilogram in terms of Planck’s constant

Redefining the kilogram in terms of Planck’s constant

The kilogram has the dubious distinction of being the only SI unit still based on a physical object; specifically, a metal cylinder kept in a vault in France. Plans are well underway to redefine the kilogram in mathematical terms instead, and to that end a team at the National Institute of Standards and Technology (NIST) has submitted a precise new calculation of a key formula.

Since 1879, the kilogram has been defined as the exact mass of the International Prototype of the Kilogram (IPK), a small cylinder made of platinum and iridium. But there are a few problems with defining a base unit in terms of a physical artefact: the IPK gathers contaminants that make it slightly heavier over time, so it needs to be regularly treated. To complicate matters, there are 40 copies around the world and they’re all getting “dirty” at different rates, meaning their masses are slowly drifting out of sync.

That’s obviously not something you want in a base unit that’s supposed to be universal. And the discrepancies don’t just affect the kilogram itself: other units such as the pound, ton or milligram are defined in terms of their relationship to the kilo, as are non-mass units like the ampere (for electric current) or the candela (luminous intensity).

A better option is to develop a new definition based on a mathematical foundation that can be calculated anywhere, and the Planck constant fits the bill. This formula allows researchers to find mass in relation to electromagnetic energy, so by finding as precise a value for it as possible, the kilogram can be redefined in terms of the official definition of the meter and the second.

NIST’s new value for the Planck constant is 6.626069934 x 10-34 kg∙m2/s, with an uncertainty of 13 parts per billion. If that number makes your eyes glaze over, the important part is the end: 13 parts per billion is incredibly precise.

To measure the Planck constant, the researchers used a Kibble balance, a device that suspends a 1-kg weight with electromagnetic forces. They can calculate the constant according to the amount of electromagnetic energy it takes to balance the mass.

The team says the more precise figure comes courtesy of having 16 months’ worth of measurements to draw from, as well as adjustments they’d made in how the electromagnetic field was created and measured.

These experiments join several other projects that were attempting to find the most precise value of the Planck constant, and while everyone’s answers were different, they have low enough levels of uncertainty to make a case for redefining the kilogram in terms of the Planck constant.

“There needed to be three experiments with uncertainties below 50 parts per billion, and one below 20 parts per billion,” says Stephan Schlamminger, lead researcher on the project. “But we have three below 20 parts per billion.”

All of these measurements have been submitted for consideration by an international body, which will review them to determine the official value of Planck’s constant. The official definition of a kilogram – along with the other units that depend on it – is set to be changed in November next year.

Your revolution was dumb and it filled us with refugees: A Canadian take on the American Revolutionary War | National Post

Your revolution was dumb and it filled us with refugees: A Canadian take on the American Revolutionary War | National Post

To be clear; Canada loves you, United States. You buy our oil, you made Drake a superstar and you haven’t invaded us for 205 years. As Poland and Ukraine keep reminding us, we really couldn’t ask for a better superpower neighbour.

However, just because it all worked out doesn’t mean that starting a brutal war over a tax dispute wasn’t a bit of an overreaction. As the National Post’s own Conrad Black wrote in a 2013 history of the United States, the Founding Fathers “do not deserve the hallelujah chorus ululated to them incessantly for 235 years.”

Canada had to fend off an invasion during the Revolutionary War, after all, so consider us qualified to deliver this Independence Day buzzkill.

The colonists weren’t fighting a “tyrannical” king so much as they were fighting one of the world’s most democratic nations

The Declaration of Independence places sole responsibility on Britain’s George III for establishing what Americans called “an absolute tyranny over these states.” But George III wasn’t an autocrat. While his power was much greater than the current Queen’s, he had an elected House of Commons and a prime minister to check him. Parliamentarians were free to heckle British war plans, and members of the British press (the freest in the world at the time) openly sided with the colonists. British democracy was far from universal, of course, with voting barred to women, Catholics and the lower classes — and with representation ridiculously concentrated in rural areas. But it was not a far cry from the soon-to-be-independent United States, whose first presidential election would only see about six per cent of the population eligible to vote.

The war did involve an autocratic tyrant though … on the colonists’ side

Speaking of autocrats, the American rebels counted one of the world’s most notorious as their best friend in Europe. Louis XVI, the absolute monarch of France, wholeheartedly backed the colonists’ cause as a way to embarrass the English. France smuggled weapons and advisers to the rebels, dispatched thousands of troops to the colonies and ordered its navy to travel the world and harass British efforts to supply their North American armies. Historians generally agree that, without French support, the British would likely have crushed the American Revolution. Meanwhile, the incredible cost of the American proxy war helped to lead an unstable France ever closer to financial ruin, revolution and, ultimately, the execution of Louis. So in effect, the United States owes its existence to an impulsive dictator who ran his country into the ground so hard that he got himself beheaded.

American colonists had sparked a world war … and then refused to help pay for it

The American Revolution was largely sparked by colonial opposition to new taxes. But Great Britain’s bid to get some American revenue makes a bit more sense when one considers that the colonies had just bungled the Brits into a wildly expensive world war. In 1754, a 22-year-old Virginia militia officer named George Washington took a group of men into what is now Pennsylvania to work out a territorial dispute with some nearby French-Canadians. Instead, the inexperienced Washington ambushed a French-Canadian patrol, accidentally executed the patrol’s commander and ended up sparking the Seven Years War. The resultant worldwide conflict — which included Great Britain’s conquest of Quebec — drove London to the edge of bankruptcy.

Canada’s plan to recognize native land and respect Catholics was deemed “intolerable” by colonists

In 1774, the British government introduced the Quebec Act, which allowed French-Canadians in British-conquered Quebec to freely practise Catholicism. Crucially, the act also extended the borders of Quebec down to what is now Ohio and kept in place a large band of “Indian” territory on the western edge of the American Colonies. It was a remarkably liberal document for the time, but anti-Catholic colonists balked at it for promoting “Popery” and for banning their hoped-for expansion into indigenous land. The Declaration of Independence, in fact, directly accused King George of kowtowing to “merciless Indian Savages.” The Quebec Act was soon cited by colonists as the worst of the so-called “Intolerable Acts,” a series of punitive measures that ultimately turned the dispute with Great Britain into a shooting war.

Revolutionary America had a pretty serious terrorism problem
In the recent book Scars of Independence, historian Holger Hoock dismisses modern depictions of the American Revolution as rooms full of men in powdered wigs discussing liberty. It was actually a “profoundly violent civil war,” he writes. One largely forgotten aspect of the war was how much the Patriot cause was driven by terroristic mobs prepared to torture judges, customs officials, newspaper editors or anyone else seen to be supporting British rule. Pro-government officials had their homes burned, their horses poisoned and many were snatched out of their beds in the middle of the night, stripped naked and subjected to mock drownings or tarring and feathering. Accounts of these outrages help explain why the conflict escalated so quickly. When hotheaded Brits backed George III’s call to swiftly put down colonial rebels, it wasn’t because they were incensed at a lack of tea tax revenue — it was because they feared that their American lands had fallen to mob rule.

It’s a little odd when a “struggle for liberty” fills Canada with refugees

Between 60,000 and 80,000 Loyalists fled to Canada following American Independence and lost everything when their property was seized by the new United States. Revolutions commonly prompt an exodus of refugees. Just in the past century, the Russian Revolution, Cuban Revolution and the Zanzibar Revolution, among others, all spawned vast refugee streams, some of which ended in Canada. But unlike the communist and vengeance-minded architects of those revolutions, the Americans were ostensibly fighting for a free, pluralistic democracy where “all men are created equal.” In hindsight, it’s pretty bad optics that vast columns of families felt the need to seek actual freedom and equality elsewhere. “With malice toward none, with charity for all” would have to wait for another civil war.

Of all the countries to obtain independence from Britain, only the U.S. and Ireland chose to do it violently

Roughly 60 independent countries around the world were once counted as British colonies or mandates. Of those, only the United States and the Republic of Ireland gained their independence as a direct result of political violence. Compare that to Spain, which violently resisted the departure of almost every one of its overseas colonies. Great Britain wasn’t afraid to get its hands dirty in colonial affairs, but London could be convinced to tolerate a colony’s peaceful transition to independence — particularly when said colony was filled with white English-speakers. Which is to say that if Americans truly wanted freedom, there were lots more options on the table than simply taking a shot at the first redcoat.

What Did Independence Day Mean to Southerners About to Secede? | History | Smithsonian

What Did Independence Day Mean to Southerners About to Secede? | History | Smithsonian

In the cooling evening air, Charleston, South Carolina’s notable citizens filed into Hibernian Hall on Meeting Street for the traditional banquet to close their Fourth of July festivities. The year was 1860, and the host, as always, was the ’76 Association, a society formed by elite Charlestonians in 1810 to pay homage to the Declaration of Independence.

The guest of honor was one of the city’s most beloved figures, William Porcher Miles, Charleston’s representative in the U.S. Congress in Washington. A former professor of mathematics at the College of Charleston, Miles had won his city’s heart with his heroic efforts as a volunteer nurse to combat an epidemic of yellow fever on the coast of Virginia. He was not a planter, and not even a slaveholder, but he believed in the Constitution and in the slave master’s rights sealed by that compact—and he had come to believe that America was best split into two.

Miles wasn’t happy when, amid the clinking of glasses, a poem approved by the ’76 Association was read out loud in the hall:

The day, when dissevered from Union we be,
In darkness will break, o’er the land and the sea;
The Genius of Liberty, mantled with gloom,
Will despairingly weep o’er America’s doom…

It was just a poem, mere words, sounded with a muted note of elegy. But there was no such thing as “mere words” in the blistering heat of this Charleston summer, with war about to erupt. Words, in 1860, were weapons. And these particular words struck a blow at an equation that secessionists like Miles had labored to forge between their cause and the broader American cause of freedom. This verse presented a quite different idea—the notion, heretical to the secessionist, that the sacred principle of liberty was bound up with Union, with the bonds linking together all of the states, and all of the people of the nation, from Maine to Texas.

So it went for Charleston in this year, beset with a complicated, even excruciating welter of emotions on the question of secession. As determined as so many in Charleston were to defend their way of life, based on slavery, under sharp challenge from the North, still there was room for nostalgic feeling for the Union and for the ideals set forth in the Declaration.

Independence Day in Charleston had begun as customary, with a blast of cannon fire from the Citadel Green at three o’clock in the morning. Roused from their slumber, Charlestonians made ready for a day of parades by militia units in colorful uniform. In the 102-degree heat, the men of the German Artillery, sweltering in their brass-mounted helmets, could only be pitied.

Surely, the town’s secessionists thought, it would be a fine occasion to trumpet their ripening movement. They would celebrate Independence indeed—the coming liberation of the South from the clutches of the nefarious Union. As odd, even bizarre, as this might seem today, Charleston’s secessionists sincerely felt they were acting in a hallowed American tradition. They saw themselves as rebels against tyranny, just like their forefathers who had defeated the British to win America’s freedom some 80 years before. In this instance, the oppressor was the Yankee Abolitionist in league with the devious Washington politician, together plotting to snatch from the South the constitutional right of an American, any American, to hold property in slaves.

By the summer of 1860, these self-styled revolutionaries seemed to be winning their improbable campaign. Back in the spring, at the Democratic National Convention, held in Charleston that year, Charlestonians packed the galleries and cheered wildly when radical Southern Democrats walked out of Institute Hall in protest over the refusal of Northern Democrats to agree to a party plank giving the slaveholder an unimpeded right to operate in western territories like Kansas and Nebraska. The rebel delegates proceeded to establish their own separate “Seceding Convention,” as The Charleston Mercury called this rump group. In its comment hailing the uprising, The Mercury, a daily bugle call for secession, declared that, “The events of yesterday will probably be the most important which have taken place since the Revolution of 1776. The last party, pretending to be a National party, has broken up; and the antagonism of the two sections of the Union has nothing to arrest its fierce collisions.” A Northern reporter strolling the moonlit streets wrote of the occasion that “there was a Fourth of July feeling in Charleston last night—a jubilee …. In all her history, Charleston had never enjoyed herself so hugely.”

In this electric atmosphere, public expressions in favor of the Union could scarcely, and maybe not safely, be heard. An abolitionist in Charleston risked being tarred and feathered. Horace Greeley’s New York Tribune, America’s largest paper by circulation and a standard-bearer for abolition, was banned in the city.

It was all the more remarkable, then, that the poem confessing to despair over the Union’s impending collapse was read for all to hear at the banquet at Hibernian Hall on July 4. Rep. Miles could hardly let a handwringing cry for Union stand unchallenged. He held his tongue at the banquet, but five nights later, at a political meeting of town folk held at the Charleston Theatre, up the street from Hibernian Hall, he gave his constituents a tongue lashing. “I am sick at heart of the endless talk and bluster of the South. If we are in earnest, let us act,” he declared. “The question is with you. It is for you to decide—you, the descendants of the men of ’76.”

His words, and many more like them, would win the summer of 1860 for his camp. Charleston’s passion was for rebellion—and the banquet poem turned out to be a last spasm of sentiment for the Union. Repulsed by such feelings, the Charleston merchant Robert Newman Gourdin, a close friend of Miles, organized rich Charlestonians into a Society of Earnest Men for the purpose of promoting and financing the secession cause. When an Atlanta newspaper mocked Charleston’s insurgents as all talk, no action, a member of the group responded in The Mercury that the Earnest Men would “spot the traitors to the South, who may require some hemp ere long.”

True to their identification of their undertaking with the American Revolution, the secessionists also formed a new crop of militia units known as Minute Men, after the bands that gathered renown in colonial Massachusetts for taking on the British redcoats. Recruits swore an oath, adapted from the last line of Jefferson’s Declaration of Independence, to “solemnly pledge, OUR LIVES, OUR FORTUNES, and our sacred HONOR, to sustain Southern Constitutional equality in the Union, or failing that, to establish our independence out of it.”

In November, with the election to the presidency of Abraham Lincoln, the candidate of the antislavery Republican Party, Charleston went all in for secession. Federal officeholders in the city, including the federal district court judge, resigned their positions, spurring The Mercury to proclaim that “the tea has been thrown overboard—the revolution of 1860 has been initiated.”

Charleston’s “patriotic” uprising ended in ruin—ruin for the dream of secession; ruin for the owner of human chattel, with the Constitution amended to abolish slavery; ruin for the city itself, large parts of which were destroyed by federal shells during the Civil War. The triumph, won by blood, was for the idea expressed ever so faintly by the men of ‘76 at Charleston’s July Fourth celebration of 1860, and made definitive by the war—the idea that liberty, and American-ness, too, were inextricably and forever tied to union.

Chip Hall of Fame: Texas Instruments TMC0281 Speech Synthesizer – IEEE Spectrum

Chip Hall of Fame: Texas Instruments TMC0281 Speech Synthesizer – IEEE Spectrum


If it weren’t for the TMC0281, E.T. would’ve never been able to “phone home.” That’s because the TMC0281, the first single-chip speech synthesizer, was the heart (or should we say the mouth?) of Texas Instruments’ Speak & Spell learning toy. In Steven Spielberg’s 1982 blockbuster movie, the eponymous flat-headed alien hacks the toy to build an interplanetary communicator. (For the record, E.T. also uses a coat hanger, a coffee can, and a circular saw.) Today, we’re increasingly accustomed to our consumer electronics talking to us; the TMC0281 was the first step toward our world of ubiquitous synthesized speech.

Released in 1978, the TMC0281 produced speech using a technique called linear predictive coding; the sound emerges from a combination of buzzing, hissing, and popping. It was a surprising solution for something deemed “impossible to do in an integrated circuit,” Gene A. Frantz told IEEE Spectrum. Frantz, one of the four engineers who designed the toy, retired from TI in 2013. Variants of the TMC0281 were used in Atari arcade games and Chrysler’s K-cars. In 2001, TI sold its speech-synthesis chip line to Sensory, which discontinued it in late 2007. But if you ever need to place a very, very-long-distance phone call, you can find Speak & Spell units in excellent condition on eBay for about US $50.

Chip Hall of Fame: Texas Instruments Digital Micromirror Device – IEEE Spectrum

Chip Hall of Fame: Texas Instruments Digital Micromirror Device – IEEE Spectrum

On 18 June 1999, Larry Hornbeck took his wife, Laura, on a date. They went to watch Star Wars: Episode 1—The Phantom Menace at a theater in Burbank, Calif. Not that the graying engineer was an avid Jedi fan. The reason they were there was actually the projector. At the heart of the projector was a chip—the digital micromirror device—that Hornbeck had invented at Texas Instruments. A DMD uses millions of hinged microscopic mirrors to direct light through a projection lens. The Phantom Menace screening was “the first digital exhibition of a major motion picture,” says Hornbeck, a TI Fellow. Today movie projectors based on this digital light-processing technology—or DLP, as TI branded it—are used in thousands of theaters. It’s also integral to rear-projection TVs, office projectors, and tiny projectors for cellphones. “To paraphrase Houdini,” Hornbeck says, “micromirrors, gentlemen. The effect is created with micromirrors.” For his efforts, Hornbeck was ultimately awarded an Oscar—unlike The Phantom Menace.

Why Do We See More Species in Tropical Forests? The Mystery May Finally Be Solved | Science | Smithsonian

Why Do We See More Species in Tropical Forests? The Mystery May Finally Be Solved | Science | Smithsonian

When Charles Darwin first sailed into the tropics aboard the HMS Beagle in 1835, he was stunned. The 26-year-old naturalist had expected to find the same level of diversity of plants and animals as he had left behind in the higher latitudes of Plymouth, England. Instead, on the balmy Galapagos Islands, he found a multitude of strange and diverse creatures thriving together.

Rowing ashore to explore, Darwin jotted in his notes that the number of different “vegetable and animal” inhabitants on tiny tropical islands was strikingly higher than at other sites along his voyage. He wondered: How was it possible that the tropics seemed to hold so much more diversity than the more northerly forests of Europe? Shouldn’t these tightly packed creatures have battled it out to extinction long ago?

Darwin never found out the answer to that particular mystery (after all, he had a lot on his mind), and so the question persisted for another century. Finally, in the early 1970s, two ecologists independently came up with the same hypothesis to explain the mysterious phenomenon—at least with trees.

Daniel Janzen and Joseph Connell put forth a seemingly counterintuitive explanation. Perhaps, they posited, the astonishing plant diversity we find in tropical forests is enabled by two factors: the presence of “natural enemies” that target specific species and keep population size in check, and the tendency of youngsters of one species to settle far away from their parents, beyond those predators’ reach.

Until recently, researchers have only been able to prove that the Janzen-Connell hypothesis holds true in localized studies. The problem was, they lacked access to the kind of global datasets necessary to explain the broader planetary pattern of decreasing diversity from equator to poles. Now, in a new study published last week in the journal Science, researchers show that this hypothesized mechanism is indeed responsible for global trends in forest biodiversity.

Last year, forest ecologists Jonathan Myers and Joe LaManna traveled to a workshop in Hainan, China focused on analysis of data generated by the Smithsonian’s Forest Global Earth Observatory (ForestGEO), a network of 60 forests across the planet that are exhaustively monitored. Myers and LaManna, both of Washington University in Saint Louis, Missouri, knew that ForestGEO could provide the global dataset they needed to answer the question that has been vexing them and other ecologists since Darwin’s voyage.

“One of the striking differences between temperate and tropics is that all of those ‘extra’ species are very rare,” says LaManna, a post-doctoral researcher and first author of the new study. Consider that temperate forests can be packed wall to wall with redwood trees, whereas the tropics are dotted with a bevy of unique trees that often exist in isolation from others in their species. “How can those rare species persist in the face of extinction?” asks Myers, a professor of biology and co-author on the study.

Answering that question required a massive undertaking. The dataset tallied 2.4 million trees from 3,000 species in an exacting fashion to ensure comparability across each forest. More than 50 co-authors from 41 institutions including the Smithsonian then analyzed the data, which spanned 24 ForestGEO plots around the planet. “It was a lot,” says LaManna. “Every stem down to one centimeter in diameter is mapped, measured, tagged and identified.”

The herculean effort paid off. After analyzing the data, they found a surprising trend: In areas with higher numbers of adult trees, there were fewer young saplings of the same species. This pattern was strikingly more pronounced in the tropics than in the temperate regions they sampled.

This means that, unlike in higher latitude ecosystems, near the equator trees are less likely to coexist around neighbors in the same family. It’s as if, at some point, the tree parents and their sapling kids unanimously agreed that was time to move out of the basement. Except in a forest, living farther apart doesn’t just allow the parent trees to luxuriate in their empty nest. It’s a matter life and death for the species.

“With trees it’s less a direct effect of the parent tree on the offspring,” Myers says. “It’s an indirect effect where the natural enemies that attack the adults also attack the offspring.” These enemies could be pathogens, seed predators or herbivores that target one species. Just as dense human populations in cities enable the rapid spread of communicable diseases, these enemies can rapidly devastate a dense forest of the same species.

If your saplings settle down farther away, however, it’s less likely that any one enemy will wipe them all out. “You think of enemies as being bad influences on trees, especially ones of low abundance,” LaManna says. “But they can be a strong stabilizing force—[enemies] can actually buffer them and keep them from going extinct.” You might say: With enemies like this, who needs friends?

“It’s changed the way I think about ecology,” Myers says. “The enemy can actually have a beneficial effect in maintaining the rare species in these communities, especially in the tropics.”

The data provides compelling explanation for why we see the global biodiversity patterns we do, says Gary Mittelbach, a forest ecologist and professor of integrative biology at Michigan State University who was not involved in the study. “The fact that they were able to show it on a worldwide basis with standardized methods helps solidify the idea,” says Mittelbach.

One weakness of the study is that, while it implies a global trend, there are no samples from north of Central Europe or south of Papua New Guinea. “I kind of wish they had more [forests] in Asia and Europe so not all the high latitude ones are in North America,” says Mittelbach. Even with the dearth of samples from high latitudes, however, “I’m still pretty convinced of the pattern,” he says.

Though the researchers succesfully showed that the trend put forth by Janzen and Connell holds true, the question of what exactly is causing the tropics to be so diverse still remains.

Myers speculates that the stability of the tropical climate may contribute to its rich biodiversity, compared to the drastic changes that have taken place over geologic time in the higher latitudes. “There’s been a lot more disturbance in the temperate zone” over the past thousands of years, he says. By “disturbance,” Myers means ice sheets that repeatedly bulldozed across North America in Earth’s past.

The tropics have not endured such disturbances. Researchers attribute the high reproduction and low extinction rates in tropical species of plants and animals to the relatively comfy climate. That’s worked out well for them until now, but forests around the world are changing as a result of more volatile climate patterns. For instance, as higher latitudes become warmer, temperate trees are migrating slowly north.

“There might be a direct or indirect influence of climate in mediating the strength of the biotic interactions between enemies and trees,” Myers says. “Where it’s warmer or wetter you might expect pathogens to have a stronger influence.”

The global trend these researchers have uncovered illustrates just how much the diversity of biological life on Earth can hinge on small-scale interactions. “This mechanism is a global scale process, and we’re talking about interactions between adults, young and their specialized enemies at the scale of 10 meters,” LaManna says. “That very local-scale interaction is contributing to a pattern of biodiversity across the entire globe.”

Take a Look at the Patents Behind Sliced Bread | Smart News | Smithsonian

Take a Look at the Patents Behind Sliced Bread | Smart News | Smithsonian

Some products are so ubiquitous that it can feel as if they were never invented at all.

Take sliced bread. Around 130 years ago, the idea of buying a pre-sliced loaf would have been met with confusion, writes Jesse Rhodes for Smithsonian Magazine. “In 1890, about 90 percent of bread was baked at home, but by 1930, factories usurped the home baker,” Rhodes writes. But the two breads weren’t the same thing–”factory breads were also incredibly soft,” she writes, making them difficult to slice properly at home with a bread knife.

Since breadmaking had moved to factories, why not bread slicing as well? On this day in 1928, in Chillicothe, Missouri, the Chillicothe Baking Company became, in the words of its plaque, “The Home of Sliced Bread.” It was the place where the bread-slicing machine was first installed, wrote J. J. Thompson for Tulsa World in 1989. Thompson was speaking with the son of the bread-slicing machine’s inventor, Richard O. Rohwedder. His father, Otto F. Rohwedder, was a jeweler who started work on the bread-slicing project years before.

The Rohwedder family all went down to the factory to see the bread-slicing machine on its first day, Richard Rohwedder said. They brought the slicer to the factory, “and I fed the first loaf of bread into the slicer,” he recalled.

The patent for the bread slicing machine explains how it worked: the machine moved the bread into the slicer and then a series of “endless cutting bands” sliced the loaf before moving it along to where it could easily be packaged by a specially designed bread wrapping machine–another patent of Rohwedder’s.

The bread-wrapping machine was just one of a number of patents for which Rohwedder was responsible: these included a cardboard bread holder that shrank as the loaf did; a retail display rack for bread; and structural improvements like an improved conveyor belt for getting bread in and out of the slicer.

Among the other bread-related products Otto F. Rohwedder invented to support the bread-slicing machine was a bread holder that shrank as the loaf did. It responded to concerns that pre-sliced bread would inevitably go stale before the consumer wanted to eat it. (U.S. Pat. No. 1,816,399)

Rohwedder’s original invention of the slicing machine dated back to 1917, writes author Aaron Bobrow-Strain, but he had worked to refine and re-refine the idea in the intervening time. “Many bakers actively opposed factory slicing,” he writes, and the inventor was almost ready to throw in the towel.

The owner of the Chillicothe Baking Company, the man who first took a chance on the machine, was named Frank Bench, a friend of Rohwedder’s. Bench’s bakery was near bankruptcy, so he took a chance on the idea even though most bakers thought pre-slicing would make the bread stale.

“The results astounded all observers,” Bobrow-Strain writes. Bench’s bread sales soon skyrocketed by 2000 percent, and mechanical slicing quickly spread around the country. “By 1929, an industry report suggested that there was practically no town of more than twenty-five thousand people without a supply of sliced bread,” he writes.

“I remember the phone ringing day and night, all the time, with bakers ordering slices,” Richard Rohwedder said.

Rohwedder’s seemingly booming business was affected by the Great Depression, and he was forced to sell his patent rights to a larger company, who kept him on as staff. But still—he had the satisfaction of knowing he was the man to invent sliced bread.