Machines and the Metric System

Unlike premodern methods of measurement, which typically incorporate disparate, unrelated units, each of the fundamental units of the metric system—the gram, meter, and liter—has a direct, well-defined relationship to the others. Metric measures are also unusual in that they are decimal: units can be scaled up or down by powers of ten, making conversion between them extraordinarily simple. There is a reason we call this collection of units the metric system: the relationships between the units make it coherent, consistent, and predictable. The whole is greater than the sum of its parts.

These qualities reflect the metric system's origins in European scientific circles, where proposals for a “universal” system of weights and measures first surfaced. These ideas, many of them connected to the larger Enlightenment, came to fruition during the French Revolution, when the National Assembly replaced the confusing diversity of existing weights and measures with a single system designed by the philosophes. The revolutionaries, optimistic that the metric system would readily supplant the older units, soon realized that old habits die hard; few people adopted the new system. These frustrations eventually prompted Napoleon to revive some of the old weights and measures, but France subsequently renewed efforts to make the metric system compulsory toward the end of the 1830s. A handful of other European nations followed suit, though resistance to the new methods of measurement meant that it took many decades for metric units to gain widespread acceptance.Footnote ⁷

The United States stood apart from these developments. Though Thomas Jefferson espoused a more rational, decimal system of weights and measures in the 1790s, his proposals rested on a very different basis than the new metric units—and never gained support. The older system of weights and measures inherited from the British remained in use, even if Congress failed to take steps to give those units legal sanction. The United States limped along on custom alone, which proved far more powerful than any ideas coming out of revolutionary France. By the 1810s, most commentators considered the metric system a failed experiment. One writer in 1813 noted that the French government, despite wielding considerably more power over their own populace than the United States could, nonetheless failed to secure adoption of the metric units. “The new measures . . . are on the counter . . . but the transactions are regulated by the old.” In 1819, a House of Representatives committee studying the issue concurred in this assessment, pointing to France's failure to secure widespread adoption of the metric system. Given this, it concluded, “whatever benefits uniformity and system [the metric system] may give to posterity . . . the present age must pay no scanty price for them.”Footnote ⁸

This same year, Secretary of State John Quincy Adams released his own report on weights and measures. Adams privately favored the metric system, preferring its simplicity and admiring its promise to transcend older, national systems of measurement. But his report did not offer a full-throated defense of the metric system; instead, it offered a comprehensive history of weights and measures throughout all of history. This disquisition was a model of evenhanded scholarship and artful equivocation, but it offered little direction for ambivalent lawmakers. Adams conceded that the metric system had promise, even detailing its virtues at great length. But he completely undermined this point by offering plenty of evidence that the United States had no ability or will to actually implement the new system. He ultimately counseled patience, prudence, and caution, noting that if there was “one conclusion more clear than another, deducible from the history of mankind, it is the danger of hasty and inconsiderate legislation upon weights and measures.” Shortly after entering this 245-page report into the public record, Congress did what it would likely have done anyway: nothing.Footnote ⁹

Nonetheless, in succeeding decades, the metric system gradually gained adherents in France and, eventually, a handful of smaller European countries as well as former Spanish colonies. This movement drew its strength from the international scientific community and eventually took root in the United States as well. The turning point came in 1863, when the newly created National Academy of Sciences recommended that the United States adopt the metric system. That same year, the United States participated in international congresses on postage and statistics that endorsed the metric system for both scientific and commercial purposes. Rep. John Kasson of Iowa, who attended the postal congress and was now the chairman of the House Committee on Coinage, Weights, and Measures, capitalized on these developments to introduce legislation in 1866 that legalized the use of the metric system. The law passed with little debate or opposition.Footnote ¹⁰

This was a significant step toward “metrication,” or the process of going metric. But the law did not make metric measures mandatory. Nor did it specify a date when the metric system would become the exclusive basis of measurement. Senator Charles Sumner, who supported the bill, explained that the metric system would “not be forced into use, but will be left for the present to its own intrinsic merits.” He nonetheless predicted that it would soon come into universal use and “become an approved instrument of commerce.” A growing number of scientists and educators shared this optimistic outlook. In the 1860s, metric advocates became increasingly hopeful that the new system might eventually become the sole system of measurement in the United States.Footnote ¹¹

Yet this same decade saw a very different development: a small coterie of the nation's most accomplished engineers and industrialists began setting inch-based standards for everything from screw threads to sheet metal to wire and pipe. Many of these standard setters had ties to the machine-tool and metalworking trades. Frustrated by the fact that basic components came in a bewildering diversity of shapes and sizes, a handful of key players pioneered voluntary industrial standards that allowed these items—nuts and bolts, pipes and flanges, and other building blocks of machines—to work together, no matter which company manufactured them. Such standards fostered economies of scale, as many different companies would compete to supply precisely the same components. They also made the construction and repair of the era's machines a simpler, cheaper proposition by dispensing with the skilled labor associated with older, bespoke forms of production. Though engineers and industrialists from around the nation participated in devising these standards, a disproportionate number hailed from Philadelphia. This was understandable; the city housed the biggest concentration of firms in these industries as well as the Franklin Institute, arguably the nation's most important technical society.Footnote ¹²

Railroads also gave rise to standards. As a national rail network took shape from the 1860s onward, freight cars began traveling over competitors’ lines via the interchange system. The need for so many different companies’ rolling stock to work together sparked a drive toward voluntary standards governing everything from screw threads to car couplers, all denominated in inches. Several railroading organizations came to play key roles in these campaigns for standardization, including the Master Car Builders’ Association and the American Railway Master Mechanics’ Association, which also drew heavily from the machine-tool and metalworking industries. Whatever the focus of their efforts, the individuals who pressed the cause of standardization believed it would advance efficiency, rationality, safety, and order.Footnote ¹³

As these efforts at standardization gathered momentum, the campaign to go metric also grew in influence, with the famed educator and president of Columbia University, Frederick Barnard, leading the charge. In 1872, Barnard published a well-received book that laid out the case for adoption of the metric system; the following year, he founded the American Metrological Society, an organization dedicated to the same end. Barnard's crusade attracted the interest of elite educators and scientists, though it never became a mass movement. Nonetheless, given developments overseas and the absence of significant opposition at home, it seemed increasingly likely that the United States would follow Europe's lead.Footnote ¹⁴

That changed in May 1874, when the American Railway Master Mechanics’ Association gathered in Chicago for its annual meeting. The same day that witnessed spirited discussions of standard axle dimensions and standard valve sizes, Coleman Sellers stood up to speak. He was well known, though perhaps less so than his cousin William Sellers, whom the famed British industrialist Joseph Whitworth once described as the “greatest mechanical engineer in the world.”Footnote ¹⁵ The two men operated the William Sellers Company of Philadelphia; Coleman served as chief engineer, William as president. The firm was the most important and efficient manufacturer of machine tools in the country, a place where standardization proceeded faster and farther than almost any other factory in the country, transforming everything from paint colors to shop drawings. William Sellers even created the first and most consequential industrial standard of the era: a system of screw threads that had gained many adherents by the time Coleman delivered his talk. The Sellers name was synonymous with standardization. And the metric system was the ultimate standard.Footnote ¹⁶

Yet Sellers had come to bury the metric system, not to praise it. He began by pointing out that earlier in the century the United States had led the rest of the world in developing interchangeable parts. More recently, this obsession with uniformity had given rise to the first industry-wide standards, creating a system of interoperable parts that could work in any machine made by any manufacturer. “Separate and distinct manufacturing establishments have come to use the same standards and to make their production interchange one part with another,” he noted. But there was a catch: “what has been done in this direction, and what is being done now, is founded on the inch as the unit of measurement in the machine shops.” This put the two imperatives—a universal system of metric measures and a universal system of standard parts—on a collision course. “While French savants were laboring to build up this decimal system of interchangeable measures,” observed Sellers, “the better class of American mechanics were solving the problem of making machinery with interchangeable parts.” These very different approaches to standardization could not be reconciled without immense cost.Footnote ¹⁷

In this paper as well as in expanded versions delivered over the rest of the decade, Sellers asked his listeners to consider the cost of going metric by examining the tools his firm used to produce components in the standard size of 1¼ inch. He counted 129 sets of articles: drills, reamers, gauges, cutters, taps and dies, mandrels, and many other implements. These pieces, he observed, “tally with and belong to the dimension marked 1¼ in many thousand places on drawings, which have been accumulating for years, to patterns loading down our pattern lofts to gear wheels interchangeable over a continent.” These could not be replaced without creating an entirely new set of patterns, taps and dies, gauges, and all the other equipment necessary to go metric. At the same time, the old system would have to be maintained: all the equipment already in existence would need to be serviced and repaired for many years, requiring that two sets of every tool, old and new, would become necessary.Footnote ¹⁸

In theory, every industrial establishment could convert existing units to their metric counterparts. Sellers argued that this solution, which metric advocates proposed, was better in theory than practice. Instead of a binary system in which everything was divisible by two—1 inch, ½ inch, ¼ inch, ⅛ inch, and so forth—a rather ungainly sequence of numbers would take their place: 2.54 cm, 1.27 cm, 0.635 cm, 0.3175 cm, 0.15875 cm, 0.079375 cm, each becoming significantly more cumbersome than the last. The same was true with larger components: boilers, for example, came in 36 inches, 42 inches, and 48 inches; when translated into the metric system, these tidy, divisible numbers, each of which shared multiple factors, became 91.44 cm, 106.68 cm, and 121.92 cm. The existing whole numbers made intuitive sense to mechanics, never mind the buyers of this equipment; their metric translations did not. The only way to clean up this problem was to change the actual dimensions, but this meant retooling at considerable expense.Footnote ¹⁹

Sellers and the growing number of engineers and industrialists who came to oppose the metric system had little sentimental attachment to other customary measures in use. They did not care whether people continued to measure their wheat in bushels or their milk in gallons. Only the inch and the standards derived from it mattered. That this humble unit could so thoroughly thwart the metric cause is understandable. Unlike the grab bag of unrelated measures still used in the United States, the metric system's appeal lay in the perfect, predictable interdependence of its units. Any country that adopted some metric units but not others undermined the conceptual foundations of the entire system, making full adoption extraordinarily difficult. Yet this was the path the United States followed, legalizing the metric system without making it the exclusive system of measurement. The result was a hybrid system, where metric measures became customary in medicine and science even as engineers made older units like the inch increasingly integral to the organization of industry.

Metric proponents, fearful of precisely this outcome, began organizing campaigns to make the metric system mandatory. In 1876, a new group known as the American Metric Bureau opened its doors, funded in part by Barnard's existing organization. Lead by the educator and librarian Melvil Dewey—who consistently ordered the world along decimal lines—the new group focused its efforts on schoolteachers and children, publishing tracts that explained the operations of the metric system, its advantages, and its growing use outside of the United States. Dewey hoped that the American Metric Bureau could create a groundswell of popular support that would ultimately lead to national legislation making the metric system the exclusive system of weights and measures. But as metric advocates marshaled their forces, a more coherent opposition coalesced within two very different organizations connected to the larger engineering community.Footnote ²⁰

The first was the American Society of Mechanical Engineers (ASME), founded in 1880 by a number of the nation's leading technical minds. Many of the founding generation shared an obsession with standardization, and in the coming years, the ASME would play a key role in coaxing industry to adopt a growing number of voluntary standards, even if it rarely formulated those standards itself. It was only appropriate, then, that attendees at the first annual meeting listened to papers on standard screw threads and the dangers of the metric system. The latter, given by founding member Coleman Sellers, proved even more influential than his first foray into the subject. It explicitly joined the campaigns of industrial standardization with a critique of the metric system, arguing that it was too late—and too costly—for the country to consider going metric. The inch had been enshrined in the industrial base; it would not be dislodged. Sellers repeated the warning he had offered earlier that decade: “America,” he wrote, “has for the last half century, been striving in its own way toward equalization of its standard sizes. The immense railroad industries demand this.”Footnote ²¹

The central role of the ASME in defeating the metric system was overshadowed by the rise of another group known as the International Institute for Preserving and Protecting Weights and Measures (hereafter, the Institute). This organization, founded in 1879, launched a very visible, if eccentric, campaign against the metric system. It promoted what became known as “Great Pyramid metrology,” a belief that the Egyptians had inscribed the inch as a sacred unit of measurement in the design of their famed structures. The movement gained numerous adherents in both the United States and England at this time, including many distinguished scientists. Like earlier generations of otherwise respectable thinkers who dabbled in astrology or alchemy, the intellectuals drawn to this movement did not see any contradiction. Over the 1870s and 1880s, pyramid metrology channeled much of the opposition to the metric system in the United States, eliciting furious rebuttals by Barnard and other metric proponents.Footnote ²²

The rise of pyramid metrology would seem to underscore the alleged irrationality and provincialism of the anti-metric movement. But the story is more complicated. Both the leadership and the rank-and-file membership of the Institute included an extraordinary number of engineers; many of them had close ties to the railroads, metalworking trades, and other industries where standardization had taken root. The founder of the Institute, Charles Latimer, may have dabbled in mesmerism and divining rods, but he was best known for being the longtime chief engineer of the Atlantic and Great Western Railway. A proponent of developing standard practices in the maintenance of rail lines, he pioneered what Railway Age would later describe as the “correct principles and . . . good practice in railway track work,” turning what had been one of the more chaotic, poorly maintained lines in the country to one of the safest and most reliable.Footnote ²³

Many members had comparable professional profiles. In a typical update on membership from 1883, the Institute's journal noted that it had elected six new members at its recent meeting, “most of them engineers.” This particular cohort included Edward Wellman Serrell, a well-known civil engineer who had worked on railroads and bridges; and Charles G. Roebling, the famed engineer, wire manufacturer, and builder of the Brooklyn Bridge. Eventually, the membership would encompass many more high-placed engineers, including John B. Jervis, the railroad and public works engineer; and William H. Searles, a civil engineer who wrote the principal textbook on railroad surveying. Though it is impossible to know why, precisely, so many of these men—civil engineers, iron foundry owners, and others—came to embrace a belief in the mystical origins of the inch, it likely affirmed the central place this unit had in their work lives, governing everything from the components used to build bridges and tunnels to the scale of the blueprints and surveys that structured their plans.Footnote ²⁴

Mechanical engineers did not join the Institute in the same numbers, but their embrace of standards did far more to halt the progress of the metric system. In the 1870s and 1880s, engineers promoting a uniform system of screw threads ran up against what seemed like an insurmountable obstacle when they discovered that the underlying unit—the inch—could not be accurately reproduced because the United States lacked an accurate reference standard. Ultimately, George Bond, a mechanical engineer connected with Pratt & Whitney, the nation's premier manufacturer of reference gauges, solved the problem with the help of William Rogers, a Harvard professor of astronomy, instrument maker—and longtime member of the Institute. The duo devised a “comparator,” which enabled them to build the most accurate inch-based gauges ever built. These supplied the metrological benchmarks used to define standards governing everything from the gauge of wire to the pitch of a screw to the thickness of iron plate.Footnote ²⁵

By the 1880s, the engineering profession had largely won the first battle over metric conversion. While a handful of historians have noted the signal contribution of engineers in this consequential struggle, they have struggled to explain it. Following the interpretive lead of Monte Calvert, David Noble and others claimed that the debate over the metric system exposed a longstanding divide between an anti-metric “shop culture,” consisting of practical, self-educated men who owned and operated small machine shops, and a pro-metric “school culture” of progressive, professional, college-educated engineers and academics. According to this interpretation, the older “shop culture” engineers feared the metric system because it would make it easier to calculate measurements on the factory floor, thereby depriving them of their esoteric knowledge. As Calvert wrote, “What could be more of a boost to the status of the college-trained engineer than for him to possess a new and arbitrarily determined system of measurement? What could better assure his ascendence over the boy from the shop? Knowledge of the metric system could become, like calculus, a badge of the formally trained.” In this reading, conservative, self-educated traditionalists defeated the metric system in order to protect old-fashioned, high-skill forms of production.Footnote ²⁶

This interpretation has no basis in reality. Metric opponents William and Coleman Sellers presided over a vast industrial empire that included Sellers and Company, one of the largest manufacturers of machine tools in the world; Edge Moor Iron Company, the world's largest fabricator of iron and steel components for bridges and other structures; and most famous of all, the Midvale Steel Company, a company one historian has aptly described as “the leading scientific steelmaker in America.”Footnote ²⁷ Neither man wanted to preserve autonomy on the shop floor. Coleman Sellers once wrote that “the attention of engineers is constantly directed to so perfect machine tools so as to utilize unskilled labor.”Footnote ²⁸ An industry journal likewise described him as “writing from the plane of experience of the practical mechanic, and yet he is a school man, too. He is the advocate of system at any cost.”Footnote ²⁹ Toward that end, Coleman and William Sellers hired university-trained engineers to wrest control from the shop floor. The most dramatic of these interventions took place at Midvale Steel, site of Frederick Winslow Taylor's experiments in scientific management; recent scholarship suggests that many of Taylor's concepts originated with William Sellers and his deputies. None of this comports with the idea that these men wished to protect antiquated shop-floor traditions from university-trained managers.Footnote ³⁰

Moreover, university-trained managers and engineers came to dominate the anti-metric cause. Consider George Bond. He studied mechanical engineering at the Stevens Institute before joining Pratt & Whitney and becoming head of the company's standards and gauge department; he authored a number of scientific papers on the problems of precision measurement and inch-based standards. He was the antithesis of the older shop culture—and yet he became a strident foe of the metric system. For example, when a dissident group of railroad engineers in New England had the temerity to recommend that the Master Car Builders’ Association study the question of adopting the metric system, Bond, like other high-placed, university-trained mechanical engineers, dismissed the idea out of hand on the grounds that it would derail standardization. The mere act of discussing the metric system, Bond warned in 1889, would “inspire a feeling of cautious hesitancy on the part of those who may be willing and even anxious to adopt a standard of whatever system may be officially recognized.”Footnote ³¹

This particular attack came at a critical phase in the metric battle. Barnard died a month after this editorial appeared, depriving the metric system of its most forceful advocate in the United States; Dewey's Metric Bureau went defunct around the same time. Though a handful of scientists carried on the campaign, engineers and managers hostile to the metric system outnumbered them. This was a logical consequence of the proliferation of inch-based standards among railroads, machine-tool manufacturers, and metalworking trades. The gradual embrace of standard sizes proceeded with little fanfare or notice—yet it proved decisive in what became the most important battle over the country's system of measurement.Footnote ³²

The Revolt of the Engineers

In 1896, the House of Representatives considered a bill that mandated the immediate, exclusive use of the metric system in the federal government, with the rest of the country to follow suit a few years later. The sudden interest in the issue had grown out of the fact that the Republican Party now controlled both the House and the Senate for the first time since 1873. Charles Stone, a pro-metric educator from Pennsylvania, became the new chairman of the House Committee on Coinage, Weights, and Measures. Stone, eager to push a pet issue, summoned sympathetic witnesses for hearings; all dutifully praised the metric system for its simplicity and consistency, as did academics and scientists who wrote in support of the legislation. The bill attracted little attention until it was sent to the floor for full consideration. It might well have passed, but growing concern that changing weights and measures in an election year might cost votes prompted legislators to send it back to the committee for further consideration.Footnote ³³

Despite its defeat, the bill sparked a backlash among engineers and industrialists, none of whom had been consulted on the proposed change. Later that year, the ASME created a committee charged with preparing “such material as may be necessary, which may be used in opposition to legislation seeking to make the Metric System and its use compulsory in the United States.” The members of this committee included George Bond and Coleman Sellers, but it also welcomed several other members, including John Sweet, a mechanic turned professor of engineering at Cornell University who had devised some of the first—and most accurate—standard gauges ever manufactured in the United States. These engineers, like most who opposed the metric system, had a significant professional stake in the existing system of standards denominated in the inch.Footnote ³⁴

They would soon be overshadowed by a younger group of college-educated engineers, most of whom had close ties to the first generation of metric foes and shared their obsession with standardization. Henry Towne was typical of the new face of the opposition. The son of one of the partners of the Southwark Foundry in Philadelphia, Towne attended the University of Pennsylvania and later studied at the Sorbonne. He worked in Philadelphia with many key proponents of industrial standards, including Coleman and William Sellers and Robert Briggs, the famed engineer who developed a system of uniform pipe threads still in use today. Towne contributed to the development of standard systems of belts and pulleys before pioneering the mass production of locks at several factories in Connecticut; he eventually became the biggest such manufacturer in the world. Like others in this circle, Towne was obsessed with increasing efficiency and rationalizing the shop floor. In 1886 he presented a now famous paper at the annual meeting of the ASME entitled “The Engineer as an Economist,” which inaugurated the new “science” of management. The connection between Towne and Taylor was well known nearly a century ago. As one of Frederick Winslow Taylor's earliest, most sympathetic biographers conceded in 1923, “if Taylor was great, Towne was his prophet.” The historian David Noble has echoed that assessment, noting that Towne's pathbreaking paper “is generally considered to be the first significant articulation of the scientific-management movement.”Footnote ³⁵

Towne's career highlights another quality found in the new generation of metric opponents: their shared enthusiasm for the constellation of ideas that sought to bring order and “system” to the management of factory floors. These thinkers marched under various banners, from “shop management” to “systematic management” and, eventually, “scientific management.”Footnote ³⁶ Taylor himself would play a pivotal role in the decisive defeat of the metric system. So, too, would another like-minded figure: Frederick Halsey. Like Towne, Halsey boasted a formal education; he attended Cornell, becoming a protégé of John Sweet. A consummate modernizer, Halsey developed cutting-edge machine tools; he also helped pioneer “systematic management,” developing a detailed “premium plan” that gave laborers carefully calculated incentives to increase productivity. Though overshadowed by Taylor's efficiency studies, Halsey's plan was adopted in some version by more factories. Halsey achieved considerable fame in economics and engineering, becoming one of the leading figures in the quest to make factories more efficient. He went on to become associate editor at the American Machinist, arguably the most influential industry journal in the United States. A gifted propagandist and relentless self-promoter, he was well positioned to lead the attack on the metric advocates.Footnote ³⁷

Advocates of standardization and “scientific” approaches to management emerged as the most vocal and effective critics of the metric system because these thinkers shared a common belief in the transformative power of inch-based standards, both within the walls of individual factories and across the larger economy. They had a preoccupation—one might say obsession—with uniformity, imposing it on everything from nuts and bolts to the most mundane movements of a worker's body. In a typical expression of this world view, Taylor counseled “the adoption and maintenance of standard tools, fixtures, and appliances down to the smallest item throughout the works and office, as well as the adoption of standard methods of doing all operations.” Or, as he put the matter more succinctly, “It is uniformity that is required.” Whatever their particular investment in standards, such uniformity was inevitably defined in inches. The metric system threatened to destroy not only the hard-fought system of standards governing the actual machines but also the performance standards that Taylor and others had spent years developing.Footnote ³⁸

The battle against the metric system, then, was waged by a technical elite of industrialists and engineers closely connected with both the standardization movement and scientific management. This argument, which goes against conventional wisdom and the academic literature, underscores that the metric debate was not a battle between pro-metric progressives and rear-guard reactionaries but between two distinct communities of self-appointed modernizers. In the end, the standards setters and scientific managers proved far better organized and more persuasive. They would triumph in what became the decisive clash over the metric system waged in the opening years of the twentieth century.

The catalyst was the creation of a new federal bureaucracy known as the Bureau of Standards. This institution, modeled on Germany's famed Physikalisch-Technische Reichsanstalt, would pursue scientific and technological research in optics, electricity, mechanics, metallurgy, and chemistry. It would simultaneously set the standards used to define these fields; it would also validate and certify the advanced instruments necessary to conduct such research. This was imperative: the swift, chaotic growth of new industries proceeded without any agreement on standards used to measure and meter electricity. As a consequence, companies—and even the federal government—sent equipment and measuring devices overseas for calibration and verification. Frustrated by these restrictions, a coterie of scientists, electrical engineers, chemists, and others associated with new technical fields pushed for a new standards bureau.

The most important player in these efforts was an electrical engineer and physicist named Samuel Stratton. A professor at the University of Chicago, Stratton's real talent lay in playing politics and building bureaucracies, and he shepherded the legislation through Congress. Though Stratton and his allies favored making the metric system the exclusive system of measurement in the United States, they understood that yoking the fate of the Bureau of Standards to the metric cause would derail their fragile political coalition. As Stratton later noted in private correspondence, “a great many would have opposed [the bill] had it been understood that the Bureau was favorable to the adoption of the metric system.” Witnesses therefore studiously avoided any mention of it in their pleas for the Bureau's creation, and pro-metric legislators steered clear of the issue as well. This defused the issue and President McKinley signed legislation creating the Bureau of Standards in the spring of 1901 and installed Stratton as its head. Over the next twenty years, Stratton would turn the Bureau into the largest national laboratory in the world.Footnote ³⁹

Stratton tackled the metric question as soon as he became director. He corresponded closely with Thomas Corwin Mendenhall, president of the pro-metric American Metrological Society, and addressed the organization in person; he also began working closely with Rep. Henry Southard, a metric advocate who now chaired the House Committee on Coinage, Weights, and Measures. Southard oversaw the introduction of two largely identical bills that would make the metric system the legal, and exclusive, system of weights and measures for the United States. In 1901, Stratton began a campaign aimed at building support for the legislation. That summer, he privately noted that “Mr. Southard and myself have been preparing the work for the next session. I have secured the cooperation of many large manufacturers.” Stratton rattled off a number of big firms he believed would go on record in support of the metric system. He predicted that the metric system would soon become the law of the land.Footnote ⁴⁰

Despite Stratton's confidence that manufacturers would support the legislation, few appeared before the committee. Instead, most of the support came from scientists, electrical engineers, educators, and instrument makers—valuable allies, to be sure, but hardly qualified to speak about the potential cost of retooling the nation's heavy industry along metric lines. When the committee began to question individuals outside of Stratton's circle, the hearings became acrimonious. The rear admiral in charge of the U.S. Navy's Bureau of Steam Engineering predicted that going metric would cause a “great deal of confusion,” undoing the Herculean efforts to standardize nuts, bolts, and other fasteners that had begun with the work of William Sellers in the 1860s. Other witnesses, most notably Pratt & Whitney's George Bond, seconded this point. Like many in the field, Bond predicted that compulsory adoption of the metric system would impose “great hardship” and necessarily “involve more expense than we would care to assume.” Though Stratton could have ignored these dissenting voices, he jumped into the fray, accusing Bond of misrepresenting the cost and inconvenience of the proposed conversion. “As far as your product is concerned,” Stratton lectured, “I am quite sure you could turn it out in the metric system.”Footnote ⁴¹

Stratton's blithe dismissal of Bond awakened the resistance. Shortly after Bond had delivered his testimony, the Franklin Institute met to hear from a committee it had appointed the previous year to report on the advisability of adopting the metric system. Unsurprisingly, the committee—which included several of the pro-metric witnesses whom Stratton had tapped—embraced the idea. But when the report came up for discussion among the larger membership, Bond, fresh from his clash with Stratton, openly attacked the committee's findings. But his real target was the metric legislation under consideration in Congress. He questioned the propriety of the hearings, noting that it had been his understanding that manufacturers would be well represented on the roster of witnesses. “I was surprised to find myself the only one, except for one gentleman,” he complained. Bond, who had played such a critical role in defining the inch and the standards linked to it, made an impassioned case against the metric system. After considerable debate, the Franklin Institute narrowly endorsed the committee's pro-metric report.Footnote ⁴²

But Bond and his allies would not be deterred, and in the succeeding months, a movement against the metric system took shape within a loose community of machine-tool manufacturers and firms in allied industries along with organizations like the National Association of Manufacturers, founded in 1895. Veterans of the first metric battle took part, including Coleman Sellers, but the movement acquired a new face: the mechanical engineer Frederick Halsey. At the turn of the century, Halsey had emerged as the leader of a band of younger engineers within the ASME. As Halsey's standing grew, he gained outsized influence within the organization, and he likely had a hand in the decision to devote most of the annual meeting in 1902 to the “metric question.” Initially, the meeting was set to hear a formal report submitted by a committee on the subject, but Halsey took matters into his own hands, writing and distributing a voluminous study in advance of the meeting. This document closely resembled a legal brief, buttressing its claims with copious “exhibits.” Though Halsey echoed many of the earlier arguments voiced by Coleman Sellers and others, he went much farther, actively seeking to demolish the metric system's pretensions of superiority. Halsey would soon publish this report as a book, pointedly titled The Metric Fallacy.Footnote ⁴³

Much of Halsey's argument centered on a key claim: every nation that made the metric system mandatory failed to abandon older units of measurements. “The fatal mistake of the metric advocates and the weakness of their case,” he wrote, “lies in their assumption that the statute book is an index of the practice of the people.” Halsey offered considerable evidence demonstrating that ostensible models of metric adoption like France were still trying to stamp out older standards. This was a devastating line of attack: Halsey knew that the metric system's popular appeal lay in the promise that it would supplant other standards entirely and immediately. By painting a picture of countries caught awkwardly between old and new standards, Halsey effectively undercut the metric system's claims to bring order to chaos. He predicted that the United States would be no different, noting that existing gas pipes alone “would keep the old system alive for fifty years.” So long as the dead hand of the past exercised its influence, Halsey argued, many of the alleged benefits of going metric would prove elusive.

Halsey also assailed the widely circulated belief that conversion to the metric system would help the United States gain an edge in overseas markets. He pointed out that the Europeans used inch-based screw thread standards and that foreign businesses and governments bought American machine tools denominated in inches because the benefits—low prices, interchangeable parts, and the interoperability of vital components like nuts and bolts—far outweighed this liability. If the United States already dominated these overseas markets, going metric offered few benefits and might even undercut this advantage. Halsey assembled testimonials from foreign buyers, including a French industrialist who reported that he knew of “no case where the fact of the machines being built to English measures affected their saleability.” And as Halsey noted, in those rare instances where foreign customers demanded metric components, American manufacturers readily produced these as well, even if such requests remained a rarity.Footnote ⁴⁴

The debate over Halsey's manifesto defined the annual meeting and marked a significant new front in the battle. The ASME gave Halsey top billing, letting him deliver his report to the assembled members; it also asked several metric advocates to offer a rebuttal, including Stratton and Southard. This was only fair: Halsey had attacked both men by name in his report. Both appeared, not anticipating the trap that Halsey had set for them. When Stratton offered a generic defense of the metric system, Halsey adopted the air of a vengeful prosecutor, accusing the Bureau of Standards’ new head of being “the prime-mover of the present pro-metric movement.” Stratton, who disliked public speaking, struggled to answer, eventually conceding a key point: that older units would persist for decades. Southard fared even worse. When he dismissed practical obstacles to conversion, some members of the audience, likely coached by Halsey, interrogated Southard on obscure provisions in the proposed bill, asking questions that he could not answer. And when Southard claimed he had invited anti-metric activists like Coleman Sellers to testify about the legislation, Halsey dramatically produced a letter from Sellers alleging that no such thing had happened. Halsey then reclaimed the floor to give his closing arguments. His performance won plaudits in the press, emboldening metric foes.Footnote ⁴⁵

In addition to Halsey's report, the committee charged with weighing in on the issue also released its own recommendations. While it was far more evenhanded, it sided with Halsey on a key point: that Congress should not, under any circumstances, make the metric system compulsory. Even the pro-metric members of the committee agreed that this was hardly practical, with the report asserting that “such legislation could not be enforced . . . so far as transactions between private individuals are concerned.” And this, as much as the relative merits of the two systems, helped forge a consensus against the proposed legislation. Indeed, when the ASME polled its members in early 1903, it found that 78 percent of respondents opposed the bills under consideration, and 67 percent objected to any legislation designed to promote the metric system. These results cannot be taken as representative of the entire membership, given that only a fifth of the members responded. But for members who cared about the issue, it was clear that a critical plurality had become more militant in their opposition. As signs of opposition grew, Southard and Stratton made an ignominious retreat, shelving the bills two months after their disastrous appearance at the ASME meeting.Footnote ⁴⁶

Over the next few years, opponents of the metric system launched other campaigns to sway public opinion on the subject. The National Association of Manufacturers, which had initially adopted a more neutral stance toward the issue in the late 1890s, registered its opposition to making the metric system compulsory as early as 1902. A year later, it moved more firmly into the anti-metric camp after releasing a poll of its members that showed they opposed going metric by a margin of three to one. This poll, which William Sellers helped administer, was misleading: only a small fraction of the membership bothered to vote—a fact that metric opponents conveniently overlooked when reporting the results. Nonetheless, it reflected a genuine shift in the organization's leadership, which became increasingly hostile to metric bills pending before Congress. Over the next few years, the group went on the offensive, lining up witnesses who could offer credible testimony about the costs of retooling the nation's industrial base along metric lines. Its powerful secretary, Marshall Cushing, forged close personal connections with many proponents of industrial standards, eventually appointing Halsey to serve as its official representative before Congress on metric matters.Footnote ⁴⁷

A number of other professional and trade organizations followed the group's lead, passing anti-metric resolutions and lobbying Congress. These included the Railway Master Mechanics and the Master Car Builders’ Association; business groups such as the National Carriage Builders’ Association, the National Metal Trades Association, and the Engine Builders’ Association; and smaller professional organizations like the American Society of Heating and Ventilation Engineers. The opposition of these groups sprang from the simple fact that most of them designed, manufactured, or sold standardized goods denominated in inches and feet. When confronted with the prospect of being forced to go metric—and spending the money to retool—most became converts to the cause. That many engineers who opposed the metric system belonged to more than one of these organizations made it far easier to steer these groups toward the same end. Halsey again played a key role in these efforts, visiting annual meetings, delivering talks, and urging members to adopt resolutions condemning the proposed legislation in Congress.Footnote ⁴⁸

Though Halsey could take significant credit for the groundswell of opposition, so too could Samuel S. Dale. Like Halsey, Dale was an editor, helming several key trade magazines in the textile business. Much like the machine-tool industry, the textile business had forged standards denominated in inches; while archaic and confusing to outsiders, these had acquired an almost sacrosanct status with the industry. The debate in Congress had awakened fears that all of this would be undone by government fiat. Dale threw himself into the anti-metric cause, helping Halsey compile the data that went into the report to the ASME. But he also authored a tract of his own that showcased the dangers that metric conversion posed for the textile industry. Dale had an obsession with facts and figures and wielded these to great effect, forcing opponents like Stratton into answering lengthy interrogatories on obscure topics. Inevitably, his opponents would misstate some minor point and Dale would pounce on the error as evidence of a nefarious conspiracy. Though a zealot, he was also a puckish, mischievous figure. The journalist Ida Tarbell described him as a “wonderful truth seeker” who had “fun” provoking powerful figures. “The rout which truth is sure to make,” she wrote, “is the joy to life for him.”Footnote ⁴⁹

In 1904, Congress held hearings on yet another metric bill, similar to the one introduced two years earlier. The first witness was Halsey, representing the National Association of Manufacturers; Dale followed him. Both men went on the offensive, attacking the metric system as a pet project of visionaries and cranks that ran counter to the will of the country's engineers and entrepreneurs. Halsey spoke with disarming certainty. “There is no intelligent man in the machine shops,” he averred, “who will for a minute contemplate the retirement of our standards for this system.” Dale opened a new offensive, arguing that whatever the merits of the metric system for scientific work, it was profoundly ill suited for the textile business. Dale walked the legislators through the arcane field of textile standards. He explained how the world's manufacturers had gradually embraced an idiosyncratic, but eminently logical, set of standards. “Unification of the world's textile standards by the English system is in sight, almost within reach,” Dale testified. “By the metric system it is an impossibility.” In Halsey's and Dale's testimony, the metric system—long billed as bringing order to a chaotic world—would instead sow confusion, disorder, and danger in its wake.Footnote ⁵⁰

Other witnesses lined up to corroborate their claims: several prominent mechanical engineers; representatives of powerful trade groups including the Metal Trades Association, the Machine Tool Builders’ Association, and the American Iron and Steel Association; and a parade of legendary industrialists who came armed with facts and figures, offering real-world examples of what it would mean to forcibly retool the nation's industrial base along metric lines. Many of these arguments focused on cost and convenience, but an equal number described the threat posed to the carefully constructed system of standards that now structured the entire industrial base. William Sellers rhapsodized about how “the screw bolts and nuts which enter into the construction of every machine, and which unite the rails on more than 100,000 miles of roads in this country, are interchangeable, so that a nut made in Maine will screw upon a bolt made in Texas.” Sellers extolled the efficiency and savings made possible by the decades-long drive toward standardization, arguing that “we have attained . . . a system superior to any other the world affords, and we are now threatened with a law, which, if adopted, will make it necessary to abandon all that we have accomplished.” This became a constant refrain in the testimony. A witness from Brown and Sharpe, the maker of machine tools, gauges, and precision instruments, emphasized that the expense of going metric was not the primary reason for his opposition: “I would again emphasize the fact that it is not alone the first cost of changing standards and gauges that is the greatest objection. This, though important, is insignificant compared with the greater evil of breaking away from our standards and interchangeable system.” Or as an engineer with the Southern Railway put the matter more bluntly, “the use of the metric system will for the time, at least, destroy all present existing standards.”Footnote ⁵¹

The National Association of Manufacturers helped organize this critical testimony, much as it did when Congress resumed hearings two years later, in the spring of 1906. What correspondence survives from this period indicates a concerted campaign to defeat the metric bills that relied heavily on the efforts of a handful of engineers and industrialists, all closely connected with standards setting and the promotion of efficiency on factory floors. Cushing tapped Towne and other familiar names to provide testimony, but he also reached out to Taylor, now president of the ASME. The two men carried on an extensive correspondence rooted in their shared antipathy toward the metric system. As Cushing confided to Taylor in one typical missive, “You know better than I do how resolute all the metric cranks will be, and how necessary it will be for all of us who are interested in this cause to double our efforts in every way.”Footnote ⁵²

Taylor's appearance before Congress proved a turning point. He readily conceded that the metric system was preferable for scientific work. He also steered clear of the usual arguments about the cost of retooling, focusing instead on how the proposed change would burden ordinary workers. The inch and its fractions, Taylor testified, was “one of the most important facts of their lives. They live with it. It is a language to them. They talk and think more in inches than in words while at work, and they are doing that all their lives long.” Taylor claimed that because the inch had become so thoroughly embedded in the nation's machines—and by extension, in the consciousness of the men who tended them—skilled workers could measure and make parts without recourse to gauges or rulers. Taylor, who had spent his life watching workers, described in minute, almost loving detail how the inch structured every step of the manufacturing process. He predicted that if Congress tried to impose the metric system on the workmen, it would invite a rebellion that he half-jokingly predicted would sweep the committee members from office. This was a clever bit of theater, but Taylor's concern lay less with the workers than with the fact that he had built his career on finding what he liked to call “the one best way”: that is, standards that banished difference and promoted efficiency. The idea of introducing an entirely new system of measurement to the nation's factory floors would be deeply inefficient, at least in the short term—and perhaps in the longer term as well. In his testimony, Taylor predicted that introduction of the metric units would likely lead to the worst of all worlds. Instead of assuming the financial burden of genuinely adopting the millimeter as the basic unit for manufacturing—something that would require new patterns, gauges, dies, and machines on a massive scale—manufacturers would simply stick to the inch, but camouflage it with metric equivalents. One inch would become 25.54 millimeters; three-fourths of an inch would be 19.05 millimeters. This awkward workaround meant that workmen would constantly toggle between the two systems. “Owing to this tomfoolery,” said Taylor, “the workman's time is wasted.” And for Taylor, the man with the stopwatch, nothing was more precious than time. His arguments, echoed in an encore performance by Towne on the final day of the hearing, sealed the fate of the legislation; after the committee finished deliberating, it shelved the bill entirely.Footnote ⁵³

In retrospect, the hearing was the high-water mark in the metric campaign. Though metric advocates continued to press for legislation, and Stratton intermittently sought to advance the metric cause, industrialists and engineers proved far more capable at shaping public opinion. In 1916, these efforts culminated in the creation of a new anti-metric organization known as the American Institute of Weights and Measures. It featured veterans of the metric wars: Halsey, Bond, Dale, Towne, and others. But it also counted many newer faces among its members: presidents of engineering societies; leaders of prominent firms in the metalworking and machine-tool businesses as well as the railroads; pioneers in industrial standardization like Henry Leland, president of the Cadillac Motor Car Company; and educators such as Alexander Crombie Humphreys, president of the Stevens Institute. Over the next decade, this organization waged a running battle against the metric system, repeating the arguments that had worked so well in the climactic struggle that took place in the opening years of the twentieth century.Footnote ⁵⁴

Much of its success can be attributed to a sophisticated public relations campaign. It placed advertisements and editorials in industry journals; successfully lobbied hundreds of trade associations, chambers of commerce, and technical societies to go on the record condemning mandatory use of the metric system; and obsessively monitored legislation on the local, state, and national levels. When the group identified a bill that endorsed mandatory metric conversion—or merely contained clauses that opened the door to greater reliance on the metric system—it mobilized hundreds of industrialists, engineers, and managers to defeat the legislation with letters, testimony, and editorials. By the 1920s, its membership rolls included many of the most important firms in the nation as well as presidents of the National Association of Manufacturers, the Association of American Steel Manufacturers, the American Railroad Association, and other national organizations. These organizations had a stake in standardization, actively joining government-sponsored efforts to bring further uniformity to the nation's economy over the course of the 1920s. As inch-based standards governing everything from automobile tires to pads of paper became the norm, the prospects for going metric became ever more remote. Only in scattered pockets of the business community—the electrical field, for example, and pharmaceuticals—did the metric system become dominant.Footnote ⁵⁵

The individuals behind the American Institute of Weights and Measures understood that the battle over the metric system went beyond the borders of the United States. Though manufacturers of machine tools and other precision products occasionally made products for the export market denominated in metric units, most foreign buyers in metric countries purchased the less expensive, more ubiquitous products defined in increments of the inch. In effect, the United States exported its inch-based standards, building significant markets in metric countries in Europe and Latin America. The new group promoted these efforts, but it also took the fight to international organizations that might threaten the American position. These efforts, which often involved both British and American anti-metric activists, built on earlier campaigns in the textile industry, where individuals like Dale had worked closely with British firms to defeat attempts to replace inch-based standards with new metric units. In 1921, for example, the organization sent delegates to the International Chamber of Commerce in order to defeat a pro-metric resolution; it did the same with meetings of the Pan American Standardization Conference over the course of the 1920s, working to ensure that the United States did not join the larger hemispheric embrace of the metric system.Footnote ⁵⁶

The American Institute of Weights aand Measures would disappear by the 1930s, but by then the die was cast. As one government-sponsored assessment would later observe, “by that time it had done its job so well that there was really no further need for it.” The path dependencies begot by hundreds, and eventually thousands, of standards created an iron cage no less rational and restrictive than the more figurative cage devised by theorists of modernity. As Walter Ingalls, a mining engineer and president of the Institute, declared in 1921, “The names of things may be changed, but the things themselves, i.e., the standards that have been developed by industry,” could not be readily altered. “What engineer” he asked, “would conceive the folly of attempting to change our standards of screw threads, pipe sizes, board measures, the dimensions of structural steel, etc.?” Ingalls, like many others, could not countenance the destruction of a carefully constructed system of standards woven into the nation's industrial infrastructure.Footnote ⁵⁷