When Oliver Smoot ‘62 talks to prospective MIT students, he likes to share a thing or two that he’s learned over the years. “One message,” he says, “is you really have no way of knowing what long-term impact any hour and a half’s worth of work is going to have.” He should know: as a freshman, he spent about that much time measuring the Harvard Bridge, using his body as a yardstick. What began as a pledge task for Lambda Chi Alpha (LCA) in 1958 has become permanently etched, not only into the bridge, but into MIT lore as well.

Smoot will return to MIT on October 4 to participate in a Smoot 50th-­anniversary cele­bration for students and alumni. Although he won’t be remeasuring the bridge, the festivities will include a Charles River cleanup, a plaque installation on the bridge, and a 1950s-theme bash at the MIT Museum, where Smoot will be presented with an official unit of measure: a Smoot stick. Check event details at web.mit.edu/smoot/.

Anointing the Shortest Pledge

As Smoot tells it, Tom O’Connor ‘60, the LCA pledgemaster, came up with the measurement idea. He was tired of making the half-mile trek across the bridge to campus from LCA’s home in Boston without an inkling of how far he had to go at any given point. O’Connor chose Smoot because he was, at 5’ 7”, the shortest pledge, thereby making the measurement more labor-intensive. Plus, the name Smoot sounded scientific, like ampere or watt.

So on a crisp Thursday night in October, seven freshmen set to work. They planned to calibrate the bridge with a few actual Smoot lengths–having Smoot lie down and marking off the distance with chalk–and then use a string to measure the rest of the bridge. But a sophomore LCA brother happened by. He was so amused that he stayed to watch, so they had to abandon the idea of using the string altogether.

They painted marks every 10 Smoots; by the end of the bridge, Smoot was so exhausted he had to be carried along. But they finished the job. According to their calculations, the bridge was 364.4 Smoots, plus or minus an ear. They knew they couldn’t come up with a precise number, Smoot explains, so they added the plus or minus, and wrote the e in ear as an epsilon. “The epsilon referred in a cutesy way to this error measurement,” he says. And therein lies another detail that has evolved over time: the epsilon has been lost from written accounts of the story, Smoot says, and the minus sign is often omitted as well.

A Career in Measurement

Perhaps the missing epsilon is a minor point, but not to Smoot. He had an illustrious career in technical standards and measurement in Washington, DC. As a unit of measure himself, he recognizes the irony in his career choice, but, he contends, “it certainly wasn’t planned that way!” He spent most of his professional life at the Information Technology Industry Council, a high-tech trade group. In 1987, he joined the board of the American National Standards Institute, and he eventually became its chair. He served two years as president of the International Organization for Standardi­zation before retiring in 2005.

The concept of Smoots has persisted, both at MIT and beyond. Every year since 1958, the Smoot marks have been repainted by LCA brothers, and when the Harvard Bridge was rebuilt in the late 1980s, the contractor scored the sidewalk every Smoot length, rather than the standard six feet. Smoot’s story has been covered by the Washington Post, the Boston Globe, and National Public Radio. And Google Earth and Google calculator recognize the Smoot as a bona fide measurement unit; for example, if you type in “25 feet in Smoots,” the calculator will convert it to 4.47761194.

Smoot’s name also graces the cover of a recently published book on measurement, Smoot’s Ear: The Measure of Humanity. In the preface, author Robert Travernor writes, “The significance of Smoot’s ear is that it is a built-in error; it recognises that fallibility is ever-­present in human affairs … that it is an essential quality of human nature, and is at the root of human creativity.”

Perhaps that’s why Smoot and his buddies never did bother to measure his ear. Nonetheless, Smoot asserts that it’s the same length now as it was 50 years ago.