The eccentric engineer: America’s most unlikely measurement

Few things matter more in engineering than measurement. A 20-metre bridge over a 30-metre canyon has obvious drawbacks. And the peak of measurement recognition may be to have a unit named after you. To achieve this you generally need two things: to have been a scientific giant in your era, and be dead.

That is unless you’re Oliver Reed Smoot. When Smoot became a student at the Massachusetts Institute of Technology, he had no idea he was going to, quite literally, become a unit of measurement. As a junior member, or ‘Pledge’, of the Lambda Zeta (MIT) chapter of the Lambda Chi Alpha fraternity, he knew he would have to do his pledgemaster’s bidding and, as it happened, his pledgemaster had an interesting job for him.

The fraternity were minded to measure the distance across the Harvard Bridge that links Boston to Cambridge, Massachusetts, across the Charles River. Now you might be forgiven for thinking that this distance was already well known – after all, the bridge engineer William Jackson, who was responsible for three bridges over the river (this one being completed in 1881) might have a reasonable idea of the distance he had to span.

Lambda Chi Alpha weren’t interested in old-fashioned yards and inches, or even metres; they decided to measure the bridge in body lengths. To make this more of a challenge, Tom O’Connor, the fraternity pledgemaster, decided they should use the shortest member of the fraternity who they also deemed to have the most ‘scientific’ name. Enter Oliver Reed Smoot.

Smoot was 5ft 7in (1.7m), and on an icy October night in 1958 he agreed to lie down at one end of the bridge, be measured off in chalk, get up, lie down again on that mark and so on, until he had covered the entire bridge. This proved rather more laborious than Smoot had imagined, as the bridge is an impressive 620 metres long, so after a while he was carried into position for each measurement by fraternity brothers.

The result of the measurement was that Harvard Bridge was 364.4 smoots – that’s 620.1 metres. Well, roughly. These being MIT students they decided to include an error margin, which they estimated at plus or minus one ear. To stress this uncertainty, they also decide to spell ‘ear’ with an epsilon – “± 1 εar.”

In later life, Smoot went on to become – appropriately enough – chairman of the American National Standards Institute (ANSI) from 2001 to 2002, and president of the International Organisation for Standardisation (ISO) from 2003 to 2004, where no doubt he came across a lot of measurement.

However, back at MIT, the fraternity had not forgotten Smoot and each semester the new members of the group were required to repaint the bridge, marking out every ten smoots, along with various other marks such as one at 182.2 smoots, which bears the legend ‘Halfway to Hell’ and an arrow pointing towards MIT.

Following an engineering study in the early 1970s, which showed the bridge to be under-strength for its load, the city considered removing the markers. But the local police force asked for them to be preserved as they used smoots to measure the location to incidents on the bridge. The markers were preserved again when the superstructure was replaced in the 1980s, and the Massachusetts Highways Department scored the new concrete surface at 5ft 7in intervals instead of the usual 6ft.

Over time, MIT began to treasure this eccentric measurement as one of its enduring traditions, even holding a 50th anniversary ‘Smoot Day’ on 4  October 2008, at which the man himself unveiled a plaque on the bridge.

Now, even beyond the hallowed halls of MIT, the smoot is spoken of, being added to the fifth edition of the American Heritage Dictionary, and hence becoming a ‘proper’ word. From 2011, even Google Earth offered the smoot as a unit of measurement. The MIT student radio station WMBR broadcasts at a wavelength of two smoots. The measurement has even found a home in the title of Robert Tavenor’s book on measuring systems, ‘Smoot’s Ear’.

Oliver Smoot is still going strong and in 2016 he served as Grand Marshal of the ‘Crossing the Charles’ alumni parade. Anders Ångström, eat your heart out!