The battle between the decimal metric system and the more old-fashioned (and mathematically taxing) imperial system of weights and measures is a longstanding one.
One of the many advantages of the metric system is its simplicity: units like meters and grams are counted in 10s, 100s, and 1000s, while the older imperial system—though more traditional, and with many centuries of use behind it—relies on less straightforward units like the 8 pints in a gallon, the 12 inches in a foot, and the 16 ounces in a pound.
But as arithmetically tricky as numbers like 8, 12 and 14 are to work with, they seem effortlessly easy compared to a bizarre unit of measurement called the smoot—which is equal to 67 inches, or precisely 5 feet 7 inches.
So where has such a seemingly random measurement come from? The story behind it involves three factors: namely, a fraternity prank; the future Chairman of the American National Standards Institute; and the Harvard Bridge, connecting Boston and Cambridge over the Charles River in Eastern Massachusetts.
It was in October 1958 that 18-year-old MIT student Oliver R. Smoot was volunteered by some of his Lambda Chi Alpha fraternity brothers to measure the length of the Harvard Bridge from one end to the other. To carry out the survey, the students decided to use Smoot himself as the measuring device, and so had him lie down on the ground where his height of 5 feet 7 inches was marked on the sidewalk with chalk. He then stood up, walked up to the chalk mark, and lay down on the sidewalk again, so his height could once more be marked onto the concrete. And so it went on, one measurement at a time, from one side of the bridge to the other. Eventually, after more than an hour of work, it was discovered that the Harvard Bridge was in total some 364.4 “smoots” in length (give or take a head or two).
The prank soon became the stuff of legend at MIT, and Smoot’s contribution to investigative surveying has not gone unnoticed in and around campus. To this day, graffiti on the Harvard Bridge still divides the structure up into several hundred Smoot-based sections. A plaque commemorating the 50th anniversary of the stunt was unveiled on the bridge in 2008. And in 2011—several years after Oliver R. Smoot had been made chairman of the American National Standards Institute—the word smoot was added to the American Heritage Dictionary, defined as “a unit of measurement equal to five feet, seven inches.”
All told, the smoot must surely be one of the most ludicrously precise units of measurement ever recorded in the English dictionary, even when compared to the imperial system!