The Harvard Bridge that spans the Charles River from Boston to Cambridge is getting new lights. An anonymous donor has given $2.5 million to illuminate the long flat stretch that takes Massachusetts Avenue across the river. What makes this civic initiative noteworthy is that the distance between the light poles will be measured not in meters or yards, but in smoots.

In October 1958, the fraternity brothers of the MIT chapter of Lambda Chi Alpha determined the length of the bridge by measuring it in body lengths of their 5’ 7” pledge Oliver R. Smoot. They concluded that the bridge was 364.4 smoots, plus or minus one ear (the “or minus” has been lost on the bridge’s markings over time).

What was originally a prank has become a Boston landmark. Every year since Smoot inchwormed his way across the bridge, Lambda Chi Alpha pledges have repainted the smoot tallies, which generally show up every ten smoots (with some exceptions: the brothers forewent the 70-smoot mark in favor of a 69). So deeply have the smoots woven themselves into Boston life that police officers identify accidents on the bridge according to their smoot location, and contractors scored the bridge’s sidewalk not at the 6 feet that is conventional for sidewalks, but at 5’ 7”. In 2001, the American Heritage Dictionary honored the Boston tradition by admitting the word “smoot” as a unit of measurement.

Mr. Smoot, who has served briefly as the chairman of the American National Standards Institute and president of the International Organization of Standardization says he is pleased with the new plan. The lights will immortalize his famous journey across the bridge not only by their distance from each other—thirty smoots—but also by the way they illuminate: in sequence, one at a time, from Boston to MIT.