On September 16 John Rhodes Cobb of Britain set a land-speed record of 394.2 miles per hour on the Bonneville Salt Flats in Utah. By so doing, he broke his own record of 369.7 mph for a measured mile, set at Bonneville in 1939. In keeping with the rules, Cobb made two runs over the salt in opposite directions, with his official record being the average speed of the two. On his second run he covered the distance in 8.93 seconds for a speed of 403.1 mph, the first time anyone had topped 400 mph on land.

Cobb set the record in a low-slung, blob-shaped vehicle called the Railton Mobil Special after its designer, Reid A. Railton, and chief sponsor, Mobil Oil. Its streamlined aluminum skin concealed a pair of 1,250-horsepower, twelve-cylinder, turbocharged Napier Lion aircraft engines that were cooled with blocks of ice. The vehicle was twenty-eight feet eight inches long.

Since the first official land-speed record (LSR) was set in 1898, by a Frenchman whizzing along at 39.2 mph in an electric car, the mark had been a hot potato, passed quickly back and forth from driver to driver. With the exception of Barney Oldfield’s war-interrupted reign from 1910 to 1922, no one had retained the LSR for longer than four years before Cobb. For example, the auto manufacturer Henry Ford grabbed the mark in January 1904 on frozen Lake St. Clair, near Detroit, with a car he had built himself. Two weeks later he yielded it to the socialite William K. Vanderbilt, Jr., racing a Mercedes over the sands at Daytona Beach. These men exemplified the two main camps among LSR holders: the motorheads and the playboys. Cobb, who had been educated at Eton and Cambridge, was the son of a prosperous London fur dealer and one of the last of the wealthy Britons who dominated LSR racing beginning in the mid-1920s.

Cobb’s 1947 record held up for an unprecedented seventeen years. (Counting his 1939 record, Cobb held the title for twenty-five years.) Then in the mid-1960s the LSR action shifted to new types of vehicles that used jet or rocket engines to generate thrust instead of turning an axle. A separate category was established for racers that delivered their power through the wheels, and in this class the 1965 record of Bill and Bob Summers, a pair of homegrown mechanics from Arcadia, California, endured for more than a quarter-century.

Cobb lived to see none of this. He had survived several decades testing the extremes of automotive technology, as well as a stint in the Royal Air Force during World War II, but after his 1947 LSR effort, tragedy stalked him. His first wife, Elizabeth, who as a bride of several months had watched him set his 1947 record, died in 1948. Soon after that Cobb became interested in high-speed motorboats. In 1952 he went to