Pi Computation Wizard John Wrench Dies at Age 97

March 26, 2009

Few today remember what mathematician John William Wrench Jr. did 60 years ago, just before the advent of the electronic computer. He and fellow mathematician Levi Smith calculated the value of pi to more than 1,000 decimal places.

Wrench died in late February at age 97.

"Computers, of course, blew hand calculations out of the water," mathematician William Dunham commented. "That someone from our pre-computer past lived well into the 21st century is quite amazing. When I spoke at Hood College (Frederick, Md.) in the 1990s, I got to meet him, and I can only liken the experience to meeting Thales."

In 1873, British mathematician William Shanks stunned the world of mathematics when he claimed to have calculated pi to 707 digits. In 1945, D.F. Ferguson, using pen and paper, identified an error in Shanks' work in the 527th place. Ferguson then carried the computation to 808 places.

In 1948, Wrench and Smith verified Ferguson's work—and continued the calculation to 1,000 places using a gear-driven calculator. In 1961, Wrench and Daniel Shanks (unrelated to William Shanks) used an IBM 7090 to calculate pi to 100,265 digits. The printout was formally presented to the Smithsonian Institution—and their feat earned a place in the Guinness Book of Records.

Wrench, who attended the University of Buffalo, received his B.A in mathematics in 1933. He earned his Ph.D. in mathematics from Yale University in 1938.

Wrench held teaching positions at Yale (1935-38); Wesleyan University (1938-39); George  Washington University (1939-42; University of Maryland, College Park (1949); and American University (1968-70). Wrench also held numerous scientific positions throughout his life, retiring in 1974 as head of the U.S. Navy's Applied Mathematics Laboratory, David Taylor Model Basin, Carderock, Md. He was a member of the MAA, the American Mathematical Society, and a fellow of the Washington Academy of Sciences. An editor of the journal Mathematics of Computation, Wrench wrote more than 150 scientific papers in his long mathematical career.

Source: Washington Post, March 25, 2009; Frederick (Md.) News-Post, March 20, 2009.