Dr. John Wrench Jr.

Dr. John William Wrench Jr., 97, died Friday, Feb. 27, 2009, in Frederick, Md.

He was born Friday, Oct. 13, 1911, in Westfield, N.Y., to John William Wrench Sr. and Mary Louise Brown Wrench.

Dr. Wrench grew up in Hamburg, N.Y., attended Hamburg schools and graduated from Hamburg High School in 1929.

He married Constance Philpitt Jacobs on Feb. 11, 1943, in Washington.

Recognized for knowledge of computing many types of numbers prior to the advent of electronic machines, he was best known for his skills in computing the value of the numerical constant Pi, a mathematical concept dating back four thousand years to the Babylonians and Egyptians. In 1873, William Shanks, of England, computed the value of Pi to 707 digits by hand. In 1945, D.F. Ferguson, using pen and paper, computed Pi to 530 places in the course of one year, locating an error in Shanks' work in the 527th place, later carrying the calculation to 808 digits.

Challenged by this accomplishment, John Wrench and Levi Smith verified Ferguson's 808 digits and continued the calculations to 1,000 places with Wrench using a gear-driven calculator by the winter of 1948. The advent of electronic mainframe computers by 1949 extended Pi to 2,037 digits. In 1961, John Wrench and Daniel Shanks (unrelated to William Shanks) used an IBM 7090 in New York to calculate Pi to 100,265 digits at an exceedingly rapid speed. The printout of this calculation was formally presented to the Smithsonian Museum, and Wrench was cited in the Guinness Book of Records. Additional calculations since then have carried the value of Pi to 1 billion digits.

Dr. Wrench attended the University of Buffalo, Buffalo, N.Y., from 1929 to 1935. While there, he was awarded the Wilfred H. Sherk Memorial Prize in mathematics in 1932. In 1933, he received his B.A., Summa cum laude, in mathematics. In 1935, he received his M.A. in mathematics. From 1935 to 1938, he attended Yale University, in New Haven, Conn., earning a Ph.D. in mathematics.

Dr. Wrench held the following teaching positions, from 1935 to 1938, Yale University, New Haven, Conn.; from 1938 to 1939, Wesleyan University, Middletown, Conn.; from 1939 to 1942, George Washington University, Washington; in 1949, University of Maryland, College Park; and from 1968 to 1970, American University, Washington.

He held the following scientific positions, from 1942 to 1943, chief computer, supervised calculations under contract with National Defense Research Committee, George Washington University, Washington; from 1943 to 1945, assistant mathematician, classified research in Interior Ballistics, NDRC contract, Geophysical Laboratory and Catholic University, Washington; from 1945 to 1949, theoretical research in high-speed dynamics and underwater explosions, U.S. Navy, David Taylor Model Basin, Carderock; in 1949, classified research in propagation of underwater sound and response of structures to underwater explosions, Navy Department, Bureau of Ships, Washington; from 1949 to 1953, Minesweeping Branch, Bureau of Ships, Navy Department; from 1953 to 1974, deputy head, Applied Mathematics Laboratory, head, Theory and Analysis Division -- developed high-speed numerical methods for structural design, hydrodynamics, wave propagation and aerodynamics. He calculated high-speed numerical methods for problems in logistics, data analysis and statistical inference. He also provided maximum effective utilization of the UNIVAC mainframe computer system in evaluations of future needs for high-speed numerical techniques, David Taylor Model Basin, U.S. Navy, Carderock; in 1974, he retired as head, Applied Mathematics Laboratory, David Taylor Model Basin, Carderock.

He was a member of Sigma Xi, Phi Beta Kappa, American Mathematical Society, Mathematical Association of America and the Association for Computing Machinery. He was also a member of Board of Examiners, Potomac River Naval Command and a fellow of the Washington Academy of Sciences.

He was the editor of the Journal of Mathematics of Computation, National Academy of Sciences, National Research Council. He published more than 150 scientific papers.

Dr. Wrench enjoyed reading, solving crossword puzzles, playing the piano, hiking and constructing dollhouses in precise detail. In 1968, he hiked the entire C & O Canal alone. He also enjoyed computing with the aid of an original Apple II computer.

He is survived by his wife, Constance P. Wrench, of Frederick; daughter, Paula W. Weston of Sheridan, Wyo.; granddaughters, Lisa Stouffer and husband, Scott, of Frederick, and Susan Barnes and husband, Andrew, of Dayton, Wyo.; six great-grandchildren; two great-great-grandchildren; sisters, Marian Roosa of Venice, Fla., and Margaret Wrench, of Hamburg, N.Y.; and brother, Robert F. Wrench and wife, Virginia, of Corning, N.Y.