Pencil, Paper, and Pi

摘要

William Shanks was one of the finest computers of the Victorian era-when the term computer denoted not a machine but a person skilled in arithmetic. His specialty was mathematical constants, and his most ambitious project was a record-setting computation of n. Starting in 1850 and returning to the task at intervals over more than 20 years, he eventually published a value of π that began with the familiar digits 3.14159 and went on for 707 decimal places. Seen from a 21st-century perspective, Shanks is a poignant figure. All his patient toil has been reduced to triviality. Anyone with a laptop can compute hundreds of digits of π in microseconds. Moreover, the laptop will give the correct digits. Shanks made a series of mistakes beginning around decimal place 530 that spoiled the rest of his work.