June 2013 | Jeremy Howell

Solving the Lincoln Problem


A poor early 19th-century Kentuckian boy splits logs from 6 a.m. to 7 p.m. If he splits sixty-five logs every half hour and then takes a five-minute break, what is the likelihood that his math homework will wind up in Harvard University's Houghton Rare Book Library? If that boy was Abraham Lincoln, up until several months ago the odds were good. Now they're certain. 


Two professors at Illinois State University have confirmed that a sheet of arithmetic problems and solutions belonging to the Houghton Library was written by our sixteenth president sometime between his eleventh and seventeenth birthdays. Exercises on the page are simple. One asks, "If 4 men in 5 days eat 7 lb. of bread, how much will be sufficient for 16 men in 15 days?" Sources confirm that most of the problems were solved correctly.


Houghton's leaf left the Lincoln family a year after the President was assassinated in 1865. Lincoln's stepmother, Sarah Bush Johnston Lincoln, gave the leaf to Lincoln's former law partner, William Henry Herndon. Herndon was collecting Lincoln material for what would become the biography Herndon's Lincoln: The True Story of a Great Life, which was published nearly two and a half decades after he was given the leaf. Over the next half century, the validity of the leaf's origin was lost.


By the time it was donated to the Houghton Library in 1954, it was only a curiosity, but now no longer. The leaf has been confirmed as belonging to a set of ten other known Lincoln arithmetic pages. Together, they form the earliest known Lincoln manuscript in existence.

Photo Credit: Houghton Rare Book Library