The Mather Sundial in McCosh Courtyard is a replica of the Turnbull Sundial (1551) at Corpus Christi College, Oxford. Princeton's sundial was given by Sir William Mather, governor of Victoria University in Manchester, England, "to symbolize the connection between Oxford and Princeton. . . [and] Great Britain and America." In 1907, Viscount James Bryce, then British ambassador to the United States, and Princeton President Woodrow Wilson presided over the dedication.

The 20-foot column supports a globe topped by a pelican, the symbol of Corpus Christi College. Inscribed around the base are these words from Samuel Butler's "Hudibras":

Loyalty is e'er the same
Whether it win or lose the game
True as the dial to the sun
Although it be not shined upon.

At one time, the Mather Sundial was the provenance of seniors, who by custom enjoyed the exclusive privilege of sitting on its steps between classes.