# On This Day

• ### 12-19-1783

Birthdate of Charles-Julien Brianchon who in 1820 published the nine-point circle theorem. Although this theorem had been independently discovered many times, Brianchon gave the first complete proof and coined the phrase "nine-point circle."

Charles-Julien Brianchon
Nine Point Circle
• ### 12-19-1894

Pioneering statistician Karl Pearson introduced the Pearson family of densities.

Karl Pearson
Pearson Distributions
• ### 12-19-1908

Scientific American offered a \$500 prize for "a simple explanation of the fourth dimension."