# On This Day

• ### 11-27-1727

Isaac Greenwood began his "private" lectures as Hollis Professor of Mathematics and Natural Philosophy at Harvard. These lectures were given to selected students and required parental permission, probably to insure payment of the attendance fee of forty shillings.

Isaac Greenwood
Hollis Professorship
• ### 11-27-1754

Abraham de Moivre died in London, England at the age of 87. It was said that he succumbed to lethargy. He was sleeping twenty hours a day, and it became a joke that he slept a quarter of an hour more every day and would die when he slept the whole day through.

Abraham de Moivre
• ### 11-27-1875

Johns Hopkins University offered J. J. Sylvester $5000 a year plus moving expenses to assume the math professorship. He set three conditions under which he would accept: The sum be paid in gold, the university provide a residence, and that he be allowed to appropriate student fees. Only the first was acceptable to the university, but Sylvester agreed when the offer was increased to$6000 in gold. Shortly after arriving, he founded the American Journal of Mathematics. In 1883 he left to become Savilian professor of geometry at Oxford.

James Joseph Sylvester
• ### 6-27-432 BCE

Meton of Athens observed the summer solstice and began his Metonic cycle of 235 lunar months or 19 solar years.

Meton of Athens
Metonic Cycle
Solstice
• ### 7-16-433 BCE

Metonic moon cycle enacted. The Metonic 19-year cycle of the moon was enacted on this date in ancient Greece. This masterpiece of approximation (19 solar years = 235 lunations) is still used today in the computation of the date of Easter.

Metonic Cycle
• ### 1-1-45 BCE

The first day of the first year of the Julian calendar, which remained in effect in the western world until October 4, 1582. The previous year, 46 BC, known as "the last year of confusion," was the longest year on record at 445 days.