UPPSALA , Sweden, Dec. 8 (UPI) -- Sweden's Uppsala University said a copy of Isaac Newton's "Philosophiae Naturalis Principia Mathematica" is back with the school after its theft 40 years ago.

CAMBRIDGE, England, Oct. 24 (UPI) -- Physicist Stephen Hawking will retire his post in 2009 as Lucasian Professor of Mathematics at Britain's Cambridge University, the university said.

DUBLIN, Ireland, Feb. 23 (UPI) -- Albert Einstein and Isaac Newton displayed symptoms of psychiatric disorders that may have been a key to their genius, a Dublin psychiatrist said.

UPI Almanac for Tuesday, Dec. 25, 2007.

MANCHESTER, England, Aug. 14 (UPI) -- British scientists say a group of scholars in India discovered one of the founding principles of modern mathematics hundreds of years before Newton.

LONDON, July 4 (UPI) -- A cache of letters from politicians, poets, scientists and composers recently found in a laundry room sold for more than $6 million at auction in London.

JERUSALEM, June 19 (UPI) -- A letter written by Isaac Newton that predicts the end of the world no sooner than 2060 has gone on display at Hebrew University in Jerusalem.

LAUSANNE, Switzerland, June 4 (UPI) -- Letters by some of the greatest figures in politics, arts and sciences offering a glimpse at life centuries ago were found in a Swiss home's laundry.

WALTHAM, Mass., Feb. 20 (UPI) -- A U.S. scientist confirmed what Isaac Newton speculated more than three centuries ago: the senses of hearing and sight are parallel.