Here are the (slightly belated) Twitter #weirdscifacts for the previous week!

319. Jan 26: The 1927 Mississippi River flood: at some points, the river was 70 *miles* wide. This is a frightening testament to the destructive power of floods.

319a. Bonus fact, via @jasonrobertshaw: Bull sharks used to swim up and down the Mississippi as far north as Illinois. Can you imagine swimming in the Mississippi outside of St. Louis and getting bit by a shark?

320. Jan 27: Snow rollers: rare, naturally-rolled snowballs! (h/t @patrickneville ) When conditions are right, sheets of snow can be blown by the wind into rolls like a carpet.

321. Jan 28: Surgeon/scientist John Hunter (1728-93) likely infected himself with gonorrhoea to test his theories. Hunter had a hypothesis that syphilis was a late-stage form of gonorrhoea, and he injected an unnamed subject to test the idea.  Scholars believe that he in fact injected himself; it’s hard to believe that someone else would have been willing to undertake the experience.

322. Jan 29: On 1/1/2010, in accordance with Life+70 law of copyright, the works of Sigmund Freud entered Public Domain. (h/t @jgold85)

323. Jan 30: Max Born had rights of German optics book stolen twice: once by Germany when he fled, once by U.S.A. when they conquered it. My Ph.D. advisor Emil Wolf shared this story with me; he worked with Born on a revised English optics book, Principles of Optics, that is still in use today.  Born was Jewish and had to flee the Nazis, who appropriated the rights of his book.  When Germany was conquered, part of the “spoils of war” involved the rights to many German books being given to publishers in the conquering countries.  Born actually received a letter from the U.S. publisher asking what parts of his old book he would be using in the new one, so that they could charge him!  (As I understand it, he more or less told them to stuff it.)

324. Jan 31: The 1903 Amundsen expedition to find NW passage sailed just in time to escape its creditors! It is oddly simultaneously reassuring and depressing to realize that scientists and explorers have always had to worry about losing funding.

325. Feb 01: Via @wiredscience: Vikings may have navigated w/ polarized skylight. This was one of those facts that was all over Twitter, but I really couldn’t beat for the day.