Underwater pull: Trolling for magnets

Q. A World War II British mine expert was investigating an unusual object washed ashore along the Thames River. An eight-foot cylinder, it lacked torpedo propellers or the mooring chains of contact mines. So why did he remove all keys from his person before bravely approaching? ­A. Magwich

 A. It was late 1939, and dozens of British ships had been blown up in shallow waters where no submarines had been detected and which had been swept for ordinary contact mines, says James Livingston in Driving Force: The Natural Magic of Magnets.

Then English spotters saw German aircraft dropping cylindrical objects that parachuted into the river and disappeared below the surface.

By lucky accident, one of these was now in full view. Suspecting a magnetic trigger, the expert removed all magnetic objects from pockets and approached with nonmagnetic tools. "Fortunately for him and for Great Britain, he successfully dismantled the device," Livingston writes.

The crucial piece of the complex trigger to the 650 pounds of high explosives was a small magnet much like a compass needle, that would respond to a large nearby steel object like a ship and close an electric circuit– kaboom!

"Degaussing" became a countermeasure, i.e., girdling ships in current-carrying cables to cancel any magnetic fields. But this was slow and expensive, so soon degaussed tugboats dragged long electrical cables through waters to trigger mines harmlessly. Other ships used electromagnets so powerful they triggered mines far ahead of the bow.

By late 1940, Hitler's first "secret weapon" was no longer a major threat, says Livingston.

Q. In modern times, is there any place on Earth where it has literally rained 40 days and 40 nights? –Noah

 A. Yes, in a few very different parts of the world, says University of Nebraska-Lincoln climatologist Kenneth F. Dewey: First, in the Tropical monsoon regions (during summer) of the Northern and Southern Hemispheres, such as the 1041 inches (86 feet) of rain that fell in Cherrapunji, India, from August 1860 to July 1861.

Also, in coastal Northern Hemisphere mid-to-high-latitude locations (during winter), such as seaside Oregon, where it rained 45 days and nights in a row from December 14, 1950, through January 27, 1951, for a total of 28 inches.

The Aleutian Islands in the Northern Pacific Ocean and Iceland in the Northern Atlantic have seen even longer continuous stretches of rainfall– over two months. "Several coastal locations in northern Scotland and western Norway have also experienced occasional Biblical drenchings."

Q. A woman lived to be over 80 but never celebrated a single birthday. When and where was she born? –Whistler's Mother

A. February 30, 1712, in Sweden, says Central Michigan University mathematician Sidney Graham. She fell through the birthday cracks during the historic switchover from the old Julian calendar to the new (and current) Gregorian one. Beginning 45 BCE, the old calendar had added a leap day every fourth year, making for a calendar year of 365.25 days to keep better in sync with the actual sun year of 365.242 days. But even this small discrepancy amounted to nearly a day a century, or 11 full days by the late 1500s!

Following Pope Gregory XIII's 1582 proclamation, a new calendar was proposed– every fourth century year now NOT a leapyear, etc.– and countries such as Italy, Spain, Portugal, and Poland switched over outright, leapfrogging the 11 days from October 4, 1582 to October 15, 1582. Others delayed, including Sweden which stalled until 1700 when it "skipped February 29, reconsidered and went back to Julian dates by adding an extra leap day (February 30) in 1712, then re-reconsidered and converted to Gregorian in 1753," says University of Ottawa's Edward Cohen in Math Horizons.

Thus any Swede born on that extra leap day February 30 fell into a no-one's land of official birthdaylessness.

Send STRANGE questions to brothers Bill and Rich at