We all know that Baltimore's airport is now Baltimore-Washington International, but what was the name before it became an international airport?

Paula Mitchell, Reston

Actually, it's always been an international airport, from the instant Harry Truman dedicated it on June 24, 1950. Then it was Friendship International Airport and was, said Truman, an embodiment of "our determination to develop the marvels of science and invention for peaceful purposes."

The airport, the first in the area to accommodate jets in those pre-Dulles days, wasn't named Friendship in some Orwellian sop to pre-Cold War amity. It was named after a Methodist place of worship that occupied the land on which the airport was built: Friendship Church.

Around the church was a cemetery. "When Friendship International Airport bought the property, they tore down the old Friendship Church," said Mark Schatz of the Ann Arrundell County Historical Society, "but they could not move the cemetery."

Some of the bodies were moved, but the rest are still there, between runway 15/33 and runway 10/28. "There still are burials there, maybe once a year," BWI's Nelson Ormsby said.

The airport's name was changed in 1973 to make it clearer to travelers exactly where it was and to emphasize its role as a regional transportation hub.

"It was the power of marketing," Nelson said, "the power of branding."

In the process, something was lost. Friendship is such a nice name. Nelson said that actress Carol Channing wrote a letter to Maryland's then- governor, Marvin Mandel, asking him not to change the name of the airport. She said it was nice to fly into an airport named Friendship.

"A lot of people liked the old name, frankly," Mark said. " 'Friendship International' had a nice sound to it. There was some opposition to changing the name to BWI."

Magnetic Attraction

When I first moved here, Reagan (National) Airport's primary runway was designated 18/36, meaning directly north/south. A few years ago, it suddenly became runway 1/19. Had the 18/36 ID been erroneous all those years, or did they redo the runway and rotate it 10 degrees in the process?

Paul Gatza, Alexandria

The easily bored might turn to something more scintillating right now -- the stock tables, for example, or a George Will op-ed. The rest of us are going to have a quick lesson in runway nomenclature.

Picture a runway, which is basically a straight line on the ground. Now imagine you are standing on that runway holding a compass. If your runway goes from north to south, the compass's needle will be in perfect alignment with it, with the red end pointing to 360 degrees. The other end will point 180 degrees away -- to 180 degrees, as it turns out. This hypothetical runway would be known as 18/36.

Why? Well, to get a runway's number, look at its compass heading, round it up or down to the nearest 10 degrees -- i.e., 174 becomes 170 -- then lop off the last digit. The second number is the "reciprocal" of the first, that is, it is 180 degrees away. The lowest number always goes first.

"It makes it easy for pilots to orient themselves," the FAA's William Shumann said.

Okay. So why did National's runway change names?

"There are two flip answers," William said. One is that the airport rotated slightly. "The other is continental drift at work."

The real reason is no less weird. The Earth's magnetic field is not fixed and permanent. The molten iron of the Earth's core -- the place where the magnetic field is generated -- boils around like a pot of tomato soup on the stove.

"The magnetic field lines that leave the core and extend out are kind of frozen into the liquid core," said John Hopkins University's Peter Olson. "As the fluid circulates, those magnetic field lines are dragged around. That dragging motion of the field lines produces the temporal changes that we measure at the Earth's surface."

In other words, the magnetic field keeps shifting slightly.

"We got to the point a few years ago where the runway went from something like 184.5 [degrees] to 185.5," said the FAA's William Shumann.

They had to round up instead of down and Runway 18/36 became Runway 1/19.

I'm Chevy Chase, and You're Not

In last week's discussion of Pekin and how the tiny Western Maryland town might have gotten its name, I mentioned in passing that our very own luxurious village of Chevy Chase was named after the pratfall-prone comedian who starred in the worst movie ever made ("Cops and Robbersons").

Several readers, including my own brother-in-law, pointed out that I had this backward. To them I say: I was joking.

I realize it's dangerous to deliver things in a deadpan fashion in a newspaper -- devoid as the printed page is of inflection and facial expression -- but this was just an example of Answer Man's dry wit, a wit that is downright Gobi-like, in fact.

To clarify: Chevy Chase is not named after Chevy Chase. Still, I've always found it an interesting coincidence that Washington shares its name with that of our first president.

Researcher Alex MacCallum contributed to this column. Answer Man without a question is like Superman without a cape. If you're curious about something in the Washington area, let him know. (Answer Man, not Superman.) Write answerman@washpost.com, or John Kelly, 1150 15th St. NW, Washington, DC 20071.