Here is one I have been trying to find the answer to for years. I have asked flight attendants on airplanes all over the world. No one knows. No one even hazards a wild guess.

Why doesn’t the plastic bag inflate? Since it doesn’t, what is it for?

I am speaking, of course, of the oxygen mask that will drop in case of emergency and that you are supposed to tie securely around your face before attending to infants or children. The plastic bag attached to the mask never inflates, and what’s more, they make a point of telling you it won’t inflate. This to me is more perplexing than some of the early undeciphered scripts I study. –Thomas G. Palaima, director, Program in Aegean Scripts and Prehistory, University of Texas at Austin

Doc, your prayers have been answered. First an inside secret: the bag does inflate, but only when you exhale.

Here’s the deal. Passenger oxygen masks give you a continuous flow of oxygen (as opposed to oxygen on demand, which only flows when you inhale). The oxygen obviously can’t flow into your lungs while you’re exhaling, so if there weren’t some way to store it temporarily it would have to be vented wastefully. The bag makes this unnecessary. When you start exhaling, your breath plus the incoming O2 flows into the bag. When a certain pressure is reached the bag stops filling and the rest of your exhaled breath, which contains more carbon dioxide, is vented through a port in the mask.

The flight attendants make a point of telling you the bag won’t inflate (right away, that is) because of an incident years ago. An airplane lost cabin pressure, the oxygen masks dropped down, and the passengers put them on–but when they noticed the bags didn’t inflate, they figured the masks weren’t working and took them off. Bad idea. Thus the warning. Simple, no? You want a hand with some of those Aegean scripts, just give me a call.


Your recent column on the neutral zones of the Arabian peninsula [February 1] said the Iraq-Saudi zone was still in existence. On the contrary, the zone was divided in 1981. This was done to stabilize the border after the Iranian revolution and the outbreak of the Iraq-Iran war “impelled Saudi Arabia and Iraq to seek closer relations,” according to one book on the subject. –Richard Jones, Washington, D.C.

I was afraid somebody was going to bring this up. Strictly speaking, you’re right–the zone was divided by treaty between Iraq and Saudi Arabia on December 26, 1981. However, for unknown reasons the treaty was never filed with the United Nations and nobody outside Iraq and Saudi Arabia was officially notified or shown the text giving the new map coordinates. So legally speaking the U.S. government has to act as though the neutral zone still exists. Practically speaking, though, it’s well aware that it doesn’t.

The Office of the Geographer at the U.S. State Department, which provides the official word on international boundaries for all U.S. government maps, continues to show the diamond-shaped neutral zone with a line running through the middle and the words, “de facto boundary as shown on official Iraqi and Saudi maps (alignment approximate).” Similar notes appear on U.S. maps showing the rest of the Saudi-Iraq border (which was basically straightened) and the Iraq-Jordan border (which was made more crooked). The de facto borders are believed to be accurate within 150 meters, or perhaps a city block–no big deal to you and me, but to government cartographers used to pinpoint precision, a constant source of irritation.

Iraq’s borders are by no means the only ones up in the air. According to maps I got from the State Department’s Bureau of Intelligence and Research (amazing what you can find out these days with a little pull and a fax machine), the boundaries between Saudi Arabia and its neighbors Yemen, Oman, the United Arab Emirates, and Qatar are either in dispute, undefined, or defined but undisclosed. If you want to stay out of trouble next time you visit the Arabian peninsula, don’t take any long walks in the desert.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.