Dear Dr. Boli: What makes my cellular telephone vibrate? I heard there were little mechanical parts in there but am quite sure there are small men inside. I have a bet for 5 crowns with my friend Goodwife Strauss that it is so. Please resolve this predicament. —Sincerely, Scuba Joe.

Dear Sir: You are partly correct. Your deduction that there must be little men involved somehow is a common one, and indeed inspired Mr. William Allingham to write the most famous poem ever written about a cellular telephone. But the truth, as is often the case in scientific matters, is a little more complex, and requires looking at the problem as a whole system, rather than as an isolated unit.

The fact is that the men are not little at all, but quite large and beefy. Instead of being distributed among all the cell phones in use, which would be prohibitively expensive, they are concentrated at the central office and the various repeating stations where cellular masts are installed.

As you know, each cell phone must be precisely tuned to one of these masts, so that it may receive the signal and the network may direct calls appropriately. When a call comes in for your telephone, the man stationed at the appropriate cellular mast is directed to strike that mast with a hammer. The mast vibrates like a tuning fork, sending waves of vibration through the air and ground in all directions. These vibrations have little effect on most of the world (although they are said to annoy voles a great deal, and if anyone cared about voles the matter would doubtless be looked into); but, when they reach a cell phone tuned at precisely the correct frequency, sympathetic vibrations begin, and the phone itself vibrates at the same frequency as the mast.

As you can see, many everyday phenomena for which popular legend has invented outlandish explanations are no less marvelous when you know the science behind them.