What's the most majestic place in this most majestic town? I nominate the main reading room at the Library of Congress.

To walk in is to know right away that you're in a place where serious people do serious work. You can almost feel ideas zipping around the room, like electrons. I've never walked into the main reading room without saying "Wow" to myself.

Now I'm saying "Wow" for a different reason. It has to do with a busload of high school students from Ellicott City, Md., and the standing-on-ceremony reception they got at the M.R.R. one day last month.

These weren't brainless, gum-popping, plugged-into-a-Walkman teen-agers. These were members of the 10th grade honors English and history class from Centennial High School.

They had come to the main reading room with their teacher, Bruce Smith, and another chaperone to do research for their honors papers. The visit was supposed to have been cleared in advance. But the students were given the boot almost as soon as they walked in.

A spokesperson for the library said high school students are not allowed in the main reading room except under any of three conditions:

1) The student is a 10th, 11th or 12th grader who has a letter signed by the principal of his school. The letter must state that the student needs specific materials for a special project that are unavailable elsewhere. It can't be a regular classroom assignment.

2) The student is part of a group that has arranged ahead of time to tour the M.R.R. That's tour, not use.

3) The student is at least 16 years old and a high school graduate.

What's the rationale behind these restrictions? "We don't have the room or the facilities to handle them here," the spokesperson said. "The library system is good enough now at the local level to serve high school students' needs . We prefer that everyone try their own library first. We're really a library of last resort."

Then why was the Centennial delegation promised over the phone that it would be allowed to use the M.R.R.? Apparently there was a misunderstanding, the spokesperson said. Permission was given for the group to take a tour of the M.R.R., in accordance with Policy 2 above, but not to use the facilities.

My question is why these rules have to be so ironclad. Nobody is suggesting that the gates be thrown open to every high school kid in the universe. But wasn't it obvious that these were kids who had come to the M.R.R. for a serious purpose? Wasn't it obvious that they were chaperoned? Wasn't it obvious that there is a time to bend policies, and that this was one of them?

A few days ago, Robert the Typist took a few whacks at a few plumbers. Now a plumber has whacked back.

He's Murray McElroy Wohlfarth, whose family has been in the plumbing business in Washington for more than 50 years. He had this to say to and about those who put down plumbers:

"If the public continually condemns, and treats the service trades this way, one day they will wake up and find no one to call.

"We are having a very hard time finding young people to train, for it is not a glamorous way to earn a living. Have you ever known anyone who took his guests down to the basement during a party to show them the new water heater?"

Fair enough, Murray. Not every pipe-fixer is late and lazy, like the ones I described in my first column on the subject. Thanks for the view from the other side of the wrench.

I hope it never comes to this, but Vance Garnett's look into the future may prove correct.

Like many of us, Vance has noticed that, at the corner of 20th and L streets NW, the pedestrian signs no longer limit you to a choice between WALK and DONT WALK. They have added a third option: DONT START.

But this latter command has met with very little success. So Vance foresees a fourth sign. It will read: DONT EVEN THINK ABOUT IT.

And then, when that fails, too, Vance bets we'll see this:

GO AHEAD, MAKE MY DAY.

Great vanity plate spotted by several readers in the parking lot of a local hospital:

I 8 2 MCH

Spies tell me it belongs to -- who else? -- that hospital's dietitian.

With that, gentle readers, I vanish for a brief vacation, after which I will no doubt complain that I 8 2 MCH. Stay warm. See you a week from Monday.