District Liner John Perry was in Eire when Pope John Paul II visited there early in October. Perry sent me a postcard telling me what an enjoyable event it had been.

His card was posted in Dublin on Oct. 2, bore a commemorative stamp with the pope's picture on it, and was sent "Par Avion, Aerphost." It was delivered to The Washington Post on Oct. 27, which would not have been good time if the card had arrived on a slow boat from China.

Freda Segal of Bethesda mailed a check to Lord & Taylor's New York office in one of the company's printed reply envelopes.

On the back of the envelope, space was provided for a return address, so Freda dutifully filled in her name and address.

Two days later, the envelope and enclosed check were delivered to her, not to Lord & Taylor.

There is this to be said for the NEW! IMPROVED! automated Postal Service: It is making some of its mistakes much faster than it used to when the mail was processed by hand. THIS IS WASHINGTON

Al Brogdon of Damascus asks:

"Do you really think Secretary Andrus did Dodd a favor by rehiring him?

"If Dodd had stayed out of Interior, he could have found a better job. Rehired, he has been set up for bad ratings, bad assignments, and all the other ways a well-oiled bureaucracy can make life miserable for a good guy."

Perhaps so. Working for the government has its advantages and its disvantages and one of the known disadvantages is living with "the system."

But a matter of principle was involved in this case, and it was necessary for all men of good will to resist the capricious firing.

Once the victim of an arbitrary firing has been vindicated, he is free to look for another job and resign in his own good time.

However, sudden dismissal can be calamitous if the person who has been fired can't find suitable employment at that particular moment. Being fired can turn out to be a blessing in disguise, but for most people it is not. SNAP JUDGMENT

The World's Greatest Grandson phoned me yesterday to lodge a protest.

"Grandpa," he said, "the White House News Photographers' Association is going to hold a free workshop, and I'd like to attend. I still have a lot to learn, but they won't let me in. They're discriminating against me."

"Why do you say that?" I asked.

"Because it's for high school students, and I'm still in junior high," he explained. "Do you think I could get in if I put on a false beard and tried to look older?"

"How do you know it's for senior high school students only?" I asked.

"Because it says on the poster that it's for high school students who are thinking about a career in photography, or have been doing photographic work for school papers, or are members of camera clubs. Your friend Jim Atherton of The Washington Post is going to conduct one of the workshops, and Randy Routt of The Star will do one, and Bob Oakes of the National Geographic, which prints the kind of color pictures I hope to make some day. It's all free, Grandpa, and I sure wish you could get me in."

"I have a suggestion," I said. "Call Bob Gilka of the Geographic on 857-7468 and ask him if 'high school' means senior high school only, or junior high school as well."

In about 10 minutes, The World's Greatest was back on the line. "I won't need the false beard," he said. "Junior high school students are welcome if they're really interested in photography."

A tip of the hat to members of the White House News Photographers' Association for caring about young people and helping them develop their talents. If any of the youngsters at your house are interested in photography, be advised that the free workshop will be held this Sunday, Nov. 4, from noon until 5 p.m. The place: The Smithsonian's Baird Auditorium in the Museum of Natural History, 10th Street and Constitution Avenue NW. Reservations are not needed. Call Gilka for additional information. THE COST OF HIGH LIVING

Predictions that gasoline is heading toward of price of $2.50 a gallon send shivers down the spine of Rulen Walker of Falls Church.

His car's tank holds 25 gallons. For him, "Fill it up" will cost $62.50.

The best thing to do, Rulen, is "top it off" when you need 10 or 15 gallons. It won't hurt so much. Take it from a friend of mine who buys a package of cigarettes every day. When I ask why he doesn't buy a carton and spare himself the trouble of going to the store every day, he says, "I can't afford a whole carton. That's too much money to spend on cigarettes."