Last Tuesday, you'll recall, was a swimming day if there ever was one. So Chuck Stolze Jr., a 19-year-old from Falls Church, decided to test his new scuba gear. He invited three friends to join him: Glen Syncoop, Randy Rudd and Marco Morales. All four had graduated last month from Marshall High School.

The four classmates hopped into Stolze's Jeep and headed for the quarry at Dickerson, Md. That is a swimming hole that means business. It's 90 feet deep. with sheer walls of solid rock.

Within minutes, a near-tragedy developed. Wyncoop was trying to swing himself into the water from a rope hanging from a rocky ledge. But he held on a little too long. When Wycoop plummeted into the water, he landed on a log that was floating close to one wall. He broke a vertebra and an ankle.

Stolze was in the water at the time, wearing his scuba gear, and he immediately went to the rescue of the weeping, moaning, sinking Wyncoop. "Without the scuba gear, Chuck might not have gotten Glen out," said Mickey Stolze, Chuck's mother.

Stolze, Rudd and Morales got Wyncopp to shore after a few minutes of hard work. Then they carried their injured friend three-quarters of a mile up a hill to where the Jeep was parked. By late that afternoon, Wyncoop had been admitted to Fairfax Hospital, where medical personnel said he is expected to recover.

A "good news" story with a nice, neat ribbon around it? Not entirely, I'm afraid.

After the three young men had placed their injured friend in the Jeep, they looked over Chuck Stolze's vehicle.

Someone had jimmied open the glove compartment while the four friends had been down at the quarry. Missing was Stolze's wallet, containing $80, some tape cassettes and pictures of his high school girl friends.

I've never doubted man's inhumanity to man. But why did it have to crop up at the same moment as the good work of Stolze, Rudd and Morales?

If it weren't for the strike this would be the night that the baseball freaks among us would have curled up around the air conditioner and the television to take in the All-Star Game.

But on drones news of labor rather than news of doubles and triples. And drowned in the backwash are not just regular season games, but, as of tonight, a chance to look at baseball's best all on one field at one time. The fan in this corner says: Nuts.

However, a DePaul University law student has hit on a way of relieving frustration, and he has asked me to commend it to all Washingtonians.

Jerry Kritz, of Hartford, Conn., has organized a nationwide group of baseball fans who will don the cap of a major league team today as a protest against both the strike "and the fact that neither the players nor the owners understand how upset the fans are."

"Especially in Washington, baseball has demonstrated that it doesn't care about the fans by moving two franchises elsewhere," Kritz pointed out. He says he sanctions the wearing of Baltimore Orioles caps here today, although "the last time I was in Washington I saw some people who still had Senator's caps. Those would be better. They'd carry a kind of double-injury message from Washington fans."

Sad Sign of the Times . . . We know that shoplifting is a problem at area groceries. Last week, at a Safeway store at 2303 Columbia Pike in Arlington, the message was brought home in unforgettable fashion.

The Columbia Pike management decided not to place any salmon, crabmeat or canned hams on the shelves because all three items were being stolen at an alarming rate. Instead, customers found signs on the shelves where the three products are normally displayed, informing shoppers that if they wanted these items, they could be obtained at the manager's office.

"Apparently they've been popular shoplifting items," said Safeway spokesman Ernie Moore. He added that the Columbia Pike store is the only one in the Safeway chain where nonstocking has been instituted to combat shoplifters.

There's a touch of irony in the case of the salmon, Moore noted. Bumble Bee pink, the most pouplar brand of Salmon that Safeway sells, cost $2.15 a can last week. That's the lowest the price has been since January, Moore said.