It's beautiful to watch somebody doing something well. Too bad everyone in the city can't be along for the ride as Officer Joe Freeman pilots Scout 148 through the streets of Northeast Washington's Trinidad neighborhood.

"Hi, Joe," the kids call out. "I'm 'Joe' on this block," Freemen says, "Reds' on the next one over and 'Officer Joe' on the one after that." Stopping to chat with people in front of an apartment house, he gets told about an unreported robbery that took place yesterday. As he rides by a liquor store, he nods hello to a man lurking in front. The man has been told by the store owner to stay out, and he knows what Freeman's nod means.

Ten years on the Metropolitan Police, six of them in Scout 148, have made Freeman capable of policing at a level most police can only dream of. And he's not alone.

Watching Officer Jimmy Washington move in on a dispute involving more than a dozen people on a block near D.C. General and deftly bring it to an end, you know you're in the presence of first-class police work -- especially when he walks away with a tip from a citizen about the identity of a felon in the neighborhood. Washington, a pipe-chomping 11-year officer, won the department's annual gold medal for the outstanding act of courage by a police officer a few years back when he ran into the gunsights of a man who had just shot a policeman, rescued the wounded officer and got him to D.C. General just in time to save his life.

Ten years ago this summer, I left the Metropolitan Police, having spent a year and a half as an officer assigned to what was then the Ninth Precinct. Last month, I rode in scout cars in Number Nine for a few nights to see if anything had changed.

Almost everything has. Some things have changed for the better, some for the worse. But the biggest change of all is that today the streets of my old precinct are patrolled by veteran police officers, men and women with years of experience.

It was the opposite 10 years ago. The streets of Washington were flooded then with young, inexperienced police. At the end of the 1960s, President Johnson ordered 1,000 men added to the 3,100-member D.C. force. And soon thereafter, President Nixon added another 1,000. The force all but doubled. At the same time, many experienced officers were promoted, became detectives or moved to quieter precincts. Number Nine, therefore, was almost stripped of experienced patrolmen. By the time I left after a year and a half, I had my own scout car and there weren't 10 officers in my section with more time on the street than I had.

Since then, the rate of promotions has slowed to a trickle, and the force has gone down by 1,300 officers. So today there is no one in the section with less than four years in the department and only one officer assigned to a car who hasn't been in it for at least three years.

The strengths and weaknesses of the D.C. police seems to stem from its veteran character. The benefits are evident when you watch a Washington or a Freeman at work. When I left, no street kids knew my name. I hadn't been there lone enough; we shuttled from beat to beat, and we spent most of our time answering radio calls, not talking to passers-by. In an emergency, you'd be much better served by having one of the men I rode with this summer come to your door than you would have been by me or one of my rookie colleagues 10 years ago, for the same reason that you'd be better off being operated on by an experienced surgeon than by someone just out of medical school.

I was also struck on my return last month by how many sensible changes that actually help patrolmen have been made by the police department administration in the last 10 years. There's less paper work, the bane of most police officers' existence. More information is available about crime on a patrolman's beat: a "crime analysis" section in the precinct spews out useful reports, and there's even a computer terminal in the precinct -- all unknown in 1970. The scout car radio is now a walkie-talkie type that an officer can carry into a house, providing instant help in an emergency.

One particularly wonderful change in this station house: 10 years ago, police changed shifts every two weeks, first working the day shift, then the midnight - to - 8 a.m., then the 4 p.m. - to - midnight. This alone guaranteed permanent exhaustion; on top of that, you had to go to court the next morning if you arrested someone during the evening. Today, a volunteer permanent crew works the midnight shift, leaving everyone else rotating only between day work and evenings, a much easier schedule.

And instead of working out of old Number Nine precinct, an ancient building that, according to station lore, had been condemned in 1956, or 1926, or sometime, the police working Northeast today go to the Fifth District, a five-year-old building at 24th and T streets NE, equipped with an officers' lounge, a pool table, two pinball machines and a nicely equipped weight room said to be paid for out of vending-machine profits. (Showing some understanding of the tradition it's responsible for, Fifth District's new building has a malfunctioning air conditioner and, of course, windows that don't open. This permits police to tell about the days when the city told them to process prisoners elsewhere. The building was too

Ride around the precinct in a scout car, and in some respects you are back in 1969: the family fights, the dog bites, the suicide attempts. But the scene has changed, as Capitol Hill renovation has spread. Along streets policemen dreaded walking 10 years ago are Volvos and newly painted houses with decorator-designed numbers out front. Jimmy Washington remembers Lincoln Park as a no man's land, a place owned by stickup men where He got beaten up as a 16-year-old tough guy.

Today, Lincoln Park trembles less with fear than with the footbeats of joggers. "Funny, though," said my steady ole partner R.A. Watson, "it seems like living in the cell block. The police go to the houses and the people are locked in." Sure enough, many houses have bars on the doors as well as on the windows.

Whatever the reason, serious crimes are down compared with 10 years ago, both in the city (71,207 "crime index" offences, the most serious, in fiscal 1969; 54,590 in the same 12 months of 1978-79) and in the Fifth District (almost 11,000 serious crimes a year 10 years ago; 7,000 last year).

"It's quieter than it was," says Joe Freeman, as we cruise past the building that used to house the Ko-Ko Club, hangout for the toughest of tough characters on H Street NE. (A judge is supposed to have said once, "Just being within a block of the Ko-Ko Club is disorderly conduct in my courtroom.") Ignominiously, the building now houses a 7-Eleven.

Freeman estimates he handles seven to eight radio calls a night, half as many as a decade ago. That leaves him freer to patrol his beat and talk to his people if he chooses to.

But only if he chooses to, and that brings you smack up against the basic problem of the city's police force. Police officers work almost unsupervised. They have enormous authority to make crucial decisions on their own: to arrest or not, to search, to take extraordinary steps to break up the family fight or leave it alone. Yet even 10 years ago, with a force of aggressive and ambitiousrookies, the most pervasive danger to the department seemed to me not the occasional callous or brutal cop -- there were, fortunately, not very many of them -- but the number (much greater) who didn't care -- who took the minimum number of calls, dragged them out and spent the rest of their time drinking coffee and avoiding contact with citizens and sergeants. Everyone at every rank level in Fifth District agreed that that's the patrol force's worst problem today. "Once they become street-wise, it's hard to get as much out of 'em," a supervisor summed up. And if you ask what motivates a patrolman to want to do good work, the honest answer is "Not much."

As R.A. Watson put it, indisputably, "Nobody's going anywhere." Here the city's other problems came into play. While many headline stories seem to have no effect inside a police station, the effects of the city's budget crisis are everywhere. On two shifts, three of the section's 10 scout cars are idle, turning officers into footmen, widely believed by police to be less effective than a man in a car. But gas is precious. The officers have been told they'll lose their scout car assignments (the disciplinary equivalent of the atomic bomb) if they let their cars idle when the engine should be shut off.

And promotions, so easy to come by in the days when the force was expanding, are now few and far between. Ironically, at a time when motivating street patrol officers is difficult, the police department's sad, funny search for a workable promotion system has led it to adopt what seems like the looniest ever. Once upon a time, promotion was decided almost entirely by a civil service exam. Critics pointed out (correctly) that the exam rewarded booklearning, memory and test-taking, not judgment and good on-the-job performance.

So more weight was given to a suitability rating by a patrolman's supervisors. But critics said (correctly) that the supervisors could easily play favorites. So today, promotion procedures interview with two police captains and a civilian psychologist, none of whom is supposed to have any familiarity with the officers he's interviewing or their work. Thus, after years of work on the street, the police get judged by their ability to make an impression on three strangers in a fleeting conversation.

At that, Joe Freeman was 140th on the list for promotion to sergeant. One hundred thirteen patrolmen had been made sergeant and another 27 were ready to be announced. Joe was congratulating himself on finally leaving Number Nine when the citywide promotion freeze hit earlier this year. He didn't make it. And since he'd assumed he'd be promoted, he didn't study for this year's exam, which governs the next two years.

Washington and Freeman each told a story that showed how much they'd changed in 10 years.A gas station had been held up earlier in the week. Washington chased a suspect down Benning Road into a pool hall. It was the last place a policeman could expect to find cooperation, but Washington did. A few friendly nudges and nods, and he hauled the man out of the bathroom.

"You couldn't have done that 10 years ago," I said.

"Hell, no," said Jimmy Washington.

Freeman's story: the same week, he got a call to a house on one of the meanest streets in town. A young woman had told her boyfriend to leave the house, and he had come back after her with a hatchet. As Freeman talked to the woman upstairs, he heard a scuffle downstairs. He looked down: a man was being dragged out of the house by another man carrying a gun. When Freeman yelled at him to drop his gun, the man turned around and faced Freeman, still holding a pistol.

Had Freeman shot the man, no one in the world could have found fault with him. But something in 10 years' experience told him he didn't need to shoot. Finally, the man dropped the gun. He was the boyfriend's brother, come to get him out of the house before he could get in trouble with the police for attacking his ex-girlfriend.

What makes a policeman do exceptionally good work when he can't get promoted for it, has little chance of higher pay for it and the words of praise are few? It is like the phenomenon of the extraordinary teacher who stays iin the classroom year after year, doing something other people can't do.

Some day, reader, if you are unlucky, you may get into trouble and need the police. If that happens, pray that Gold and the dispatcher send you someone like these two, or their equivalent in every other station house in town. For 10 years, they have handled the drunks and the family fights, gotten chewed out by sergeants, cared about little cases, goofed off less than most, helped out kids and looked down a gun barrel or two. For this you pay them $400 a week.

You're lucky to have them.