They appeared, like Hamlet's father's ghost, out of the morning ground fog, two ethereal figures on a baseball diamond. They'd take turns running across the infield dirt toward first base, raising their right arms high, giving big out signs. They wore umpires' uniforms and, though they didn't make a sound in the gray-cloak mist of 7 a.m., they were real. It was the players who were the phantoms.

If you're thinking about becoming a professional umpire, you have to work at it even when no one's around. You imagine the players, the game situation, the batter and where he hits the ball -- and you make the call. You better know why you made the call, too, because when those players and their managers come to life they can actually leap at you like lions after raw meat.

It's the fifth and final week of Joe Brinkman's umpire school, and there's tension beneath the all-smiles surface. One hundred fifteen started the course. Five dropped out. Only 16 will advance to a one-week "finishing" school run by major league baseball in Bradenton, Fla., then likely be assigned minor league jobs. Fourteen will make a waiting list. All the others will be given the big out sign.

It's highly competitive, that's why the two have gotten out on the field before 8:15 class, and why they're pretending -- even if people think it odd. If you're worried what people think, you can't be an umpire. One of the students, Jeff Wolfe, of Upland, Calif., would say later that he often practices umpiring alone at night in his town's little stadium -- he's got the keys to the place and, after the evening games, keeps the lights on until about midnight. He goes around shouting, "He's out!" even though nobody's out there except him. "A couple of times the police came by -- they thought I was a little crazy," he said.

And remember, as any Brinkman staffer will tell you, to say, "He's out," or "safe." Never say, "You're out." "If you say 'you're,' you're getting a little personal," said Larry Reveal, an International League umpire and Brinkman school instructor. "The guy you call out doesn't want to hear, 'You're out.' Try to make it as impersonal as possible."

Another thing, if the guy you call out is to believe it, you've got to believe it. You've got to sell the decision. "You're selling without the product," said Reveal.

And . . . you better be prepared to take abuse. Reveal has had beer poured on him three times; another staffer, John Higgins, of the Pacific Coast League, was punched in the face during a game in January in Puerto Rico by Vic Power, the Caguas manager and former big leaguer.

Maybe most of all, you've got to beat the loneliness. Deep in the minors, where only two umps call a game, there's just you and him. "It's like marriage without sex," said Reveal.

"I'm just giving a dream a chance," said Rocky Arrington in answer to the question of why anyone would want to be an umpire. The sun is up now, and he's leaning against a wire fence encircling one of four manicured diamonds at the Joe Brinkman Umpire School. Life seems full of possibilities. He'll be working home plate in just a few minutes.

Arrington does not look like a Rocky -- like Marciano, or Balboa. Nor does he look like the quintessential grizzled ump, say, Doug Harvey of the National League. Tall and slender, with thinning sandy hair, Arrington is a soft-spoken 35-year-old elementary school principal from Cordell, Okla. But maturity's important in umpiring, he says, "and I'm about as mature as anyone."

Students at the Brinkman school include a 46-year-old New York cab driver, a clinical psychologist from Detroit, a John Madden lookalike, a teacher at a maximum security prison . . .

With the exception of 5-foot-6 Herb Diaz, who wants to keep hacking, all 110 students aspire to be Joe Brinkmans -- that's Joe Brinkman of the American League and pine tar fame.

Brinkman was chief of the umpire crew that on July 24, 1983, ruled George Brett's bat was illegally coated with pine tar. With two out and one on in the top of the ninth at Yankee Stadium and his team trailing, 4-3, Kansas City's Brett homered to right. But in the wake of then Yankee manager Billy Martin's protest, the umps enforced Rule 1.10 (b), which was perfectly clear about glopped-up bats. They called Brett out, subtracted the two runs and declared the game over. Four days later, the American League president then, Lee MacPhail, sided with Brett, gave Kansas City back its runs and said the game was still on.

Talk about an umpire's tough life; they were right, strictly speaking, and they still weren't right.

"This year they took the rule out of the rule book," says Brinkman. "As it was, we had no choice once Billy brought it to our attention. You could have 18 inches" -- no pine tar more than 18 inches from the end of the bat -- "but it wasn't even close. That's why we laid the bat on home plate, to show it wasn't close. It was 24, 26 inches. Nineteen, you say the hell with it. But when you get it down past the trademark, there's nothing you can do about it."

For the opportunity to someday experience grief of this kind, Brinkman's umpire candidates have plunked down $1,300 for the course. They get three meals a day, three to a room and all the umpiring they can handle, or sometimes not. Like this: National League ump Steve Rippley, whose firm jaw and sunglasses give him the appearance of a marine drill instructor even before he opens his mouth, play-acts as a manager disputing a student umpire's call. Rippley sounds as if he could be heard in Orlando.

"This game's under protest," he screams, face to face with the student.

"Who was the batter?" he goes on. "I want my fastest runner at second base. You guys better think it over."

Another field, another confrontation: "He's out? Why's he out?"

Soft voice: "I just made the decision."

Roaring voice: "No, no, no. You gotta tell me why. Why-y-y-y-y-?"

"He's out on the force-out," comes the sharp reply.

"Okay."

The Brinkman school is one of two principal ways to get into professional umpiring. Almost all the other prospects come from National League ump Harry Wendelstedt's school in Daytona Beach. This year, more jobs are available than usual because Double A is going from two- to three-man crews. Umpires are being advanced from the lower leagues, creating openings at the rookie level.

Yet few ever manage to climb from the lowest minors to the big leagues. Like scaling an Alp, it's rugged and takes time. The pay isn't great -- $1,350 a month to start at the bottom. So you don't stay at the Ritz, if there were one. Reveal remembers a room in Wausau, Wis., "above the kitchen, and the kitchen was open all night. The heat came through the floor, and you heard the noise of the dishes." Though he's reached Triple A, and hopes hard for big league expansion, he adds, "I don't think I've ever adjusted to the life style."

To start the final week of school, Brinkman, 40, a stocky man who once played football in the Army, gathers his staff in the umpires' room at 7:45. "We haven't covered rubbing the balls up yet. We're going to do that tonight." A young staffer spits tobacco juice into a cardboard cup. "We have to cover motels, where to eat, what to do when you get to the ballpark," Brinkman continues. "What screwed you guys up will screw them up."

Thirty-eight students' mug shots, their names stripped across their chests, remain hung in the room. The others have been peeled away. Only 38 have a chance to make it. Brinkman walks along the panel of pictures. "-----, he should be ready to show you his best stuff. -----, for a guy who's never umpired, he's okay. Push on him. All these guys here, give 'em a good hard push. They need something to push 'em over the edge."

On the way to the classroom, a big block building, Brinkman relates death-and-taxes facts about umpiring: "I don't care if you're God, you'll get arguments . . . You've got to die with your mistake. It's impossible to 'even it up' . . . You've got to have nerves of steel." This is especially true because of hecklers in the stands; they're worse in the minors, where you hear them loud and clear. Because of hecklers, Brinkman tells umpiring prospects who need glasses to get contacts. "The extra abuse, you just don't need. You don't need guys calling you Four Eyes."

But, of course, in the minors you don't encounter the Billy Martins and Earl Weavers. There is a slight difference between the two, allows Brinkman. "If Weaver saw you on the street, he'd still think you were a bad guy, the scum of the earth."

Vic Voltaggio, American League ump, is at the podium addressing the assembled students -- most are wearing gray Joe Brinkman Umpire School T-shirts and some have on their short-peaked blue umpire caps; they all have their rule books and notebooks. Voltaggio is telling them to behave themselves at Saturday night's end-of-school banquet, which will be attended by "outside guests." Voltaggio intersperses the same four-letter word into his pointed warnings. "We want to see how you act with human beings around," he says.

Voltaggio gets mock booing.

When the group settles down, Larry Reveal covers "umpire behavior." He tells a story about a minor league umpire who "flirted" with a woman in the stands before a game. It turned out to be the wife of one of the managers, he says. "Be very careful whom you relate to. Things like that will get you out of the game. Usually, you'll have more problems off the field than on the field."

Reveal, 36, a former teacher, cautions aspirants to watch for players from opposing teams "fraternizing" before games. But "don't go with paper and pencil. Remember the numbers, tell the managers. Let it go the first time." He says umpires will hear rumbles from the dugouts -- from managers, coaches, players -- but when it comes to trainers, "I'm not saying run 'em," as in eject them from the game, "but you don't take anything off 'em."

Oh, yes. "Try not to run bat boys." Laughter. "It's been done. And try not to run anybody out of the press box. Try not to run any mascot. Two years ago in Buffalo somebody ran a bison . . .

"When a manager comes out, keep control. Try to think what's happening. If he's coming slow, he's thinking, too. Try to tell him the right thing, why you made that decision. Above all, keep your composure. As long as they don't get personal, it's okay. 'That's horse----,' that's okay. But 'you're horse----,' they got to go . . .

"There's no reason to visit the club offices except to pick up your mail and get the balls . . . Carry your rule book. It's better to hold up a game 10 minutes to resolve a knotty problem than have a game thrown out later on a protest . . . Get set, get your eyes fixed on the play, rather than try for extra steps to get closer . . . "

The two-hour class ends in applause -- they've finally finished the rule book. Then, it's off to the field for calisthenics. Some come running with chest protectors and shin guards. "You've got to hustle and look sharp, look professional -- those are probably the two biggest things," says Nick Phillips, a candidate who's completed two years at Ohio State. Phillips is right -- simply being overweight, or lacking mobility, already has eliminated a surprisingly large number, says Reveal, leaning on a fence. "Size and bad legs," he says.

Many students believe it helps to be a good size -- a strapping fellow like Phillips looks like an ump. "If I were 6 feet, 196-200 pounds instead of 6 feet, 163 pounds, I'd be a shoo-in," says Chuck Sorrentino, 25, the clinical psychologist from Detroit. The diminutive Diaz adds, "A big guy has to prove he can't ump. A little guy has to prove he can ump."

"Big guys, small guys, it doesn't matter as long as you can get the job done selling," insists Reveal. An out sign, he says, is "designed to look as strong as possible, even for little guys. Wrap the thumb along the fingers. Arm up, hand above the head. Bring it up and snap it down just a little bit."

Calisthenics over, the student umps adjourn to the fields to practice play situations, or to a long pitching shed for ball-and-strike work. A booming "strike one" can be heard from the shed. On the diamonds, the two-man umpiring system is taught -- it's the one the successful students will use in the low minors and one others might find helpful if they umpire amateur baseball. Positioning -- where to stand and where to move to in almost every conceivable circumstance -- is emphasized. Being in position to see a play is fundamental but takes practice, says Rocky Arrington.

Sorrentino is worried. He says he's like just about everyone in camp: "A lot of these guys have the game in their blood. They've got it inside themselves and can't get it out. They really love the game." But . . . "But I had a bad day last Saturday morning. My head just went blank. It was terrible.

"I want a job badly. It's something I've always wanted, to be part of baseball, major league baseball." But having been baffled temporarily by an obstruction call at third base, he's not so sure of his future. "I hope they look at it as just a bad day."

As Brinkman tells the students, noting that several are borderline cases and urging all to a strong finishing week, "I don't want to put pressure on you, but there is pressure in this game."

"There's a lot of uneasiness in camp now," says Sorrentino. Unlike, for example, a football camp, where one can release his anxieties by, say, tackling harder, umpire school requires rare restraint. The hotter things get -- staffers challenging students on their calls, decision day approaching -- the cooler one has to be. You can sense the edginess.

"I'm expecting gags to begin, like shaving cream," says Sorrentino. "That's a way to relieve anxiety."

John Glynn, 29, of Boston, seems to have the temperament to be an umpire. A teacher of inmates at Massachusetts' Walpole prison, he says with a broad smile, "I love being in stressful situations."

"It'd be great, that'd be real great if I went to Bradenton," says Brian O'Nora, 22, of Youngstown, Ohio. "They can send me to Alaska, anywhere they want to."

Across the fields come the cries of fledgling umpires: "Strike two . . . He's out . . . That's a balk . . . Ball two . . . "

On one field, runners keep circling the bases -- students serve as players when they're not umpiring. A single play is being repeated long into the afternoon: a man is tagged for the third out on the base paths as another crosses home plate. Did he cross before or after the third out?

"He's out," booms the plate ump, giving the base runner the out sign. Then he turns and looks up toward the imaginary official scorer in the imaginary press box and shouts into the slanting afternoon sunlight, "The run scores. Score the run."

The stadium crowd roars. The scorer, upstairs, nods and writes down the run. Turning, the umpire sees the number go up on the board. He spits, and, casually confident, holding his mask, alone and in command, awaits the next half-inning.