The Masters fields "ebb and flow like a great whale," a former pro once observed. "Guys get hot. Then they have bad streaks. You just don't get hot and keep the upper hand against the course for a very long time."

That description of the competition over Augusta National proved accurate again yesterday as the 42nd Masters got under way. Gusty, inconsistent winds made consistently brilliant play nearly impossible, with one notable exception. John Schlse shot birdie-birdie-birdie birdie midway of the back nine to enable the 38-year-old one time student of Ben Hogan to record a four-under-par 68 for a one-stroke lead over Joe Inman.

Lee Trevino and Bill Kratzert followed, two strokes off the pace, with Tom Kite, Jerry McGee and Steve Melnyk the only other players in the field of 78 to break par, at 71 Trevino, of course, has often declared he "can't play this course."

Jack Nicklaus, the tournament favorite, was forced to settle for evenpar 72, placing him in a cluster of 12 that included Gary Player, Jerry Pate, Tom Weiskopf, Gene Littler and Don January.Tom Watson, the defending champion, posted a 73 along with Arnold Palmer, Washington's Lee Elder, Hale Irwin and 10 others.

The greens were slow. The pin placements were "most like a Sunday closing than a Thursday opening," McGee noted, and the wind "was maddening, changing and swirling all the time." Nicklaus, Watson, Elder and Weiskopf all had putting problems, to name a few. Schlee did, too, at times, but he drove consistently deep, reached three of the par-5 holes in two for birdies and struck several excellent irons during his hot streak from holes 12 through 15.

Schlee was one under going out. A long drive and a four-iron to the green set up two puts from 25 feet for a birdie on the par-5 second. A six-iron to within three feet on the pin on six sent him two under.

"Then, at seven (par 4, 365 yards), I hit an iron off the tee, something I never do," the 6-foot-3, 165-pound veteran from Dallas declared. "I hooked it, punched a seven-iron out to a back trap, made a good sand shot to six feet . . . and missed the putt. I misread it, for a bogey."

His only other bogey of the day, on 11, when he overshot the green with a three-iron, reduced Schlee's card to even par. But he played the next four holes flawlessly.

A seven-iron set up a 12-foot putt for a birdie on the par-3 12th. A tremendous drive, approximately 320 yards, reduced the par-5 12th to a six-iron to the green, from where he two-putted from 35 feet out for a birdie. Another long drive and a pitching wedge led to a 12-foot birdie putt on 13, and a good drive and a four-wood on the par-5 15 put him in position to chip back for a six-foot birdie putt.

"The par 5s . . . They're the key," Schlee said. "I should have made it five under on 17 when a good drive and a pitching wedge had me within five feet for a birdie. That's when I made my big mistake of the day. My caddy, who had been perfectly quiet told me, "That putt's straight.' It broke right."

Inman, playing in the last twosome, made a bid to overtake Schlee. The bespectacled little guy from Clover, S.C., rolled in a 16-foot birdie putt on 16 to briefly gain a share of first place, only to three-putt from 80 feet on the next hole for a bogey.

"My game doesn't intimidate anybody (as his record attests)," Inman acknowledged. "More guys have turned pro watching me. They say if he can make it, anybody can make it. Today, I think I got a break by playing late. Conditions were calmer and there wasn't so much commotion out there by then."

"I'm the blindest man out here," he said. "My sight's so bad I can't wear contacts. The edges of my glasses are getting so thick the field of vision gets smaller all the time, but I really was pumped up today. It's just nice being here."

Schlee, rookie of the year on the PGA Tour in 1966, has not appeared regularly on the professional circuit in recent seasons, primarily because of injuries. He won the 1973 Hawaiian Open and was second in the 1973 U.S. Open, when Johnny Miller shot a 63 in the final round, but has earned only $3,469 in four appearances this year.

"I won over $100,000 in '73," Schlee recalled, "to be 10th on the money list. "But in '74, my back started bothering me. I had an operation for the removal of the nucleus of a disc - the same type of surgery Trevino had - in January of '75.

"Then, in June of '76, I injured my left knee while remodeling my home in Dallas and was operated on for slightly torn cartilage. Which was enough, until last year, when I finished in a tie for eighth place here. My the left thumb started hurting during the last round. I had a dragging action with the left hand, instead of letting the club release. The thumb got so bad I couldn't hit a ball. It didn't clear up until Mike Morley showed me how to change my release this year in Hawaii."

Shlee believes he can continue to be healthy contender for this Masters title. He credits Hogan for molding his game.

"I met Ben in '68," Schlee said. "We set out to play a hole for $20, down home in Texas. I did everything wrong, but made a series of long putts. It was unreal, this little guy in the white hat holding the pim while I rolled them in from 40 feet. Finally, he said, 'You're destroying everything I believe in in golf. Come on over to Fort Worth and I'll teach you how to play the game.'