Call the truant officer. On the first day of school, those loyal fans of summer stayed away en masse, leaving a mere 7,658 to enjoy and/or endure the Orioles' 10-4 victory over the Seattle Mariners tonight.

Those who spurned the living-room telecast and ventured out into the 89-degree mugginess were rewarded with a tension-free evening, after John Lowenstein upset some first-inning Seattle strategy with a three-run homer. Dan Graham followed with another four-bagger and it was left only to wonder how this awful Seattle club leads the Orioles on the season, six games to five.

Seattle Manager Maruy Wills chose to walk Eddie Murray intentionally with Al Bumbry on second and two out in the first. The move backfired when Lowenstein drilled Jim Beattie's 1-2 slider just inside the right-field foul pole. It was only his third homer.

"I've hit homers after an intentional walk before, but not that early," Lowenstein said. "I was slightly surprised when they walked Eddie."

Was he angry at the implied slight?

"You'll have to talk to the bat," replied Lowenstein, who added, "Gee, I'd forgotten I hit that homer for a while. I was wondering why everyone was standing here."

Graham's blast two pitches later, to the deep shadows of right center, created Baltimore's fifth back-to-back homer barrage of the season.

Before Beattie left, the score was 8-0, as two walks to Lowenstein were converted into scores by Rich Dauer hits and Kiko Garcia added a two run single. Beattie still was out there, with a one-ball count on Bumbry in the sixth, when he paid too much attention to Garcia and balked.

That mistake and Wills' immediate hook provided the ultimate revenge for the fans, who had booed lustily while Beattie spent an interminable time trying to hold Bumbry on first in the opening inning. Bumbry eventually stole his 35th base when catcher Larry Cox muffed a pitchout.

That this was a crowd aching for blood became apparent in the seventh. With Baltimore ahead, 10-2, first baseman Joe Simpson dropped Dauer's line drive but recovered and threw to pitcher Dave Heaverlo for the out. Dauer raged at umpire Dallas Parks, Manager Earl Weaver joined the dispute and the fans chatted the usual obscenity.

The beneficiary of his teammates' largesse for once was right-hander Jim Palmer, who boosted his record to 15-9 with his 204th career victory, trying Clark Griffith and Herb Pennock for 38th on the all-time list.

"We're spoiling Palmer; we're getting him too many runs," benchbound Rick Dempsey said, laughing, afterward.

Palmer, although gaining his sixth success in his last seven decisions, was not laughing, elbow in usual bucket of ice and inaccessible to media interrogation. Palmer has not finished a game since July 20 and he wanted a complete game. Instead, he left with one out in the ninth, leading 10-3 and with two men aboard.

"When I went to the mound in the ninth, he said to me, 'I made two stupid pitches, you don't have to come out here,'" Weaver related. "But when the bloop hits start falling in for runs, that's enough."

Once again, the Baltimore relief corps was less than sparkling. Dave Ford was tagged for a single and two long drives that were hauled down by Bumbry, one with his back to the plate, on the warning track.

Palmer, through six innings and 70 pitches, was superb, yielding only two singles and no walks. He gave up eight hits and two walks in the next 2 1/3 innings.

Lowenstein, who did not see a strike after his first inning homer, walking three times on 12 pitches, has batted at a .343 clip since returning from the disabled list June 11. The surge has boosted his average from .186 to .298.

Lowenstein has had some problems in the outfield recently and he noted the Orioles' third four-figure crowd of the season by saying, "Nobody noticed I had a perfect night in the field, even though there was more glare tonight from the seats."