In this spiffy concrete stadium with its brassy blue plastic seats and its pool-table-hard playing surface, Nolan Ryan's performance today colored the day sepia--sepia being the shade of many old baseball photographs, including pictures in which the image of Walter Johnson throwing his sidearm fast ball is captured.

Few, if any, of those here today ever saw Johnson in his 21 years with the Senators. But when Ryan struck out Expos pinch hitter Brad Mills in the eighth inning to break Johnson's 55-year-old record for career strikeouts, it became clear once again how little baseball has altered.

Never mind that he got his record 3,509th strikeout in Canada wearing psychedelic pajamas; today Nolan Ryan made time and change irrelevant for one delicious moment.

It happened like this.

Ryan and the Houston Astros were leading the Expos, 4-2, going into the eighth inning. Ryan had struck out Tim Wallach and Tim Blackwell in the second inning and Bryan Little in the sixth. That brought his lifetime total to 3,507. Ryan was pitching masterfully, allowing only four hits and one walk.

"I lost my groove a little in the middle innings," Ryan would say. But he drained a blister on his middle finger after the seventh inning, and regained his form in the eighth.

Ryan ran a full count on Blackwell, the leadoff hitter. The crowd, sensing a strikeout, seemed to draw its collective breath as the Expos' catcher began to swing for a possible third strike. But he fouled it off. The exhale was nervous and brittle. Ryan circled the mound.

On the next pitch, Ryan abandoned pretense and threw a screaming fast ball across the center of the plate.

Swing. Miss. Nice to meet you, Walter Johnson.

Scheduled up next was Doug Flynn. Before the game, Flynn said of the prospect of facing Ryan, "It ain't fun, I'll tell you that. It's not exactly a day when you say, 'Oh. Ryan's pitching. Two hits, easy.' "

But Manager Bill Virdon spared Flynn and sent up Mills.

"I sort of thought the whole thing was over because the crowd had gone so nuts when Blackwell went down," Mills said. "No one was really talking about it much on the bench."

Mills faced the music with a mighty thin baton. The first pitch was a fast ball, low and away, a called strike. Then Mills checked his swing on a low curve, but umpire Bob Engel fired up his right arm and blared the news. 0-2. Ryan tried to lure Mills to the dugout with an outside fast ball, but the 26-year-old left-handed batter let it go by.

With the count one ball and two strikes, Mills did what any right-thinking batter would do against a man whose pitches reach home plate in 38/100ths of a second. He looked for a fast ball, and tried hard not to blink.

Ryan, with 17 years of experience and five no-hitters as teaching credentials, answered his student's anticipation with finesse.

His looping curve ball caught the outside corner of the plate.

Mills cocked his bat but did not swing. The ball banged into Alan Ashby's glove. Strike three.

Mills was history, and now Ryan is, too.

"It was too close to take," Mills said. "I kind of got vapor-locked."

"I just felt relieved," said Ryan. Last Friday in Houston against the Phillies, Ryan, who has averaged 9.45 strikeouts per nine innings, managed only three. "I didn't put as much pressure on myself (today). Against Philadelphia, I got wrapped up in the whole thing a little bit."

Ryan received praise from all after the game, but he seemed genuinely unimpressed with what he had done.

"I don't get too excited about anything," he said impassively.

When the record fell, though, the Montreal crowd was plenty excited. As Ashby tossed the ball into the dugout for safekeeping, 19,309 people stood and cheered Ryan for more than two minutes.

Their Expos would lose, 4-2, with Ryan leaving for a pinch hitter in the ninth and Frank LeCorte relieving, but this was a day for a pleasure greater than victory. It was a day for the present to consider the past even as it was surpassing it. The scoreboard flashed side-by-side photographs of Johnson and Ryan, and there they were, young at the same time.

In his own dugout, Mills watched the sepia settle.

"I guess if I had a choice, this wouldn't be the way I'd like to make history," he said. "The whole historical content hasn't sunk in yet."

Ryan, who is in the final year of a $4.5-million contract, betrayed no immediate fascination with baseball history, either, especially when it concerned a player who died in 1946, one year before Ryan was born.

"It's been so long since (Johnson) played. I once looked in the baseball encyclopedia for him, but that was about all," Ryan said. "When I broke Sandy Koufax's season strikeout record (with 383 in 1973), I was more familiar with him. I was a big Koufax fan growing up. But I don't compare myself to anyone, not to Feller or Koufax or any of the great fast ball pitchers."

Some of Ryan's opponents, however, were more than willing to talk about the prospects of hitting against the man whose fast ball is said to have been clocked at 100.9 miles per hour.

"It's tough to go up there and even see the ball," said Andre Dawson. "It's hard to think you can turn his gas around. And you can't guess on him, because he'll just turn you around."

"First I try to see the ball," said Tim Raines. "That gets a little tough, though, when he's throwing 90-plus (miles per hour) on the black of the plate."

Two more pitchers--Steve Carlton with 3,480 strikeouts and Gaylord Perry with 3,466--will surely pass Johnson's mark this season and pursue Ryan. But that takes nothing away from anything--not from Walter Johnson, not from Nolan Ryan, not from this fine, timeless day in April.