Chris Veech, 11, blond-haired and growing by the minute, knew why he had brought his dad all the way from Washington to Baltimore's Memorial Stadium.

"We came to see Rod Carew," said the boy. "And it's Black Bat Day, too."

"Yes," said the father-chauffeur, "it's like when I was a boy going to see Ted Williams play the Senators."

"Dad," asked the boy, " what's a Senator?"

Heaven knows what he would think a "Nat" was. A whole generation of Washington children have grown up for whom the Washington Senators, like the Louisiana Purchase, are just something to be learned as lifeless history.

In seven years, the turnover in city's kids is complete.The 11-year-olds who rooted for Frank Howard are now old enough to vote, while the children who root for Carew today were toddlers then.

Baseball is an itch that is acquired when young scratched when old. Whoever met a child with a season ticket?

Once that itch takes root, seven years can't cure it. Washington adults still scratch their way up the parkway when the summer urges comes, truckin' to Crab City to get their dose of Oriole medicine.

Perhaps the reason that the clamor for baseball to return to Washinton has been relatively mild - no picketing of the mayor's office, no wild-eyed terrorist in a Nats cap hijacking an Oakland A's charter jet - is because adult fans are not seriously inconvenienced.

"I'm a genuine fan," said Kennedy Center employe Jim Weiner, standing in the O's ticket line. "I'd love to see us (D.C.) get a team. Everybody would. But I can't honestly say I get worked up about it.

"I've changed allegiances," he said tapping his L.A. Dodgers cap. "I go to more games in Philadelphia and New York than I do Baltimore. I just can't make myself root for the Orioles. There's a cultural and sports moat between these cities and I haven't met one fan who has bridged it."

If seven years is, as scientists say, long enough for every cell in the body to be replaced, it is certainly long enough for daramatic shifts in the atitudes of fans.

"I'm about ready to adopt the dern Alexandria Dukes," said Nothern Virginia's Rich Leverrier. "If they start winning, I think I'll stop driving 2 1/2 hours to Bal'mer."

For grownps, baseball is just another part of the painfully real world that constantly forces them to copromise.

"I make do," said Dave DeMatteo of Gerogetown, who played four years in the minors. "I've been to the Dukes . . . pretty good talent for 'A' ball.

"But I'll still come to the Orioles, too. I enjoy this park, the casualness of it, the music between innings. It's homey."

Children like Chris Veech, however, do not know that baseball is part of the real world - governed by economics, played by mortals with tobacco breath.

Baseball is two games - one for adults, another for children. And kids have no lobby in Washington.

In fact, most Washington 10-year-olds, those in the midst of the baseball prone half-decade of 8 to 13, don't eyen know that they are missing.

One has to dig into the archives of a former child to get first-hand testimony about what a Senator was.

Senators can be found in old dresser drawers next to a transistor radio broken 20 years ago. They peek from the crumbling pages of old yearbooks, programs and scrapbooks.

No reference text in the galaxy can tell how many times Norm Zauchin, Rocky Bridges and Herb Plews drew walks in spring training of 1958. It's an unresearchable stat, unless you happen to have "My Baseball Book for 1958," a battered green Easyrite spiral notebook that is child's ply to read because the 10-year-old's writing is large.

There in the "Baseball Book," each game for each Senator player is broken down on a special page. Bridges alone has 11 columns of numbers devoted to him, plus a neat annotation at the bottom, saying, "Games 20, At Bats 66, Hits 19, Homers 2, Runs Batted In 6, Batting Avg .288, Walks 8."

Next to the Green Easyrite is the Yellow Easyrite full of newspaper clippings with headlines telling how the "stubborn Roy Sievers," who had hit 42 homers the year before, thought that Calvin Griffith should raise his $18,000-a-year salary. Griffith threatened to trade Seivers "within a week" if he didn't "come to his senses."

Between the Easyrites is the Nats Yearbook. Seivers is on the cover, done in red-white-and-blue oils, and looking far stronger and more handsome that "Washington's First Home Run King" ever did in life.

Behind the oil Sievers is a ghostly blue Captol building. That is the image that draws the yearbook cover together and makes it personal. The author of the Easyrites lived six blocks from the Capitol, ran on its marbel steps, played hide-and-seek among its magnolia trees, and hit baseballs on its lawns before the cops arrived in force. Sievers-Captol-home, that was the connection, a kind that can no longer be made.

The fans of Washisngton who make up an estimated 10 percent of Baltimore's crowds, may miss having a ballclub in their backyard, but are not truly deprived. Adults know how to make do. They see games somewhat as they are and can take them or leave them.

But what Washington child now keeps a library of scrapbooks, as so many used to, filled with pictures, stories and boxscores of players from another town? Where are the spring training photo supplements in the newspapers, or the thousand-word theses on momentous topics like "Abernathy Sent to Minors."

A boy on an Ohio farm a hundred miles from Cincinnati can idolize Johnny Bench because Cincinnati is "his" nearest bog city. But the psychic distance form Washington to Baltimore is continental.

On the scale of social deprivations, perhaps "What is a Senator?" hardly leaves a ripple. Nevertheless, the heart has its own illogical seismograph.