Thirty Medal of Honor winners and their families came together in the National Archives last night to view a film called "Heroes" and to try to explain to some reporters and some hard-charging TV people what is essentially inexplicable.

The oldest person in the room was Ed Izac, World War I veteran, who is 91 and tends tomatoes in a Bethesda backyard now, and the youngest person in the room was Zach Jacobs, who was two weeks old last Friday and who gurgled and squirmed and flowed his tiny crimson fists against the ramrod bosom of his father.

The father's name is Jack Jacobs, and he is a square-jawed, sad-eyed lieutenant colonel in the Army. A long time ago, in a green jungly dream called Vietnam, Zach Jacobs' daddy saved 14 comrades crying out for help. Then as now, he was just 5-foot-3, just a 115-pound soldier. To read about his heroism, to hear it described, is to picture a very small man galloping terribly against very large fates.

"I, uh, managed to carry out a lot of my buddies," Jacobs said last night, swaddling his new son in a green blanket. "I, uh, don't remember a lot of it. We were in the Delta. It was a very large Cong force, and we stumbled right into it. In the first 15 or 20 seconds, 130 of us were killed or wounded. I was very lucky. I got wounded in the head. Principally a head wound. Mortar rounds."

He said this and his eyes seemed to glisten and his baby son swam against his breast.

Mrs. Jacobs sat nearby. She held a drink with a napkin around its base and picked politely at a roll with some ham in it. "I don't know what a hero is," she said. "But I hope Zach Jacobs will be able to grow up without proving he is one."

The heroes represented four wars and all branches of service and came from Signal Mountain, Tenn., and from Margate City, N.J., and from Peckville, Pa. These were American-sounding places, and their sons had American-sounding names--Ron Ray, Leon Johnson, Charlie Coolidge. Some of the honorees were in uniform and some were in polyester, but each of them wore a rich blue ribbon around his neck. Dangling from the ribbon was an ornate piece of metal that Lyndon Johnson once said he'd rather own than be president.

The film they watched and applauded and even audibly sniffled at was narrated by Orson Welles and made by 20th Century-Fox Television. It will be shown around the country on various networks and at various times this coming Fourth of July weekend. As documentaries go, it is a rather prosaic, maybe even corny, job. But there is nothing prosaic or corny about the people who speak in it. "I have the constant burden of believing I'm worthy of it," one honoree says. "My buddies were going down like stalks of corn," says another.

There is no explaining it, of course, the "it" being that moment in eternity, that flicker-flash of dream-time when a man seems instantly to live in awe and wonder and the overpowering pride of his countrymen. Call it the finger of God. Whatever it is, something happens, something heroic goes snap. In the microseconds that follow, you are either berserk or someone the poets write about. Maybe you figure you are going to die, and maybe you grow calm, and maybe then you decide you are going to do a few things that are right. And so you save, you leap.

The theory is that there aren't any heroes any more, or at least that there's a terrible dearth of them. Has a technological world and the constant glare of the camera dried them up? A hero is a kind of bridge from man to God, as author Joe McGinniss wrote in a book called "Heroes," and maybe it's all tied up with the search for the father. Maybe what we really need, in a world of vicious contradiction and nuclear fear, is a new definition of hero, one that isn't necessarily military or even a masculine ideal. "The ancient hero," critic Victor Brombert has said, "provided a transcendental link between the contingencies of the finite and the imagined realm of the supernatural."

Granted, it is easier to jump a few generations back, to the shank of the century, and then heroes seem to glide off the memory and imagination: Babe Ruth and Dempsey and Teddy Roosevelt and, of course, Lindbergh, who may be the most mythic American hero of all. Lindbergh was "that single lonely boy," as his biographer called him, upon whom "abruptly across America, a hundred million minds had become one mind dominated by one emotion--and that almost a religious one."

There seemed nothing transcendental about the men gathered at 8th and Constitution last night. If they didn't have the medal around their necks, you might not guess at all. It could have been a college reunion of the variegated classes of '18, '42, '52 and '67.

These days Charlie Coolidge owns the Chattanooga Printing and Engraving Co. He came with his wife, Frances. "Honey, do you think you can make it up there?" his wife asked, helping her now partially infirm husband. Frances Coolidge is a gracious southerner with a gracious accent. Her husband had a cane and white shoes and a little brass bar on the vest pocket of his coat that gave his old rank.

"I was born up on Signal Mountain," he said. "By the time I got out of the service I had more time on the front than any other living American. I was in Africa, the invasion of Italy, made the invasion of southern France, afterward went to the mountains of Austria. I got my medal in southern France in '44. We fought the Germans for three days. After three days a German stuck his head out of a tank and said, 'You guys want to give up?' He said it in perfect English. I remember he used the word 'guys.' I said, 'I'm sorry, Mac, you'll have to come get me.' He did, too. He closed that hatch down and wheeled that damn 88-millimeter around and we played tag for three days. I was swapping trees with him. Altogether I killed 26 Germans and wounded 60."

"Oh, honey," his wife said.