"Each small drop makes big sea," said Malohat Shahobova, who is from Tadzhik, U.S.S.R. She, with 14 of her countrywomen, yesterday began a 10-day tour of the United States that will include visits to Las Vegas, a blue-jean factory and a quilting bee, all in the name of peace.

The theory is not new: If ordinary people from different countries could just meet each other they would never want to blow each other up in a nuclear war. And if enough ordinary people don't want war, then the leaders will agree to live and let live.

In Washington, amid talk of the upcoming summit conference, such a theory is considered naive. But another group is giving it a try.

The group is Peace Links -- Women Against Nuclear War, which counts 40,000 members in 30 states. Founded three years ago by Betty Bumpers, wife of Sen. Dale Bumpers (D-Ark.), it has attracted a number of congressional wives as well as other women. The Soviet women are all members of the Soviet Women's Committee, billed as a nongovernmental group to "promote friendship and understanding among women all over the world."

Their start yesterday was a little rocky. Only a few of the women speak English, and the only proficient translator, Vera Soboleva, 38, a staff member of the Soviet Women's Committee, was much overworked as the Tourmobile left the Capitol. Journalists jockeyed for awkward interviews, while the tour guide proceeded with her spiel as though everyone could understand her.

A van carrying a television crew drove by, filming the group inside the bus.

"Ah, America," said Yuta Renzer, 54, editor of a magazine for youth in Estonia.

Margarita Zabelina, 44, a staff member of the Presidium of the Supreme Soviet in Moscow, took out a compact and touched up her makeup. She was wearing a frilly pink blouse, a white skirt and jacket, and spike heels. "We are now passing the Archives . . ." said the tour guide. "Among the documents there is the Bill of Rights . . ."

Zoya Samoletova, 55, is a seamstress. Lyubov Gubyas, 38, is an English teacher in Moscow. Oydin Abbsova, 48, is the minister of education in Uzbek, and Larisa Shuratovskaya, 46, is a physician in Moscow. Together they will travel with Barbara Levin, wife of Sen. Carl Levin (D-Mich.), to Salt Lake City, where they will see the Mormon Tabernacle Choir sing. They'll have a Mexican dinner in Phoenix, and attend a seminar and tour a "Levi distribution facility" in Las Vegas.

"We want them to see a broad spectrum of American life," said Karen Sherman of Peace Links.

Shahobova, 57, is the chief of foreign languages at the Tadzhik Academy of Sciences. Her husband is an economist, and she shows pictures of her two children and two grandchildren. This is her second such trip to the United States; the first was in 1962.

A shirtless man jogged by the bus in the noonday sun. "Running in the sun!" she said. In Tadzhik there are joggers, but they wouldn't jog during the day and they certainly wouldn't take their shirts off. "We are a Muslim country and have our traditions," she explained.

The Soviet Women's Committee paid for the trip as far as Montreal, and the American group raised the money for the rest of it.

"Women give birth to the life, and we must preserve it," Shahobova said. "When I became grandmother I thought how our generation has the responsibility to keep the civilization. You like or don't like our system, but the Earth belongs to everyone."

The summit conference may do some good, she thought. "We have to be optimistic. What is left for the people but hope?"