Shortly after 10:40 Tuesday night, Father Ralph de Bricassart, his black cassock shed for a three-piece, off-white suit, walked slowly across an Australian beach to declare his desire for Meggie.

She protested and ran.

He pursued and caught her.

They tumbled across the sand in a frenzied clinch, and moments later Ralph's thick golden shoulders enveloped Meggie in bed.

Not only did Meggie succumb, but nearly every woman watching succumbed to Father Ralph, too.

"Let's put it this way," said one Capitol Hill lobbyist yesterday. "I'd leave the convent for him."

What is it about Richard Chamberlain--who plays Father Ralph in "The Thorn Birds," ABC's steamy mini-series that concluded last night--that had women leaving their exercise classes early to sink in rapture in front of their television sets?

"I think he's gorgeous--especially last night," said Diane Krawiec, legislative assistant in Sen. Don Riegle's (D-Mich.) office, referring, of course to Tuesday, The Big Night.

But what is it about him? Krawiec's not sure: "His gentleness? His eyes?"

Whatever it was, she, like many others, had to watch it. "Tuesday night, I was out having drinks with a friend," she said. "Things were going along fine and I suddenly realized it was a quarter of 9. I had to go. Right in the middle of the drink."

Richard Chamberlain, at 48, is not exactly a fresh face. The former Dr. Kildare and the man People magazine recently described as a "confirmed bachelor" was a sex symbol 20 years ago. After that, he left television for success and respect--but not much fame--in the theater, particularly doing Shakespeare. In more recent years, he has become the king of made-for-television extravaganzas.

Explained one Hill aide, "Three weeks ago Richard Chamberlain was sitting in Japan in 'Shogun' and now he's in the outback of Australia. The guy gets around."

"He's the best looking man in a dress I've ever seen," said Debra Berlyn, a Common Cause staffer.

And there's one waitress at the Bottom Line bar who insisted that a group of rugby players assembled there watch the show. "They were very glum," said one witness. "She was talking about him the whole time . . . that one scene when Meggie kisses the priest for the first time, she started yelling, 'Get him, you can do it.' "

Chamberlain, though, isn't offering any insight on himself. He's on a 17-day retreat in Hawaii with his holistic teacher, Brugh Joy, according to his agent.

Even Ted Koppel is talking about him. "Nightline" devoted nearly half its Tuesday show to a serious discussion of the question posed by Ralph's little interlude with Meggie--celibacy and the priesthood.

Clearly, the forbidden nature is part of the allure.

"I think the part lends something to thinking that he's a very exciting man," says Berlyn. "It's not only his looks but the fact that he's a sensitive, caring man--the qualities of a priest--but he also has the normal feelings of a man."

And he's finally all grown-up. No more young Dr. Kildare.

"During all the shows, I've been on the phone with my friends for hours discussing how good he looks in every scene," said a Washington sales representative. "I felt comfortable with him on 'Dr. Kildare' because as far as I was concerned, he was my doctor. From an intern to sex symbol is a pretty big jump. Those robes do wonders for him."

Ralph's appeal is no Rhett Butler macho. Not when he's holding Meggie's hand as she gives birth to another man's baby. "He's sensitive and romantic," said Dorothy Cecelski, another Common Cause staffer. "There's sort of an old-world melancholy about him that's attractive--terribly attractive."

Of course, there are those who complain he's still just a pretty-boy doctor and those who complain that he should be the doctor, not the romance-prone priest.

"I'm still part of the 'Dr. Kildare' generation," said Alvin Lodish, an attorney at the Justice Department. "I liked him much better in white than with his shirt off."

And then there are some who would say poor, tragic Father Ralph has overdone it.

"He's a bummer," said John Graykowski, a legislative assistant in Riegle's office, who read the book and has been watching the show. "I wouldn't like him at a party. The guy just contemplates too much. He tries too much for tragic. Oh, God, these dark moods, this pensive face . . . I mean, come on. Go and have a beer."

But after all, Graykowski is a man.