Derrick A. Bell Jr., the activist law professor who left Harvard to protest its faculty hiring policies, said yesterday that he cannot envision ever returning to the University.

"To use an expression, I've borne the burden in the heat of the day, and I think it's time for others to do or not do," he said in an interview after a talk and book signing in Cambridge.

Bell, who was the first Black tenured professor at the Law School, took a leave of absence two years ago to protest the absence of minority women on the faculty. Bell was released from the faculty this summer after the administration denied his request for an extension of the leave.

In a conciliatory letter this fall, Law School Dean Robert C. Clark expressed regret about the departure and stated his desire for Bell to return.

But Bell, now teaching at New York University Law School, said he would not seek reappointment. The 61-year-old scholar said he is skeptical about the prospect for meaningful change at the school, and about the administration's commitment to faculty diversity.

"So often in the past serious upsets have been defused by setting up committees, calling for greater commitment..that the current call is burdened by that precedent," he said.

In his 16 years at the Law School, Bell was an outspoken and often controversial advocate of increased minority faculty hiring. He left Harvard in 1980 to serve as dean of the University of Oregon Law School, but resigned over a faculty hiring dispute in 1985 and returned to Harvard.

At the Inn at Harvard yesterday, Bell said discrimination is so systemic that increased hiring of minority faculty would not be enough. "I think that while race and diversity are dramatic things, they are only visible pieces of much deeper problems," he said.

Responding to questions from a standing-room only audience, Bell discussed his experiences at Harvard as well ashis new book, Faces at the Bottom of theWell.

"I sometimes wonder what would've happened ifnot myself but one of the other established whiteprofessors had taken a protest leave," he said. "Ithink the response would have been different."

Asked about Harvard's new president, Neil L.Rudenstine, Bell shook his head in resignation. "Iwould've hoped that there was going to be a newstart there, but...