A group of 462 Yale University faculty members mailed a letter Saturday to President Johnson urging an "unconditional halt" to U.S. bombing of North Vietnam. The signers did not claim to represent the University.

In the four paragraph letter, the writers said that although they realized the difficulty of the decision to stop the bombing, they felt "the potential benefits outweighed the risks, and that the gamble is a necessary one."

"We are very much strengthened in this view by the events of the last few days, particularly U Thant's growing conviction that the cessation of bombing is the necessary key to the opening of peace talks," the letter said.

The signers thought that Pham VanDong's interview with Harrison Salisbury indicated a new flexibility in the willingness of Hanoi to negotiate.

Robert A. Dahl, professor in Yale's political science department, and Louis H. Pollak '43, dean of Yale Law School, were among the signers.