Professor Margenau remembered the girl's name.

Didn't you know that she's a pink, practically a red, and so is the whole organization? the FBI man asked.

Professor Margenau did not know.

Well, next time you get an invitation from a group you don't know about, you better call us first.

'Advice' Not Policy

Spokesmen for the FBI admit that such gratuitous advice to private citizens is not permitted by FBI policy. They have indicated that any agent caught in such an act would be fired if the facts got back to Washington.

But Professor Margenau was cleared as a trustworthy citizen of the US only four years ago. So now he calls the New Haven FBI office every time he has doubts about a group which has asked him to speak.

The case of Robert S. Cohen is not so clear-cut. Mr. Cohen was cleared by the FBI, Army Intelligence, and Navy Intelligence during the war for work with the Joint Chiefs of Staff communications board.

Always interested in the philosophy of science, Mr. Cohen entered Yale's graduate department of physics after the war. In spring, 1948, he received his Ph.D.

Also in spring, 1948, Mr. Cohen joined the Wallace party. During the summer, he actively campaigned for Henry A. Wallace and other party candidates. His work resulted in appointment to the party's Third Congressional District campaign committee.

After the election, Mr. Cohen dropped out of politics to devote full time to his graduate work in philosophy, mainly under the direction of Professor F. S. C. Northrop.

Then, this spring, Mr. Cohen learned of an opening in the philosophy department. It was an instructorship in Directed Studies, similar to tutorial at Harvard and designed for outstanding freshmen and sophomores.

Under the Yale appointment system, a candidate's application first must be approved by his department. The philosophy department unanimously approved Mr. Cohen's appointment.

Also, since the appointment was in Yale College, it had to be recommended by the college faculty. This vote was also unanimous.

Only one barrier remained, the Prudential Committee. This group has always been considered a "rubber-stamp."