Heisenberg agrees that if they can involve some scientists from the USSR the conference will make better progress than previous attempts. On the other hand, his understanding is that the UNO will largely fill the same purpose. Heisenberg personally has too many obligations to join. He feels it is best to leave it up to the UNO for the time being.

Cambridge University, Churchill College, Churchill Archives Centre; Joseph Rotblat Archives, RTBT 5/1/1/5.