It might be good for you to get in touch with Miss Franklin, if you decide that this is a good plan, and arrange for us to see her also. If the King’s College people (Miss Franklin has left King’s College, and is with Bernal at Birkbeck) express an interest in having me visit their place, perhaps this could be worked in on the same day. I am not planning, however, to approach them on the matter.

Then, after another paragraph in which he described his precise travel plans, Pauling continued:

I have received a letter from Watson and Crick, describing their structure briefly—a copy of their letter to Nature is enclosed. The structure seems to me to be a very interesting one, and I have no strong argument against it. I do not think that their arguments against our structure are strong ones either.

Later in the letter, Pauling recognized that the water content of the molecule could be very important: “We give an argument . . . to support the assignment of three nucleotide residues . . . However, if the specimen of reasonably dry nucleic acid contained about 30% water . . . there would be only two residues on this length.” He concluded, “I think that the Wilkins photographs should settle the question definitely.”

I asked Alex Rich if Pauling truly thought that he could hold on to his triple helix model, and that the double helix was uncertain. Rich’s answer was fairly categorical: “Of course Pauling knew that the double helix was the correct model,” he said. “All this talk about it being uncertain was just bravado.” Indeed, Pauling came to Cambridge the first week in April (figure 17 shows him in 1953), and after seeing Watson and Crick’s wired model and Franklin’s X-ray photo, and having listened to Crick’s explanation, he acknowledged graciously that the structure appeared to be correct. A couple of days later, Pauling and Bragg left for the Solvay Conference in Brussels, Belgium. At that meeting of the world’s top researchers, Bragg first announced the double helix. With great style, Pauling admitted during the discussion that followed, “Although it is only two months since Professor Corey and I published our proposed structure for nucleic acid, I think that we must admit that it is probably wrong.”