27 March 1953
I am glad to have your letter, and to know about your plans.
I shall arrive on the morning of 3 April, as communicated to you already, and I shall
meet you at the terminal in London.
I do not have any hotel reservations of any sort, nor any definite plans for the visit
in England. Will you please make whatever plans are necessary for us.
I had thought that we would stay in Cambridge throughout the period of our visit.
Riley has written that he would be pleased if we could visit him in London. Perhaps
it would be worth while to check our bags and spend a part of Friday at the Royal
Institution, and then go on to Cambridge or Oxford. 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 Kings College people (Miss Franklin has left Kings 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.
I feel that we must spend sometime in Cambridge. If we go up to Cambridge Friday
evening, we might stay there until Monday, and then take off for the continent – my
plane leaves about 1:30 PM on 6 April, for Brussels. Another possibility is to stay
in Cambridge from Friday to Sunday, to shift over to Oxford, in order to see Dorothy,
on Sunday, and then to go down to London Monday morning. This means spending a good
bit of time traveling, however, that could be better used in talking to people in
Cambridge, and I feel that it would be best to plan to visit only London and Cambridge
during the three days of my visit.
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. It is evident that
one structure or the other can be eliminated easily. Their structure places two nucleotide
residues in the length 3.4 Å along the axis of the molecule, and ours places three
nucleotide residues in this length. Data on the cross-sectional area of the unit
of structure of a fiber, the composition of the specimen, and the density of the specimen
should decide definitely between these alternatives, and definitely eliminate one
of them. These data would not, of course, show the other structure to be correct
in its details. In our paper we give an argument, based on data for sodium thymonucleate,
to support the assignment of three nucleotide residues to this length of 3.4 Å. However,
if the specimen of reasonably dry nucleic acid contained about 30% water (50% on the
pure sodium thymonucleate basis) there would be only two residues in this length.
Our own measurements, which are only rought ones, favor three residues, but they are
not good enough definitely to eliminate the possibility of two residues. I think
that the Wilkins photographs should settle the question definitely.
We are finishing up the job of determining the revised parameters for our structure.
It will not be done, however, before I start out on my trip.
I am just putting the final touches on my paper on a new theory of ferromagnetism.
It will appear in the May issue of the Proceedings of the National Academy of Sciences.