In 1953, in a letter to the journal Nature, Watson and Crick proposed a structure for DNA — generally referred to as “The Double Helix”. In a full article published the following year, they wrote:
“The information… was very kindly reported to us prior to itspublication by Drs Wilkins and Franklin. We are most heavily indebtedin this respect to the King’s College Group, and we wish to point outthat without this data the formulation of our structure would havebeen most unlikely, if not impossible.”
My question (which I intend to answer myself) is:
What, precisely was the data referred to by Watson and Crick, and how did it (in particular that obtained by Rosalind Franklin) contribute to the proposed structure?
N.B. This question only concerns the scientific facts in their historical context — not opinions on the behaviour of the individuals involved. It has a different focus to a previous question concerning Franklin’s interpretation of her own data.