Linus Pauling showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 Watson and Crick proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. During the time Pauling was researching the problem, Rosalind Franklin in England was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert
Francis Crick structure of DNA. Orgel also later worked with Crick at the Salk Institute for Biological Studies. Soon after Crick's death, there have been allegations about him having used LSD when he came to the idea of the helix structure of the DNA. While he almost certainly did use LSD, it is unlikely that he was doing that as early as 1953. In 1954, at the age of 37, Crick completed his Ph.D. thesis: ""X-Ray Diffraction: Polypeptides and Proteins"" and received his degree. Crick then worked in the laboratory of David Harker at Brooklyn Polytechnic Institute, where he continued to develop