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
Rudolf Signer from the Thymus of calves, of which he took 15 grams of extraordinarily pure DNA to London. In England he gave it to various scientists, among them Maurice Wilkins, in order to promote research in the field. The analysis of X ray images of these DNA samples in Wilkins' laboratory allowed James Watson and Francis Crick to discover the double-helix structure of DNA. Rests of the DNA which Signer brought to England, survive today in the collection of King's College, London. Over 250 of Signer's scientific writings were published during his lifetime. The Lavoisier Medal was awarded to him for