Franklin’s X-ray diffraction pattern of TMV. Klug thought her diagrams were “beautiful” because they showed many more distinct intensity maxima (spots) than other researchers had obtained, which indicated both the quality of her sample preparation and her superior diffraction techniques. These maxima appear on horizontal layer lines that are perpendicular to the fiber axis. Reprinted with permission from Rosalind E. Franklin, “Structure of Tobacco Mosaic Virus,” Nature, 2005, 175:379–381, on p. 379. Copyright 1955 Macmillan Magazines Limited.