On Sun, 2013-09-01 at 22:28 +0200, James Holton wrote: > ... but Bragg's genius was in simplifying all this to a little > rule which tells you how much to turn the crystal to see a given spot. > We sort of take this for granted now that we have automated > diffractometers that do all the math for us, but in 1914 realizing that > the rules or ordinary optics could be applied to x-rays and crystals was > a pretty important step forward.
The history of all this can be read in chapter 5 of "Fifty Years of X-Ray Diffraction", edited by Ewald, that can be found here: <http://www.iucr.org/publ/50yearsofxraydiffraction> As noted on page 58, recognising that the principles of optics could be applied to X-rays and crystals meant that W.H. Bragg had to abandon his cherished view of X-rays as having a purely particle-like nature. An object lesson in open-mindedness, I think. Regards, Peter. -- Peter Keller Tel.: +44 (0)1223 353033 Global Phasing Ltd., Fax.: +44 (0)1223 366889 Sheraton House, Castle Park, Cambridge CB3 0AX United Kingdom
