Letter to the Editor

Letter to the Editor

Dear Bill,

As one who did his first Fourier summations (2-D, and 3-D Harker sections) with Beevers-Lipson strips (incidentally, one can do structure-factor calculations with them, too), I would like to say that the process was not actually 'unthinkable' - the alternative then was log tables! They remain a useful teaching device for what is actually going on in a Fourier summation. I agree with Bob Gould (page 25 of Vol. 8 No. 3, 2000) about the mental arithmetic - it was faster than the calculators available at that time. I am pleased to have preserved the memory, at least, of Beevers-Lipson strips in a book, with my colleague R.A. Palmer, on Structure Determination by X-ray Crystallography (Chapter 6) - 4th Edition appearing later this year.

Mark Ladd (m.ladd@surrey.ac.uk)