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> - When Rontgen discovered a new kind of light, he called it "x- > rays". Now only the Germans call them Rontgen rays. Thanks for a great essay! Since I have nothing of real value contribute here, I won't pass over the opportunity to be a "besserwisser" (as the Swedes say, using a borrowed word...) the Röntgen moniker has stuck here in northern Europe too: in Swedish: Röntgenstrålning, in Danish and Norwegian: Røntgenstråling, in Dutch: Röntgenstraling. Also thanks to Wikipedia, I can inform you that it's called Röntgengeislun in Icelandic and Röntgensäteily in Finnish. Eastern Europe seems to have adopted various forms based on "Rentgen", but I won't pretend I knew that before 5 minutes ago ;-) Derek > > > - When the largest protein ever was discovered, it was called > "connectin", but a subsequent paper called it "titin" and the second > name has stuck. I actually can't remember who the "connectin" guy > was ... > > - When Joseph Fourier discovered that heat radiated from the earth > could be reflected back by gasses in the atmosphere, he simply named > it by describing it (in French). Now this is (incorrectly) called > the "greenhouse effect". Why not the Fourier effect? Fortunately > for Fourier, a mathematical series was named after him, although he > neither discovered it (Budan did that), nor implemented it (Navier > did that). All Fourier did was present a theorem based on a flawed > premise that turned out to be right anyway. > > So, I decided to look up Friedel and Bijvoet in the Undisputed > Source of All Human Knowledge (wikipedia) and found that Friedel's > Law "... is a property of Fourier transforms <http://en.wikipedia.org/wiki/Fourier_transform > > of real functions." > > I am willing to believe that. And considering this origin I would > think it appropriate to call (hkl) and (-h-k-l) a "Friedel pair" (or > "Friedel's pair" as it is described in the USAHK). G. Friedel was > indeed a crystallographer, but I doubt he considered more than this > simple centrosymmetric property. Who would care in 1913 which is F+ > and F-? The atomic scattering factors had not yet been worked out > at that time. Ewald may have predicted it, but anomalous scattering > was not shown to exist until the classic work of Koster, Knol and > Prins (1930). I guess that goes to show that if you want something > named after you... keep it at one or two authors. > > Perhaps it has to do with the original paper getting old enough that > it gets too hard to find. I'm sure in G. Friedel's paper in 1913 he > cited Joseph Fourier's Paper from 1822. Or did he? I wonder if > they were already calling it a Fourier Transform at that time? > > Okay, so what, exactly did Bijvoet do? Everyone cites his Nature > paper (1951), but one thing that I was NOT KIDDING about in my April > Fool's joke was that this paper (like so many other high-profile > papers) contains almost no information about how to reproduce the > results. I was also not kidding that boring little details like the > reasoning behind the conclusion (the hand of the microworld) were > relegated to a more obscure journal (the one in the Proc. Royal. > Soc. Amsterdam). I WAS kidding about having found and read that > paper. I have never seen it. Still, Bijvoet did the first > experiment to elucidate the absolute configuration, and he > definitely deserves credit for that. > So, particularly in that light, I would agree that any pair of > reflections that would be equivalent if not for anomalous scattering > effects could be called a "Bijvoet pair". This is because they > contain the information needed to apply Bijvoet's technique. > Something that has always eluded me is who decided which is F+ and > F-? After all, the reciprocal lattice is very very nearly > centrosymmetric. You cannot tell by looking at a single diffraction > image whether that spot at a given X,Y pixel coordinate is F+ or F-, > you need to know the axis convention of the camera. At some point > in writing the CCP4 libraries with their asymmetric unit > definitions, someone must have established a convention. What is > it? To me, the reasoning behind these assignments is, in fact, they > key to assigning the absolute configuration, not the anomalous > scattering effect itself. So, who worked this out? Should we > really be calling them Dodson pairs? > > -James Holton > MAD Scientist