> - 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