XPost: alt.usage.english   
   From: kehoea@parhasard.net   
      
    Ar an naoú lá déag de mí Méan Fómhair, scríobh Christian Weisgerber:   
      
    > I'm sorry, I don't know where to post this.  I'm crossposting to   
    > alt.usage.english, because statute miles as a unit mostly afflict   
    > the English-speaking world.   
    >   
    > So you want to convert between miles and kilometers.  The conversion   
    > factor is... uh...  A 40-year-old calculator book provides a useful   
    > tip:  Unless you're designing a space probe, you can use ln(5).   
    >   
    > WHAT?   
    >   
    > Yes, the natural logrithm of 5 approximates the conversion factor   
    > between miles and kilometers; specifically one mile is about ln(5)   
    > kilometers.  It's accurate to four digits.   
    >   
    > If nothing else, it's faster to type on a calculator.   
    >   
    > I think that's hysterical.   
      
   The old units were completely neglected when I went to school, which is   
   unfortunate, it’s routine that we need to convert between vulgar feet and   
   inches for height to centimetres in daily life, or between vulgar stones and   
   pounds to kilograms. What I learned from my father (born 1945, went to school   
   before it was neglected) was that a kilometre is 5/8 of a mile, which helps in   
   converting the speed limit signs in Northern Ireland to what my speedometer   
   shows.   
      
   I will attempt to bear ln(5) in mind going forward!   
      
   --   
   ‘As I sat looking up at the Guinness ad, I could never figure out /   
   How your man stayed up on the surfboard after fourteen pints of stout’   
   (C. Moore)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)