platinum-iridium

platinum-iridium
 adj.

   Standard, against which all others of the same category are measured.
   Usage: silly. The notion is that one of whatever it is has actually
   been cast in platinum-iridium alloy and placed in the vault beside the
   Standard Kilogram at the International Bureau of Weights and Measures
   near Paris. (From 1889 to 1960, the meter was defined to be the
   distance between two scratches in a platinum-iridium bar kept in that
   same vault -- this replaced an earlier definition as 10^-7 times the
   distance between the North Pole and the Equator along a meridian
   through Paris; unfortunately, this had been based on an inexact value
   of the circumference of the Earth. From 1960 to 1984 it was defined to
   be 1650763.73 wavelengths of the orange-red line of krypton-86
   propagating in a vacuum. It is now defined as the length of the path
   traveled by light in a vacuum in the time interval of 1/299,792,458 of
   a second. The kilogram is now the only unit of measure officially
   defined in terms of a unique artifact. But this will have to change;
   in 2003 it was revealed that the reference kilogram has been shedding
   mass over time, and is down by 50 micrograms.) "This
   garbage-collection algorithm has been tested against the
   platinum-iridium cons cell in Paris." Compare {golden}.
    

platinum-iridium

   <standard> A standard, against which all others of the same
   category are measured.  Usage: silly.

   The notion is that one of whatever it is has actually been
   cast in platinum-iridium alloy and placed in the vault beside
   the Standard Kilogram at the International Bureau of Weights
   and Measures near Paris, as the bar defining the standard
   {metre} once was.

   "This {garbage collection} {algorithm} has been tested against
   the platinum-iridium cons cell in Paris."

   Compare {golden}.

   [{Jargon File}]

   (1997-02-20)