THERE CAN BE ONLY ONE
By definition, the International
Prototype ‘K’, a 39mm-cylinder of
90% platinum and 10% iridium kept
safely inside a vault in the basement
of the BIPM, is one kilogram. Even
though it seems to have lost weight
in comparison to its copies.
Metrologists worldwide seek to get
rid of it and search for a new defini-
tion which ties the Kilogram to a
fundamental constant of nature.