On Mon, 06 Aug 2007 15:11:22 -0700, BottleBob wrote:

While most dimensional metrologists know that the reference temperature
for dimensional measurements is 20 °C, very few know how or why that
temperature was chosen. Many people have thought it was, in some sense,
arbitrary. In actuality, the decision was the result of 20 years of
thought, discussion, and negotiations that resulted in the International
Committee for Weights and Measures (CIPM) unanimous adoption of 20 °C as
the reference temperature on April 15, 1931.

None of which explains "how or *why* that temperature was chosen" G.
Just who.
--
Cliff