On 03/06/12 07:12, Niall Martin wrote:
The problem with that comment is what standard other countries are using. The
yard was
an imperial unit, based on a bit of metal kept in London, and until say Canada
and India went
metric, their units were based on that. But in the 80s it was discovered that
the length of the
bit of metal kept in London, the Imperial yard, had been drifting down over
time, and the
legislation was based on an estimate of what that length once had been. I
suppose the USA,
as usual a law unto itself, has done something else, or ignored the problem,
but if it has, its
measurements will still be based on the Imperial yard. (I do know that their
volume
measures are different from the Imperial units, but that is not at issue here.
Though, does
anybody know of another country still using the pound/foot measurement system?)
from wikipedia:
"From July 1, 1959, the United States and countries of the British
Commonwealth defined the length of the international yard to be exactly
0.9144 metres.[5][6] Consequently, the international inch is defined as
exactly 25.4 millimetres. This creates a slight difference between the
international units and American surveyor's units which are described in
the article on the foot."
--
Mike Scott
Harlow, Essex, England
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