Hi Tom,
I'm not exactly sure how or when it was later determined that the Earth
is really larger than what was surveyed (1792-1799) by the French but my
guess is that satellite data was the key. Also, as Gorden mentions, the
survey did not involve the full 90deg of the quadrant but instead only
about 10degs of latitude from Dunkirk (through the Paris Observatory) to
Barcelona, both of which are at sea level. I'm not sure if the French
incorporated the fact that the Earth is not a perfect sphere. My
reference, "The Science of Measurement - A Historical Survey" by Herbert
Arthur Klein, mentions that instead of the standard quadrant being
10^7meters (which I assume was originally arbitrarily assigned and the
meter length itself being found via the survey measurement) it is really
10,002,288.3 meters in length (2+ parts in 10,000).
Best,
Luke
Tom wrote:
> SNIP
>
> I wonder if this is where Luke gets the 0.023% figure? Does it imply that
> Delambre and Me'chain (under the supervision of Jean-Charles chevalier de
> BORDA?)
> measured the quadrant to be 9,997.3 km instead of 10,000 km?
