Thanks Gordon, I searched Delambre and Me'chain and came up with an excellent little historical summary of the "Bureau des longitudes" at http://193.48.190.6/bdl1795_eng.html and with short biographies of the forefathers of the Bureau at the slow loading http://193.48.190.6/membres1795_eng.html Were any of these folk, Lagrange, Laplace etc sundialists?
Wow. That is a heavy article on the Plane Pendulum. (No pun intended!) Gordon Uber wrote: SNIP > Delambre and Me'chain measured the arc of the meridian between Dunkirk and > Barcelona. It states that the Metre des Archives is about 0.2 mm shorter than > 1 ten-millionth of the quadrant. 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? Do you know of a website which goes into HOW they did this? Did they run level to keep a MSL reference? Then measure circumferential length directly, and laborously no doubt? Then by knowing the two Latitudes of these two points along the same meridian, and the above, they could easily calculate the "radius" of the spheroid and hence the quadrant, I guess. Am I on the right track? Thanks for your insights, Gordon. Tom Semadeni
