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For those interested, I tracked down one interesting quote on al-Biruni's measurement on the Earth's circumference, using the dip angle technique we'd previous discussed.   

I agree with those on the board that his measurement was 'accidentally correct', as he didn't know to take into account refraction.  I'm currently interested in the growth of the legend of this from a paper published in 1973.

The most recent instance of this in a reputable (?) venue was a BBC documentary that first aired on Monday, January 12, 2009, entitled Science and Islam, narrated by physicist Jim Al-Kalili.   He spends something over  5 minutes describing the technique, including carrying around a huge astrolabe to dramatize and repeat the measurement. His final quote on this piece is:

"With this formula, Biruni's able to arrive at a value for the circumference of the Earth that's within 200 miles of the exact value we know it to be today; about 25,000 miles.   That's to within an accuracy of less than one percent; a remarkable achievement for someone a thousand years ago."    

So, there you have it - it's propagated into popular science, not just Wikipedia.