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According to the act of September 28, 1850 (9 Stat. 515) "... the meridian of
the observatory at Washington shall be adopted and used as the American
meridian for all astronomic purposes..."  The Washington meridian passed
through the center of the dome of the old Naval Observatory at 24th Street and
Consititution Avenue according to two sources.  They both gave the longitude
as 77 degrees  3 minutes  2.3 seconds west of Greenwich.  The zero milestone
on The Ellipse looks to be at about 77 degrees 2 minutes 15 seconds.
The Cartographic Materials manual gives 77 degrees 0 minutes 34 seconds, which
is close to the dome of the U.S. Capitol.
    Two Washington meridans??, bad math??, total confusion on my part??
    misprint??
 
Johnnie Sutherland
University of Georgia
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