A friend of mine just pointed this out to me.
If anyone will be near this point some time in the future to get more accurate 
coordinates, this would make a great virtual cache.

Brian Cluff
Team Snaptek

# From Peter Ilieve <peter@memex.co.uk> (1994-07-06):
#
# On 17 Jan 1994 the Independent, a UK quality newspaper, had a piece about
# historical vistas along the Thames in west London. There was a photo
# and a sketch map showing some of the sightlines involved. One paragraph
# of the text said:
#
# `An old stone obelisk marking a forgotten terrestrial meridian stands
# beside the river at Kew. In the 18th century, before time and longitude
# was standardised by the Royal Observatory in Greenwich, scholars observed
# this stone and the movement of stars from Kew Observatory nearby. They
# made their calculations and set the time for the Horse Guards and 
Parliament,
# but now the stone is obscured by scrubwood and can only be seen by walking
# along the towpath within a few yards of it.'
#
# I have a one inch to one mile map of London and my estimate of the stone's
# position is 51 deg. 28' 30" N, 0 deg. 18' 45" W. The longitude should
# be within about +-2". The Ordnance Survey grid reference is TQ172761.
#
# [This yields GMTOFF = -0:01:15 for London LMT in the 18th century.]