I am interested in the question of the background colour of a
vertical sundial. On the University administration building here,
Heslington Hall, we have a very fine clock - sundial pair of 1855, by
Thomas Cooke of York, possibly more famous for his telescopes. For some
reason clocks (unless they are lit internally) usually have a blue face
and the specification for the sundial here demanded a matching blue face
for the sundial. Cooke did actually remark that blue was not a very good
colour for the sundial shadow to fall against; nevertheless blue it is.
I would also be interested to hear of other clock - sundial pairs,
especially of this sort of period when sundials enjoyed a brief revival in
importance reflecting the increased pressure to set clocks accurately
brought about by the railways.
Richard Crossley.
Dept. of Physics, University of York, York YO10 5DD, England.
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