Dear Roger,

You are right...

> This gets more interesting with each note.

The business of labelling gnomonic features
elegantly can be a nightmare!

With an ordinary sundial you have a chapter
ring of one kind or another for the labels of
the hour-lines and life is straightforward!

When you try to label Babylonian hours and
Italian hours it is easy to get into a mess.

[You especially get into a mess if you
insist on using Roman Numerals.  A time
like XVIII takes up a lot of space!]

You say that...

> ... on the sundials in Istanbul, Topkapi
> Palace ... they assigned 6 to noon.  On
> the equinox all the lines cross the meridian
> at 6.  The others then fall into place.

This certainly makes things easier but could
you confirm my interpretation of what you
are saying?

Are you saying that at the crossing point,
on the equinoctial line, at one hour before
noon, they number the four times:

   Babylonian = 5
   French     = 5
   Italian    = 5
   Temporary  = 5

Clearly Babylonian and Temporary would be
called 5 anyway but not French and Italian.

Have I misunderstood?

> The horizontal 12 line on the south facing
> dial is interesting.

Sorry.  I am lost here!  Is this the line
which I would call Italian = 24 but which
is now being numbered 12 because it is 6
at equinoctial noon?

> In Istanbul they used two 12 hour cycles
> so there were no numbers in the teens and
> twenties.

Given your assertion that noon = 6 are you
saying that when there are 14 hours of
daylight the French hours are numbered:

   11 12 1 2 3 4 5   6   7 8 9 10 11 12 1

Also, do they use *real* Arabic numerals?

Very best wishes

Frank

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