Please, let me be a little bit pedantic... ;-))
Sundialists know well the shadow of the gnomon of the vertical type sundial
on the wall rotates anticlockwise.
Well, this is true only if the wall's declination is lower than +/- 90
deg. If the wall looks, so to say, NorthEast or
NorthWest the hours rotate clockwise. You'll probably get an hiatus, but
the sense of rotation is clockwise.
Of course this is not the reason why clockmakers chose that rotation
convenion: in Rohr's book we can see that,
as Mike said, it was probably due to the fact that first sundials were
rather astronomical instruments than clocks
and they were more or less similar to an spherical sector (its name was
scaphe) where the shadow of a needle
moved from left to right, ie, clockwise.
And, by the way, I think I heard somewhere in the Discovery Channel that
aboriginals in Chile knew about
rudimentary sundials wich rotated, obviously, Southern-clockwise ;),
that is, from right to left. Does anybody
know something about this or similar (maybe in New Zealand or in
SouthAfrica?)
Cheers,
Anselmo
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