As always, I tried to locate this "Mayall and Mayall". The only thing
I found was "The Sky Observer's Guide : A Handbook for Amateur
Astronomers"
by Robert Newton Mayall, Margaret W. Mayall (Illustrator),
Jerome Wyckoff
which certainly is not the one you've mentioned. :-(
- fernando
"Wm. S. Maddux" wrote:
Beginning on p.180 of "SUNDIALS" by Mayall and Mayall, there
is a description, and construction advice, for dials of this type.
It includes: ......."However, the shadow will not fall on the outer
arc between 9 in the morning and 3 in the afternoon, unless
the height of the gnomon is proportioned to the altitude of the
sun at noon on June 21. But this makes the gnomon look too
high for the dial. Therefore, the shadow of a shorter gnomon
usually is extended by eye to the date arc during the period
when the shadow the shadow does not fall on the arcs."I would like to suggest that a string can be loosely tied as a
loop ('bowline") around the base of a "too short" cylindrical
gnomon, and stretched along the center of the gnomon's too
short shadow as in the attached sketch, (SPUN.GIF) in order
to make clear the time as extended to an arc of greater radius
than the shadow. (In sketch, to just before 3 p.m. on 1 April.)
--
Fernando Cabral
Padrao iX Sistemas Abertos
mailto:[EMAIL PROTECTED]
http://www.pix.com.br
Fone Direto: +55 61 329-0206
mailto:[EMAIL PROTECTED]
PABX: +55 61 329-0202
Fax: +55 61 326-3082
15º 45' 04.9" S
47º 49' 58.6" W
19º 37' 57.0" S
45º 17' 13.6" W
