Yes, until the 19th century, it was not uncommon for people to set their watches and clocks by means of sundials. In the earlier period, sundials were more accurate than clocks. Noon marks, whether from a sundial like those you mention or produced by a dipleidoscope (a 19th c. invention), were expressly for this purpose.
Sara ------------------------------------------------------- Sara Schechner, Ph.D. Center for History of Physics American Institute of Physics 1 Physics Ellipse College Park, MD 20740 Tel: 301-209-3166 / Fax: 301-209-0841 [EMAIL PROTECTED] Gnomon Research __Curators on Call __Outreach Adventures 1142 Loxford Terrace Silver Spring, MD 20901 Tel/Fax: 301-593-2626 http://www.wam.umd.edu/~sschech [EMAIL PROTECTED]
