At 23:27 7/11/98 -0500, you wrote: >Hi Mario, > >The oldest "Ivory Diptych" or 'tablet dial' from Nuremburg that I am aware >of was made by Lienhart Gresel in 1531. There were earlier ones made of >wood some time in the 1480's. >
Hi Mario, I have a book called "The Ivory Sundials of Nuremberg, 1500-1700" by Penelope Gouk. It is a catalogue of diptych dials from the Museum of the History of Science, Oxford, and the Whipple Museum of the History of Science, Cambridge. The book is published by Cambridge press, 1988. It states on pages 28-29 that the date of the earliest ivory diptych sundial is not known but would most probably be at the very end of the 15th Century. It goes on to say that the British Museum has a complete example (pictured) of an instrument from this period. Quoting "It has a vertical and horizontal dial with hour lines calibrated for about 48 latitude for use with string gnomon and compass. On the outside of the upper leaf is a relief carving of St John the Baptist. The herring-bone grain in this specimen of ivory is unusual; it is cut from a tusk which in the living animal had been exposed to some form of stress or temperature change." Another also likely from the same period was found in the Thames. Only the lower leaf exists. "Two upper leaves of dials of this type are also known: one is now in the Metropolitan Museum of Art, New York, while the other is in the Museum at Niort, France. The carvings on these upper leaves, which depict children at play, are reminiscent of a style of woodcut found in Germany about 1480." These dials are calalogued in the book at c. 1500. I can provide scanned images of these dials if you can send me your email address (I lost the original posting) in a day or so if you are interested. Hank de Wit Adelaide Australia Hank de Wit Regional Computer Manager Bureau of Meteorology South Australia [EMAIL PROTECTED] ph: 08 8366 2674 http://www.sa.bom.gov.au/~hdewit (INTRANET access only)
