(This thread may be cold by now. My response has been delayed because my service provider, Earthlink, has problems delivering mail to this list as well as some addresses in Europe. Are there other Earthlink users on this list? I am trying to post this through the eGroup archive site)
Dr. Rafael Soler sent me some information about his "bifilar" sundials after the Reutte competition in 1998. (Interestingly, his English translation refers to these as "Bithread Quadrants". In drawings he refers to the styles of the gnomons as "threads" or directrix curves.) "Frans W. MAES" wrote: >I found a picture (without explanation) of another, unique bifilar dial >by Mr. Soler at: http://sundials.org/conference/1999/confpix/reutte.htm >(bottom of page). Has that design actually been realized somewhere? This was a picture of the model he sent to the Reutte competition. In August '99, Karl Schwarzinger found that the pedestal was broken and so it may no longer be on display at the Reutte Museum. However, some small, desk sized, portable dials of a similar, but horizontal, design were made in 1998 for the Department of Tourism, Government of the Balearic Islands as gifts for VIPs. The design for the Reutte competition also came in a form with the horizontal disc hung from above by vertical rod that acted as the second gnomon. > I have searched the web for additional information on Mr. Soler's > motivation. I found a large pole-style bifilar dial, including >picture, in Barcelona, where the catenary is a parabola, (snip) >http://www.gnomonica.org/es/it1.htm As one can see in the photo, the N-S gnomon is horizontal. The E-W gnomon is a parabola opening upwards. The resulting hour lines are not straight except near noon. This dial was built in 1993 for the Olympic Village of Barcelona. Concerning motivation, I can only guess that it was a desire for "sculptural presence". In the Genk park dial there may have been the desire to combine a natural curve, the catenary that a hanging chain forms, and a polar style. The polar style provided straight hour lines and the intersection provided a marker for datelines much like a nodus on the style would. His drawings showed a proposed size that would have the chain hanging from supports 3.5 m high and 5 m apart. Unfortunately, only a small version was built and the chain is easily vandalized. In papers Dr. Soler recently sent me, he describes another "bifilar" design he submitted for Genk. This was for a fountain. A N-S gnomon is placed horizontally like a fence about 25 cm above ground level. A jet of water flows E-W over this at a controlled height 50 cm above the N-S gnomon. Now the intersection of the shadow of this parabola of water and the horizontal fence makes the marker on the dial. None of the lines are straight except near noon. The dimensions were kept small enough to have a horizontal dial of about 9 m in diameter. Too bad this was not built. I've often wondered how to do a sundial fountain with a water gnomon! As before, I think the "motivation" was to use the intersection of some natural curves. Claude Hartman 35N 120W
