Hi Steve, You wrote: > "[The source] said they carved out deep narrow notches which, when the sun > fully filled the notch, it was that particular time". > > That's sounds very much like a shadow-plane dial, but reversed to use > illumination rather than shadow as the indicator. But according to the > report, these dials were used to indicate time left before supper. This > situation got me thinking - could a shadow plane dial be constructed in > such a way as to show time since sunrise / time to sunset? The > descriptions I've read, as I remember them, all relate to modern hour > markings.
Yes, I believe so. I was told that the notches were made not only angled to different compass directions but that the blade of the knife was also rotated around the axis of the handle so that the notch was not normal to the horizontal surface. He said they had templates. I can see how a template could be made. If you take the cone gnomon horizontal italian hour sundial for a given latitude, place your knife tight against the cone and angled it to touch the line for one hour before sunset and cut along that line you would have your first notch. Repeat this for each other time period before sunset and you would have a notch dial with italian hours. It is not inconceivable that one could take a pinecone of the right cone angle, place it down on a level surface with the point of the cone facing south, place your knife blade flat against the side of the cone, then, at any hour before sunset, angle your knife blade so it cast a minimum shadow, then slice deeply into the sill to complete the notch. One could make a flat sundial of this type with the notches actually all the way through say a 1.5 cm thick board. If this board then had an compensated compass and a bubble level attached then when oriented to the south and level any kind of cutting device could be slipped through the slits to create a notch. The surface notched would not have to be perfectly level or smooth, in fact could slope downward to shed rain. If a thin sawblade were used instead of the knife then the sundial could be made in stone or metal. Since it is each individual slot that is doing the work the board could be slid around on the surface, keeping it pointed south and level and then any slot could be made at any point on the surface, allowing any kind of decorative pattern desired. The kind of knife that was used was a kind of hook billed knife, simular to a linoleum knife or a large chip carving knife. I'm not saying this is how it was done, but, it seems this would work. Of course one could use Babylonian hours, or possibly other hours as well. Hope this helps, Edley McKnight [43.126N 123.357W]
