A couple of notes about finding declination:
1. Mention was made of Waugh's use of a horizontal board. I looked that up and found he referred to such methods written by Nicolas Bion in 1709. When I looked in that work I found a bit different method. He describes what he called a "Declinatory". This is a flat board with a 180 degree scale or protractor. At the center is attached a movable arm to aid reading the angle. He describes using a magnetic compass (!) but warns about variation and local disturbances. The interesting part is that he also shows using a small horizontal sundial against this moveable arm. (see attached copy of his drawing.) In his day the correct sun time was to be obtained as he said "from some good Dial, as the Astronomical Ring Dial". Then, holding the board in the horizontal, the arm and small dial are rotated until it reads the correct time and the declination is noted. Today we could use the NASS Dialist and put in the date, latitude and longitude to get what the sundial should read for a known good clock time. In the drawing you can see a plumb bob attached also. This was for finding the wall's inclination. 2. In sending materials to a distant client several people mentioned methods using clock time. I would NOT trust the client to know what that is! Include a small digital watch in the materials that you send. That way you know what time was used. If the materials are all returned you can check the watch for what error it may have accumulated. Considering the difficulty I had with a client using "clock" time I would favor having a client that used Zarbula's method at several times during a day. The problem would be the man hours required. Claude Hartman Arroyo Grande, CA 35N 120W Attachment converted: Macintosh HD:Bion declinatory small.gif (GIFf/«IC») (000E763F)
