Greetings fellow dialists, At last we seem to be approaching a conclusion for the Hawkshead dial. So many valuable contributions and I am awed, even overawed, at the erudition of our contributors. Among your messages have been three suggestions among the many that looked particularly promising. First, from Tom Kreyche, that the longitude given on the dial plate was measured from St. Petersburg. This at first looked attractive but the dial, which is almost exactly 3deg. west of Greenwich has the cited longitude of 35deg. 43min. 40sec. while the observatory at St. Petersburg is 30deg. 18min. 23sec east of Greenwich, giving a discrepancy of over two degrees.
Second, a clever suggestion from Gianni Ferrari, which was sent before the actual word "longitude" on the dial plate was promulgated by me, proposed that we are dealing with a polar latitude. This value requires explanation, which I do not here pass on, but it concerns the compliment of the reduced latitude which in turn depends on the compression of a spherical earth. Gianni Ferrari produced a value for this polar latitude of 35deg. 43min. 24sec. which is impressively close to the cited value. However, it does not deal with the word longitude. The most likely explanation, it seems to me, was proposed by Fer de Vries. It was finally revealed from one of a number of photographs that a declination of 30deg. 20min. was painted on the dial plate beside the latitude. From this it is possible to calculate the style angle, the substyle angle and, critically, the hour angle. If the hour angle is presented as an angular measure it works out at 35.75deg. or, in time, 2hrs. 23min. as opposed to the cited longitude of, in time, 2hrs. 22min. 54sec (see angular value above). In other words, at 9.37 am the sun will be directly over the style and the cited longitude is the hour angle. This explanation has the added advantage that no geographical longitude is involved; longitude values must be rare indeed on dials of 1845. But we still have no explanation of the letters PI (or perhaps P1) although Frans Maes notes that Waugh uses the symbol P in his treatment of declining dials. In conclusion there is an excellent general account of the dial, together with a photograph, written by Robert Sylvester in the Cumbria chapter of "Sundials of the British Isles", pub. Mike Cowham, 2005 (PO Box 970, Cambridge CB3 7FL). Grateful thanks once again to all who have helped this extensive topic along and so, farewell. Frank 55N 1W -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.463 / Virus Database: 269.6.1/778 - Release Date: 27/04/2007 13:39 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
