The Homan sundial was also patented in the U.S.: Patent # 946,223 issued on 11 Jan. 1910. I have a copy of the patent papers in a 320Kb pdf file which I will send to anyone who requests it (off-list please).
Fred Sawyer ----- Original Message ----- From: "Andrew James" <[EMAIL PROTECTED]> To: <sundial@rrz.uni-koeln.de> Sent: Wednesday, July 31, 2002 7:33 AM Subject: Heliochronometer by Homan > I have recently been shown an interesting brass heliochronometer made by W. > Homan of Glasgow according to his patent 18,568 of 1911. (I hope to receive > a copy of the patent shortly.) > > It is quite large, based on a 13 1/2" diameter hemisphere. It has two > "gnomons", upright brackets carried on and perpendicular to a circular plate > 11" diameter. The plate has, over an adjustable 15 degree arc at its edge, a > scale divided in minutes, and can be rotated by hand against an outer fixed > ring marked with hours from 1 to 12 twice. Each upright carries a half > analemma, one for positive and the other for negative solar declination > (summer and winter), and a slit - with in one case a small hole adding a > nodus to the slit - to project light onto the half analemma on the other > upright 7 7/8" (200 mm) away. > > It is set for a latitude (not adjustable) of about 7 degrees North, and a > time difference from the local meridian of 5 minutes (added to the reading, > so it was sited just over 1 degree West). This indicates it was made for use > not in Britain but somewhere tropical, perhaps West Africa or Ceylon. > > Has anyone come across other example(s), or information about this device or > its maker? > > Andrew James > N 51 04' W 01 18' > - > -
