Hi Andrew: One thing you can do is read the patent images and look for citations of prior art. Sometimes this is on the first written page, sometimes on the last page and sometimes in the description of prior art. Once you have the patent number then go there and look for more citations.
I have some Sundial Patents at: <http://www.pacificsites.com/~brooke/SD_Pat2.htm> Have Fun, Brooke Andrew James wrote: > Brooke > > Thank you for that - and thanks Fred for sending me the file off-list. > > >From that I now see that the US Patent 946,223 is actually for a design > completely different from UK 18,568 of 1911 and the instrument I saw! > > As I understand that he made at least two other known mean time dials on yet > another principle, Homan would seem to have been quite a prolific inventor > in the field. > > Perhaps he took out other US Patents? But as you say apparently one can't > search for the inventor on-line at that date. I'll have a look, in case, for > other UK ones using good old paper-based technology! > > Andrew James > N 51 04' W 01 18' > > -----Original Message----- > From: Brooke Clarke [mailto:[EMAIL PROTECTED] > Sent: 31 July 2002 17:03 > To: sundial@rrz.uni-koeln.de > Subject: Re: Heliochronometer by Homan > > All US patents are on line. > Sources for free on line TIF viewers can be found under help\How to Access > Patent Full-page Images. > Older patents can only be accessed by traditional US class number or patent > number, none of the other search methods will work. > - -
