Hi Chris, You are correct again. Old habits of being given non-working projects and turning them around, sorry! Yes, as written the patent would seem to not work well, but even inventors may not grasp the hidden promise in their work. Azimuth dials do need to be compensated in some more complex fashion for latitude and time of year and even then only work in a narrow range of latitude as far as I have seen thus far.
Thanks, Edley. > Hi Edley, > You are literally bending over backwards to try to justify this > design. But the patentdoes say the > time scale and shadow pointer are.."both revolvable about a common > axis, said axis to be held in > a vertical position during the reading of the dial" (column 1, line > 31).So it is a horizontal dial, not > equatorial. > > As for magnetic variation, it would be possible toallow for thisto > some degree in the placing of the > time zone marks. But the picture makes clear that this was not in > fact done, as they are all > marked in 15 degree intervals. > > The patent goes on to claim the watch can be used "over the whole > world without any difficulties > depending on the number and the kind of the marks" which is utter > rubbish as it is totally useless > in the tropics, for instance. A southern-hemisphere version could be > made by merely reversing the > order of the hour numbers - perhaps this is what he had in mind. > > It is well known that you can veryapproximately find north by > pointing the hour hand of a watch to > the sun, mentally bisecting the angle between the hand and noon to > find north-south. This > invention merely reverses the process - given north-south, find the > time. Why you wouldn't put a > wristwatch movement inside the case instead of the sundial escapes > me. > > Regards > Chris > > > ----- Original Message ----- > From: Edley McKnight > To: Chris Lusby Taylor ; [email protected] ; > [email protected] > Sent: Tuesday, March 09, 2010 5:16 AM > Subject: Re: Would this dial work? > Hi Peter, Chris, Patrick, and all. > > I agree with Chris if the plane of the watch is positioned > horizontally, but from the patent, > there is no regard taken for positioning the watch other than to > magnetic north. If the central > axis of the watch was made parallel with the earth's axis it > would then function even better > as an equatorial dial. Of course it would have to be held upside > down in winter time and > would have the times backward. One would also hope that magnetic > deviation was not too > far off. ( It's about 20 degrees about our area. ) The two > threads function much like rotating > a knife blade to minimise the shadow thickness. I wonder if many > of them were ever made. > > Best Wishes! > > Edley. >
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