I just found the horn that still works, tucked way back on a shelf in my barn. I bought it over 50 years ago in a large box of antique auto parts along with nos pedal pads, brand new 40 Ford Deluxe hood, doors, 33 Dodge headlights etc. The sale was a close out for urban renewal, of a very large old garage who's owner did at one time have an early Rolls Royce, I did also find in the box a Rolls gas or starter pedal. Nobody I have talked within the car community including friends with brass era Packards, Auburn, 1910 Cole, Pierce Arrow, T's etc. and no one has ever seen anything like it. Years ago I did manage to find some info on the company that seemed to disappear about 1914 but now cannot find anything besides the Sonora phonograph Co. that was in NYC about the same time.
The nameplate says, Sonora - Manufactured by Sonora motor horn co. - 1741 broadway - no 4143 - New York USA
If anyone has ever seen or heard anything about them I'd sure like to hear about it.
Thanks,
Smiley458