About a day after I had put this article on my web site, Piet Andriessen emailed me and provided much more information about the section that I had titled "On Switching the Fusee Arbor Between the Sun and the Annulus, Andriessen". So I have revised the article to attribute this design correctly to Abraham Tappy and add references to Piet's articles about Tappy and the fusee. I have taken the opportunity to change a couple of other parts. The most important is to add a bit on planetary gears, because Tappy's design is less than perfect (in common with John Arnold who also didn't really understand the mechanism). I am sorry about this, but better late than never!