We’re not specialists, but the Maillardet Automaton is one of the more amazing mechanical machines that we’ve seen in a while, and [Fran Blanche] got to spend some time with it in an attempt to figure out how it’s mysterious missing pen apparatus would have worked. The resulting video, embedded below, is partially her narrative about the experiment she’s running, and part straight-up mechanical marvel.

If you need a refresher course on Maillardet’s Automaton, we’ll send you first to Wikipedia, and then off to watch this other video , which has a few great close-ups of the cams that drive everything.

floating-stylus-test-for-the-maillardet-automaton-with-commentary-yuw30scp_98mkv-shot0001And then come back to [Fran]’s video. Many parts of the machine, including the pen and his clothes, are missing. Because the machine’s hand moves in three dimensions, pressing down on the pen harder in the downstroke than on the upstroke, the pen’s construction is important for a faithful reproduction of the machine’s full abilities. [Fran] builds a weighted ball-point pen design to test out her theory that the missing pen was essentially a spring valve that feeds more ink when pressed down further.

Besides hearing [Fran] work through the experiment, you also get to watch this enchanting machine do its thing for ten minutes, and that alone is worth your time. If you want more Maillardet Automaton goodness, check out our previous coverage of [Fran]’s work on the machine or her blog coverage thereof. Or lighten up a bit with this whimsical “robot” café.