Words New to Me

Chronolith – a coinage (time + stone) you may be familiar with if you’ve read the book by Robert Charles Wilson. A clever and unusual clock created by Marcel Bétrisey also bears the Chronolith title. The pendulum of the clock is powered by light, using the principle you may have observed in a Crooke’s radiometer. Two sensors help keep the clock accurate by checking the swing of the pendulum using the lights that power it. Ingenius. (thx j.r.)

Tellurians and Orreries – when a globe just isn’t enough. A tellurian (or tellurium) is designed to show phenomenon such as seasons and eclipses which are best illustrated by showing the relationship between the earth, sun, moon and maybe a planet too. You can operate the gears to watch the earth go around the sun and the moon around the earth. An orrery shows all the planets and their positions, sometimes not to scale, around the sun. It may even include the moons of the other planets as well. Again, mechanical gears allow you to see the various orbits.