Desktop Celestial Tide Dial by Hemisferium. Instrumentos Cientificos Antiguos, S. L

If you can believe it, there was a time when humans did all kinds of complex computations without computers. This desktop gadget is a prime example. Available in two sizes, it’s a replica of a tidal abacus from 1570 that currently resides in a museum. It uses the moon to calculate the tidal cycles, and on the large model, the back side is a nocturnal dial that uses fixed stars to tell the time. Both dials are accurate, fully functional tools that don’t require an electrical outlet. Each size features a handsome Sapele mahogany base—all the more reason to display one on your desk or in your beach house. Comes with detailed specs about the use of the dial and its history. Made in Spain.