German-made Radiometers Sold as Interior Design Items at Antique Store in Kisarazu, Chiba Pref.

Glass spheres with four small blades inside line Kanedaya Lichtmuhle, an antique store in Kisarazu, Chiba Prefecture. When exposed to light, the blades rotate noiselessly. These spheres are radiometers, an experimental tool developed in the 19th century to measure the energy of light. Their simple f...