Smithsonian Secretary and astrophysicist Charles G. Abbot tests a solar radiation steam boiler of his design. The National Broadcasting Company films the test and a short program is broadcast by solar power. The solar radiation steam boiler exposes thirty-six square feet of mirror surface, and it is intended to produce about one half horsepower at the engine. The device has many defects and is too large to be practical for generating solar power. After the test a smaller solar flash boiler is prepared and offers greater promise.