On the Cover

A pre-prototype leading to the Eimac 304T, from an affidavit filed by Ronald H. Gordon, laboratory glassblower. He certified having made the tube “before1940.” The objective was to contest, successfully, a claim of inventing a “plurality of grids in an envelope” in a patent application by Harold Zahl of the Signal Corps. Zahl got his patent, but without his claim. Photo: Perham-Eimac Archive, a resource of History San Jose.