I was brought up under strict conditions. Bedtime was at a certain rigid time every night. Lights out meant no reading; it meant sleep. It certainly did not include listening to radio broadcasts.But as a child of thirteen, I discovered the delights of the
crystal set. It was a frustrating affair. The workings of it
have remained a complete mystery. How, I wondered then, could a lump of gray mineral possibly capture radio waves and do so without a battery?Now, several decades later, the answers .