a detector consisting of a fine wire in contact with a galena crystal; acts as a rectifier

English writer noted for early detective novels (1824-1889)

the lowest level of stimulation that a person can detect

the lowest level of stimulation that a person can detect

the lowest level of stimulation that a person can detect

prolific English writer of detective stories (1890-1976)

prolific English writer of detective stories (1890-1976)

prolific English writer of detective stories (1890-1976)

novel in which the reader is challenged to solve a puzzle before the detective explains it at the end

novel in which the reader is challenged to solve a puzzle before the detective explains it at the end