A study of wireless telegraphy and wireless telephony
A 1915 University of Illinois student thesis by Aram Movses Eleazarian surveying the circuits and apparatus of wireless telegraphy and telephony, written for engineering examiners. The plates are hand-inked circuit schematics on tinted paper: spiral coils, spark gaps, batteries, antenna and ground symbols, and electrolytic and vacuum detectors, each part tagged with single letters — useful as loose, irregular line diagrams and as a vocabulary of early radio symbols.
