The third of five personal essays on the voice and radio. Former BBC journalist and now media professor David Hendy explores how, in the early years of radio, the voices coming through the airwaves were heard and regarded. Why did a heard voice carry more swaying power than written words, why did a radio voice carry - so experiments and test showed - even more potency? How did radio become a tool for demagogues? Why are our ears susceptible?

An essay given in front of an audience at the British Academy in London in October 2014 as part of a series of events marking the 100th anniversary of the birth of Dylan Thomas. Producer: Tim Dee.