First episode

 
William Hooker Gillette

Based on the popular characters created by Sir Arthur Conan Doyle,
The Adventures of Sherlock Holmes aired on coast-to-coast radio 
beginning Monday October 20, 1930 and ran until June 5, 1955. Over 
time, there were 574 broadcasts on the NBC, Mutual and ABC network 
stations.

The original cast featured William Gillette as Holmes and Leigh Lovell
as Dr. Watson. The first sponsor was George Washington Coffee. The
announcer was Joseph Bell.