The Talking Machine World, January 15, 1917, page 11:
MUSIC THROUGH THE AIR
Talking machine music is now becoming a popular fad. It is said that the De Forest Wireless Co. of New York entertains quite a host of people with music by wireless certain evenings of the week, while in San Francisco recently a talking machine concert on the roof of the Fairmount Hotel was enjoyed by passengers aboard the Steamer "City of Para" when four miles out at sea. The transmission in this instance was by wireless telephone.