Remember calling a phone number to get the precise time? While our automatically synchronizing cell phones and laptops have rendered that service unnecessary, providing the exact time used to be a big business, and far earlier than might be expected.
In the late Nineteenth Century, when railroads were beginning to criss-cross the United States, the need for precise time grew. No longer could the time in one town be a bit later than the town to its west. While it made sense when it came to thinking about sunset, it caused chaos for the rail system and its schedules.
Stepping into this anarchy were several time services, including the Harvard Observatory. In fact, from 1872 to 1892, the Harvard Observatory sold time signals throughout New England (and further) by sending precise pulses along telegraph wires. These signals had many uses, from helping to regulate stock exchanges to determining when time balls would drop.
Peter Galison discusses this in a thematic guide for an exhibit of scientific instruments (PDF) at Harvard University, and a much more detailed discussion about this can be found in the book Selling the True Time by Ian Bartky.