This is the second part in a series.

Today we follow wars with minute-by-minute or day-by-day updates. It’s hard for us to think it wasn’t always this way.

A look at 250 years ago shows us how much has changed. In mid-June 1775, the Continental Army was formed out of the local militia surrounding Boston. George Washington was chosen by the Continental Congress in Philadelphia to lead it, and he at once began preparing to join the new command.

To his wife, Martha, he wrote on June 23, “As I am within a few minutes of leaving this city, I could not think of…