Based on references to datable external events, the story covers at
least ten years. The parts of the book that take place in Connecticut
are filled with descriptions of changing seasons. Europe and the
southern states have no climate.
"two young gentlemen of Connecticut ... graduated at Yale College"
"Beauman ... came regularly once in two or three months"
"Beauman's visits to Melissa became more frequent"
"[Beauman's] visits became more and more frequent."
"It was summer, and towards evening when [Alonzo] arrived."
To accommodate Beauman's repeated visits, a full year would have to
pass.
"The troubles which gave rise to the disseveration of England from
America had already commenced, which broke out the ensuing spring into
actual hostilities, by the battle of Lexington, followed soon after by
the battle of Bunker Hill."
The battles took place in April and June of 1775; "the ensuing spring"
would mean that the year is 1774.
"Winter came on; it rapidly passed away. Spring advanced..."