In Burnaby's Travels through the middle settlements of North America, in
1759 and 1760, published in 1775, is expressed this sentiment:--

"An idea, strange as it is visionary, has entered into the minds of
the generality of mankind, that empire is traveling westward; and
every one is looking forward with eager and impatient expectation
to that destined moment when America is to give the law to the rest
of the world."

John Adams, Oct. 12, 1775, wrote:---

"Soon after the Reformation, a few people came over into this New
World for conscience' sake. Perhaps this apparently trivial
incident may transfer the great seat of empire to America."

On the day after the Declaration of Independence, he wrote:--

"Yesterday the greatest question was decided which ever was debated
in America, and a greater perhaps never was, nor will be, decided
among men."

In 1776, Galiani, a Neapolitan, predicted the gradual decay of European
institutions, to renew themselves in America. In 1778, in reference to
the question as to which was to be the ruling power in the world, Europe
or America, he said:--

"I will wager in favor of America."

Adam Smith of Scotland, in 1776, predicted the transfer of empire to
America.