In 1763 Smith resigned his professorship
and became the tutor for the duke of  
Buccleuch. This was an interesting story. 
The
Chancellor of the Exchequer Charles
Townshend
, who became famous by
imposing high tax on tea imported to
English colonies in America, and so
causing the Boston "Tea Party" and
eventually the American revolution,
this Charles Townshend married in
1754 the  Countess of Dalkeith, the 
very rich widow of the Duke of Buccleuch. 
In 1763 Townshend wanted to educate his
stepson the young Duke of Buccleuch by 
sending him for several years to Europe.
He needed a tutor to accompany the
young Duke.
Townshend wanted Smith
for this job and offered him the salary
almost twice as high as the one Smith was 
getting at the university and, of course,   
also coverage of all the travel cost. After
returning from the trip Smith would be 
getting the same amount as a pension for
the rest of his life.
Smith accepted, he was searching for such a job for many
years. Tutoring children of powerful nobility was at that
time quite common and respectable job of intellectuals.
In the years 1464 - 1766 Smith traveled with young Duke
of Buccleuch mostly in France. This gave him opportunity
to meet there some famous philosophers, economists and
scientists. Among them it were
Voltaire, Russeau, Quesnay, Turgot, D'Alambert and Helvetius.