In 1819 , he became editor and owner of the Upper Canada Herald , a weekly newspaper , which soon had the largest circulation of any newspaper in Upper Canada .
In 1815 , his employer returned to France and Thomson purchased the Kingston store .
In 1819 , Thomson became editor and owner of the Upper Canada Herald , a weekly newspaper , which soon had the largest circulation of any newspaper in Upper Canada .
In 1815 , his employer returned to France and Thomson purchased the Kingston store .