Aberdeen Journal 2-3-1831:
Died, at Manse of Boyndie, on the 9th Feb. ALEXANDER JOASS, A.M.
aged 75 years, who has been the parochial schoolmaster there for upwards of
half a century. He was an excellent teacher, and highly respected by all
classes of society, and his memory will be long revered by his numerous
pupils, many of whom are the children and grand-children of those he
first taught in that parish.
There is a 1925 book, "The Schools and Schoolmasters of Banffshire", which has a section on each parish, which lists teachers and gives some biographical details. I don't think it is available to read on-line.
I have a copy of James Godsman's book on the parish of King Edward. In the entry for Cowsmill, It says that George Joass, tenant there, was the son of William Joass and Isabella Porter, Burnside of Cullen, and grandson of Alexander Joass and Mary Duncan. George's brother, Alexander, succeeded to the tenancy of Burnside. It says that Alexander the schoolmaster was George's uncle.