alternatehistory.com

With the settlers at Louisbourg having been forced to Ile Saint Jean or the mainland in the wake of the Seven Years' War, British colonial authorities intended to resettle the area with loyal subjects.
To this end, a survey team divided the island into some 130 lots, which were then allocated by lottery to supporters of King George III. This angered the few remaining Acadien or Irish squatters by preventing them title from the land they worked. Rent charges from the new absentee landlords to little to avail them.
The land had been given, in fact, with numerous stipulations encouraging development and settlement, but these were largely ignored. The settlers began years of trying to convince the crown to release the land from absentee holders.
The island's extensive coal resources had been retained by the crown for development; but this wasn't done, most likely because of the extensive investments required due to their dilapidated state.
These factors, as well as its terrain and relative remoteness from Halifax meant that its efforts' to attract Loyalist settlers in the wake of the American Revolution met with limited success.
In 1775, however, a highland Scot named Mícheal Mor MacDonald spent the winter at Judique under his upside-down boat. He would be Cape Breton Island's first permanent Scottish settler, and under the shelter of his boat, he composed a song about the lands he witnessed called, "O, 's slain an t-àite"; 'O, Fair is the Place'.

Thomas Douglas, the 5th Earl of Selkirk, was born the seventh son in Galloway, Scotland in 1771.
As a seventh son, he hadn't expected an inheritance and had therefore trained as lawyer at the University of Edinburgh.
While there, he noticed poor crofters being displaced by their landlords in the highland clearances; captivated by their plight, he began investigating ways to help them acquire lands in the British colonies. In 1794, his last remaining brother died, leaving him his father's heir; his father died unexpectedly in 1799, leaving Selkirk a vast inheritance in Scotland, the Earldom, and several lots on Cape Breton acquired by lottery years earlier.
He immediately used his money and political connections to begin settling poor crofters on his lots near the colonial capital of Sydney (now Selkirk).
He arrived at Halifax in 1804, and travelled extensively throughout North America. He became frustrated, like the settlers of Cape Breton, with the lack of development or settlement from other landlords. After much pressure, he succeeded in convincing the colonial authorities to "buy back" the 20,000 acre holdings at 2 pence per acre for allocation to settlers, in exchange for investments into making the crown-owned coal mines operable.
He died in 1821, just shy of 50, and his son, the 6th Earl, divested his Canadian holdings (at a generous rate) in 1834; but Selkirk's efforts led to as many as 50,000 Scots emigrating to the east coast of Canada in the first half of the 19th century; by 1850 Cape Breton had a substantial Gaelic speaking majority. By 1920, the Cape Breton colliery was the single most productive coal mine in the British empire.

-Gzowski, Our Cultural Mosaic