A Scotsman, a Jacobite in the '45 and then fighting on the French side in the conquest of Canada sounds like a plot from an implausible historical novel but that's what the Chevalier de Johnstone's life was like - and he wrote his memoirs and they are online to read. What a great invention the internet is. Biography of de Johnstone.
Book to download here
As usual I post a little quote to whet your appetite - this passage deals with the rivalries he found among the garrison at Louisbourg
I there enjoyed a true and perfect satisfaction from the esteem and friendship of all my comrades, which was not an easy matter to secure, for the corps of the Royal Isle, composed of more than a hundred officers, was divided into three factions, the ancients of the country ; those who had come from Canada, and the reformed officers of France, who had their settlement at Louisbourg, and all these three mutually detested each other, and were continually quarrelling; but having entered the corps by declaring that I would not enter into their cabals, which did not mix me up, in any degree, in their disputes and animosities, so that I chose my friends on the whole where I found them to my taste, only taking my part to defend myself against those who wished to insult me, or who sought to embroil me in a quarrel ; thus by the strict neutrality, which I always observed, I had always the good-will of every one, and I heard the horrors which these officers, eternally in discord, came to tell me daily, the one against the other, without ever having a bias for one side or another, hearing them without answering them.
Gutenberg version here