E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The Nova Scotians.
Pray, sir, said one of my fellow-passengers, can you tell me the reason why the Nova Scotians are called Blue-noses?
It is the name of a potato, said I, which they produce in the greatest perfection, and boast to be the best in the world. The Americans have, in consequence, given them the nickname of Blue Noses.Haliburton: Sam Stick.