For fun, pointing out this Manhattan recipe from Charlie Paul’s 1884 American and Other Drinks (discussed here):
My supposition is that, at that time, American rye whiskey was as scarce in England as scotch was plentiful, and thus the Rob Roy was born in all but name. Less clear is whether this particular variant achieved much traction.
By the time Paul created his expanded 1887 edition, he had two advertisers on board who were importing American rye. He left the above recipe untouched, however, instead adding a new Fancy Manhattan Cocktail that specified rye.
Although this recipe is rewritten, it otherwise precisely matches the proportions of the Manhattan Cocktail recipe found in the 1887 (posthumous) edition of Jerry Thomas’ book.