:D

Alas, I do not have the whole letter, but Broster quotes from it in the Horn Book Magazine article (the writer assumed she was a man):

“I have just finished the book, which has moved me more profoundly than anything else I have read for years. I had no notion I was so Highland and so Jacobite. . . . The landscape is marvellously true; not a false touch, not an overstrained note. . . . He has touches, too, that only a poet could have written, so quiet and so full. . . . But how the devil (damn him) did the author get this intimate, inside knowledge of the Highland character? . . . It is marvellous, and makes this book far and away the finest Highland Jacobite story I know.”