Cooper uses ethos to win over the reader's trust in his historical and geographical expertise, via the motif of footnotes. For example, in Chapter 20, he includes a footnote explaining the beauty and significance of Lake George:
The beauties of Lake George are well known to every American tourist. In the height of the mountains which surround it, and in artificial accessories, it is inferior to the finest of the Swiss and Italian lakes, while in outline and purity of water it is fully their equal; and in the number and disposition of its isles and islets much superior to them all together. [...]
Cooper added a great number of explanatory footnotes such as this one in later editions of his novel, once it became clear that there was a big market for The Leatherstocking Tales in London. He needed to make sure London readers were not put off by the assumption that they had been to the region where the novels were set. But the footnotes accomplish more than making the book accessible to English readers unfamiliar with the geography of upstate New York. In this footnote, Cooper makes clear that he has been to both Lake George and also "the finest of the Swiss and Italian lakes." This casual assertion that he is a world traveler gives him the authority to speak more confidently about geography than a mere "provincial" author who has never left upstate New York. Furthermore, the very inclusion of explanatory footnotes gives the reader the sense that Cooper's novels are steeped in historical and geographical research. He never lets anyone forget his authority over the narrative and over the historical moment he claims to be depicting through that narrative.
