I stated that I believed his character had been cruelly and unjustly libelled, and that I had the peculiar satisfaction of believing that I had justly defended it, and given the merited rebuke at the fountain of all his misfortunes, which I described as follows:--
"On my return from an eight years' residence amongst the remotest tribes of Indians in America, and paying a visit to my old friends in the city of Philadelphia, M. Duponceau, of whom your Royal Highness has spoken, an old and very learned gentleman, and deeply skilled in the various languages of America, and who was then preparing a very elaborate work on the subject, invited me to meet several of his friends at his table to breakfast; which I did. He was at this time nearly blind and very deaf, and still eagerly grasping at every traveller and trapper from the Indian country, for some new leaf to his book, or some new word to his vocabularies, instead of going himself to the Indian fireside, the true (and in fact the only) school in which to learn and write their language.
"After our breakfast was finished and our coffee-cups removed, this learned M. Duponceau opened his note-book upon the table and began in this way,--'My dear Sir (addressing himself to me), I am so delighted with such an opportunity--I am told that you have visited some forty or fifty tribes of Indians, and many of them speaking different languages. You have undoubtedly in eight years learned to speak fluently; and I shall draw from you such a valuable addition to my great work--what a treat this will be, gentlemen, ha? Now you see I have written out some two or three hundred words, for which you will give me the Blackfoot, the Mandan, the Pawnee Pict, &c. You have been amongst all these tribes?' 'Yes.' The old gentleman here took a pinch of snuff and then said, 'In this identical place, and on this very table, it was, gentlemen, that I detected the imposture of that rascal Hunter! Do you know that fellow, Mr. Catlin?' 'Yes, I have seen him.' 'Well,' said he, 'I was the first to detect him;--I published him to the world and put a stop to his impostures. I invited him to take breakfast with me as I have invited you, and in this same book wrote down the Indian translation of a list of words and sentences that I had prepared, as he gave them to me; and the next day when I invited him again, he gave me for one-third at least of those words a different translation. I asked for the translation of a number of words in languages that were familiar to me, and which he told me he understood, and he gave them in words of other tribes. I now discovered his ignorance, and at once pronounced him an impostor, and closed my book.'