The literary interest is much more complex. In my Opinion, the first and indispensable requirement for this is that the letters reveal to us the writer, not his Opinions or his history, but the man himself, in his weakness and his strength, his unreasoned tastes and his unfounded prejudices; they must be letters and not essays. Whatever does not meet this need may have great interest and value, but must rank in an other class. I know of course the danger and the difficulty of classification; if any one chooses to pro nounce Burke's Letter on the French Revolution or the correspondence between Goethe and Schiller the very ideal of letter-writing, there is nothing to be said. But the ordinary man would shrink with horror and alarm at the receipt of such letters, and the judgment of the ordinary man on such a point must be accepted as conclusive.