An Autobiography, Chapter XX:
And so I end the record of my literary performances,—which I think are more in amount than the works of any other living English author. If any English authors not living have written more—as may probably have been the case—I do not know who they are. I find that, taking the books which have appeared under our names, I have published much more than twice as much as Carlyle. I have also published considerably more than Voltaire, even including his letters. We are told that Varro, at the age of eighty, had written 480 volumes, and that he went on writing for eight years longer. I wish I knew what was the length of Varro’s volumes; I comfort myself by reflecting that the amount of manuscript described as a book in Varro’s time was not much. Varro, too, is dead, and Voltaire; whereas I am still living, and may add to the pile.