John Stuart Mill is said to have acquired a fair knowledge of Greek, at the age of three years, and to have memorized Hume, Gibbon, and other historians, at the age of eight. Shortly after he mastered and memorized Herodotus, Xenophon, some of Socrates, and six of Plato's "Dialogues." Richard Porson is said to have memorized the entire text of Homer, Horace, Cicero, Virgil, Livy, Shakespeare, Milton, and Gibbon. He is said to have been able to memorize any ordinary novel at one careful reading; and to have several times performed the feat of memorizing the entire contents of some English monthly review. De Rossi was able to perform the feat of repeating a hundred lines from any of the four great Italian poets, provided he was given a line at random from their works--his hundred lines following immediately after the given line. Of course this feat required the memorizing of the entire works of those poets, and the ability to take up the repetition from any given point, the latter feature being as remarkable as the former. There have been cases of printers being able to repeat, word for word, books of which they had set the type. Professor Lawson was able to teach his classes on the Scriptures without referring to the book. He claimed that if the entire stock of Bibles were to be destroyed, he could restore the book entire, from his memory. Rev. Thomas Fuller is said to have been able to walk down a long London street, reading the names of the signs on both sides; then recalling them in the order in which they had been seen, and then by reversing the order. There are many cases on record of persons who memorized the words of every known tongue of civilization, as well as a great number of dialects, languages, and tongues of savage races. Bossuet had memorized the entire Bible, and Homer, Horace and Virgil beside. Niebuhr, the historian, was once employed in a government office, the records of which were destroyed. He, thereupon, restored the entire contents of the book of records which he had written--all from his memory. Asa Gray knew the names of ten thousand plants. Milton had a vocabulary of twenty thousand words, and Shakespeare one of twenty-five thousand. Cuvier and Agassiz are said to have memorized lists of several thousand species and varieties of animals. Magliabechi, the librarian of Florence, is said to have known the location of every volume in the large library of which he was in charge; and the complete list of works along certain lines in all the other great libraries. He once claimed that he was able to repeat titles of over a half-million of books in many languages, and upon many subjects.