is another Sibyl, who is next in the direction of the altar on the other side, displaying certain writings, and, with her boys in attendance, is no less worthy of praise than are the others. Beyond her is the Prophet Isaiah, who, wholly absorbed in his own thoughts, has the legs crossed over one another, and, holding one hand in his book to mark the place where he was reading, has placed the elbow of the other arm upon the book, with the cheek pressed against the hand; and, being called by one of the boys that he has behind him, he turns only the head, without disturbing himself otherwise. Whoever shall consider his countenance, shall see touches truly taken from Nature herself, the true mother of art, and a figure which, when well studied in every part, can teach in liberal measure all the precepts of the good painter. Beyond this Prophet is an aged Sibyl of great beauty, who, as she sits, studies from a book in an attitude of extraordinary grace, not to speak of the beautiful attitudes of the two boys that are about her. Nor may any man think with all his imaginings to be able to attain to the excellence of the figure of a youth representing Daniel, who, writing in a great book, is taking certain things from other writings and copying them with extraordinary attention; and as a support for the weight of the book Michelagnolo painted a boy between his legs, who is upholding it while he writes, all which no brush held by a human hand, however skilful, will ever be able to equal. And so, also, with the beautiful figure of the Libyan Sibyl, who, having written a great volume drawn from many books, is in an attitude of womanly grace, as if about to rise to her feet; and in one and the same movement she makes as if to rise and to close the book--a thing most difficult, not to say impossible, for any other but the master of the work.