The third and last period emancipates the Student from subjection to any authority, but what he shall himself judge to be supported by reason. Confiding now in his own judgment, he will consider and separate those different principles to which different modes of beauty owe their original. In the former period he sought only to know and combine excellence, wherever it was to be found, into one idea of perfection: in this he learns, what requires the most attentive survey, and the most subtle disquisition, to discriminate perfections that are incompatible with each other. He is from this time to regard himself as holding the same rank with those masters whom he before obeyed as teachers; and as exercising a sort of sovereignty over those rules which have hitherto restrained him. Comparing now no longer the performances of Art with each other, but examining the Art itself by the standard of nature, he corrects what is erroneous, supplies what is scanty, and adds by his own observation what the industry of his predecessors may have yet left wanting to perfection. Having well established his judgment, and stored his memory, he may now without fear try the power of his imagination. The mind that has been thus disciplined may be indulged in the warmest enthusiasm, and venture to play on the borders of the wildest extravagance. The habitual dignity which long converse with the greatest minds has imparted to him will display itself in all his attempts; and he will stand among his instructors, not as an imitator, but a rival. These are the different stages of the Art. But as I now address myself particularly to those Students who have been this day rewarded for their happy passage through the first period, I can with no propriety suppose they want any help in the initiatory studies. My present design is to direct your view to distant excellence, and to show you the readiest path that leads to it. Of this I shall speak with such latitude, as may leave the province of the professor uninvaded; and shall not anticipate those precepts, which it is his business to give, and your duty to understand. It is indisputably evident that a great part of every man's life must be employed in collecting materials for the exercise of genius. Invention, strictly speaking, is little more than a new combination of those images which have been previously gathered and deposited in the memory: nothing can come of nothing: he who has laid up no materials can produce no combinations. A Student unacquainted with the attempts of former adventurers is always apt to overrate his own abilities; to mistake the most trifling excursions for discoveries of moment, and every coast new to him for a new-found country. If by chance he passes beyond his usual limits, he congratulates his own arrival at those regions which they who have steered a better course have long left behind them.