There is a class of books written with the praiseworthy intention of stimulating young men to intellectual labor, in which this danger of the intellectual life is systematically ignored. It is assumed in these books that the satisfactions of intellectual labor are certain; that although it may not always, or often, result in outward and material prosperity, its inward joys will never fail. Promises of this kind cannot safely be made to any one. The satisfactions of intellectual riches are not more sure than the satisfactions of material riches; the feeling of dull indifference which often so mysteriously clouds the life of the rich man in the midst of the most elaborate contrivances for his pleasure and amusement, has its exact counterpart in the lives of men who are rich in the best treasures of the mind, and who have infinite intellectual resources. However brilliant your ability, however brave and persistent your industry, however vast your knowledge, there is always this dreadful possibility of _ennui_. People tell you that work is a specific against it, but many a man has worked steadily and earnestly, and suffered terribly from _ennui_ all the time that he was working, although the labor was of his own choice, the labor that he loved best, and for which Nature evidently intended him. The poets, from Solomon downwards, have all of them, so far as I know, given utterance in one page or another of their writings to this feeling of dreary dissatisfaction, and Albert Dürer, in his "Melencolia," illustrated it. It is plain that the robust female figure which has exercised the ingenuity of so many commentators is not melancholy either from weakness of the body or vacancy of the mind. She is strong and she is learned; yet, though the plumes of her wings are mighty, she sits heavily and listlessly, brooding amidst the implements of suspended labor, on the shore of a waveless sea. The truth is that Dürer engraved the melancholy that he himself only too intimately knew. This is not the dulness of the ignorant and incapable, whose minds are a blank because they have no ideas, whose hands are listless for want of an occupation; it is the sadness of the most learned, the most intelligent, the most industrious; the weary misery of those who are rich in the attainments of culture, who have the keys of the chambers of knowledge, and wings to bear them to the heaven of the ideal. If you counsel this "Melencolia" to work that she may be merry, she will answer that she knows the uses of labor and its vanity, and the precise amount of profit that a man hath of all his labor which he taketh under the sun. All things are full of labor, she will tell you; and in much wisdom is much grief, and he that increaseth knowledge increaseth sorrow.