93 PLEASURES OF RESEARCH. [IV. looks for; makes discoveries that are not less delightful because they are accidental. Of course it may be said that a great deal of useless knowledge is accumulated in this way ; what good can be done, it may be said, by analysing Matthew Paris, and determining how much of his narrative is drawn from ancient charters, or foreign letters, lives of saints, or such stribiligines : it is his historic power and authority that gives them value, not they that give authority to him. Not quite so, I think, and even if it were so, there might be a lesson in the mere proof of the fact ; the analysis is necessary for the due estimate of his value as a historian ; the writer who can pass such an ordeal where it is possible to apply it, may be trusted where it is not possible to apply it. But I take the higher ground and say, how far can any knowledge be said to be useless ? there may be much useless learning, I allow ; accumulations of other men's thoughts, and crude heaps of second-hand memories that are alike useless to their owner and to the world. But not real knowledge, not a substantiated fact, however remote it may seem from the interests and uses of the day, or the object of the day. It may serve to complete a chain of demonstration, the necessity of which is not as yet apparent ; it may furnish, as an undesigned coincidence, an important element in a discussion yet in its elementary stages. How great is the debt that History owes to the ant-like instincts of collectors of memoranda, the recorders of births, deaths, and marriages, the savers of old letters and old newspapers, of the very things that seemed most useless. If there is any useless knowledge in History, we may say,—as Dr. Maitland said, when people talked of the Dark Ages, they meant the ages that were dark to them,—the uselessness of the knowledge is generally the fault of those who do not know how to use it. It would be doing great injustice, however, to my subject if I were to lead you to suppose that I regard the great