It is easy to say that the greater part of the books and periodicals thus acquired are trash; but it is to be considered that very substantial reasons can be urged why one library should preserve the entire product of the American press, irrespective of intrinsic value. First, every nation should have, at its capital city, all the books that its authors have produced, in perpetual evidence of its literary history and progress--or retrogression, as the case may be. Secondly, this complete assemblage of our literature in the Library of the Government (that is, of the whole people) is an inestimable boon to authors and publishers, many of whose books, after years have elapsed, may owe to such a collection their sole chance of preservation. Thirdly, it is a most valuable aid to would-be writers to have access to all the works that have been published in the special field they seek to cultivate. Fourthly, one comprehensive library--inclusive and not exclusive--should exist, because all other libraries must be in a greater or less degree exclusive. Fifthly, all American books should be preserved as models--even if many of them are models to be avoided. One learns as much frequently from the failures of others, as from their successes. Sixthly, it is already provided by law (and very wisely), that all copyright publications of whatever character, shall be deposited in the Library of Congress, and the Nation is as much bound to conserve these things, in evidence of copyright, as to preserve the models in the Patent Office, in evidence of patent right. Seventhly, there is no standard of selection or of exclusion that could be adopted which would stand against the fact of the endlessly varying judgments of different men, or even of the same men at different periods. What is pronounced trash to-day may have an unexpected value hereafter, and the unconsidered trifles of the press of the nineteenth century may prove highly curious and interesting to the twentieth, as examples of what the ancestors of the men of that day wrote and thought about. Of course it should be one of the foremost aims of our National Library to secure all books, pamphlets, maps and periodicals relating to our own country. Everything that can illustrate the discovery, settlement, history, biography, natural history, or resources of America should be gathered. The already rich collection of Americana comprises a large share of the earlier works respecting America, nearly all of which are now rare, as well as of the early printed books of the various American presses, and many published in places where no books are now printed. Assiduous pains have been taken to increase these collections from auctions and from sale catalogues in this country and in Europe.