Another reader wishes, we will suppose, to hunt up the drawings of all patents that have been issued on type-writers, and type-writing inventions. You put before him the many indexes to the Patent Specifications and Patent Office Gazette; he makes out from these his list of volumes wanted, which are at once supplied, and he falls to work on his long, but to him interesting job. A reader who has seen in the library or elsewhere a book he would much like to own, but cannot find a copy in town, wants to know what it will cost: you turn to your American or foreign catalogue, covering the year of publication, and give him not only the price, but the publisher's name from whom he can order it, and he goes on his way rejoicing. An artist engaged upon a painting in which he wishes to introduce a deer, or a group of rabbits, or an American eagle, or a peacock, asks for an accurate picture of the bird or animal wanted. You put before him J. S. Kingsley's Riverside Natural History, in six volumes, and his desire is satisfied. In dealing with books of reference, there will often be found very important discrepancies of statement, different works giving different dates, for example, for the same event in history or biography. Next to a bible and a dictionary of language, there is no book, perhaps, more common than a biographical dictionary. Our interest in our fellow-men is perennial; and we seek to know not only their characteristics, and the distinguishing events of their lives, but also the time of their birth into the world and their exit from it. This is a species of statistics upon which one naturally expects certainty, since no person eminent enough to be recorded at all is likely to have the epoch of his death, at least, unremarked. Yet the seeker after exact information in the biographical dictionaries will find, if he extends his quest among various authorities, that he is afloat on a sea of uncertainties. Not only can he not find out the date of decease of some famous navigators, like Sir John Franklin and La Perouse, who sailed into unexplored regions of the globe, and were never heard of more, but the men who died at home, in the midst of friends and families, are frequently recorded as deceased at dates so discrepant that no ingenuity can reconcile them.