3. There are two natural cravings, which assert themselves strongly in every mind not entirely absorbed by the daily work for bread and by the anxious care how to procure that work: these are the wish, on the one hand, to learn how the people who came before us lived and what they did, on the other--to transmit our own names and the memory of our deeds to those who will come after us. We are not content with our present life; we want to stretch it both backward and forward--to live both in the past and the future, as it were. This curiosity and this ambition are but parts of the longing for immortality which was never absent from any human soul. In our own age they are satisfied mainly by books; indeed they were originally the principal causes why books began to be made at all. And how easy to satisfy these cravings in our time, when writing materials have become as common as food and far cheaper, and reading may be had for nothing or next to nothing! For, a very few dollars will supply a writer with as much paper as he can possibly use up in a year, while the public libraries, the circulating and college libraries and the reading-rooms make study a matter more of love and perseverance than of money. 4. Yet if the papermill and the printing press were the only material aid to our researches into the past, these researches would stop short very soon, seeing that printing was invented in Europe scarce four hundred years ago, and paper has not been manufactured for more than six hundred years at the outside. True, other materials have been used to write on before paper: bark of trees, skins of animals--(parchment)--cunningly worked fibres of plants--(papyrus, byblos)--even wooden tablets covered with a thin layer of wax, on which characters were engraved with a pointed instrument or "style,"--and these contrivances have preserved for us records which reach back many hundreds of years beyond the introduction of paper. But our curiosity, when once aroused, is insatiable, and an area of some twenty, or thirty, or forty centuries seems to it but a narrow field. Looking back as far as that--and no kind of manuscript information takes us much further--we behold the world wondrously like what it is now. With some differences in garb, in manners, and a much greater one in the range of knowledge, we find men living very nearly as we do and enacting very nearly the same scenes: nations live in families clustered within cities, are governed by laws, or ruled by monarchs, carry on commerce and wars, extend their limits by conquest, excel in all sorts of useful and ornamental arts. Only we notice that larger regions are unknown, vaster portions of the earth, with their populations, are unexplored, than in our days. The conclusion is clearly forced on us, that so complicated and perfect an organization of public and private life, a condition of society implying so many discoveries and so long a practice in thought and