But such ascents are as little the normal work of the university as of the road-builder. Its course lies chiefly along the broad highways of learning. Not books of power, but books of use, which sum first general, and then special and professional knowledge, occupy the greater portion of its time, just as the most saintly of mortals devotes more of his days to earning his living than to saving his soul. If the study of books of power is rendered more valuable by a library, the adequate teaching of books of use without one is impossible. Every text-book is a compromise between what is known and what can be taught. Two classes, I know, the publishers and the public, cherish the belief that there are text-books which sum current knowledge on this subject and that; but there are none. Every text-book is out of date the day after it goes to the printer, and the day before it gave out, not what is known, but the view of what is known then in vogue. It measures the advancing tides of learning by a gauge itself incessantly changing. We love to speak of authorities and standards. We delude ourselves. The whole field of letters and of learning is in a perpetual flux, whose only complete record is the library. We know that in science discovery succeeds discovery. There is nothing certain about a scientific book except that it will be wrong in five or ten years. Only now and then does some law-giver in science, some Newton or Darwin, descend the mount of discovery, bearing eternal and lasting laws of nature, writ by Nature's God. But in literature we dream of permanent reputation. Here, too, "Every century gives the last the lie." All the lesser priests of letters stand at shrines like that of Nemi and the Golden Bough, "Beneath Aricia's trees, Where the ghastly priest doeth reign, The priest who slew the slayer And shall himself be slain,"