It is in a certain sense a positive relief to find that the really persistent literature of the past is so compressible, and it is reassuring as one looks forward to the long future, to think that the people towards the end of time will not be so unimaginably burdened with the deathless monuments of their past; although when one multiplies five feet, the sediment of five millennia, by x, the classic library of the end of things seems to us of this unheroic age, a trifle depressing. Of course, the men of the Ultima Thule of time may take their classics less seriously, and it may be that they will find less of a gap than we between the thoughts and speech of the immortals and those of daily intercourse. But since the immortals die not, there is no escaping their accumulation. Yet after all, come to think of it, there is a good deal of an assumption in the assertion that our five feet of immortals are all going to perch upon that last library shelf. There have been immortals of the past who failed to reach even our days; had they all fulfilled their promise and the prophecies of their friends, the publishers would not be willing to let us buy our modest set of unquestionable classics on monthly payments without the guarantee of our great grandchildren. Paradoxical as it may seem, many immortals have proved mortal, and the deathless have died. We must lay this troublesome fact to the loose speech of our forefathers. They were hyperbolic now and then, and they dubbed a volume immortal without stopping to think whether the twentieth century A. D. would also find it interesting, and so, of course, really immortal. Humanity has been fallible in the past, and the result is that we are forced most unscientifically to accept contradictory ideas with gravity--in short, to speak of "relative immortality." The work that outlives its contemporaries is, we may admit, relatively deathless. Such a statement makes no prophecy, however, as to the remote future. Relative immortality merely means that a work goes on interesting for a few years, a generation or two, a century or more. It is only the simon pure immortal who will not have to get up at the sound of Gabriel's trump. Blessed relief--the final shelf of unforgettable classics may be only five feet long after all, and may be even shorter! Naturally, your enduring work must have a strong constitution; it must have all the characteristics of a live creature except the power of growth within itself, and, alas, of propagating its kind. Perhaps one might liken it to the Leyden jar which we of the older generation used to read of in our physics--I do not know whether it is remembered now-a-days. It has a charge of electricity of more or less strength, and it has a retaining capacity of more or less endurance, so that to touch it as the ages pass, is to receive a spark of life.