But to go on with a few more contrasts of the past with the present. Once men wrote only in symbols, like wedges and arrow-heads, on tiles and bricks, or in hieroglyphic pictures on obelisks and sepulchres,--afterward in crude, but current characters on stone, metal, wax, and papyrus. In a much later age appeared the farthest perfection of the invention: books engrossed on illuminated rolls of vellum, and wound on cylinders of boxwood, ivory, or gold,--and then put away like richest treasures of art. What a difference between perfection then and progress now! To-day the steam printing-press throws out its sheets in clouds, and fills the world with books. Vast libraries are the vaulted catacombs of modern times, in which the dead past is laid away, and the living present takes refuge. The glory of costly scrolls is dimmed by the illustrated and typographical wonders which make the bookstore a gorgeous dream. Knowledge, no longer rare, no longer lies in precarious accumulations within the cells of some poor monk's crumbling brain, but swells up like the ocean, universal and imperishable, pouring into the vacant recesses of all minds as the ocean pours into the hollows under its shore. To-day, newspapers multiplied by millions whiten the whole country every morning, like the hoar-frost; and books, numerous and brilliant as the stars, seem by a sort of astral influence to unseal the latent destinies of many an intellect, as by their illumination they stimulate thought and activity everywhere. Once art seemed to have reached perfection in the pictures and sculptures of Greece and Rome. Yet now those master-pieces are not only equalled on canvas and in fresco, but reproduced by tens of thousands from graven sheets of copper, steel, and even blocks of wood,--or, if modelled in marble or bronze, are remodelled by hundreds, and set up in countless households as the household gods. It is the glory of to-day that the sun himself has come down to be the rival and teacher of artists, to work wonders and perform miracles in art. He is the celestial limner who shall preserve the authentic faces of every generation from now until the world is no more. He holds the mirror up to Nature, paralyzes the fleeting phantom, by chemical subtilty, on the burnished plate,--and there it is fixed forever. He prepares the optical illusion of the stereoscope, so that through tiny windows we may look as into fairy-land and find sections of this magnificent world modelled in miniature.