When a letter is written no envelope is needed. The tablets are folded over upon themselves, fastened with crossed thread and then at the point when the ends are knotted is placed a round piece of wax, stamped before it can cool with a signet ring. The name of the person to whom the letter is going can be written on the outside, and then the communication is ready. Letters can be transmitted to distant places usually only with tedious difficulty, but around Rome delivery from writers of any high position is extremely prompt. The carrying of letters is one of the commonest duties for otherwise idle slaves, and from a mansion like Calvus’s it is easy every morning to send off ten packets each by its own hurrying messenger. =184. Personal Correspondence and Secretaries.=--Calvus, like every man of distinction, has a heavy correspondence. It is a fine thing to be a good letter writer, to make your epistles seem easy, natural, gossipy, and yet in such faultless language that they can be collected presently and published in a book. To a few special correspondents, especially to absent relatives, Calvus writes almost daily in his own hand. But he dictates even more frequently. He has a couple of slave _amanuenses_ who are with him constantly; they can take down his dictation in a kind of abbreviated long hand; then write it out in handsome script, always submitting the final text to their master not for his signing but for sealing. As a consequence of all this correspondence, the demand for new tablets in Rome is prodigious. The wax, indeed, can be melted upon letters which one does not care to preserve, and the wood used a second time, but the waste inevitably is great. [Illustration: BOOK CUPBOARD.] =185. Books Very Common: Papyrus and the Papyrus Trade.=--Nevertheless, the activity of such secretaries is vastly less important than that of another set of scribes, the makers of books. Poor is the tenement suite that does not contain a few musty papyrus scrolls, while a parvenu freedman will inevitably acquire a large library (which he may never read) just to show himself a man of fashion. Books are so common that their divided sheets are wetted, and used in kitchens to keep fish in fresh condition, or, if dry, to make wrappers for incense and spices. Paper is unknown, and parchment although not unknown is used mainly for very important correspondence, public documents, and the like, which require extremely durable material. Practically all books are written on papyrus arranged in rolls.[112] The papyrus is strictly an Egyptian monopoly, and if the importation of this precious article should cease, apparently all Greece and Italy would be doomed to partial illiteracy.