ĀTRĀMENTUM, a term applicable to any black colouring substance, for whatever purpose it may be used, like the _melan_ (μέλαν) of the Greeks. There were, however, three principal kinds of atramentum: one called _librarium_, or _scriptorium_ (in Greek, γραφικὸν μέλαν), writing-ink; another called _sutorium_, which was used by the shoemakers for dyeing leather; the third _tectorium_, or _pictorium_, which was used by painters for some purposes, apparently as a sort of varnish. The inks of the ancients seem to have been more durable than our own; they were thicker and more unctuous, in substance and durability more resembling the ink now used by printers. An inkstand was discovered at Herculaneum, containing ink as thick as oil, and still usable for writing. The ancients used inks of various colours. Red ink, made of _minium_ or vermilion, was used for writing the titles and beginning of books. So also was ink made of _rubrica_, “red ochre;” and because the headings of _laws_ were written with rubrica, the word rubric came to be used for the civil law. So _album_, a white or whited table, on which the praetors’ edicts were written, was used in a similar way. A person devoting himself to _album_ and _rubrica_, was a person devoting himself to the law. [ALBUM.] ĀTRĬUM (called αὐλή by the Greeks and by Virgil, and also μεσαύλιον, περίστυλον, περίστῳον) is used in a distinctive as well as collective sense, to designate a particular part in the private houses of the Romans [DOMUS], and also a class of public buildings, so called from their general resemblance in construction to the atrium of a private house. An atrium of the latter description was a building by itself, resembling in some respects the open basilica [BASILICA], but consisting of three sides. Such was the Atrium Publicum in the capitol, which, Livy informs us, was struck with lightning, B.C. 216. It was at other times attached to some temple or other edifice, and in such case consisted of an open area and surrounding portico in front of the structure. Several of these buildings are mentioned by the ancient historians, two of which were dedicated to the same goddess, Libertas. The most celebrated, as well as the most ancient, was situated on the Aventine Mount. In this atrium there was a tabularium, where the legal tablets (_tabulae_) relating to the censors were preserved. The other Atrium Libertatis was in the neighbourhood of the Forum Caesaris, and was immediately behind the Basilica Paulli or Aemilia.