Illustrated Companion to the Latin Dictionary/Specus

This article incorporates text from a publication now in the public domain: Rich, Anthony (1849). The illustrated companion to the Latin dictionary, and Greek lexicon. p. vi. OCLC 894670115. https://archive.org/details/illustratedcompa00rich. 

SPEC'US (σπέος). Literally, a cave or cavern; whence transferred to the dark, covered channel which forms the water-way in an aqueduct (Front. Aq. 17. 21. 91.) Vitruv. viii. 7.), as shown by the part marked A in the illustration (Specus/1.1), representing a portion of the Alexandrine duct now existing at Rome. It was sometimes tunnelled through a hill, at others raised upon one or more tiers of arches, accordingly as the level of the source, or the undulating nature of the country required; and in some cases two, and even three, of these channels were carried, one above the other, over the same file of arches.

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  Specus/1.1