Illustrated Companion to the Latin Dictionary/Fortax

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. 

FORTAX. (Varro, R. R.. xxxviii. 4.) Applied to masses of chalk arranged together in the form of an arch (fornix) over the fire in a lime kiln, so as to support themselves by mutual gravity, and the whole mass above them in the kiln, while under the process of burning for making lime.