Samuel Ball Platner, Thomas Ashby, A Topographical Dictionary of Ancient Rome

MANALIS LAPIS

a phrase subject to two different interpretations, according to Fest. 128. (1) Manalem lapidem putabant esse ostium Orci, per quod animae inferorum ad superos manarent, qui dicuntur manes. It has been supposed that the reference is to the stone which closed the entrance to the lower part of the mundus, but this is only a conjecture (Mull. in loc.; cf. also JRS 1912, 29). (2) Manalem lapidem vocabant etiam petram quandam, quae erat extra portam Capenam iuxta aedem Martis (see MARS, AEDES) quam cum propter nimiam siccitatem in Urbem pertraherent, insequebatur pluvia statim, eumque, quod aquas manaret, manalem lapidem dicere; cf. Varro ap. Non. 637. This was obviously a rough mass of stone, which was used when prayers for rain were made; see IUPPITER ELICIUS; and cf. RE ii. 310 ; WR 121; James in Hastings, Enc. Rel. Eth. art. Rain; Rose, Primitive Customs in Italy, 57.