Item supra cameram materies ex calce et harena mixta subinde inducatur, ut, si quae stillae ex contignationibus aut tectis ceciderint, sustineantur.
Further, on the upper surface of the arch, mortar, mixed with lime and sand, is to be spread, so that if any drippings fall from the floor or roof above, they may be held up.
final_alignments\Vitruvius_Architecture_Book_7.json