On making cement. A cement which, once dry, is not affected by any liquid. Take quicklime, powdered tile, iron rust, sand, oil, and water, and make a cement. Or again, for a cement for mending marble and other stones: take three parts of powdered tile and four parts of iron rust, and two parts of pitch, and one of wax, and some of the powder of the stone in question, and make a cement, and do the mending. And see to it that both the stone and the cement are warm.