Usta1890 was accidentally discovered at a fire in the Piræus, some ceruse having been burnt in the jars there. Nicias, the artist above-mentioned,1891 was the first to use it. At the present day, that of Asia, known also as “purpurea,” is considered the best. The price of it is six denarii per pound. It is prepared also at Rome by calcining marbled sil,1892 and quenching it with vinegar. Without the use of usta shadows cannot be made.1893