Old writing, reviving, [164.]

Opening books, care in, [169.]

Overcasting, [18.]

Oversewing, [18.]

Ox gall for marbling, [71.]

Oxford vellum, [147.]

Oxymuriatic acid, restoring writing effaced by, [165.]

Painting covers, [133.]

Pallet (cut), [118.]

—— using the, [123.]