A series of photographs, not retouched, of the details of dated monuments of the Roman Empire. Not an excessive demand for a student of Roman sculpture to make : the kind of apparatus—a good thesaurus—which a student of language would possess in his earliest studies at a university. But although it could be made with a fraction of the labour expended on any thesaurus, nothing like a scientific corpus of details yet exists or is contemplated; and this must serve to justify the publication of that which was begun in leisure some years ago as an elementary aid to private study, incomplete, and without immediate prospect of completion.