And this investigation, so far from interrupting, will facilitate our examination of the history of the nobler arts. You will see in the preface to my lectures on Greek sculpture that I intend them to be followed by a course on architecture, and that by one on Florentine sculpture. But the art of engraving is so manifestly, 'at Florence, though not less essentially elsewhere, a basis of style both in architecture and sculpture, that it is absolutely necessary I should explain to you in what the skill of the engraver consists, before I can define with accuracy that of more admired artists. For engraving, though not altogether in the method of which you see examples in the print-shops of the High Street, is, indeed, a prior art to that either of building or sculpture, and is an insepara ble part of both, when they are rightly practised.